User talk:Martin Hogbin

Earlier discussions are found at /Archive1

Missing my point

The correct place to discuss that is with the editor who removed the comment, not on the article's talk page. Adding an off-topic section to discuss the removal of off-topic comments just makes matters worse. Use the editor's user talk page. Thanks. Guettarda (talk) 18:01, 8 January 2010 (UTC)

Thanks for your 'advice'. The problem that I have is that I am unlikely to get any sensible response from the tag-team member who removed my comment. In order to get anything done, I need to attract the attention of other editors. There clearly is a band of editors exerting total control over this page. Martin Hogbin (talk) 18:26, 8 January 2010 (UTC)

Again?

Hello, Martin Hogbin. You have new messages at HJ Mitchell's talk page.
You can remove this notice at any time by removing the {{Talkback}} or {{Tb}} template.

Hello, Martin Hogbin. You have new messages at HJ Mitchell's talk page.
You can remove this notice at any time by removing the {{Talkback}} or {{Tb}} template.

And another. HJMitchell You rang? 19:22, 8 January 2010 (UTC)

Global warming

Thank you for your contributions to the encyclopedia! In case you are not already aware, an article to which you have recently contributed, Global warming, is on article probation. A detailed description of the terms of article probation may be found at Wikipedia:General sanctions/Climate change probation. Also note that the terms of some article probations extend to related articles and their associated talk pages.

The above is a templated message. Please accept it as a routine friendly notice, not as a claim that there is any problem with your edits. Thank you. --TS 13:01, 9 January 2010 (UTC)

Dear Martin,

Ref [1] please note that asking for an explanation of a revert is completely acceptable and should be done on talk. However undoing a revert whilst asking for an explanation, on an article on probation, in my view is edit warring. There is a fine line in an edit war as each side inches a little further forward and there is a degree of arbitrariness on when the line is crossed which is why I am dropping you a note rather than taking action. I am sure that you wish to contribute constructively to this article: please do not edit war. --BozMo talk 07:40, 11 January 2010 (UTC)

Thank you for your advice. I am not sure that a single revert could be classed as edit warring. Regarding article probation, this requires all editors to act to the highest standards. Reverting a good faith addition (even if inaccurate) with no edit summary and with the change being marked as minor is also not acceptable, especially on an article on probation, and I was bringing this to the attention of all editors as this type of activity seems to be endemic on the GW article. I have mentioned this before on the talk page, only to have my comments deleted. To contact each editor in turn to make the point is not practical.

I accept that my action was a little over zealous but, had the reversion had a short edit summary saying something along the lines of, 'Text not supported by cited source', then I, or any other interested editor, could have checked my facts before reverting. The editor concerned has apologised and that is the end of the matter as far as I am concerned. Let us hope that everyone has learned a lesson. Martin Hogbin (talk) 10:07, 11 January 2010 (UTC)

I don't think this [2] can be regarded as a good-faith addition. Sourcing something clearly controversial to the Daily Mail is not acceptable, even if the material is good, which in this case it wasn't. In 2010, some of the world's most eminent climate scientists said is nonsense. Martin: if you really know the GW topic so badly that you can't recognise this text as obviously unacceptable, then you should make a habit of discussing your proposed edits on talk *first* rather than reverting them back in William M. Connolley (talk) 10:19, 11 January 2010 (UTC)

The text may have been unacceptable and should have been reverted, but not without without comment. A terse edit summary would have done the job. Martin Hogbin (talk) 13:14, 11 January 2010 (UTC)

@Martin. That's fine, I am sure you realised I also complained to CC about the lack of edit summary at the same time but I am not sure that I accept the original edit which you reverted back in was good faith; aside it itself being done under "minor" with content which Dalej78 must have realise would be unacceptable, I have been through the last couple of years of Dalej78's edits and it is unclear to me that there have been any positive contributions at all since 2007, just deliberate attempts to undermine the atmosphere. I think the Dalej78 account as it stands would qualify for indef blocking as vandal only. Therefore although I do not doubt your good faith, someone reverting Dalej78 as a minor edit without comment was also understandable. --BozMo talk 10:49, 11 January 2010 (UTC)

I do understand the frustration felt by the regular editors of a FA when poor quality material should be added. I also agree that, in many cases, immediate reversion is appropriate, but in the case of a highly contentions topic like this, that is also under probation, there is an onus on both sides to act properly. As I said above, a terse edit summary would have allowed interested editors to check the facts. In the current climate (no pun intended) this should be the expectation for all edits except genuine minor ones (typos etc).

I cannot accept that Dalej78 is a vandal just because his edits do not meet the standards required for an FA. He is clearly trying to balance the article by adding to the 'Debate and scepticism' section. He may be making a bad job of this, but that is not vandalism. Martin Hogbin (talk) 13:14, 11 January 2010 (UTC)

Your edit to List of scientists

Whilst I don't disagree or agree with your edit this page has had a lot of wrangling over the text and most changes are discussed on the talkpage, so don't be surprised if it is undone. I do disagree with your edit summary. The page is not a list of 'climate scientists' who oppose the mainstream view, it is a list of 'scientists'. If we had a list of climate scientists first of all it would be difficult to define and secondly we might actually find it difficult to find enough who fit the criteria for a list. Therefore majority does not really properly address this, "vast overwhelming majority" might but then those are words we tend not to use on wikipedia. Polargeo (talk) 16:34, 11 January 2010 (UTC)

I understand what you are saying but the article made no sense as it was. I am sure that there are some climat scientists who disagree, so to start with 'climate scientists agree' is nonsense. The first section, and indeed most of the text seems to be promoting what it is that the list of scientists disagrees with. Martin Hogbin (talk) 17:38, 11 January 2010 (UTC)

Monty Hall problem mediation

A request for formal mediation of the dispute concerning Monty Hall problem has been filed with the Mediation Committee (MedCom). You have been named as a party in this request. Please review the request at Wikipedia:Requests for mediation/Monty Hall problem and then indicate in the "Party agreement" section whether you would agree to participate in the mediation or not.

Mediation is a process where a group of editors in disagreement over matters of article content are guided through discussing the issues of the dispute (and towards developing a resolution) by an uninvolved editor experienced with handling disputes (the mediator). The process is voluntary and is designed for parties who disagree in good faith and who share a common desire to resolve their differences. Further information on the MedCom is at Wikipedia:Mediation Committee; the policy the Committee will work by whilst handling your dispute is at Wikipedia:Mediation Committee/Policy; further information on Wikipedia's policy on resolving disagreements is at Wikipedia:Resolving disputes.

If you would be willing to participate in the mediation of this dispute but wish for its scope to be adjusted then you may propose on the case talk page amendments or additions to the list of issues to be mediated. Any queries or concerns that you have may be directed to an active mediator of the Committee or by e-mailing the MedCom's private mailing list (click here for details).

Please indicate on the case page your agreement to participate in the mediation within seven days of the request's submission.

Thank you, Rick Block (talk)

Request for mediation accepted

A Request for Mediation to which you were are a party has been accepted. You can find more information on the case subpage, Wikipedia:Requests for mediation/Monty Hall problem. For the Mediation Committee, Seddon talk and Xavexgoem (talk) 00:45, 22 January 2010 (UTC)

This message delivered by MediationBot, an automated bot account operated by the Mediation Committee to perform case management.
If you have questions about this bot, please contact the Mediation Committee directly.

Mediation is getting underway. Do you have Wikipedia:Requests for mediation/Monty Hall problem on your watch list? -- Rick Block (talk) 14:37, 5 February 2010 (UTC)

Thanks, I will add it. Martin Hogbin (talk) 22:34, 5 February 2010 (UTC)

Why is there such friction at GW?

Hi Martin. I worry that part of the problem at Global Warming is that there are many ways to change the article but only one way for it to stay the same. I wonder if it would be worth listing the different views on what direction the article should be taking. eg

(The "Improvement "Chart" removed from here and placed at my TalkPage here). MalcolmMcDonald (talk) 08:25, 24 January 2010 (UTC)

In my experience attempts to organise the improvement of a page rarely succeed. Some editors will not participate in your scheme, others will start up their own schemes.

In my opinion the most important problem on the GW page is that of oppressive editing and page ownership, especially the rapid deletion and archiving of discussion. Once these issues are resolved it might be easier to move forward. Martin Hogbin (talk) 15:34, 23 January 2010 (UTC)

There is a massive problem of page ownership and oppressive editing and it's obvious to a lot of people. TalkPage deletions of other people's comments and rapid archiving are a big part of it. I wondered if a table might highlight the fact there were about 6 editors rejecting all suggestions for improvement, and up to 20 who have changes they'd like to make. The stone-walling we see damages the cooperation that many other editors long to embrace. MalcolmMcDonald (talk) 16:02, 23 January 2010 (UTC)

I think you would find that any attempt to poll editors in the way that you suggest will be rapidly sabotaged. By all means give it a try. Martin Hogbin (talk) 16:28, 23 January 2010 (UTC)

How do you feel about hosting it on your page? I could lift the whole thing and put it on mine, were mine not sullied by very respected but angry-looking experts making accusations that "of course the article is fit for purpose, how dare you suggest otherwise".

In the not too-distant future, some editors might face demands "if your name is not linked to a view on Martin's page it must be because you're fringe and progress here will continue without you". Two can play at the game "you're not main-stream, therefore we can ignore you". MalcolmMcDonald (talk) 16:45, 23 January 2010 (UTC)

I think your page would be better. It is your idea. Martin Hogbin (talk) 17:14, 23 January 2010 (UTC)

Do you feel that any of the options fully reflect your current position and would you be willing to enter your name, and a synopsis of your position, in the appropriate place? MalcolmMcDonald (talk) 17:24, 23 January 2010 (UTC)

I would be happy to add my name. I think one section should read 'Censorship currently makes cooperative editing and improvement possible'. This is the key issue to me. Also maybe 'the section on debate and skepticism should reflect the views of sceptics' Martin Hogbin (talk) 17:50, 23 January 2010 (UTC)

There we are, make any other suggestions and I'll take it away. MalcolmMcDonald (talk) 20:23, 23 January 2010 (UTC)

It is all yours. Now we need to get the views of other editors. Martin Hogbin (talk) 20:32, 23 January 2010 (UTC)

I imagine this being a slow-burning project and I'm contacting critics of the article first. If I can get a reasonable turn-out (perhaps 20 or so) then I can list and/or request that supporters of the current article show their hand. All suggestions gratefully recieved. MalcolmMcDonald (talk) 16:26, 24 January 2010 (UTC)

Perhaps you should formulate this as a RFC. Contacting critics of the article first seems like a poor choice of strategy. Surely the opinions of the uninvolved would be more useful. --TS 16:51, 24 January 2010 (UTC)

If you wish to help with this important project, you'd be very welcome. You could start by adding your name to the "basically going OK" category, with any caveats you have. MalcolmMcDonald (talk) 17:45, 24 January 2010 (UTC)

You have been requested by Awickert (talk) to provide examples here of "GW article reads like an advertisement". MalcolmMcDonald (talk) 19:14, 25 January 2010 (UTC)

ANI

There is an issue being discussed at WP:ANI#Deleting and readding of talk page comments in which you may be involved.--Jojhutton (talk) 21:30, 23 January 2010 (UTC)

"I didn't hear that"

As I remarked to MalcolmMcdonald on a separate subject:

You're becoming a stuck record, ignoring the clearly stated comments of other editors and coming back again and again to the same rejected suggestions, like an old fashioned gramophone whose needle has stuck in part of the record, replaying the same section of music repeatedly.

You've asked the same question repeatedly on talk:global warming: [3] [4] [5]. The answer to this question, you've been told, is complex, yet you repeat the question demanding an answer. This seems unrelated to improving the article (and thus the potential problem here is more egregrious than in MalcolmMcDonald's case).

There are appropriate forums and blogs in which you could pose this question and argue over the reponses. Wikipedia is not one of them.

Please clarify how you see this line of questioning improving the article, and stop simply parroting the same question. --TS 16:48, 24 January 2010 (UTC)

Thank you for your kind remarks. I have covered the issues that you have raised on the article talk page. Martin Hogbin (talk) 17:40, 24 January 2010 (UTC)

I have repeatedly made real and detailed suggestions to improve the Global Warming article, my own particular gripe (backed by numerous examples) being that the article fails to be informative. I've yet to come across examples where the article could be descibed as informative. For this I suffer personal attack.

Other people have other serious gripes about the article, eg "Include politics of GW", "the views of sceptics are not represented properly", "Censorship makes cooperative editing and improvement extremely difficult" and "Article reads like an advertisement". I don't understand why it's such a problem to write this article to be useful to readers. MalcolmMcDonald (talk) 17:42, 24 January 2010 (UTC)

Indeed. Conformance to the Copenhagen Accord must have had some expected gain in GW terms. It would be useful and informative if the article were to state a value for this. What is the problem with doing so. Martin Hogbin (talk) 17:47, 24 January 2010 (UTC)

The whole point of this article or suite of articles is (presumably) to make information easily accessible. Instead of which, it sometimes appears that the article is being made as un-helpful as possible. Sorry to bang on about things, but "Amazon" and "desertification" have been taken out - how can that be helpful? No mention of the Antarctic - an astonishing omission! If people can't answer questions on TalkPages, then it becomes doubtful they can write articles that answer questions either. MalcolmMcDonald (talk) 18:02, 24 January 2010 (UTC)

Malcolm you are confusing "not anwering" with "not knowing". Wikipedia policy does not allow for talk-pages to become a question&answer forum. We are "refusing to answer" questions that is not going to improve the article. You have to turn to blogs or other forums to get answers to your questions. We are also not here to seek the WP:TRUTH, but instead to describe the subject, as seen from science.

Some of your questions btw. are answered on Wikipedia, but they are answered on sub-articles, since every topic cannot be discussed at the top-level article.

Glaciers are described in Retreat of glaciers since 1850. IPCC ARII criticism is covered in Criticism of the IPCC AR4. Antarctica in Climate of Antarctica (amongst others), Coral bleaching in Coral bleaching, Arctic shrinkage in Arctic shrinkage, .....

There are so many different sub-topics that are related to global warming, that the top-level article only summarizes some articles, which again may have summaries of several other articles. At each step details are lost, that is not from ignorance, but from necessity. --Kim D. Petersen (talk) 18:18, 24 January 2010 (UTC)

I see people not being helpful in direct interaction and it immediately explains what I and so many others have noticed, the product of this labour is almost completely unhelpful. I've proved that so often, from so many angles, that I'm getting sick of repeating myself.

Then I make suggestions to improve the article and I'm told off for "advocating". I cannot deny it. I advocate that the article should inform its readers/provide answers to their questions. MalcolmMcDonald (talk) 19:09, 24 January 2010 (UTC)

There is no rule against collecting opinion from already involved editors. Martin Hogbin (talk) 21:00, 24 January 2010 (UTC)

Good, I didn't think there should be. But I need to do a list of all the people to ask. MalcolmMcDonald (talk) 21:34, 24 January 2010 (UTC)

The trouble is, from what i can detect, that your defintion of how the article would be "usefull" isn't encyclopedic. An encyclopedia "attacks" a topic/subject from a standpoint significantly more like a text-book, than a Q&A/Debunking angle. We are here to describe what science says about the subject, and from the balance/view that scientists consider important. What you seem to be looking for is something that can answer your questions about the current news-cycle on global warming, and for that you need to go to other sources. --Kim D. Petersen (talk) 21:47, 24 January 2010 (UTC)

The article is entitled 'Global warming' not 'The science of global warming'. It should therefore cover the whole subject, including, science, causes, effects, mitigation, adaptation, and politics. The mitigation action of states, for example, is not controlled by science but by a mixture of science and politics. Martin Hogbin (talk) 00:31, 25 January 2010 (UTC)

I always thought an encyclopedia was written to answer questions, to solve arguments, to inform. I never realised that articles were intended to teach along the line of text-books. In fact, I wonder where that comes from. MalcolmMcDonald (talk) 08:16, 25 January 2010 (UTC)

@ Martin Hogbin - making some other changes, I've taken out the part where you said the chart is for the GW article only. Though you may have a clearer idea on this than me and be right. MalcolmMcDonald (talk) 12:56, 26 January 2010 (UTC)

It is your chart, so I guess that I should have left you to answer the question. Might I suggest that you create a special page in your user space for the table. Martin Hogbin (talk) 12:58, 26 January 2010 (UTC)

Thanks

For [6]. I was probably silly not to start a new section. BTW I think it was Boris not TS who complained (but I think it is fine, and if you do kind of break any rules along the lines of "now we know what we want lets russle up a lynch party" I will try to discuss it with you first). --BozMo talk 13:35, 26 January 2010 (UTC)

That's right. My comments were that it might be better as a RFC and instead of involved parties (for and against the global warming article in its present form) it might be more helpful to seek opinions from those uninvolved. --TS 14:15, 26 January 2010 (UTC)

The Improvement Chart is a work in progress to try and discover what changes have widespread support amongst people who've tried to make other improvements. MalcolmMcDonald (talk) 14:43, 26 January 2010 (UTC)

Have you tried analyzing how the successful improvements in the article actually take place? By examining these and comparing with those that have been proposed but failed, you might get a good handle on how to make successful proposals. --TS 14:59, 26 January 2010 (UTC)

I know how "improvments" are done. Just when a discussion on the value of key-words is attempted (maybe they're the single most important and valuable aid to readers navigating for specific information/references?) and shortly after we were told we're stupid for not doing this already, vested editors come along and further reduce the small number of key-words in the article. That happened during a process where there were editors trying to stop the censorship.

WP:PRESERVE states "Try to preserve useful content. As long as any of the facts or ideas added to the article would belong in a "finished" article, they should be retained and the writing tagged if necessary, or cleaned up on the spot". Care to guess how that works in practice? MalcolmMcDonald (talk) 15:16, 26 January 2010 (UTC)

TS, I do not need to make proposals. This is Wikipedia - the encyclopedia that anyone can edit. Please tell me why you would not want key data on AGW mitigation to be in the article. Martin Hogbin (talk) 17:09, 26 January 2010 (UTC)

Can I possibly plea for the article to be shorter not longer? BTW there are fixes on the key words which work for search engines using section redirects (create an article with the name you think the search should win and e.g. Freaking Hawking put in something like #REDIRECT [[Stephen Hawking#Appearance on the Simpsons]] of course we need to decide whom we wish to send where, and a lot of admins get tetchy about articles created to redirect but you don't have to mention the key word to get the query whereever you want, and if you do it with a bit of discussion first it should survive trial by fire. --BozMo talk 21:31, 26 January 2010 (UTC)

Are you sure this on the right page, I have no idea what you are talking about. Martin Hogbin (talk) 22:08, 26 January 2010 (UTC)

Sorry mainly it was at Malcolm ref the comment above on keywords. Agree I will tell him somewhere else sometime. --BozMo talk 22:12, 26 January 2010 (UTC)

I'd be very interested to hear from you on this subject. But my proposal does not concern raising the article in Google ratings, but including key-words in each article (eg "Amazon" and "Antarctic", puzzlingly missing from the main Global Warming article) with links leading to sub-articles containing the detail. It's not difficult to get to the articles, it's the difficulty of navigating them that is so frustrating. As we were told, Good grief, how much spoon-feeding do you need?, we're meant to navigate by "search" on words within articles. Unfortunately, this won't work unless we facilitate it by providing the "key-words" people will tend to use. MalcolmMcDonald (talk) 15:48, 29 January 2010 (UTC)

Please note

From WP:BAN: A banned user who evades a ban, may have all of their edits reverted without question. Short Brigade Harvester Boris (talk) 11:57, 28 January 2010 (UTC)

Thanks

Sorry that no one wanted to discuss what you had to say on talk:Global warming. But thank you so much for showing the good faith and trying to start a new section on content. So it goes :( Awickert (talk) 03:26, 8 February 2010 (UTC)

Request for Amendment to Arbitration

Hello, Martin Hogbin. This is to inform you that there is a request for amendement regarding an arbitration case that you have commented on.Likebox (talk) 05:03, 8

Standing in the way of a productive mediation

You seem to be spending more time criticizing me or your opposing parties than contributing to a productive mediation. Furthermore I urge you to be open-minded as to the real-time option which has "unstuck" many intractable mediations in the past; your statement that you "will not accept mediation through those media" is obstructionist and unhelpful. Andrevan@ 21:03, 15 February 2010 (UTC)

I have not criticized you or those you call my opposing parties. You asked (referring to IRC) , 'Does everyone feel comfortable with that sort of approach?'. I have replied that I am not. Martin Hogbin (talk) 22:44, 15 February 2010 (UTC)

Modification of Brews' sanctions

Thanks for your generous support in modification of my sanctions. Unfortunately, and for no stated reasons, no change is likely. I am sorry that no assessment of the suggestions and evidence was made. Brews ohare (talk) 19:22, 16 February 2010 (UTC)

It seemed only fair to me that you should be able to express your own opinion in your own user space. Martin Hogbin (talk) 19:32, 16 February 2010 (UTC)

Your RFC suggestion

Your RFC suggestion is a good one, to say to Pedant17, "Come clean and admit you are using E-prime, explain why you thing it is appropriate to this page, and try to get a consensus to use it. If you do not get a consensus to use E-prime throughout, you can expect your edits to be rapidly reverted". I think that as you are the one that suggested this idea, perhaps you could leave that comment/suggestion at his talk page? Thank you for your time, Cirt (talk) 16:32, 20 February 2010 (UTC)

The problem is that Pedant17's motivation does not seem so clear cut to me. Martin Hogbin (talk) 00:09, 21 February 2010 (UTC)

Hrm, it was not I that came to the assessment that Pedant17 was motivated by E-Prime, but multiple different editors previously-uninvolved with this particular article, and I agree with them. Cirt (talk) 06:06, 21 February 2010 (UTC)

Paywall source?

Regarding this request: I've sent you an email. I'll see if I can locate an online transcript of the Feynman lecture. Gabbe (talk) 17:23, 16 March 2010 (UTC)

Thanks. Martin Hogbin (talk) 17:37, 16 March 2010 (UTC)

RfC on Talk:Nahum Shahaf

Thanks for your sugestion, I'm sorry an editor dismissed it so flippantly. I would hope you could participate in the discussion further the article could benefit from the neutral perspective of uninvolved editors. Respectfully, RomaC (talk) 13:54, 21 March 2010 (UTC)

I am happy to help if I can. Martin Hogbin (talk) 21:36, 21 March 2010 (UTC)

Faster than light

Sorry, I don't know if you'll see this. But I've been blocked from articles, discussion pages, and even, it seems, most talk pages. And as I pointed out that the blocking was unjustified, I don't expect that will change any time soon. So I don't know if you'll even see this. 216.239.82.80 (talk) 10:48, 5 April 2010 (UTC)

I can see your message OK. How long have you been blocked for? Martin Hogbin (talk) 10:52, 5 April 2010 (UTC)

A higher up person in Wikipedia persisted the blocking. Now I'll probably be in trouble for being on another IP. 216.239.88.76 (talk) 07:04, 6 April 2010 (UTC) also known as 216.239.82.80

My suggestion would be that you register then explain that you are currently blocked for edit warring and ask to be unblocked. Registering gives you a fixed identity on WP. Once you are unblocked you need to take care to remain within the rules of WP by not holding discussions on the article page and not edit warring. Martin Hogbin (talk) 09:04, 6 April 2010 (UTC)

April 2010

You currently appear to be engaged in an edit war according to the reverts you have made on Doctor Who. Note that the three-revert rule prohibits making more than three reversions on a single page within a 24-hour period. Additionally, users who perform several reversions in content disputes may be blocked for edit warring even if they do not technically violate the three-revert rule. When in dispute with another editor you should first try to discuss controversial changes to work towards wording and content that gains a consensus among editors. Should that prove unsuccessful, you are encouraged to seek dispute resolution, and in some cases it may be appropriate to request page protection. Please stop the disruption, otherwise you may be blocked from editing. magnius (talk) 14:36, 5 April 2010 (UTC)

Thanks for your comments. I note that you do not appear to be a recent contributor to the article or an administrator so I am not sure on what basis you are contacting me.

Your comments on the matter in question would be of interest as there seems to be a number of non-British editors having a bizarre argument with some native British English speaking editors as to the normal word used in British English to refer to a set of episodes. I note that you use the term 'series' on your user page. Martin Hogbin (talk) 16:02, 5 April 2010 (UTC)

Discussions are not limited to participants who speak a particular variant of the language. The discussion is a bit bizarre but you started said discussion, which is about the use of "season" or "series" relating to the classic episodes of Doctor Who and not what is the normal word for all British television programmes. Please take care to not misrepresent your fellow editors when restating their comments. Many scores of people have Doctor Who on their watchlist. The above warning likely comes from seeing the article in their watchlist. That is how i came across the discussion. delirious & lost ☯ ^~hugs~ 21:02, 7 April 2010 (UTC)

Tesla vs. Marconi deletion

I dispute your assertion (again) that the Tesla vs. Marconi section within Invention of radio is irrelevant to the article. Please do not remove it again without obtaining consensus on the article's Talk page. HarryZilber (talk) 00:28, 6 April 2010 (UTC)

Perhaps you would like to discuss the issue on the article talk page then. I have been trying to do this for some time, with no response from anyone. Martin Hogbin (talk) 09:10, 6 April 2010 (UTC)

WP:NPOV

Hi martin. Given the disagreements we had concerning evolution as fact or theory, I thought you might wish to weigh in at this discussion at the NPOV page. Best, Slrubenstein | Talk 09:05, 11 May 2010 (UTC)

Thanks for thinking of me. I will take a look. Martin Hogbin (talk) 09:24, 11 May 2010 (UTC)

IPA

Thanks for chiming in. I agree with everything you say. For months I tried to argue the same things you are saying, but I got bullied off the discussion with abuse, personal attacks, and downright insulting behaviour, but I refused to be drawn into incivility by the two defendants of everything that's wrong with their private version of the use of the IPA and its implementation in the Wikipedia.--Kudpung (talk) 15:13, 16 May 2010 (UTC)

Thanks for your comment. I am new to this subject, I was drawn in by the Worcester RfC but soon realised that the issue was much broader than Worcester.

As I see it, a relatively small bunch of editors have attempted to deal with the issue of multiple English pronunciations and have come up with a half-baked scheme that abuses the IPA and is ill-suited to the needs of WP. Worse still they are attempting to enforce their scheme throughout the encyclopedia. Martin Hogbin (talk) 15:52, 16 May 2010 (UTC)

Your perception is 100% accurate. It is sad that (bunch = 2) they are totally intransigent and remain so by blinding normal readers with pompous linguistic jargon (God knows, I' a linguist...), smoke screens, strawman arguments, deliberate off-tracking, and even exceptionally insulting behaviour. Ironically also, neither of them appear to be even qualified linguists, or to have a first hand knowledge of British English! I have prepared a proper RfC with a neutral proposition, with the help of some friends, to discuss this IPA issue. If you wish to see the draft and make any suggestions, you would have to let me know how I can contact you off line, because while it was in my sandbox it just caused more abuse and ill sentiment.--Kudpung (talk) 00:42, 17 May 2010 (UTC)

Anyone is free to email me at wiki@hogbin.org Martin Hogbin (talk) 12:24, 17 May 2010 (UTC)

Survey

Hi Martin,

I am a PhD student at the Open University of Catalonia. I am currently preparing a research project about the governance processes in online collaborative communities, and I would like to kindly ask for your collaboration based on your experience in Wikipedia. Interested in participating? Please drop me a note in my talk page. This would take around 20 of your time.

Thanks! Aresj (talk) 09:35, 24 May 2010 (UTC)

Thanks for your note. Looking forward to getting your answers. Aresj (talk) 10:32, 28 May 2010 (UTC)

Conditional solution references in lead and/or explanation

Do you object to including sentences like, "The Monty Hall problem can also be solved by a conditional probability problem, see #below." being placed in the lead or the initial explanation sections? Andrevan@ 17:44, 28 May 2010 (UTC)

I thought we had all agreed that the lead is fine as it is. What is the sentence supposed to mean? Martin Hogbin (talk) 18:02, 28 May 2010 (UTC)

The lead wasn't the key point I was asking about, so feel free to disregard it. Andrevan@ 22:57, 28 May 2010 (UTC)

Is there a typo? I do not understand what it means. Martin Hogbin (talk) 23:31, 28 May 2010 (UTC)

I asked if you objected specifically to including references to an explanation of the conditional probability analysis of the Monty Hall problem and related sub- or parallel problems in the sections which are actually primarily dealing with the simple approach. Andrevan@ 00:28, 29 May 2010 (UTC) 00:27, 29 May 2010 (UTC)

I object strongly to anything that might make the reader believe that the simple solution might give the wrong answer or answer the wrong question or that even sows the seeds of doubt in their minds about these things. "The Monty Hall problem can also be solved as a conditional probability problem" [presumed typo corrected] could suggest that there are two answers to the problem, one obtained by the simple solution and the other by means of conditional probability. Thus the reader may feel that to get the 'real' answer they have to study the conditional solution.

I also see no purpose in a statement that tells the reader that there are two ways of solving the problem when this will be self-evident from the fact that, immediately after, we show two ways of solving the problem. Any talk of 'other ways' or conditional probability etc should come at the start of the conditional solution section. Martin Hogbin (talk) 10:10, 29 May 2010 (UTC)

Clafication

Hi Martin, I just wanted to let you know that my edit summary ("Removed bad advice" ) for this removal of the two sections at Talk:Theory of relativity was not referring to the advice you gave at the bottom, but to this anonymous remark. The idea was to avoid talk page degeneration into another sci.physics.relativity madness ;-) - Cheers - DVdm (talk) 07:28, 31 May 2010 (UTC)

Thanks for letting me know. I thing the OP was a genuine young enquirer and probably did look at the pages that I referred him to, but I understand your point. The talk pages are not really the place for teaching and learning about the subject. Martin Hogbin (talk) 09:50, 31 May 2010 (UTC)

Ok. By the way, your further assistance might be needed here or on the relevant page and talk page. Thanks - DVdm (talk) 10:10, 31 May 2010 (UTC)

Happy to help. I have already commented as you have probably seen but I will try talking to the guy. Martin Hogbin (talk) 10:33, 31 May 2010 (UTC)

Notification

As you have commented in an ANI thread or RfC relating to User:Pedant17, this is to notify you that the same user's conduct is being discussed here, along with sanction proposals. Ncmvocalist (talk) 13:24, 11 June 2010 (UTC)

Possibly time to go to the Conflict of Interest noticeboard

I have left some advice on Blackash's userpage and told her that I am considering reporting her to the Coi noticeboard. She was reported once before but the discussion seems to have simply fizzled out. I plan on waiting about 48 hours to see if it sinks in before acting on this. I imagine you agree? If not please let me know what you think the best option is. Thanks, Colincbn (talk) 14:24, 23 June 2010 (UTC)

As I said on the talk page, I propose to move the page to a neutral title. If, after I have done that, if Blackash's reverts I think that would show a clear conflict of interest which should be reported to the COI noticeboard. If the new title holds then we can start discussing a new title more sensibly. I still would not rule out reporting a COI but I think it would be best to move the page first. What do you think? Martin Hogbin (talk) 15:49, 23 June 2010 (UTC)

It looks like either COI noticeboard or user RfC are the only options left now. Martin Hogbin (talk) 20:29, 23 June 2010 (UTC)

Arborsculpture

If there is any “wiki-legal” way to re-open the proposal to change the title of the article about arborsculpture to “Arborsculpture” that is exactly what we should so. THIS is the verifiable, written evidence I would have introduced had the debate not closed so quickly. --Griseum (talk) 17:22, 23 June 2010 (UTC)

As I said on the talk page, I am planning to move the page to a neutral title. We can then start the discussion about where it should finally be. Martin Hogbin (talk) 18:13, 23 June 2010 (UTC)

It looks like either COI noticeboard or user RfC are the only options left now. Martin Hogbin (talk) 20:31, 23 June 2010 (UTC)

If we can't change the title to match the article another option might be to change the article to match the title. In other-words rewrite the article to be about actual "tree shaping" and not Pooktre. Then the impetus would be on other editors to show the term "tree shaping" is not used to mean that which it is used to mean. Colincbn (talk) 03:40, 24 June 2010 (UTC)

Probably not a good idea. It would be seen by many as disruptive. Like you, I have no real interest in arborsculpture but I see what is happening on that page as an attack on the integrity of WP. It seems that one editor is able to manipulate the whole system for commercial advantage. I think COI noticeboard and user RfCs are the only way to go. Martin Hogbin (talk) 07:45, 24 June 2010 (UTC)

Except for User:Blackash, everyone who has opined on the matter of the arborsculpture article, even those disagreeing with us, seems to have the improvement of Wikipedia as a motive. Please keep that in mind as we proceed. While I empathize with your level of frustration, statements like “...I suggest that you do not give up your day job” aren't going to help our cause. Thanks. --Griseum (talk) 09:57, 26 June 2010 (UTC)

It is hard to know what to say when dealing with frivolous non-sequiturs but I take your point. Martin Hogbin (talk) 10:21, 26 June 2010 (UTC)

She is now trying to rid the entire article of the word Arborsculpture. I have never brought another user to the noticeboards, but I think someone must. I do not know the procedure but if someone can point me to the right way of doing it I suppose I would be willing. Colincbn (talk) 02:00, 20 July 2010 (UTC)

I can only suggest a user conduct RfC. I do not know exactly how you do this but I know it need two complaints. I am happy to support you in opening one. The alternative is just to revert all removals of the 'Arborsculpture'. Martin Hogbin (talk) 08:03, 20 July 2010 (UTC)

Ministerpräsident

Voting has started here. Kingjeff (talk) 03:22, 6 July 2010 (UTC)

Second round of voting has started. Kingjeff (talk) 14:02, 14 July 2010 (UTC)

Hi, friend

I'm reopening an old can of worms. Your input is welcomed... Talk:IBM_and_the_Holocaust Carrite (talk) 15:52, 8 July 2010 (UTC)

Draft on fermentation for article kimchi

Hi. This is the draft I wrote on fermentation process for the article kimchi which you suggested me to write. Please have a look and tell me what you think. I sent the same draft to User:Knorrepoes too, and asked him to proofread and revise it. Thanks. Hkwon (talk) 17:26, 11 July 2010 (UTC)

The vegetables are sliced, highly seasoned with ingredients such as red pepper, onion, and garlic, and fermented in brine traditionally in large earthenware jars. Dried and salted shrimp, anchovy paste, and oysters are sometimes used as additional seasonings. The fermentation process is initiated by various microorganisms originally present in the raw materials, but is gradually dominated by lactic acid bacteria. Numerous physicochemical and biological factors influence the fermentation, growth, and sequential appearance of principal microorganisms involved in the fermentation. The early and intermediate phases of fermentation are considered crucial to the taste of kimchi. When optimally ripened, acidity increases with sourness and a unique flavor with refreshing and coolness results from ethanol and other products.

During fermentation, which takes approximately one month depending on weather conditions, the kimchi jars are stored totally or partially underground in cellars or sheds built expressly for this purpose. Recently, however, kimchi refrigerators have become very popular in South Korea. This household electronic device maintains the temperature for the proper fermentation of kimchi, saving the trouble of burying kimchi jars underground.

It looks OK to me but I know nothing about the subject. I was also hoping that thes section might say when kimchi is fermented and under what circumstances it is eaten unfermented. Martin Hogbin (talk) 17:39, 11 July 2010 (UTC)

Spelling of Spitsbergen RFC

I've refactored my comment, and replied to your question at the RFC. Let me know if there are any further issues. Mjroots (talk) 11:36, 15 July 2010 (UTC)

Sorry it was my mistake, I misread the heading - see reply on talk page. Martin Hogbin (talk) 11:47, 15 July 2010 (UTC)

FYI

Please check out [7].Melonbarmonster2 (talk) 18:23, 21 July 2010 (UTC)

Thanks, I will add my thoughts. Martin Hogbin (talk) 18:50, 21 July 2010 (UTC)

Notice of ANI Discussion (Fut.Perf's topic ban of Hkwon)

Hello. This message is being sent to inform you that there currently is a discussion at Wikipedia:Administrators' noticeboard/Incidents regarding an issue with which you may have been involved. Thank you.Qwyrxian (talk) 12:41, 24 July 2010 (UTC)

Confidential mediation

Belatedly replied[8] to you at Wikipedia talk:Mediation Committee/Policy. I've been on holiday, and so unable to respond until now. Hope you're well, AGK 16:13, 27 July 2010 (UTC)

Thanks for that, I have replied on the mediation page. Martin Hogbin (talk) 16:33, 27 July 2010 (UTC)

interjections in talk

Martin - You've lately been breaking up comments without making it clear who's saying what. I've fixed a couple of these but can you please be more careful about this? In general, there's usually no reason you need to interject. Adding your comments at the end is almost always just fine. Thanks. -- Rick Block (talk) 14:39, 29 July 2010 (UTC)

Sorry, it makes it easier to address individual points, I will try to be more careful. Martin Hogbin (talk) 16:44, 29 July 2010 (UTC)

PQ 18 OOB

Hah! beat me to it! I was drafting a proposal for just that. Xyl 54 (talk) 23:44, 29 July 2010 (UTC)

BTW the entry for Oligarch in "Merchant ships" was the same; did you have a reason for not doing that too? Xyl 54 (talk) 23:46, 29 July 2010 (UTC)

No, I just missed it. Pleas feel free to change it, we seem to have a consensus. Martin Hogbin (talk) 08:40, 30 July 2010 (UTC)

Proposed deletion of Redefinition of the Metre in 1983

The article Redefinition of the Metre in 1983 has been proposed for deletion because of the following concern:

No reason for this to be a separate article. This appears to be mainly about the speed of light rather than the Metre. The main article on Metre already mentions this redefinition as is the appropriate place for this.

While all contributions to Wikipedia are appreciated, content or articles may be deleted for any of several reasons.

You may prevent the proposed deletion by removing the {{dated prod}} notice, but please explain why in your edit summary or on the article's talk page.

Please consider improving the article to address the issues raised. Removing {{dated prod}} will stop the proposed deletion process, but other deletion processes exist. The speedy deletion process can result in deletion without discussion, and articles for deletion allows discussion to reach consensus for deletion. noq (talk) 12:29, 30 July 2010 (UTC)

Articles for deletion nomination of Redefinition of the Metre in 1983

I have nominated Redefinition of the Metre in 1983, an article that you created, for deletion. I do not think that this article satisfies Wikipedia's criteria for inclusion, and have explained why at Wikipedia:Articles for deletion/Redefinition of the Metre in 1983. Your opinions on the matter are welcome at that same discussion page; also, you are welcome to edit the article to address these concerns. Thank you for your time.
Please contact me if you're unsure why you received this message. JohnBlackburne^words_deeds 13:47, 30 July 2010 (UTC)

MHP analysis

Okay Martin how general do you want the problem to be?Nijdam (talk) 19:01, 2 August 2010 (UTC)

Standard game rules, Monty always offers the swap and always opens an unchosen goat-hiding door. Initial car placement, player initial door choice, and host goat door choice not specified. Was there something in particular that you were thinking of? Martin Hogbin (talk) 19:17, 2 August 2010 (UTC)

Spitsbergen, (again!)

Hello Martin
Ive moved your comment down, as it was confusing where it was ( I trust you take no offense) and Ive replied (it's here).Xyl 54 (talk) 22:50, 4 August 2010 (UTC)

No problem. I was just trying to make my position clear, which is that the place is now properly called 'Spitsbergen' in English. I agree any historic names of other things ,such as the 'Spitzbergen group' of ships should be spelled as thay were a the time. Please let me know if this is not clear and I will clarify. Martin Hogbin (talk) 08:14, 5 August 2010 (UTC)

reformat

Hi. I reformatted because at first I didn't see your comment that was within my message unsigned and it might be confusing to others by being placed that way, as far as who said what. Regards, --Bob K31416 (talk) 14:01, 6 August 2010 (UTC)

No problem. Martin Hogbin (talk) 15:43, 6 August 2010 (UTC)

Merge decision for Redefinition of meter in 1983 at DRV

Thanks for drawing my attention to this. I have responded at the deletion review - basically, I made a mistake in judging the consensus in this case, and would support the decision being overturned to no consensus. Regards, -- PhantomSteve/talk|contribs\ 11:56, 8 August 2010 (UTC)

Thanks for your response. What happens now? Martin Hogbin (talk) 12:02, 8 August 2010 (UTC)

To be honest, I'm not sure. From the DRV, I would have thought that it will be overturned - but how that's done (and when) I'm not sure - it'll be an education for me too! I assume that the admin who closes the DRV will do the deed. -- PhantomSteve/talk|contribs\ 13:36, 8 August 2010 (UTC)

Thanks for letting me know, it's too bad I didn't see the message in time to participate. I would have suggested "overturn to keep" based on 1) existence of multiple reliable sources, 2) WP is not paper, and 3) the fact that it was an especially important redefinition of the unit. Also, this is fundamentally an editing question (structurally speaking, how can we most effectively present the information about the history of the meter) rather than a notability one, so it is not proper for AfD's, but should rather be discussed on the talk pages.

It's an example of a growing awkward side effect of the AfD culture - that related topics tend to get crammed into big unreadable monster articles, lest each part individually get deleted. In the big picture, this is detrimental to one of wikipedias core structural advantages over paper - namely the "mass of concise readable articles nicely interlinked" paradigm. It also makes it difficult to maintain interlinks to specific sub-topics. For example, if a reader is on a page about scientific redefinitions and clicks a link to the 1983 redefinition of the meter, she will get redirected to the article on the meter, when she is only looking for information about the particular redefinition. This happens to me all the time when I'm simply reading wikipedia and it's very annoying. AfD hero (talk) 05:49, 22 August 2010 (UTC)

Thanks for your interest. The issue has been resolved now, the article was reprieved and it has now ben expanded to incluse the whole history of the metre. Martin Hogbin (talk) 11:19, 22 August 2010 (UTC)

Mediation resumes

The mediation of the MHP case has re-started. If you wish to participate, would you be willing to check in on the case talk page here? Note that the mediators have asked that participants agree to certain groundrules. Sunray (talk) 06:58, 11 August 2010 (UTC)

Hi Martin. I have spent all day "doing my stuff" on the mediation page. In an effort to decrease my verbosity I put up some footnotes to my new mediation page contributions on my talk page. Still struggling with how to do links in wikipedia and how to get notifications when important things are changed. I hope you have time to take a look and do please comment, in whichever way you like. Gill110951 (talk)

SoL and the asymmetry of the krypton line

I thought I'd reply here to your question about how the asymmetry of the krypton line increases the measurement uncertainty of the SoL measurement, as I don't think it's controversial and the section on the talk page is getting very long ;)

What happens with an asymmetric line in interferometry is that the interference fringes get "smudged out" – that is, they are broader than would be expected for a simple Lorentzian line shape and so the fall-off in intensity between fringes is more gradual. As you're not actually "counting" fringes, but measuring intensity over a (relative) length scale, so as to be able to get "thousandths of fringes" for example, the lower variation in intensity over length means that you can be so sure as to how far along the fringe you are (for any given precision of intensity measurement, to which there are of course limits). So yes, this appears in your random measurement uncertainties as well.

I hope this clarifies things for you, feel free to drop me a line if you want to discuss it further. Physchim62 (talk) 15:08, 11 August 2010 (UTC)

Time out?

Hello Martin, do you take a break or something alike, or can we continue the analysis of MHP?Nijdam (talk) 10:21, 14 August 2010 (UTC)

I am still here. I must have missed your most recent posts. Please could your read and respond to my comment on the analysis talk page. Martin Hogbin (talk) 11:22, 14 August 2010 (UTC)

Martin, please continue the discussion on the combined doors solution. Nijdam (talk) 11:45, 22 August 2010 (UTC)

Birds

Hi Martin. Please note that it is a Bird Project convention that all bird species are fully capped, thanks Jimfbleak - talk to me? 07:06, 1 January 2011 (UTC)

Who am I to argue, but this a new one to me. How widespread (outside WP) is this convention? Martin Hogbin (talk) 11:30, 1 January 2011 (UTC)

Monty Hall discussion

I have moved this to its own page at User_talk:Martin_Hogbin_Monty_Hall_discussion Martin Hogbin (talk) 19:53, 16 January 2011 (UTC)

Request for feedback on a draft

If you're willing, I would appreciate some feedback and criticism from you on trimming "bloat", smoothing out the parts where the text was merged, indicating important points that should be included, and whatever else on a draft for a merged article to replace the Centrifugal force and Centrifugal force (rotating reference frame) articles. In writing the draft and in the rationale for a merger, I'm looking at example #3 at Wikipedia:Disambiguation#Deciding_to_disambiguate where this would be the primary topic for the most common usage, with a hatnote to the one other usage of the term (the reactive centrifugal force). I realize that it is still a bit of a frankenstein cut-and-paste from the other two pages, but I didn't want to lose some of the good work and wording by other editors. I've found that it is helpful when advocating for a change to present a concrete example of an alternative rather than an abstract idea, so I'd like to get a polished (but not necessarily perfect) draft together before restarting a merge discussion. So like I said, any feedback and criticism would appreciated. --FyzixFighter (talk) 20:27, 29 January 2011 (UTC)

I suggest we sandbox this somewhere. Rather than a hatnote to another article I would suggest just a section 'Alternative meanings'. Martin Hogbin (talk) 20:43, 29 January 2011 (UTC)

Re: sandboxing - do you mean a sandbox in article space as opposed to my userspace? In other words, where is the appropriate "somewhere"? --FyzixFighter (talk) 22:15, 29 January 2011 (UTC)

No anywhere is fine with me. Actually I am not so sure it is a good idea to do it this way round now. I think it be difficult to get consensus for replace a whole article with a pre-written one. I think it would be best to work on the two articles as they are now with a view to proposing a merge again. Martin Hogbin (talk) 22:36, 29 January 2011 (UTC)

arbitration case

You are involved in a recently-filed request for arbitration. Please review the request at Wikipedia:Arbitration/Requests#Monty Hall problem and, if you wish to do so, enter your statement and any other material you wish to submit to the Arbitration Committee. Additionally, the following resources may be of use—

• Wikipedia:Arbitration/Requests#Requests for Arbitration;
• Wikipedia:Arbitration guide.

Thanks, Rick Block (talk) 06:38, 9 February 2011 (UTC)

Monty Hall problem opened

An Arbitration case involving you has been opened, and is located here. Please add any evidence you may wish the Arbitrators to consider to the evidence sub-page, Wikipedia:Arbitration/Requests/Case/Monty Hall problem/Evidence. Please submit your evidence within one week, if possible. You may also contribute to the case on the workshop sub-page, Wikipedia:Arbitration/Requests/Case/Monty Hall problem/Workshop.

On behalf of the Arbitration Committee, (X! · talk)  · @144  ·  02:27, 12 February 2011 (UTC)

Martin - a number of the edits in your evidence section are anonymous - is this you logged out? --Elen of the Roads (talk) 23:21, 17 February 2011 (UTC)

Yes, sorry I forgot to log in. Martin Hogbin (talk) 00:08, 18 February 2011 (UTC)

You're still a bit over on your wordcount in the evidence section (around 350 words). It is a valuable contribution, but do you think you could rewrite it a little shorter, or indicate if anything you have said is a direct response to evidence elsewhere (as that is generally not included in the 1000 words). Thanks. --Elen of the Roads (talk) 14:28, 20 February 2011 (UTC)

Oblateness in the plane of rotation

So what caused the oblateness of the earth in its plane of rotation?WFPM (talk) 23:42, 18 February 2011 (UTC)

Everything below is from the viewpoint of Newtonian physics.

Some philosophy of physics

You can ignore this bit if you like.

Physics does not purport to explain in an absolutely fundamental sense why things happen. Physicists leave that to philosophers and the religious. Physics aims to generate an accurate, and preferably philosophically pleasing, quantitative model of what does happen, that is all.

I certainly agree with that!!!!WFPM (talk) 16:31, 21 February 2011 (UTC)

Frames of reference

You said that you were confused about frames of reference. A reference frame is a conceptual framework (it has no physical reality) against which all distances and motion are measured. You might think of it as a grid of invisible lines. These lines could be in a rectangular grid, like 3D graph paper or in polar coordinates, like the lines of latitude and longitude on the Earth. Whether we measure something to be moving or not, or whether we measure it to be accelerating or not depends on what frame of reference we measure it against. When I was reading Einstein about his theory of relativity he made the point that when an observer was stationary or even in non-accelerated motion in Euclidian space, all other non-accelerated motion would be observed to be in a straight line. So when you track non-linear motion, you are in some kind of non-Euclidian motion.WFPM (talk) 18:33, 19 February 2011 (UTC)

Inertial frames

Although whether we measure something to be accelerating or not depends on our frame of reference, there does seem to be a fundamental difference between motion at a constant speed in a straight line, and acceleration. This difference is embodied in Newton's laws, which tell us that a body continues in a straight line at constant speed unless a force acts upon it. A body with no forces acting on it is said to move inertially. A reference frame in which every point is moving inertially is an inertial frame, in other words, if there wire no forces like gravity acting (say in outer space), you could place a marble at every intersection of your grid lines of an inertial frame and it would just stay there. Inertial frames are very natural, and it is only in inertial frames that Newton's laws apply. This sounds like observations made by an observer that is stationary or in non-acceleration linear motion.WFPM (talk) 18:36, 19 February 2011 (UTC)

Non-inertial frames

A non inertial is one which is accelerating in one way or another. This could be linear acceleration or rotation, which is a constant acceleration towards the center of rotation. In an accelerating frame an object moving inertially would be measured to accelerate, thus Newton's laws do not apply in a non-inertial frame, unless we adjust them in some way. Non-inertial frames are weird. Weird to explain with relation to Newton's principles, which still apply to the motion.WFPM (talk) 18:39, 19 February 2011 (UTC)

Measurements in different frames

The values for distance, velocity, and acceleration depend on the reference frame in which we measure them but it is a generally accepted principle of physics (and common sense) that what happens is the same in any reference frame. The Earth bulges at the equator whether you describe the physics in an inertial frame, a frame rotating with the Earth, or a frame rotating in the opposite direction. All that changes is the explanation. Martin Hogbin (talk) 10:24, 19 February 2011 (UTC)

But you can make statements which don't involve frames of reference, like that the earth is oblate, and infer from that that there is a force of repulsion of material in the outward direction from the axis and in the plane of axial rotation that is a factor in controlling the non-spherical shape of the material of the earth, which would otherwise be spherical due to the action of the gravitational force.WFPM (talk) 18:47, 19 February 2011 (UTC)

The shape of the Earth is, of course, the same in any frame of reference but the explanation as to why this is so differs according to your reference frame, see below. Martin Hogbin (talk) 21:12, 19 February 2011 (UTC)

Why the Earth bulges at the equator

Explanation in a non-rotating frame

In a non-rotating frame a small piece of rock at the equator is moving as the Earth spins. The only forces acting on it are the gravitational force of the rest of the Earth and any elastic forces between it and the rest of the Earth. It its inertia makes it tend to move in a straight line as the gravitational and elastic forces of the rest of the Earth pull it continuously round in a circular path. Just as the water does in a cf pump, the piece of earth on the equator tends to move outward from the Earth in its inertial tendency to continue in a straight line.

The rock adopts the right position so that the combination of elastic and gravitation forces are just right to cause it to move in a circular orbit of slightly greater radius that the average for the Earth.

So now we have to examine as to what constitutes the so called elastic force that counteracts the so called gravitational centrical attractive force on the earths constituent materials. And then we note that the materials are rotating around the center of gravitational attraction of the earth. And thus on an individual mass value basis we conceive as to the existence of a force of repulsion of the rotating individual mass, and determine its value to be proportional to its kinetic energy value, divided by its radius of circular motion value. and we name that the "Centrifugal force" value. And since it's an operative force, why should we deny its existence.WFPM (talk) 19:02, 19 February 2011 (UTC)

Because such a force is not necessary to explain what happens the material that makes up the Earth at the equator tries to continue in a straight line. In a gravitational system the direction of motion is toward the center of gravity. Only in a rotating system is there motion at right angles to the axis of rotation, and that motion has to be constrained to prevent the radius from expanding. And that force of restraint acts against the force of gravitational attraction in the equatorial plane as per Sokolnikoff.

Besides that's what it said in my Sokolnikoff reference.WFPM (talk) 19:06, 19 February 2011 (UTC)However, when you get right down to fundamentals, Purists have a right to deny the legitimacy of both the instantaneous centrifugal and gravitational force values on the basis that they are not values in a constant direction but are momentary values in a transient direction. And that's where you get into arguments about the rules of Euclidian geometry activity.WFPM (talk) 19:30, 19 February 2011 (UTC)

I don't. I thought that you were interested in learning some physics, not telling me about 'Euclidian geometry activity'.Martin Hogbin (talk) 21:16, 19 February 2011 (UTC)

I'm doing my best to learn about the rules of physical activity, and what we have here is what Paul Newman called "a lack of communications" about the details.WFPM (talk) 23:30, 19 February 2011 (UTC)

Explanation in a frame rotating with the Earth

Problems involving the Earth are often ones where use of a rotating frame can make things easier. In a frame rotating with the Earth, every point on the Earth is stationary. To explain the bulge in the equator, we invoke an special force that is required to make Newton's laws apply in our rotating frame, this is the centrifugal force, which pulls the equator out. Martin Hogbin (talk) 10:53, 19 February 2011 (UTC)The only frame that I can think of where every point of the earth of the earth is stationary is that at the earth's center of gravity and in a rotating condition matching that of the earth. And from that frame we would never even notice that the earth was rotating.WFPM (talk) 19:49, 19 February 2011 (UTC)And if the frame were not rotating, we could notice the lateral motion of the earth's constituents and thus the amount of their angular motion. But we wouldn't be able to measure the axial distance and it would look like the image of our system of starlight illumination and we wouldn't know about the oblateness of the system.WFPM (talk) 20:44, 19 February 2011 (UTC) But if the oblateness exists and we can't avoid the issue, we must assume the existence of some force capable of shaping the 3 dimensional property spacial distribution of the earth's material constituents. And that seems to be due to the fact that in linear motion all the masses components partake equally in the contained Kinetic energy of the system, whereas in circular motion they don't and thus require a special set of rules that explains how the contained kinetic energy is distributed among the constituents of the rotating matter, and which involves the angular rotation and resulting angular momentum value properties of the individual masses of the matter.WFPM (talk) 21:15, 19 February 2011 (UTC) And since both linear and angular momentum values increase with linear velocity values, whereas the kinetic energy value increases as the linear velocity squared, it may be stated that the angular momentum of a rigid system of rotation increases in proportion to the square root of the increase in kinetic energy.WFPM (talk) 22:23, 19 February 2011 (UTC)And thus, under a condition of stable rotary motion, there is no way for a linear force to correct this unbalance in contained kinetic energy, but only a way to add or subtract an incremental amount of kinetic energy, which is internally equitably distributed among the rotating system constituent mass values.WFPM (talk) 22:44, 19 February 2011 (UTC)

I am afraid that your understanding of physics is different from mine, there is no point continuing this conversation. Martin Hogbin (talk) 04:17, 20 February 2011 (UTC)

As to Newton's understanding of the concept of Centrifugal force, you might read what he said about it in Volume 2 of his Principia.WFPM (talk) 15:18, 20 February 2011 (UTC)

Question

Martin, please respond to my question on User: Martin Hogbin/Monty Hall History#Nijdam. Nijdam (talk) 00:09, 21 February 2011 (UTC)

I am always happy to discuss the subject with you, I have moved the question here and will respond here shortly. Martin Hogbin (talk) 09:00, 21 February 2011 (UTC)

The same problem with the "combined doors solution".

The chosen door No. 1 has chance 1/3 on the car. Hence the doors No. 2 and No. 3 together have 2/3 chance on the car. As the opened door No. 3 shows a goat, the remaining door No. 2 has chance 2/3 on the car.

Explain, how i.e. door No. 2 can have chance 1/3 on the car, due to the random placement, and also chance 2/3 on the car, as stated in the reasoning. Nijdam (talk) 17:33, 30 December 2010 (UTC)

Nijdam, you continue to try to teach me what I already know. Let me start by giving you a brief moment of victory. Using modern probability theory and with the sample space that you prefer and seem to assert is the only possible one to use, what you ask cannot be done. You are quite right, on the basis that you prefer, the "combined doors solution" makes no sense.

However, there are other ways of tackling this problem, even within modern probability theory. Please explain to me why you select the sample space that you do. Martin Hogbin (talk) 09:20, 22 February 2011 (UTC)

If this is victory, so be it. But you did not explain anything. Sorry, Martin, most of our discussions end by you finally not responding. What sample space are you talking about? Be my guest and select your own sample space and derive the appropriate probabilities. Nijdam (talk) 09:50, 22 February 2011 (UTC)

We have done this before. My sample space consists of only two elements. The player originally picks a car having probability 1/3, and the player originally picks a goat - probability 2/3.

The combining doors explanation merely shows what we both well know, that if the player switches they get the complement of their original choice. Martin Hogbin (talk) 14:23, 22 February 2011 (UTC)

Well, your sample space is not appropriate for the MHP. For instance, how do you express that the host opens door 3, or how that door 3 hides a goat. Etc. See, that's why I say, you're still a layman on probability. I've tried to explain you a lot, but somehow you refuse to understand. I say on purpose "refuse", because I'm sure you're capable of understanding. I'll give you the tools: the variables C (car), X (choice) and H (host) may be used to describe the MHP. No one of these three can be left out. Other sample spaces are equivalent. As far as I recollect, we used these on your MHP analysis page. Now back to the question. Nijdam (talk) 20:33, 22 February 2011 (UTC)

You say of C, X, and H may not be left out but that is not so. It is quite obvious that door numbers are not relevant to this problem. As Richard Gill has said, there is a stage before you put the problem into mathematical form where you have to decide how to formulate the question in mathematical terms. For a start, you must decide what sample space is appropriate to the problem. You have to make a decision as to what events are independent of the event of interest before you start to put the problem into mathematical terms. You already do this, it seems without realising it. Please tell me why, for example, the event that the host says the word 'pick' is not included in your sample space in any way? Martin Hogbin (talk) 21:44, 22 February 2011 (UTC)

Please Martin, not again. To describe any situation in the MHP problem, we need as a minimum C, X and H. That's why I say no one of these can be left out. Of course you may enlarge your sample space, i.e. with an event taking account of the host saying "pick" or whatever. That is not the issue. The issue is you can not do with less than C, X and H (or equivalent). Focus on this, and then respond to the question, at last. Nijdam (talk)

I have already agreed that, with a sample space based on door numbers in the way you suggest, the 'combining doors' solution makes no sense. There is no question to respond to, you are correct.

My question to you is this. Given Whitaker's question, what is it that tells you that a sample space using C,X, and H to represent door numbers chosen by various people is the correct sample space? What exactly tells you that including the word 'pick' is not necessary? What tells you that my sample space of only two elements is deficient? Or to put it anther way, in explaining to one of you students how to set up your sample space based on a natural language problem statement, what advice would you give? Martin Hogbin (talk) 09:26, 24 February 2011 (UTC)

To try and clarify what I am getting at, you say above, 'how do you express that the host opens door 3' in my sample space. My response would be that it is not necessary to express that specific event, given that the problem is totally symmetrical with respect to door number. It is only necessary to specify the event that the player picks a goat or the player picks a car. No doubt, you would respond in a similar manner to my question about the word 'pick'. You would say that it is not important what the host says, the problem is symmetrical with respect to the word 'pick' therefore we need not include terms containing this event in our sample space.

Now, if you were to ask me which is the better way of approaching the problem, I would agree with you. If in doubt as to whether a particular event is relevant to calculating the desired probability, it is always better to include it. Specifically, if a particular event was given as a condition of a problem, we would be wise to include it in our sample space. So we do not disagree about much. Given reasonable assumptions about the meaning of the problem, it is wise to tackle it in the way proposed by Morgan to avoid missing what could be an important point, however, in the totally symmetrical case, this is not the only way to tackle the problem. Symmetry is a very powerful concept. Martin Hogbin (talk) 09:39, 24 February 2011 (UTC)

Makes more sense what you say here. You only forget that speaking about symmetry is only possible in the sample space like the one I gave you. I never denied the importance of the use of symmetry. More than a year ago I already showed how to derive the conditional probability by means of symmetry, other than with Bayes'. That's not the issue. The point is how can i speak about choosing a door, if that door is not in my sample space. What you are aiming at is the reduction of the original sample space, by the use of the symmetry. That reduction, you may already guess, means conditioning. You may argue that for the final answer, the reduction leads to an equivalent sample space, rich enough to get the desired answer, but! also then you have to show the reduction and the equivalence. It is of course, for a sound explanation, not sufficient to just say "I know this". I hope, that, when you come to understand this, you give up your resistance against the criticism of the simple solution (the one without (factually) mentioning the use and significance of the symmetry). Nijdam (talk) 12:34, 24 February 2011 (UTC)

Starting from the start

I still think you are missing my point. You have to get from this:

Suppose you're on a game show, and you're given the choice of three doors: Behind one door is a car; behind the others, goats. You pick a door, say No. 1, and the host, who knows what's behind the doors, opens another door, say No. 3, which has a goat. He then says to you, "Do you want to pick door No. 2?" Is it to your advantage to switch your choice?

to a sample space before you do anything.

Suppose I say right at the start that it is obvious from a Bayesian perspective that the door numbers and even the doors themselves are not important. There are only two events in my sample space: I pick a car, I pick a goat. The door number that I pick and the door number opened by the host and the door number remaining are all irrelevant. What is wrong with this approach? Martin Hogbin (talk) 16:55, 24 February 2011 (UTC)

Corrections, make that four terms: I pick a car and swap, I pick a goat and swap, I pick a car and do not swap, I pick a goat and do not swap. Who cares about doors or door numbers? Martin Hogbin (talk) 17:38, 24 February 2011 (UTC)

Before I may get to this, I insist you explain the following. A: The car is with probability 1/3 behind each of the doors 1, 2 and 3. B: The car is also with probability 0 behind door 3, opened by the host. doesn't this strike you ass odd? Or do you have an explanation? Nijdam (talk) 23:05, 24 February 2011 (UTC)

If the question is taken to ask specifically for the probability of winning by switching given that the player initially chooses door 1 and that you must use as condition of the problem the fact that the host has opened door 3 then you are correct. The first set of probabilities that you quote are prior to the condition and the second is after. We all agree about that.

Indeed is the question posed to the player who has chosen a door, be it door 1 or door 2 or door 3, that does not matter for the way of arguing. Your second "if" is just something you come up with to avoid reasoning that you have to condition. Nijdam (talk) 09:27, 25 February 2011 (UTC)

But what if I do not care which door the car and goats are behind? All I care about is whether the player has initially chosen a car or a goat and whether he swaps or not. The fact that the host is stated to open door 3 is not a condition, it is an irrelevance. We know the host must open a door to reveal a goat and we know, from symmetry right from the start, before we set up our sample space, that the door number that he opens is unimportant. Thus we do not include door numbers in our sample space and we do not take the door opened by the host as a condition of the problem, even if the host is stated to open a specific door. Martin Hogbin (talk) 23:43, 24 February 2011 (UTC)

I know, but this is a different MHP, the so called unconditional formulation. At least accept that the full MHP has to be solved by the conditional solution, whereas the unconditional version is solved by the simple solution. And ... the simple solution does not solve the full MHP. This is what you till now refused to accept. If we agree on this, what's left, is what's left in the discussion with Richard, namely which version of the MHP should be considered more acceptable and presented first to the readers. Nijdam (talk) 09:27, 25 February 2011 (UTC)

Nijdam's  "correct MHP", his  "full MHP"  is the  "conditional MHP",  based and conditioned on the given existence of non-existent, but "assumed" records of log lists that allow obscure presumptions about "additional info" on the contents of the remaining two closed diaphanous doors. Nijdam's additional "condition" is the given existence of (non-existing, but "assumed") records of log lists that have to "proof" a very special (but forever unknown) peculiar kind of behavior of the host in giving additional info on the actual secret location of the car behind the two still closed but diaphanous doors, in each and every game. That's his "conditional MHP", his "full MHP". That unconditionally has to be shown first, before proper, famous paradox is allowed to be shown to the reader. Gerhardvalentin (talk) 10:50, 25 February 2011 (UTC)

I think that we can all agree, therefore, that Whitaker's statement is open to different interpretations, some of which do not require the Morgan solution.

K&W formulation

So let us move on to the K&W formulation. Here the door numbers are clearly stated, as is the order of events. The player has to choose after the host has opened a door.

Nijdam, I am sure that you would say that this problem must be solved using a sample space based on the door numbers X, H, and C. I agree that that might be the wisest way to approach the problem since it covers possibilities such as those raised by Gerhard above, that the host might not act evenly.

However, in the K&W formulation, we are specifically told that the host acts evenly, thus, right at the start we are free to observe that, although door numbers are clearly given, and the host has already opened a specific door, the door numbers can, by symmetry, make no difference to the probability of interest (that the player wins the car by switching). We are free to ignore door numbers and choose a sample space that does not depend on them. I do not mean that we start with a sample space based on door numbers, then condition it, I mean that we start with a sample space that ignores door numbers, even though they are clearly given on the question. Whether you wish to use the term 'conditional' or not to describe the problem and solution I do not care. Martin Hogbin (talk) 14:10, 25 February 2011 (UTC)

Let me first ask you this: is it your intention to show that the simple solution (you know the one without any conditioning or reference to the symmetry) may serve as a valid solution to the full MHP? Even knowing that also Richard Gill admits it is not? Or do you just want to know where the error in your argumentation lies? Nijdam (talk) 18:50, 25 February 2011 (UTC)

I think the simple solutions are satisfactory solutions to the K&W formulation. I would also be interested to know where you think my error lies. Martin Hogbin (talk) 23:52, 25 February 2011 (UTC)

To be sure we understand each other: You say: "satisfactory" solution, does this mean "correct" solution? And with "simple solution" you mean just the following statement: "the car is with probability 2/3 not behind the chosen door 1, hence when you switch you get the car with probability 2/3". Nijdam (talk) 22:56, 26 February 2011 (UTC)

I think your terminology is invalid. This is not just one 'correct' solution to any given mathematical problem, there can often be several valid ways of solving it. Mathematical solutions have varying degrees of rigour, ranging from the most rigourous solutions known (which are completely incomprehensible to all but specialists) to hand-waving arguments that demonstrate a degree of plausibility. I believe that the simple solutions, meaning "the car is with probability 2/3 not behind the chosen door 1, hence when you switch you get the car with probability 2/3", are as correct and rigourous as the conditional solutions given in the article.

The point that you consistently miss is the first stage, where you have to turn a natural language statement into a clearly defined mathematical question. There are no formulae or fixed methods for doing this, it can only be done by applying a degree of common sense and logic to the question. In particular, one should always try to find out what is is that the questioner actually wants to know. Failure to do this is a failure to answer the question at all.

So for the sake of this discussion, I do mean that the simple solution, as defined by you, is a correct answer to the K&W problem statement. Martin Hogbin (talk) 10:03, 27 February 2011 (UTC)

The decision asked for will be based on some probability ( if we consider the MHP to be a probability problem). Let us consider the player,knowing having chosen door 1 and seeing door 3 opened with a goat. The player will consider his probability to find the car behind door 1 (or equivalent behind door 2). So he considers his situation as a realisation of several possibilities. Well, several means hre only two possibilities: either the car is behind door 1 or it is behind door 2. The probability law governing this is the conditional probability given door 1 chosen and door 3 opened. The player may take his situation as equivalent to a Bernoulli trial with outcomes 1 and 2, being the number of the door with the car. Do you recognize the similarity with you urn problem, containing 9 white and 1 black ball, and you the third to draw a ball without replacement. Then you had no problem at all to understand the conditional nature. If it is more understandable for you, the player could also compare the probability on the situation (event) with door 1 chosen, door 3 opened and door 1 hiding the car, with the probability on the situation with door 1 chosen, door 3 opened and door 2 hiding the car. And then decides for the one with the larger probability. This is completely equivalent to the more natural description with conditional probabilities.

In your reasoning I do not understand this phrase: the door numbers can, by symmetry, make no difference to the probability of interest (that the player wins the car by switching), Because if there is only one probability of interest it cannot depend on the door numbers, with or without symmetry. So you clearly mean the different probabilities of interest, due to the symmetry, do not depend on the door numbers. And there you are right, but you doesn't seem to understand what these different probabilities are. And, it will not be a surprise to you, they are the conditional probabilities. What else could they be? Nijdam (talk) 21:30, 27 February 2011 (UTC)

You seem fixated on door numbers. The numbers on the doors are completely unimportant, as are the doors themselves. As have said before, my sample space, which does not have any relation to door numbers or doors, has only four elements (picks car and stays, picks car and swaps, picks goat and stays, picks goat and swaps). You have yet to tell me what is wrong with this way of tackling the problem.

Just because door numbers are given in the problem that does not mean that we have to use them in any way. They are unimportant, irrelevant and I choose to formalise the problem without reference to them. Martin Hogbin (talk) 22:31, 27 February 2011 (UTC)

Note

1. It is you who said: the door numbers can, by symmetry, make no difference to the probability of interest (that the player wins the car by switching). What do you mean then??
2. As the door numbers are given in the problem we must use them. Why else are they given? And the player sees the door he has chosen and the door opened.
3. You change the problem into the version I called the unconditional problem. It is the version in which we the audience have to decide before anything has happened. And indeed, I've repeated that several times, Morgan says so, it is the version the simple solution applies to.
4. You cannot consider the full MHP to be the problem of interest and then just concern your sample space to describe it.

Nijdam (talk) 09:09, 28 February 2011 (UTC)

Our disagreement

Nijdam, I think the points above show where we disagree. If the problem is formalised as a conditional probability problem based on a sample space that uses door numbers then it must, of course, be treated as a conditional probability problem based on a sample space that uses door numbers, so we do not disagree there, so let us now discuss the points above.

You formulate this a little odd. The problem may be formulated in the sense as I described several times, that the player is offered to switch, after the host has opened a door. This is what is called the conditional formulation, like the K&W version. Or the audience is asked whether the player should switch, before he makes his first choice. This is the unconditional formulation. The appropriate sample spaces follow from the formulation. Nijdam (talk) 15:53, 28 February 2011 (UTC)

Even when answering the K&W natural language problem statement there is a stage where you have to decide how to state the problem in mathematical terms. Please tell me, what are the rules by which you do this? Martin Hogbin (talk) 22:02, 28 February 2011 (UTC)

The K&W formulation ends with: After Monty Hall opens a door with a goat, he will ask you to decide whether you want to stay with your first choice or to switch to the last remaining door. Imagine that you chose Door 1 and the host opens Door 3, which has a goat. He then asks you "Do you want to switch to Door Number 2? Is it to your advantage to change your choice? Isn't this clear enough? The decision will be made after the player picked door 1 and the host opened door 3. Natural language.Nijdam (talk) 22:22, 28 February 2011 (UTC)

Door numbers are not important

By this I mean that, at the start of the game all the door numbers could be swapped round and this would make no difference to the probability of interest. The problem is symmetrical with respect to door number, meaning that changing the door numbers, or any other means of identifying the doors, will not affect the probability that the player will win by switching. Note that this is not the case if the host has a known door choice policy. For example if the host always preferred to open door 2 when legal, the problem would have a different answer if the player had initially chosen door 3 and the host had opened door 1.

You again speak of "the probability of interest", whereas I made it clear that either there is only one probability of interest, and hence it cannot depend on the door numbers, or there are several probabilities of interest, all with the same value, and hence independent of the numbers of the doors. Don't you understand this? Nijdam (talk) 15:53, 28 February 2011 (UTC)

No I am sorry but I do not. Imagine the K&W statement followed by the words 'What is the probability that the player wins by switching'. That is what I mean by 'the probability of interest'. I mean that natural language statement. Martin Hogbin (talk) 22:02, 28 February 2011 (UTC)

Then the probability of interest can only be the conditional probability that the car is behind door 2, given door 1 chosen and door 3 opened, What else could it be? But explain to me what you mean by independent of the door numbers.Nijdam (talk) 22:22, 28 February 2011 (UTC)

There is no obligation to use all the information given in the problem statement. We have to make a judgment as to whether any particular piece of information is important. We agree that we do not need to use the information given in the words used by the host because they contain no relevant information. Similarly, there is no relevant information given in the door numbers, thus, although they are clearly given in the natural language K&W problem statement, we do not need to use them in our solution. Thus the probability of interest is the probability that the car is behind the remaining door, given an originally chosen door and a different, goat-hiding door which has been opened. In other words the unconditional formulation. Martin Hogbin (talk) 09:25, 1 March 2011 (UTC)

The point you are making is that the unconditional formulation is equivalent to the full problem in the case of symmetry. And indeed that's the case. And what you do is arguing why this is the case. And that's just my intent: we have to argue (show) that the full problem is equivalent to the simple formulation. Without the arguments it is logically flawed. Either we show the equivalence of the problems and use the simple solution to the full problem, or we use the symmetry argument to simply derive the conditional solution. It's either way. We cannot do without reasoning. Nijdam (talk) 10:49, 1 March 2011 (UTC)

That is not my point. You do not seem to realise that you, and everyone else, has to use some form of reasoning at the start of the problem in order to turn a natural language question into a well-defined mathematical problem. Before this stage the problem is neither conditional nor unconditional because it is not yet properly defined.

As part of this process you dismiss the words that the host says as unimportant but you insist on treating the door number opened by the host as being significant. The reverse could in reality be true. You have never yet explained to me why you make this decision. Perhaps you do not even realise that you are doing so, but you are. Please explain to me the basis on which you do this. Martin Hogbin (talk) 11:57, 1 March 2011 (UTC)

Must we use door numbers in our formalisation

You ask why they are given. The actual reason, we know, is that vos Savant added them to to Whitaker's question to try to make it clearer. She now agrees that this was a great mistake. K&W kept the door numbers in their formulation but that still does not compel us to use them. Whether we to use them depends on our understanding of what the questioner really wants to know. I doubt that Whitaker was interested in door numbers.

Well, to most people the problem becomes tricky, when they actually see an open door with a goat and two still closed doors, between which they have to decide. I really do not see any charm in the unconditional formulation. Nijdam (talk) 15:53, 28 February 2011 (UTC)

Whether you see any charm in it does not matter. The fact is that many people get the answer wrong. ther is no way to tell whether they have in mind the conditional or the unconditional formulation. Probably they do not distinguish between the two cases. Martin Hogbin (talk) 22:02, 28 February 2011 (UTC)

We are also told that the host says the word 'pick' but you choose (quite reasonably) to not make use of that event (although is some circumstances it could be highly significant). We have to use our own judgment in formalising the problem.

???Nijdam (talk)

See my reply above. Martin Hogbin (talk) 09:26, 1 March 2011 (UTC)

I changed the problem into an unconditional one

No, based on a plain language statement, you formulate it as a conditional problem and I formulate it as an unconditional problem.

Okay, but be aware they are different problems, and your concept is not the K&W version. Nijdam (talk) 15:53, 28 February 2011 (UTC)

No, the K&W statement can be made into an unconditional problem. Martin Hogbin (talk)

What is "made into"? Nijdam (talk) 22:22, 28 February 2011 (UTC)

Mathematically formalised as. Although the K&W natural language statement practically invites us to treat the problem as one where the doors chosen by the player and host are taken as conditions of the problem and this would, no doubt, be the way you might expect a student to formalise the problem, it is possible to conclude right at the start that the door numbers are not important and that the problem can be formalised as an unconditional one. Martin Hogbin (talk) 14:24, 2 March 2011 (UTC)

I cannot consider the full MHP to be the problem of interest and then use my sample space to describe it

If by 'the full MHP' you mean the conditional probability problem using your sample space then no, of course not. If you mean a perfectly valid interpretation of either Whitaker's question or the K&W formulation then my sample space is fine. Martin Hogbin (talk) 13:29, 28 February 2011 (UTC)

As above, the K&W formulation is a conditional problem. Accept it. Nijdam (talk) 15:53, 28 February 2011 (UTC)

You are arguing by decree. You have yet to tell me why this must be so. Martin Hogbin (talk)

An alternative sample space

Nijdam, please tell me why I cannot use this reasoning and sample space to solve the K&W problem statement.

There are three objects of interest one car and two goats, let us call them A and B.

My sample space consists of the following elements, X is the object originally chosen by the player and H is the object revealed by the host. The doors are of no interest. The only possible outcomes (up to the point that the player decides whether to switch) are:

(X=C,H=A),(X=C,H=B),(X=A,H=B),(X=B,H=A)

This sample space allows us to include the possibility that the host may have a preference for one or other of the goats. In what way is it not satisfactory? Martin Hogbin (talk) 22:13, 28 February 2011 (UTC)

Convention in probability questions

Nijdam, there are many conventions and understandings in probability questions but these vary according to the context. To give a simple example, there is a convention in general statistical discussions that a ball drawn from an urn is deemed to be selected uniformly at random from all the balls within the urn. In reality, this might not be the case; the picker might be lazy and prefer balls at the top of those within the urn, for example. This convention is used to enable people to communicate without giving a lot of unnecessary detail. Let me now give three contexts where the conventions used might vary:

A undergraduate statistics examination

Here I suggest that when information, such as door numbers, is given there is a strong expectation that this information will be relevant to the problem. Certainly, the student would be wise to formulate their approach to the problem on the basis that all information given in the question might be important.

A simple probability puzzle

In these there is generally a stronger set of conventions. Selections with no obvious bias are generally taken to be made uniformly at random. In general, the convention is to make the puzzle as simple as possible. Martin Hogbin (talk) 09:43, 1 March 2011 (UTC)

The real world

Here conventions and 'everybody knows' understandings can be misleading and dangerous. If a statistician were approached by a client who asked the Whitaker question they would be obliged to ask more questions to find out, as Seymann put it, the intent of the questioner. To try to answer without finding out exactly what the client wanted to know would be a failure of their professional duty. Martin Hogbin (talk) 09:43, 1 March 2011 (UTC)

Even when the door numbers were not mentioned in the problem statement, you had to use them. It is not mentioning of the door numbers, but the moment the player is offered to switch that makes the problem conditional. And about the K&W version: the player is only then offered to switch, after the host has opened a door. You may try to proof the equivalence with the unconditional formulation, it's pkay, but then you have to show the proof (reasoning). This all has been said before. Nijdam (talk) 23:52, 8 March 2011 (UTC)

The problem may be conditional, as are all problems in Bayesian probability, the question is, 'What is the condition?'. Is the condition that the host has revealed a goat? Is it that the host has revealed Billy the goat (as opposed to Annie)? Is it that the host has said the work 'pick'? Please explain what the condition is and why. Martin Hogbin (talk) 00:20, 9 March 2011 (UTC)

There we go again. Every event that has occurred is a condition. At the stage when the player is offered to switch, the events "initial choice of door 1' and "host opens door 3" has happened. Nijdam (talk) 10:25, 9 March 2011 (UTC)

There's no requirement, Whitaker didn't ask, and vos Savant says she didn't mean to imply, that it must be "initial choice of door 1' and "host opens door 3". It could equally, or more likely be, "initial choice of a door" and "host opens another door". That recognizes the event that occurred. Your continued exclusive claim to The Truth is, and has been BS. Glkanter (talk) 12:11, 9 March 2011 (UTC)

Nijdam, you quite rightly say, 'Every event that has occurred is a condition'. But many events have occurred, a door has been opened, a goat has been revealed, the host has spoken several words, how do you decide which of these events to condition on? Martin Hogbin (talk) 17:46, 9 March 2011 (UTC)

I hope you do understand that the notion "event" has a specific meaning in probability theory. So, if you took all the 'events', you mentioned, as events in your sample space, than, yes, you have to condition on them all. Your choice. Nijdam (talk) 23:53, 9 March 2011 (UTC)

Right, so we are back to my original question, 'How do you decide on which events to include in your sample space?'. Martin Hogbin (talk) 00:26, 10 March 2011 (UTC)

You tell me what is needed to describe the problem. Then I tell you which events you need. Nijdam (talk) 20:26, 10 March 2011 (UTC)

This is exactly the point that I am making (and Gerhard too I believe) it is up the the person who is answering the question to decide which events are important and which events are not. This has to be done right at the start based on your understanding of the context, any relevant conventions, and what the questioner actually wants to know. Maybe the door number opened by the host is important, maybe not, maybe the words said by the host are important, maybe not, the point you juts do not seem to get is that when you set up your sample space you have to make some judgments as to what events to include, what events not include and why. There is no mathematical formula or algorithm that tells you how to do this, so perhaps you could tell me how you decide what events to include. Martin Hogbin (talk) 10:43, 11 March 2011 (UTC)

No, the problem description tells you what is relevant. Whether a specific aspect is important, and I guess you mean with important, makes a difference for the solution, only appears after the analysis. If you want to decide that some aspect is unimportant beforehand, you have to argue, So, either you introduce the position of the car, the choice of the player and the door opened by the host as relevant aspects, or you reason that for instance by symmetry you may reduce your sample space. But then you cannot do without this reasoning. And this reasoning is about the conditional probabilities being all the same and equal to the unconditional. But, as you notice, also then it is about the conditional probability. And the simple solution just does not give the needed arguments, is actually not set up for this reasoning.Nijdam (talk) 13:09, 11 March 2011 (UTC)

You say, 'If you want to decide that some aspect is unimportant beforehand, you have to argue', so what is your argument for not including each word spoken by the host in your sample space? The words are clearly given in the problem statement. Martin Hogbin (talk) 23:06, 11 March 2011 (UTC)

I rather liked you stay serious, and do not digress to such pointless questions. Anyway, the words do not form aspects of the problem, as nothing depends on it, and nowhere in the problem formulation is said that the host may vary his words. Nijdam (talk) 22:14, 12 March 2011 (UTC)

And nowhere in the problem formulation is said that the host could/would / can/will present a log-list showing records of hitherto results of game shows that never did happen. I doubt that you watched all of them? This "one hypothetical game show" we are talking about did never happen. Repeat: Just one "hypothetical" game show. Please show me your log-list. As I repeatedly said before: In 100 million games you never can be sure to "know" that your "detected host's bias" is real, and so your "closer" result will be just for the birds. Counterproductive. Worse than "just for the birds."  Please apprehend that "conditional probability assumptions" belong to the field of probability calculus. Without impact on the very "one hypothetical game-show" called Monty Hall paradox. Still squirming? Gerhardvalentin (talk) 22:56, 12 March 2011 (UTC)

Which events go in the sample set

I am being serious. Please tell me how you distinguish between these events, based on Whitaker's question: Suppose you're on a game show, and you're given the choice of three doors: Behind one door is a car; behind the others, goats. You pick a door, say No. 1, and the host, who knows what's behind the doors, opens another door, say No. 3, which has a goat. He then says to you, "Do you want to pick door No. 2?" Is it to your advantage to switch your choice?

• The host opens door 3
  

This is stated to occur in the problem statement.
It is not stated that the host could open door 2, but we could assume that he might.
It happens after the player's initial choice and before his final choice.
It could be a relevant fact if (contrary to TV game show rules) the host gives additional information to the player by his choice.

• The host says the word 'pick'
  

This is stated to occur in the problem statement.
It is not stated that the host could say a different word, but we could assume that he might.
It happens after the player's initial choice and before his final choice.
It could be a relevant fact if (contrary to TV game show rules) the host gives additional information to the player by his choice.

Please tell me why the first event should be incorporated into your sample set and the second not. Martin Hogbin (talk) 00:24, 13 March 2011 (UTC)

The problem states: ...and the host, who knows what's behind the doors, opens another door,..., and then continues: say No. 3, which has a goat. It is quite clear, and (almost) anyone interprets so, that the host does not in every game opens door 3. Nothing, on the other hand, indicates that the host sometimes does not say pick, in order to influence the game. On the other hand, if you like, take thee host saying pick as part of your probability space, please go ahead, it does not change a bit.

But let us stick to the point of interest, i.e. why you do not want to take the picked door etc. as events. Nijdam (talk) 23:07, 13 March 2011 (UTC)

The point of interest to me is the means by which you select events for your sample space. You say, 'if you like, take thee host saying pick as part of your probability space...it does not change a bit'. How do you know that it will not change the outcome?

My answer to you question will be exactly the same as yours to mine, 'if you like, take the host opening the specific door 3 (as opposed to 'the host opens any legal door to reveal a goat') as part of your probability space...it does not change a bit'. How do I know it will not change the result a bit? The obvious symmetry with respect to door number tells me. Martin Hogbin (talk) 23:23, 13 March 2011 (UTC)

The difference is, as I explained above, that nowhere in the problem formulation is spoken of the host saying anything different. There are however three different doors. So you may freely add "pick" to your events, but you cannot leave the door numbers out. Well, having said this again, I have the idea you do not want to understand it. Nijdam (talk) 23:20, 14 March 2011 (UTC)

Neither does it mention that the host might open door 2, this is an assumption on your part, a very reasonable one I admit, but still an assumption.

The point that I am trying to lead you to is that in turning any natural language statement into a well-defined mathematical problem you need to apply some logic to determine what events are important. Your argument is essentially this, 'We are given door numbers in the problem statement, this must be for the reason that we are expected to use them in solving the problem'. This is good logic for an exam question but in other circumstances it may not be so good. It may be that some information available to us is irrelevant, and indeed in this case that turns out to be true; the door numbers are completely inconsequential, the value of the probability of winning by switching would be exactly the same had the player initially chosen door 2 and the host opened door 1. Maybe a little thought before formulating the problem in mathematical terms would reveal that fact and save you the trouble of performing and unnecessary complicated calculation. Martin Hogbin (talk) 13:26, 15 March 2011 (UTC)

I know what you're aiming at, but your way of applying does not make sense. In the first place is in the problem statement spoken of the host opening another door. As we do not know which one we add the possibility for each door, Secondly: as you say, it turns out that the door numbers are not relevant. You also could give the answer: switching is better, without any further explanation, because you gave it a little thought before. You see, we do not give the answer, we try to explain. That's why we describe our thoughts. It is not up to us to decide what arguments may be left out, because, in our opinion, anyone will know. And I asked you not to come up every time with your alleged complicate calculation. I explained it is not about the WAY the calculation are done, but about WHAT is to be calculated. Nijdam (talk) 22:57, 15 March 2011 (UTC)

You say, 'It is not up to us to decide what arguments may be left out', but we must do that or the problem becomes impossibly complicated. You have decided to leave out that the host says the word 'pick' but you still cannot give a clear reason for this. The only reason is that you think it is not relevant.

Perhaps you could answer my question below. Martin Hogbin (talk) 23:06, 15 March 2011 (UTC)

Another question

Let me ask you this. Assuming we take it that the player might have chosen any door to start with and the host may have opened any unchosen goat-hiding door, why do you not insist that the starting sample space must include all the possible door combinations? Martin Hogbin (talk) 13:23, 15 March 2011 (UTC)

I do not understand your question. I DO insist that all the combinations are in the sample space. You have seen them in the past. What is your point?Nijdam (talk) 23:00, 15 March 2011 (UTC)

You support the solutions given in the article which show only the case where the player initially picks door 1. These solutions are incomplete. Martin Hogbin (talk)

What's the connection with our discussion about the appropriate sample space???? Nijdam (talk) 23:14, 16 March 2011 (UTC)

Surely the solutions in the article should show the whole sample space? This is then conditioned using the initial player and host door choices. Martin Hogbin (talk) 23:18, 16 March 2011 (UTC)

I'm sorry, but your opening sentence sounds like: the car definitely has to be filled with distress. What on earth do you mean? A sample space is a reflection of the problem, reducing it to the necessary mathematics. The needed sample space, do you remember, consists of the 27 combinations of car location, player's choice and opened door. Some of these outcomes have probability zero, and may be left out, but this is unimportant. Tell me what you want to say. Nijdam (talk) 23:48, 16 March 2011 (UTC)

What I am asking is why, in the decision tree in the article and the diagram immediately below it which you support, do we only show the results of the player initially choosing door 1? These diagrams should show the results if the player initially chooses any door. Martin Hogbin (talk) 15:41, 17 March 2011 (UTC)

If it was up to me the diagram only showed the player choosing door 1 and the host opening door 3. But in general you're right, either my choice, i.e. conditioned, or showing the total of possibilities. Nijdam (talk) 15:17, 22 March 2011 (UTC)

Well we agree then. So the difference between the simple solution given in the article and the one you have supported is fairly minor, neither shows the full sample space.

By the way, I cannot understand why you have been treated so harshly by arbcom, I have tried to say that but it seems very hard to get through to them. Martin Hogbin (talk) 16:06, 22 March 2011 (UTC)

Comment by Gerhard

Please pardon for intruding  –  I just feel this comment really amusing for the audience, but boring soon. You really don't know what is needed to describe the paradox?
Well,  that's a fine how d'ye do.  I tell you what: You need a contestant. A contestant who just has selected one of those three doors. And you need a host. A host, who cannot change the location of the car anymore. A host that is totally unable to influence the "overall Pws" in any way, but who exactly knows where the car actually is. And: his action of showing a goat is needed. And his voice in offering to switch is needed. Yes, his voice. Does he say those words with a laughter and quite aloud, or with a moderate voice in an insinuating mode? That makes a great difference, you know. Because you are free to assume that, in most cases if he has got two goats to show, then he will make his offer to switch in a rather seducing tone, yes, with a really seductive voice. Might be in about exactly 73 % of those cases, you are free to assume. And, if the door in the middle should actually hide the car, we all are free to assume that he will almost never use the word "pick" then, but some quite other wording, like  "wouldn't you opt for"  or  "select",  but almost never will use the word "pick",  in that case. And everyone else also is free to make similar presuppositions,  and all of those specific assumptions enable you, and me, and anyone else, to exactly calculate a much  "better"  result for the actually given situation, than only the average probability to win by switching of just 2/3.  A quite better result, that obviously will be of great advantage for an exact "probability". Although we do not know whether our beliefs will ever correspond to reality. But that does not matter anyway, because that game has indeed and in fact never been played, anyway.  Not one single time in exactly that "MHP-way".  Never. Not one single time. But you can assume whatever you want. Whatever you like. And you even can assume that you knew what you don't know but what you would like to "need to know" in order to "know better". Repeat: Whatever you like.
Yes, maths and "q" can be a quite enjoyable illusion, indeed. So imho you better should stick to reliable sources, that never use such very absurd nonsense for "solving" and for getting better and "much closer results". And imho you should also show conditional probability, easy to understand in odds form, by using the clear functions of the doors, as there were no "door numbers" written on them. For that show that never was reality. There were no "door numbers", just three doors. No, they never had numbers, in this only one single game we're talking about, that never was for real.  And those two still closed doors never were transparent at all, not even at exactly 19 %. You understand? You can formulate anything you assume to be of any importance. You can assume it in an exact manner. And you may suppose that your assumptions to be of eminent importance. But you never proved that this illusion helps in any way to find a better decision than always to switch. Once more: You really should show conditional probability in odds form, and even show "q", but you should admit that all of this is just an illusion, and just a way to help to understand what the lemma is about.  Regards, Gerhardvalentin (talk) 21:39, 10 March 2011 (UTC) A fine game.

Of course you are right Gerhard, what seems obvious to you is somehow being missed by Nijdam. Martin Hogbin (talk) 10:43, 11 March 2011 (UTC)

This is just your interpretation, nowhere does it say that the host may open door 2. Martin Hogbin (talk) 00:37, 15 March 2011 (UTC)

This is getting silly, but okay. The player is given the choice of three doors. So we have to account for these possibilities. The host then opens another door. We have to account for these possibilities too. See? Nijdam (talk) 09:20, 15 March 2011 (UTC)

I do not doubt the reasonableness of what you say but you must understand that you are interpreting the original statement, which does not actually say that the host could open door 2. Martin Hogbin (talk) 12:48, 15 March 2011 (UTC)

This has nothing to do with reasonableness. I'm not interpreting, but modeling. And indeed, it is not said that the host may open door 2, but neither is said he cannot open it. That why we have to account for this door. Nijdam (talk) 23:10, 16 March 2011 (UTC)

Neither is it said that the host might not have said 'choose' instead of 'pick'. There is nothing in the problem statement that tells us that the words spoken by the host are less important than the number of the door that he opens. Martin Hogbin (talk) 18:38, 18 March 2011 (UTC)

No big deal; if you want, do add the host saying "pick" to the sample space. This comes down to extend any outcome with the host saying "pick". It doesn't change any relevant issue. But, be my guest. And to end all further discussion of this sort, extend any outcome with all other non-relevant info. The sample space you will end with, is equivalent to mine. Nijdam (talk) 11:37, 24 March 2011 (UTC)

The flawed full solution vs. any correct solution

You are through, Martin, with the so called "conditional frequentists", getting better knowledge by telling door 2 apart from door 3 and distinguishing carefully for students of cond.prob.?
Yes, he's here again, our and everyone's good old friend, and everyone calls him the "Ol' Catch 22". If he accompanied us to the casino, we were sure to win. No one doubts?
If s.o. assumes to have "additional frequentist's information", or even that "he could have any", regarding that one special game the contestant is in, and the famous question is about, and he "assumes his assumption to be right", and even given he "assumes to know his assumption to be right" regarding that one special game, then – with or without using maths – then he for sure "could" give a much closer answer indeed for this very game, than just only the honest:

Pws is within the range of "at least 1/2" (but never less) to "1", and on average it is 2/3, and that's all we know and will ever know.

Yes, then  –  without any question  –  this frequentist "could"  assign a much closer value to Pws indeed, for this one special game the contestant is in.  More than that, he could assign "really a correct one". But that will just be based on the famous flawed assumption that "if he knew" what he doesn't know indeed, and never will know, "then he could and would know much better, indeed".

Because all of those flawed assumption never can nor will be "given to be right" regarding that one special game the contestant actually is in, and it just remains the "Ol' Catch 22":

"He could know much better if he just knew better, or vice versa "if he just knew better, then he could know better".

So all of that reported "correctness" offered by those frequentist's conditional probability solutions proves to be just a flawed "if you knew better, then you could know better" -joke, indeed. Yes, and: If the doors were assumed to be made of glass, then the contestant could know a much closer probability to win by switching, than she actually knows.

That's why serious reliable sources emphasize that, although mathematically absolutely correct, it's useless to mention this

only correct but absurd "Ol' Catch 22 – The cat bites her tail circle". Because it's just suitable to train students of probability theory, only.

Though mathematically absolutely correct, but of no avail whatsoever for the decision to be made. Because the "range of Pws" (it never can be of disadvantage to switch) is sufficiently known in advance, anyway. Just by the humble acceptance "what if he always uses ..." and "what if he never uses ..." The only "advantage" of conditional probability is that it can show this insight in a very clear manner. But not more. Because that's all of its marginal utility for the MHP.

Other formalists with narrow prospect firmly believe in that "if you just knew, then you really could know much better" circle and they are quite happy with it. Amusement for the audience, but boring soon. Just suitable for students to train stubborn conditional probability calculus methods, with no need to question the underlying "never-to-be-given" -basics.

Though mathematically absolutely correct, its only merit is that it can show the exact range of Probability to win by switching of   "at least 1/2, but never less"   to   "1".
Repeat: That is all of its marginal utility for the MHP.

Though mathematically absolutely correct, it's no "solution", it's just only very well suited for practicing a method of probability calculus for students. And, written in odds-form, it can help to understand the MHP.  But it is no "solution".  And so for good reasons this is not perpetually repeated in most reliable sources. And yes, for a very good reason.  Gerhardvalentin (talk) 21:57, 27 February 2011 (UTC)

• (1) The first thing I noticed about all the "simple is flawed" arguments from editors, and the "here's where the simple solutions can fail" sources is that they immediately start with different premises to the problem. Well, that approach does nothing to demonstrate any flaws in any problem statement that does not include these new or changed premises.
• (2) It's a lot of hot air receiving way too much attention in the Wikipedia article (UNDUE WEIGHT).
• The argument I just presented (1) is not OR, or my opinion, it is a logic/philosophy fact. That the ownership editors will not acknowledge this is the NPOV violation. And the emphasis on this fallacy/canard is what ruins the article so early. Glkanter (talk) 11:55, 11 March 2011 (UTC)

Timeline for evidence in Monty Hall case

Please see Wikipedia talk:Arbitration/Requests/Case/Monty Hall problem/Evidence#Timeline for Evidence, Proposed Decision. On behalf of the Arbitration Committee, Dougweller (talk) 16:42, 21 February 2011 (UTC)

The goats

I know that this has been discussed before by various editors, but can anybody give me a reason why the problem is normally formulated in terms of the door numbers (1,2,3) and not the objects behind the doors (the car, goat 1, and goat 2). Is this just because the door are given numbers in the problem statement but the goats are not given names? Martin Hogbin (talk) 10:07, 27 February 2011 (UTC)

I can answer that. It's because the premise of your question is invalid.

• It's because the goats are of no interest. Selvin had car keys & 2 empty boxes. You gonna name them 'emptiness 1' and 'emptiness 2'? Go for it!
• Countless sources give car/goat solutions. It's only the Wikipedia MHP editors who don't acknowledge their existence. We call these 'simple' on these pages, unfortunately. Nijdam ignores them because he knows they are 'wrong', and therefor not reliable. See how that works?
• Glkanter has tried, with no success whatsoever, to rename these as 'simple conditional', as distinct from the simple, unconditional tables of outcomes from Selvin & vos Savant
• Richard has insisted on telling me that my terminology differs from all the other editors, and refuses to acknowledge that there are 3 solutions put forth by the reliable sources. He posted 'The Truth' as Evidence on the arbitration page, completely ignoring the solution you are now asking about. I am trying to discuss this on Richards talk page, with little success.
• Glkanter has turned those solutions into a conditional decision tree. You have found problems with it, something about the 100% condition being of no value, I think. Richard's only criticism was that the column headings should not have door #s. Still, he does not acknowledge these solution in his 'The Truth' section in his evidence.
• The editors who dominate the article are aided and abetted by this imprecise terminology, and it's corresponding confusion/dismissal, so have no interest in bettering it.
• Nijdam's point about [paraphrasing] 'the contestant must be faced with exactly two doors' is satisfied by these solutions (the 100% condition is the host opens another door revealing a goat). The Combining Doors solution does, too. Now, on Richard's talk page, Nijdam has *actually engaged me* on this very topic! ps whatever happened to "1/3 <> 1/3"? Oh, right, that decision tree proved that wrong, too.
• Glkanter is about to be blocked from his own arbitration for making this very point, both in his evidence and on the talk pages. The sources overwhelmingly provide this solution, and the article's POV is contrary to this. That is, the article's POV is based on OR, not the sources. But I can't get anybody to pay attention to this simple fact.

Glkanter (talk) 10:36, 27 February 2011 (UTC)

Tree shaping

Can you point to the examples of spamming, because I don't see them. SilkTork *^YES! 13:09, 7 March 2011 (UTC)

Thanks for contacting me. For a start, pretty well all of the section 'Chronology of notable practitioners' seems to be a series of advertisements for non-notable small businesses. We do not find this in articles on other subjects. An IP thought it looked like spam and I agree. Martin Hogbin (talk) 15:39, 7 March 2011 (UTC)

The section you mention contains sourced information about people who developed Tree shaping. When reliable sources write about something then that something becomes notable according to our guidelines, which includes small businesses. Apart from that section, what other reason do you have to feel there is spam in the article? SilkTork *^YES! 18:50, 7 March 2011 (UTC)

I think we need some outside opinion on this. To me and to at least one other it looks like blatant commercialism. Martin Hogbin (talk) 22:30, 7 March 2011 (UTC)

Can you point to the blatant commercialism and explain it? At the moment you are asserting your opinion without giving me much evidence. I've looked at the section, and I see information culled from various books and journals on the people who are most notable in the field of tree shaping. I do not see direct links to commercial sites, and while the language is not top class, and does fly close to promotional in nature in places, I do not see it as obvious advertising. It has to be borne in mind that primary sources are allowed, and information about practitioners and artists, such as the works they have done, books they have written, etc, is part of what we deliver. If you have specific concerns about any of the links or any of the wording, this is a good opportunity for you to point to it, and discuss it. If you are unable to do that, then it may be that you have got the impression that the material was promotional when it wasn't. These things happen. SilkTork *^YES! 02:52, 8 March 2011 (UTC)

SilkTork, if you cannot see what is plainly there in front of you there is no point in my trying to convince you of anything. Have a look at the articles on topiary and bonsai for example, we do not see a small business advertisement there. As I said, we need to get outside opinion on this. Martin Hogbin (talk) 09:46, 8 March 2011 (UTC)

Other people have looked - you are aware that the article is under the scrutiny of various people who do look into such matters - you have yourself commented on this thread on the COI noticeboard where people have said that they don't see a problem in the article, rather, just a problem with the ongoing dispute between the two main contributors. I'm going to remove anything from that section that is near to the line, and then remove the tag. If you feel that there is any promotional material left, then please either directly remove it yourself, or let me know what the material is. Putting the tag back would be unhelpful and somewhat provocative, as you are unable to indicate any specific problems. See WP:Tagging. SilkTork *^YES! 12:43, 8 March 2011 (UTC)

OK. I will have a go at making the section more encyclopedic and less promotional. No doubt ther will be some resistance from at least one editor with a commercial interest. Martin Hogbin (talk) 14:59, 8 March 2011 (UTC)

Archiving your talkpage

It's up to you - there's no specific guideline or rule. Your talkpage is quite large which makes it difficult for others to navigate and use your talkpage, so it would be helpful to archive it. Information is given in: Help:Archiving a talk page. SilkTork *^YES! 18:56, 7 March 2011 (UTC)

ANI notification

Please see Wikipedia:Administrators' noticeboard/Incidents#Proposed Topic Ban for Blackash and Slowart on Tree shaping related articles where I have mentioned your name. Johnuniq (talk) 07:36, 9 March 2011 (UTC)

• I suppose I should let you know that I mentioned you again at User talk:Hilarleo#Blackash talk page. I hope I am recalling things correctly. Johnuniq (talk) 00:40, 16 March 2011 (UTC)

Whatever Happened to "1/3 <> 1/3" ?

I'll tell you what happened.

The simple conditional decision tree based on Monty Halls's and Carlton's, and Morgan's F5 (and countless others') simple solutions show that the 1/3 likelihood that the contestant selects the car is *still* 1/3 after a door has been opened revealing a goat. Because that condition is 100%, and a number multiplied by 1 doesn't change. That the 2/3 *did* change from 1/3 + 1/3 to 2/3 + 0 is of no importance. Because of the law of total probability.

Nijdam uses that 1/3 <> 1/3 argument (without any sources) to say that all simple solutions are wrong.

Morgan clearly shows that 1/3 * 1 = 1/3:

• "Solution F5. The probability that a player is shown a goat is 1. So conditioning on this event cannot change the probability of 1/3 that door 1 is a winner before a goat is shown; that is, the probability of winning by not switching is 1/3, and by switching is 2/3."

Nijdam (without any sources) argues that all simple solutions are unconditional, and don't address the 'deciding between 2 doors' nature of the problem. The same simple conditional decision tree demonstrates clearly that the contestant is choosing between exactly two doors.

Morgan clearly states it's a conditional solution:

• "Solution F5. The probability that a player is shown a goat is 1. So conditioning on this event cannot change the probability of 1/3 that door 1 is a winner before a goat is shown; that is, the probability of winning by not switching is 1/3, and by switching is 2/3."

Nijdam's only remaining argument is that the problem must be solved specifically for door 3 being opened. Well, that's not derived from the sources or any science. He doesn't have a leg to stand on. Glkanter (talk) 12:46, 11 March 2011 (UTC)

Mediation

Martin, I'm asking you to agree to mediation. I give some more details on Tree shaping talk page. Blackash have a chat 05:36, 12 March 2011 (UTC)

I am happy to participate in any dispute resolution process. Martin Hogbin (talk) 10:00, 12 March 2011 (UTC)

Martin going by your comment on ANI noticeboard you seem unsure. I'm ready to list. Are you still willing to go ahead with formal meditation. Blackash have a chat 12:10, 17 March 2011 (UTC)

Done listed [[9]] Blackash have a chat 14:33, 18 March 2011 (UTC)

Sex and psychology

Thanks for joining the discussion. I've replied at Talk:Sex and psychology#Sex and psychology. Kaldari (talk) 03:28, 13 March 2011 (UTC)

Proposed Topic Ban for Blackash and Slowart on Tree shaping related articles

It looks like there is a consensus for a ban. Martin Hogbin (talk) 19:09, 17 March 2011 (UTC)

It would be appropriate for an uninvolved admin to close the discussion. The discussion has, unfortunately, somewhat wandered so the consensus is not clear, and there is a fair bit of reading to be done. When discussions get complicated, it takes longer for them to be closed. SilkTork *^YES! 07:15, 18 March 2011 (UTC)

I have asked AGK to look at the case. Martin Hogbin (talk) 18:39, 18 March 2011 (UTC)

Glkanter

You seem to be a friend of his. He has been blocked for his behaviour in the past few days, not because of the evidence presented by anyone at the Arbcom case. Can you persuade him that edits like this aren't helping his case. Three admins have already reviewed his unblock request on the grounds that his behaviour was sufficient to warrant the block, and far from making any attempt to address it, he is denying that he has done anything wrong, and saying that he'd do it all again. Arbcom hasn't yet decided that banning him is an appropriate step, but the more he carries on like this, the likelier it becomes. --Elen of the Roads (talk) 15:40, 18 March 2011 (UTC)

Thanks for your response. I should first point out that my comment on the ban was not prompted by friendship but by a sense of fair play. The ban does seem disproportionate to the offence. However, I will do what I can to help the situation. Martin Hogbin (talk) 18:34, 18 March 2011 (UTC)

Formal mediation has been requested

Formal mediation of the dispute relating to Arborsculpture 3 has been requested. As an editor concerned in this dispute, you are invited to participate in the mediation. The process of mediation is voluntary and focuses exclusively on the content issues over which there is disagreement. For an explanation of what formal mediation is, see Wikipedia:Mediation Committee/Policy. Please now review the request page and the guide to formal mediation, and then, in the "party agreement" section, indicate whether you agree to participate. Discussion relating to the mediation request is welcome at the case talk page.

Message delivered by MediationBot (talk) on behalf of the Mediation Committee. 18:42, 18 March 2011 (UTC)

Request for mediation rejected

The request for mediation concerning Arborsculpture 3, to which you were listed as a party, has been declined. An explanation of why it has not been possible for this dispute to proceed to formal mediation is provided at the mediation request page (which will be deleted by an administrator after a reasonable time). Questions relating to the rejection of this dispute can be directed to the Committee chairperson or e-mailed to the mediation mailing list. For more information on other available steps in the dispute resolution process, see Wikipedia:Dispute resolution.

For the Mediation Committee, AGK [•] 17:13, 22 March 2011 (UTC)
(Delivered by MediationBot, on behalf of the Mediation Committee.)

As requested...

"Guy, perhaps you could explain to me on your (or my) talk page what you think is going on and how it conforms to WP policy. I really do not understand it."

Glad to do what I can. DISCLAIMER: I am by no means an expert on Wikipedia policies, but I have read a lot of them and wached as they are applied.

Thanks, it is good of you to discuss this with me.

"The indefinite ban in Glkanter was made not by Arbcom but by a single admin."

Nope. Blocks are not bans. Bans are not blocks. WP:BLOCKBANDIFF explains the difference.

Fine but from the point of view of the person blocked a block is worse, they are physically prevented from editing WP. I see no point in making this distinction

BTW, I am guessing that you might think "indefinite" means "permanent." It does not. In this case, the indefinite block (blocks are not bans) will almost certainly be lifted when the arbcom makes its final decision.

I though that may be the case but it is still very unpleasant for the receiver. Indefinite prison sentences are genralyy considered bad, by much of society and the prisoners themselves.

"My understanding is that admins are not police or arbitrators but people carrying out administrative work on behalf of the WP community."

Nope. Not only is it true that admins are police, but it is also true that all editors are police. Many police powers (revert) are given to everybody including IP editors who are here for the first time. Other police powers (rollback) are given to editors who have shown some trustworthiness (I have rollback privileges). Other police powers are given only to admins, others only to the arbcon, and a few (deleting the main page, deleting everything and shutting down Wikipedia permanently) are only given to Jimbo Wales.

"They have the right, indeed the duty, to ban people as a result of a community consensus, but in the case of Glkanter there was no such consensus, there was not even a discussion."

Nope. There are things that are basically police actions (you or me reverting edits, any admin applying a block) that require no prior consensus. The reason they require no prior consensus is because they can be undone with a single mouse click by another editor or another administrator. In such cases you are free to seek consensus after the fact that the action was wrong and should be undone, but no prior consensus is required.

I guess a prisoner can be freed with only a key click. Martin Hogbin (talk) 19:22, 23 March 2011 (UTC)

"It is my belief that Elen acted completely beyond her powers and contrary to the spirit and policies of Wikipedia."

I, the 14 admins on the arbcon. and 3 uninvolved admins all disagree. Do you have any specific quotes from specific policies that you believe were violated? If so, I will be glad to examine each one and give my opinion.

"Glkanter's comments were relatively mild and made in his own user space about a WP editor who had brought the Arbcom action against him."

I, the 14 admins on the arbcon. and 3 uninvolved admins all disagree. I strongly disagree. Such behavior is totally unacceptable by any Wikipedia editor. He cannot plead ignorance; he was blocked twice before. I personally told him that he should be on his best behavior during arbcom. There is a pattern here. The 1000 word limit does not apply to him. The rules about not editing another user's evidence section do not apply to him. The warnings attached to his two earlier blocks (see his talk page) do not apply to him. And now the rules about civility and personal attacks do not apply to him.

"and made in his own user space"

Irrelevant. Show me a policy that says personal attacks are allowed on user pages.

"about a WP editor who had brought the Arbcom action against him."

Irrelevant. Show me a policy that says personal attacks are allowed in retaliation for bringing a dispute to arbcon.

Seriously. The above is not just empty words used for emotional impact. You are the one claiming that certain things are allowed and certain others are not allowed. The burden is on you to supply specific quotes from policy documents supporting your claims.

"It may well be that, had the matter been pursued through the proper channels, Glkanter would have ended up with a ban (although I doubt an indefinite one from the whole of WP) but this is no excuse for not following the proper procedure."

Proper procedures were followed. Name one that wasn't.

(In response to "the block imposed on Glkanter is not a ban") "Sorry that I got the terminology wrong but the fact is that he cannot edit due to the action of an admin."

If you had bothered to read WP:BAN you would have read this:

"Banning should not be confused with blocking, which is a technical mechanism used to prevent an account or IP address from editing Wikipedia. While blocks are one mechanism used to enforce bans, they are most often used to deal with vandalism and violations of the three-revert rule. A ban does not, in itself, disable an editor's ability to edit any page. However, editors who violate a ban may have their account access blocked entirely, as a way of enforcing the ban."

May I gently suggest that you read the policies before accusing people of violating them? Guy Macon (talk) 16:55, 23 March 2011 (UTC)

Martin, excuse me for butting in, but both you and Gill need to reconsider your "allegiance" to Glkanter. You probably see Glkanter as "on your side", but from my brief interaction with him just before he was blocked, he was not acting like someone who is here to collaborate, and even assuming that was temporary lapse in his judgment, Glkanter has some wp:competence issue with respect to MHP. What happened to Glkanter is absolutely not unusual to what happens to any editor behaving like him in an article subject to WP:Discretionary sanctions. Check out WP:AE... Tijfo098 (talk) 21:04, 23 March 2011 (UTC)

Tijfo098, perhaps you should assume good faith on the part of myself and Gill. I have not questioned Glkanter's block because he is 'on my side' as you put it, I have questioned it because it is, in my opinion wrong, and I believe that Gill takes the same view. In his professional life he has acted in court cases where much more serious injustices have taken place and has a strong interest in miscarriages of justice in general. Martin Hogbin (talk) 21:47, 23 March 2011 (UTC)

I am just disappointed that, after specifically asking for my input, Martin ignored it except for making the one comment above. Guy Macon (talk) 21:26, 23 March 2011 (UTC)

Guy, I do not understand. In what sense have I ignored your input? Martin Hogbin (talk) 21:47, 23 March 2011 (UTC)

If you think the rules of Wikipedia are unjust, then direct your arrows against these rules, and try to get them changed. If you feel that in this case the rules were wrongly applied, then explain which rule was applied wrongly how. If you can't do that, then do not blame the people who enforce the rules while exculpating someone who consistently refuses to pay attention to them.  --Lambiam 23:26, 23 March 2011 (UTC)

Lambiam, you may recall that you left the MHP article in disgust because of the iron grip over the page by a small group of editors. It is only because of the persistence of Glkanter that you and others are now free to improve the article. Martin Hogbin (talk) 00:24, 24 March 2011 (UTC)

I can only interpret this reaction by assuming you think the block was punitive and meant to be long-lasting. I don't see how or why you would think it is punitive, and Glkanter could have had it lifted in an instant by promising to stop his ranting (which he did all over Wikipedia) and become a good editor. Instead he just went on and on even after having been blocked.  --Lambiam 18:47, 24 March 2011 (UTC)

Martin, rest assured, I do assume good faith on behalf of both of you and Gill. But there is such thing as cognitive dissonance, and after several admins (some of them arbitrators) failed to reach a compromise with Glkanter on his manner of communicating, and you don't see that as a problem, what else can I say; WP:NOTLAW and WP:GIANTDICK. Tijfo098 (talk) 23:33, 23 March 2011 (UTC)

Perhaps you all read WP:BLOCK differently from me. This is what I see:

...blocking is a serious matter, and administrators should avoid imposing blocks that are unlikely to be preventative in the reviewable circumstances.

Blocks should not be punitive

Blocks should not be used:

1. in retaliation against users; 3. as punishment against users,

Blocks should be preventative

Blocks intended solely to "cool down" an angry user should not be used, as they often have the opposite effect. However, an angry user who is also being disruptive can be blocked to prevent further disruption.

Those are the bits which tell you not to block him. Under which part of the policy was Glkanter blocked? Martin Hogbin (talk) 00:08, 24 March 2011 (UTC)

They prevented him from annoying (almost) everyone any further—wikijargon for that is WP:CIVIL and WP:DE. Isn't that obvious? Tijfo098 (talk) 00:19, 24 March 2011 (UTC)

The quoted reason for his block was text on his talk page. From what I know of it it was a relatively polite criticism of Rick but unfortunately we cannot see what he wrote now. Martin Hogbin (talk) 00:24, 24 March 2011 (UTC)

He was warned by a couple of Arbs to stop that several times, e.g. (and the next diff from Glk is another giant rant about Rick). Since you like legalisms so much, do yo expect to spit a judge in the face in the courtroom and walk out? Or a more appropriate one: spit your boss in the face and not be fired? Tijfo098 (talk) 00:43, 24 March 2011 (UTC)

Re: "I guess a prisoner can be freed with only a key click", such melodramatic language is not helpful. The correct analogy isn't someone being put in prison, but rather someone being denied admittance to a privately-owned business because of repeated disruptive behavior. We don't own Wikipedia and we are here as guests of the owners. Anyone can start an online encyclopedia, and Wikipedia will even give you the software needed to run it for free. Many have tried to start alternative encyclopedias with different sets of rules, including at least one that was based upon giving disruptive editors like Glkanter free reign. All have failed. Please consider that perhap the nasty old rules are not as bad as you think they are.

Re: "Under which part of the policy was Glkanter blocked?", WP:BLOCK says "A user may be blocked when his or her conduct severely disrupts the project; that is, when his or her conduct is inconsistent with a civil, collegial atmosphere and interferes with the process of editors working together harmoniously to create an encyclopedia." If this longstanding pattern of disruptive behavior doesn't qualify, I don't know what does. Obviously you disagree, but just as obviously a bunch of people who don't know each other are telling you that you are wrong. There are few things more disruptive than personal attack on arbitrators during an arbcom.

Re: "Blocks should be preventative" and "Blocks intended solely to 'cool down' an angry user should not be used, as they often have the opposite effect. However, an angry user who is also being disruptive can be blocked to prevent further disruption.", nobody even hinted that Glkanter needed to cool down. Quite the contrary, actually; many have noted that warnings and blocks have no apparent effect on his behavior.

Re: "Blocks should not be punitive", "Blocks should not be used in retaliation against users" and "Blocks should not be used as punishment against users", Nobody but you seems to think they are in this case. I have been monitoring arbcon cases (without commenting) for a long time, and it is my observation that arbitrators are hypersensitive to any hint of such behavior by other arbitrators, and do not hesitate to say so.

Re: "The quoted reason for his block was text on his talk page. From what I know of it it was a relatively polite criticism of Rick but unfortunately we cannot see what he wrote now", not even close. The quoted reason for his block is still there, and was an attack on an arbitrator after repeated warnings not to attack anyone. The following (from the diff Tijfo098 posted above) couldn't have been more clear:

"If you have something to say about him or anything else to say to the arbitrators, present it calmly and neutrally, otherwise your talk page access will be removed so that arbitrators don't need to keep reading your posts here. If that happens, you will still be able to communicate with the arbitration committee via email, however you will be put on moderation and rants will be rejected."

So, in summary, you have failed to show a single policy that was not followed. Guy Macon (talk) 04:41, 24 March 2011 (UTC)

Thanks for coming to my talk page to explain things to me I understand very well now. Martin Hogbin (talk) 21:17, 24 March 2011 (UTC)

A brief comment on the MHP arbitration

Hello Martin, as you know, I was not involved in the process at all, other than being named in arbitration and being at the receiving end of a somewhat unkind and (IMHO) undeserved comment from you. Lack of time and (mostly) of interest. Now that it is coming to an end, and with a fairly predictable conclusion, I just want to point you to a short WP essay: I hope that reflecting upon it may be useful to you as a WP editor and to the project as a whole. It's Wikipedia:Randy's enablers. Cheers glopk (talk) 03:18, 24 March 2011 (UTC)

Glopk, you have made some unkind remarks about me in the past. Let us call that quits.

I read your essay. I guess the main reason that I have supported Glkanter is justice. This is a very fragile concept that is easily eroded by convenience. Those enforcing rules need to maintain higher standards than those breaking them. 'He had it coming' and similar arguments must not be accepted.

Today's heros were yesterday's troublemakers. There is agreement amongst the arbitrators that there was a degree of page ownership and tendentious editing by some editors. As I have pointed out to Lambiam above, it is thanks to the action of Glkanter the many editors who were driven away from the page by those factors can now return and edit the page.

Finally let me make clear that I do not agree with the way that Glkanter has dealt with this arbitration and I have told him so. Martin Hogbin (talk) 09:16, 24 March 2011 (UTC)

Re "I would also point out that it is often because of people like Glkanter that things get done" my rebuttal consist of the following arguments:

Wikipedia, which does not tolerate such behavior, is a huge success. Every online encyclopedia - in fact just about every online forum of any kind - that does tolerate such behavior has been a resounding failure.

You are in a very small minority that believes that people like Glkanter get things done. Many people from highly experienced administrators to totally uninvolved editors have told you that his behavior hurts Wikipedia.

Re "it is thanks to the action of Glkanter the many editors who were driven away from the page by those factors can now return and edit the page". highly debatable, almost certainly not true, and even if it were true, two wrongs don't make a right. Justice means that everybody has to play by the same rules. Even Jimbo Wales must follow the rules. See http://en.wikipedia.org/wiki/Jimmy_Wales#Controversy There is no exception for someone who does what you describe, and what you describe is not a credible claim.

Re: "I guess the main reason that I have supported Glkanter is justice", I take great offense to the implication that I am not supporting the consensus view of Glkanter's behavior because of justice. Give me a real example of someone being treated unfairly and I will be the first to defend that person. This is clearly not such a case.

In summary, your assertion that Glkanter has been treated unfairly and your assertion that Glkanter has been a force for good are, in the opinion of pretty much everybody who has examines them, totally without merit. Glkanter has been treated fairly and within the rules. This is a fact, and you are simply wrong if you think otherwise. If you think the rules are unfair, try to change them. Go ahead and introduce a proposal to the effect that "getting things done" excuses an editor from the rules concerning civility and personal attacks. But until the rules are changed to accommodate you, live by the current rules and admit that you have no case when you claim that the rules were not followed. Guy Macon (talk) 11:59, 24 March 2011 (UTC)

Martin fighting Arbcom and the people who regularly go there is much akin to pissing in the wind, you may good and valid reasons that are perrfectly valid and make sense and they the wind will only blow them back in your face. It's a pointless debate that only ends in frustration. Hell In A Bucket (talk) 14:16, 24 March 2011 (UTC)

True, but in this case the reasons are neither good nor valid. Guy Macon (talk) 14:28, 24 March 2011 (UTC)

I think there are plenty of very good and valid reasons. You have to carefully observe the whole history and you have to have some understanding of the content, before you are able to make a good judgement on this, I think. Appearances can be deceptive. You can't judge behaviour without any sensitivity to the content. Richard Gill (talk) 14:48, 24 March 2011 (UTC)

Hell In A Bucket, you are right, of course. Martin Hogbin (talk) 14:59, 24 March 2011 (UTC)

One Arbcom member (John Vandenberg) did "carefully observe the whole history" and commented: "I have had the joy of reading all the archives; I tried to poke out my eyes afterwards." Some others of us have had the joy opportunity to observe the history in realtime and have no quarrel with the apparent outcome. hydnjo (talk) 18:23, 24 March 2011 (UTC)

I, on the other hand, have been careful not to read the MHP page, the MHP talk page, or any sections of user pages covering MHP content. That is because I categorically reject the assertion that "You can't judge behaviour without any sensitivity to the content." Bad behavior is bad behavior, and no possible content (or bad behavior by others) can turn bad behavior into good behavior. I have avoided MHP content because of a simple principle: either evidence of bad behavior is presented in the diffs or it isn't. If it isn't, no sanctions are allowed and anyone who tried to impose sanctions without someone posting diffs showing bad behavior would have a dispute with me and we would be going through the dispute resolution process. On the other hand, if the diffs do show misbehavior, ignoring that misbehavior based upon content is not allowed

It seems clear that some here are setting themselves up so they can conclude that the arbitration committee - every one of them - is wrong, that I am wrong, that Hydnjo is wrong, etc. I am going to predict that despite claiming that we are all wrong, there will be no attempt to go through the various steps of dispute resolution, because that would require evidence rather than assertions. Guy Macon (talk) 20:53, 24 March 2011 (UTC)

'Some here'. That is not a personal attack I trust. Martin Hogbin (talk) 21:19, 24 March 2011 (UTC)

Yes, Guy, but John learned Tsirelson's theorem, and you haven't! ;-) Tijfo098 (talk) 00:24, 25 March 2011 (UTC)

I'm not saying everybody was wrong, nor am I saying that anybody in particular was wrong. I'm saying that something fishy has happened. I'm not surprised and I'm not complaining. I'm analyzing and commenting.

A wikipedia admin gets a minor penalty for ownership issues. A newcomer editor who strongly fought those ownership issues, because he was confronted by them on his very first day on wikipedia, gets a very heavy sanction. Whereas it seems that his most serious crime was to carefully document said ownership issues on his talk page. OK, so everyone superficially can see that he is breaking wikipedia rules that you mustn't say things about other editors, which can be interpreted as personal. But if you objectively document behaviour of another editor and say that it comes across to you as unfair, ownership, and so on .. I don't think that that is a personal attack.

Please also remember that it was said admin who requested the arbitration because in his opinion said newby editor was the cause that mediation was failing.

Please also recall that said newby who got this heavy punishment said ugly things about yours truly, and yours truly reciprocated in the same spirit, without either of us reporting the other to the authorities. Please also recall that said newby complained about other editors' OR and other editors' lack of respect for Verifiability, and these findings were confirmed by the arbitration. Richard Gill (talk) 15:53, 25 March 2011 (UTC)

OK, I know I'll regret this - and make no promises to continue this conversation, but this is really too much. Richard, I do think you too should read Wikipedia:Randy's enablers and meditate upon it. Let's take it point by point:

A wikipedia admin gets a minor penalty for ownership issues -- Could it be because the documented issues were found to be minor? And occurring in the course of a neverending effort to reach consensus by offering practical solutions in the form of actual and proposed edits, rather than rants and venting and personal attacks?

A newcomer editor who strongly fought [...] gets a very heavy sanction -- Under what definition of "newcomer" would Glkanter fall? Have you any idea of the size of his own diffs? It's large. Did he not participate in this MHP debate for near two years? He did. Did he not go through rounds if RfC, mediation and - finally - arbitration? Ditto. Is it a fair expectation that after all that he should have learned the rules of the WP house and, if he had a case, prevailed? It is. But not only he did not learn the rules, he actually managed to follow nearly to the letter points 1,3,4,6,7,8,10 and 11 of the BGD template, with a predictable result.

OK everyone superficially can see that he is breaking wikipedia rules [...] But if you objectively document behaviour of another editor [...] I don't think that that is a personal attack -- That is an interesting notion of justice. Let's see how it may apply in real life: if I publish nasty and entirely unfounded smears about you, and you sue me for libel in the Crown's Courts to protect your reputation, and all the available objective evidence indicates that you would indeed prevail, do you think that your barrister would advise you that, by all means, you jolly ought to go every day to Court and rant and personally attack me, the jury, the clerks, and the judge?

Remember that it was said admin who requested the arbitration because in his opinion said newby editor was the cause that mediation was failing -- Entirely irrelevant to the conclusion - please re-read carefully Guy's comments above: arbitration and mediation cover separate problem areas. In fact, it was Glkanter inability or unwillingness to understand this fact that caused the first scuffle between him and the arb clerks. Glkanter was named in arb by Rick because of his behavior, not his opinions regarding the MHP article.

Recall that [Glkanter] said ugly things about yours truly, and yours truly reciprocated in the same spirit, without either of us reporting the other to the authorities -- That was between you and him. Does it imply that everybody else should put up with such behavior?

Other editors' lack of respect for Verifiability [...] confirmed by the arbitration -- And how does that excuse Glkanter's own behavior?

Regards, glopk (talk) 17:29, 25 March 2011 (UTC)

Wikipedia:Arbitration/Requests/Case/Monty Hall problem closed

An arbitration case regarding Monty Hall problem has now closed and the final decision is viewable at the link above. The following is a summary of the sanctions that were enacted:

• Standard discretionary sanctions are enacted for all articles related to Monty Hall problem (broadly interpreted)
• Glkanter is banned from Wikipedia for one year, and is further subject to an indefinite topic ban on subjects related to the Monty Hall Problem.
• Nijdam is topic banned from the subject of the Monty Hall problem for a period of one year.
• Rick Block is restricted to 1RR on the Monty Hall article for a period of one year.

For the Arbitration Committee, NW (Talk) 00:47, 25 March 2011 (UTC)

Discuss this

Tree shaping

SilkTork, as you will see, Blackash continues to exert a strong opinion on the talk page on issues with a strong commercial and personal COI. I think it is essential for Blackash to be banned from the Tree shaping talk page so that editors with no commercial interest or personal involvement can discuss the issues of article name and current practitioners without continual interference.

This argument has gone on for years now. Several editors who came long ago in response to an RfC in this subject have been unable to make any progress because of continual interference from COI editors. Slowart obviously also has a COI but at least seems willing to withdraw from certain discussions if Blackash does the same. Something needs to be done. Martin Hogbin (talk) 08:52, 31 March 2011 (UTC)

I did consider suggesting that the topic ban should include discussion of the topic anywhere on or linked to Wikipedia as I felt that the matter would not die simply with a ban on directly editing the article. I'll take a look. SilkTork *^YES! 10:31, 31 March 2011 (UTC)

Thanks for that. Martin Hogbin (talk) 11:14, 31 March 2011 (UTC)

April 2011

[comment deleted; issue was resolved] Guy Macon (talk) 13:53, 9 April 2011 (UTC)

I have struck out my original intro and replaced it with a more appropriate one. Martin Hogbin (talk) 08:23, 9 April 2011 (UTC)

Copying signatures

Hi Martin, I don't want to come across as being overly picky, but I really do not approve of copying my signature into a reply post as you did at Talk: Mail (armour). This can make it look like I signed something I did not write. Would you mind amending your post please? SpinningSpark 09:36, 10 April 2011 (UTC)

No problem, I will attend to the matter. I sometimes copy sigs as an easy way of referring to or addressing an editor but I also object when this causes confusion as to who said what. I will be more careful about copying sigs in the future. Martin Hogbin (talk) 09:41, 10 April 2011 (UTC)

Thanks, I have no problem with linking to my page but an exact copy of my signature does cause confusion - especially to me. I have now withdrawn the RfC, it does seem pointless if Samurai is going to work on the article. SpinningSpark 10:11, 10 April 2011 (UTC)

You are involved in a recently filed request for arbitration. Please review the request at Wikipedia:Arbitration/Requests#Tree shaping and, if you wish to do so, enter your statement and any other material you wish to submit to the Arbitration Committee. Additionally, the following resources may be of use—

• Wikipedia:Arbitration/Requests#Requests for Arbitration;
• Wikipedia:Arbitration guide.

Thanks,

Arbitration case regarding tree shaping

An Arbitration case involving you has been opened, and is located here. Please add any evidence you may wish the Arbitrators to consider to the evidence sub-page, Wikipedia:Arbitration/Requests/Case/Tree shaping/Evidence. Please submit your evidence within one week, if possible. You may also contribute to the case on the workshop sub-page, Wikipedia:Arbitration/Requests/Case/Tree shaping/Workshop.

On behalf of the Arbitration Committee, Salvio ^{Let's talk about it!} 10:40, 28 April 2011 (UTC)

Edwards revisited

Greetings,

I happened to find a paper yesterday which briefly mentions Edwards' transformations.

Malykin, G. B. (2009). Classical optical experiments and special relativity: A review. Optics & Spectroscopy, 107(4), 592-608.

I'm not posting this to the "one-way" talk page because I'm not suggesting it be included. It does contradict the wiki article, but I strongly suspect Malykin is incorrect in his conclusion. I thought you might be interested.

It's a three-sentence subsection within a section titled incorrect para-Lorentz transformations. Malykin lists quite a few of these, followed by a section with "correct" para-Lorentz transformations, of which he lists just two: Tangherlini and Sjödin transformations. Below is the section.

Edwards Transformations

In 1963, W. F. Edwards proposed the following transformations:

$x'=\left(1+2v/c\right)^{-1}\left(x-vt\right), \quad y'=y, \quad z'=z,$

$t'=\left(1+2v/c\right)t.$

It follows from these that

$c'_x=\left(c-v\right)\left(1+2v/c\right)^{-2}, \quad c'_{y,z}=c\left(1+2v/c\right)^{-1}.$

It is clear that these transformations cannot explain the results of the Kennedy–Thorndike experiments.

<end of article section>

It seems likely from the quote cited to Edwards in the "one-way" article and from other discussions of Zhang elsewhere, that Malykin's analysis didn't properly take into account that these transformations are anisotropic for the outbound and return legs.

Also, to answer your query from ten months ago, Tom's contact information can be found from the FNAL Phone Book (a web search will find it). He mentions that at the top of the "experimental basis of SR" faq. You may or may not want to contact him at this point, but in case you do for any reason that ought to work. Tim Shuba (talk) 20:24, 4 June 2011 (UTC)

Good to hear from you. I would certainly prefer Zhang's, and even Tom's, analysis over Malykin's. Thanks for the contact info. Martin Hogbin (talk) 22:12, 4 June 2011 (UTC)

That's it bully users

Undo what you did on 2011 wimbeldon for the following reasons. You have not followed a single MOS guidline, didn't discuss with the user and then locked it for the anon so that you can do your own thing. An encyclopedia must be fullfilling and state everything. Your edit is so wrong undo it now. — Preceding unsigned comment added by Rageing Bull (talk • contribs) 20:05, 6 July 2011 (UTC)

There is no place in WP for advertising. It is an encyclopedia not a billboard. Martin Hogbin (talk) 20:50, 6 July 2011 (UTC)

That's not an answer that's a POV. Plus you removed the reference which was being used else where. Well done for fine work of incompetence— Preceding unsigned comment added by 78.147.179.68 (talk) 22:50, 6 July 2011 (UTC)

The above post is by banned sockpuppet user:KnowIG Fyunck(click) (talk) 23:37, 6 July 2011 (UTC)

Wikipedia:Arbitration/Requests/Case/Tree shaping

An arbitration case regarding Tree shaping has now closed and the final decision is viewable at the link above. The following remedies have been enacted:

1. The topic covered by the article currently located at Tree shaping, interpreted broadly, is placed under discretionary sanctions.
2. User:Blackash is topic banned from all discussion on the correct name for the tree shaping/arborsculpture/pooktre topic for one year. The topic ban includes talk pages, wikipedia space and userspace, but only covers discussion of what name should be given to the practice, and what title should be used for any articles on the subject.
3. User:Sydney Bluegum is topic banned from the subject of tree shaping/arborsculpture/pooktre widely construed for one year. The topic ban includes talk pages, wikipedia space and userspace.
4. User:Slowart is topic banned from all discussion on the correct name for the tree shaping/arborsculpture/pooktre topic for one year. The topic ban includes talk pages, wikipedia space and userspace, but only covers discussion of what name should be given to the practice, and what title should be used for any articles on the subject.
5. The community is urged to open up a discussion, by way of request for comment, on the article currently located at Tree shaping to determine the consensus name and scope for the subject matter, whether it should stand alone or whether it is best upmerged to a parent article. To gain a broad consensus, naming and scope proposals should be adequately laid out and outside comments invited to gain a community-based consensus. This should be resolved within two months of the closing of this case. Parties that are otherwise topic banned are allowed to outlay proposals and background rationale at the commencement of the discussion, and to answer specific queries addressed to them or their proposals. This concession is made due to their experience and familiarity with the area.
6. Within seven days of the conclusion of this case, all parties must either delete evidence sub-pages in their user space or request deletion of them using the {{db-author}} or {{db-self}} template.

For the Arbitration Committee, Dougweller (talk) 15:48, 15 July 2011 (UTC)

Two envelopes problem

hi mate, from previous discussions I recall you might be of more of a philosophical than mathematical bent. If you're interested I would like to play the two envelopes problem with you, to illustrate the fallacy in the switching argument.... If you're not interested, no worries. To kick it off, there is $1 in one envelope and $2 in another. You are holding an envelope. Now - what is A? Dilaudid (talk) 17:45, 21 July 2011 (UTC)

I get the impression that you are going to tell me something I already know. Have you seen the new section that I added called, 'Introduction to resolutions of the paradox'? In that, I point out that for a finite distribution step 6 fails. Martin Hogbin (talk) 20:19, 21 July 2011 (UTC)

Well apologies for patronising your math skills. But what I'm trying to point out is that for any proper distribution, step 6 fails. There is nothing in the switching argument that distinguishes between a finite or infinite distribution. Therefore if it is not valid for one, it is not a valid argument for either. This is what happens when one defines A sloppily. Dilaudid (talk) 05:16, 22 July 2011 (UTC)

Let me start with where I think we agree:

• For a finite distribution, step 6 always fails.

• A distribution such as 'chance that the smaller of the two envelopes contains an amount between 2n and 2n + 1 is p(n), where n is any whole number' is improper and this leads to a non-sequitur regarding step 6.

However, if you look at the second variant, you will see that, 'examples can still easily be found of proper probability distributions, such that the expected value of the amount in the second envelope given that in the first does exceed the amount in the first, whatever it might be'. Here, step 6 holds good, but the expectation is infinite for both envelopes. This essentially invalidates step 8. I do not see anything about a sloppy definition of A. Martin Hogbin (talk) 08:49, 22 July 2011 (UTC)

Can I suggest moving this conversation to the talk page, where others can join in. Martin Hogbin (talk) 08:50, 22 July 2011 (UTC)

The sloppy definition of A that I was worried about is whether it's a random variable A (and we are frequentists) or it's a positive real number x (and we are bayesians). It's clear we are talking about a Bayesian approach, which means that the probabilies of x being the greater or lesser are functions of x, and a prior distribution. While you are correct that you can have a proper prior with infinite expectation, you cannot have a proper prior where the probabilities are ¹⁄₂ for all x, so either step 6 fails or the prior is improper. And it is true if you allow an improper prior the infinite expectation means that step 8 fails (although I hadn't realised that until you explained it) this means irrespective of the prior we choose, the argument is fallacious. Let's take this back to the main talk page when we are in agreement, if that's ok with you. Dilaudid (talk) 10:30, 24 July 2011 (UTC)

Just to clarify - I think the quote you have there is from Chalmers paper. I was interested and confused by that point for a little while after I read his paper, you just explained its resolution rather well (infinite expectations mean that it *doesn't matter*). This isn't relevant to what we are interested in, which is the precise flaw in the switching argument (which is using an infinite uniform prior, an improper prior). It's more relevant to the St Petersberg Paradox. I think we need to be careful not to start mixing our paradoxes, that leads to madness. Dilaudid (talk) 10:39, 24 July 2011 (UTC)

Dilaudid, I seem to be having a related conversation on the 'arguments' page. Let us continue there. Martin Hogbin (talk) 08:31, 26 July 2011 (UTC)

Ok will take a look at the talk Dilaudid (talk) 07:28, 27 July 2011 (UTC)

Your RFC

The best ref, IMO is Horticultural Reviews, Volume 35 [10] Horticultural Reviews, Volume 35 Edited by Jules Janick Copyright & 2009 John Wiley & Sons, Inc. Page 442. section 4. Creation of Unusual Growth Forms. In the ornamental nursery trade, it is a common practice to graft a scion from dwarf or weeping cultivar onto a tall straight stem of a compatible understock to mimic an arborescent growth habit. Tree roses can be formed by double working using a shrubby garden rose scion, a Multuflora de la Grifferaie interstock, to form a straight trunk, and ‘Dr. Huey’ rootstock. Grafting to create unusual growth forms in a practice called arborsculpture involves intertwining and grafting together the stems of two or more plants in order to create domes, chairs, ladders, and other fanciful sculptures (Fig. 9.2)" Thanks for asking. Slowart (talk) 21:31, 29 July 2011 (UTC) Martin Slowart is Richard Reames Arborsculpture him self.?oygul (talk) 01:43, 2 August 2011 (UTC)

Yes, I know, why are you telling me this? Martin Hogbin (talk) 08:07, 2 August 2011 (UTC)

A barnstar for you!

	The Civility Barnstar
	For polite and sensible discourse in an RfC at Tree shaping. Noleander (talk) 19:26, 4 August 2011 (UTC)

fictitious centripetal force?

From an observer at the north pole of the earth looking straight up, all the stars appear to be orbiting and affected by a fictitious centripetal (not centrifugal) force. Why is this type of fictitious force not included in the wiki articles about the various types of fictitious forces? Rcgldr (talk) 17:49, 12 August 2011 (UTC)

It is! In the rotating reference frame of the Earth, the stars are subject to a (outwards) centrifugal force and a greater (inwards) Coriolis force. The net result is the required centripetal force that holds them in orbit. But why are you asking me? Martin Hogbin (talk) 19:04, 12 August 2011 (UTC)

Yes, I later realized the apparent coriolis force has double the magnitude and opposite direction of the apparent centrifugal force giving the appearance of an apparent fictitious centripetal force, but one that is covered by the existing coriolis and centrifugal forces. I asked you about this since you posted on the dicussion page for centrifugal force. Rcgldr (talk) 15:52, 13 August 2011 (UTC)

I am glad that is resolved. Martin Hogbin (talk) 17:42, 13 August 2011 (UTC)

Levels

I read what you wrote on the MHP talk page about levels of the problem. Maybe you yourself do believe such levels exist. Rather then just mentioning them it would give more insight to formulate what you mean. Just mention what the problem should be on the different levels. Nijdam (talk) 17:22, 13 August 2011 (UTC)

Sockpuppet checks

Hiya, when you file a checkuser request on an account, please consider notifying the related users about the request, thanks. --Elonka 00:33, 14 August 2011 (UTC)

The SPI instructions state that there is no requirement to notify suspected sockpuppets of a pending investigation. This is in contrast to most other WP processes (ANI, Arbitration, etc) where notification of involved persons is required. I suppose that SPI notification may seem like the polite thing to do, and in some cases it may be desirable, but there are situations where it may increase drama and should be avoided. --Noleander (talk) 01:50, 14 August 2011 (UTC)

True, notification is optional according to SPI instructions. But in this situation, related to Tree shaping, I am asking Martin Hogbin to make the notifications. Since they are on public pages anyway, I do not see any compelling reason why they should be kept quiet, and filing the requests without informing other parties is tending to just add confusion to an already confusing situation. --Elonka 02:11, 14 August 2011 (UTC)

I have never used SPI before and, after reading that notification was not a requirement, I actually forgot to notify those involved. I am happy to do so if yo wish, if I can work out how to do it. Martin Hogbin (talk) 08:27, 14 August 2011 (UTC)

Done! Martin Hogbin (talk) 08:31, 14 August 2011 (UTC)

Academic extensions

I do comment here on your point 1 - 6. Concerning point 2. it is not necessary to assume the contestant chooses uniformly. Concerning the symmetry with respect to the door numbers: this means that for every combination of door numbers the decision will be the same, based on the different conditional probabilities, having the same value for every combination. Nijdam (talk) 12:34, 14 August 2011 (UTC)

Nijdam, it might be best to continue these discussions by email, or are you allowed to discuss the subject in user space? Martin Hogbin (talk) 21:45, 14 August 2011 (UTC)

I'm only banned from pages typically about the MHP itself. Nijdam (talk) 03:48, 15 August 2011 (UTC)

OK. Let me start with the term 'conditional'. I do not find this term particularly helpful but, nevertheless, let use the convention that events which occur with certainty in our scenario (those required by the game rules) are not considered conditions.

One immediate problem we encounter is that the game rules are not very well described in the Whitaker/vos Savant statement. In fact we have to make many of them up. Iet us make the normal assumptions, that the host always offers the swap, for example, even though the question only tells us that in this particular instance the host offers the swap we choose to assume that the host always offers the swap. You might note at this stage that the same applies to the words spoken by the host. We take it that the host is required to say exactly the same words each time he offers the swap. If we do not make this decision we should consider every word that the host uses to be a condition of the problem. Alternatively we could make the assumption that the words spoken are of no significance or, more specifically, that the position of the car after the host has spoken is independent of the words he says. Do you agree so far? Martin Hogbin (talk) 08:30, 15 August 2011 (UTC)

Concerning the term conditional. what do you mean by "not finding it helpful"? If it is just the word, you know, as Rick end I have often said, it is easy to avoid the word, and use some understandable terminology. But in this discussion it is easier to use this word, as we know exactly what it means. And in this discussion we cannot avoid it, because is crucial in the solution.

Do not try to confuse the discussion again with words said by the host, audience coughing, wind blowing etc. No source ever takes such thing into account. Neither do I. No one, except you, does. Any source, even the less reliable, describe the MHP in terms of the door with the car, the chosen door and the door opened by the host. So, just start from there. Nijdam (talk) 21:48, 15 August 2011 (UTC)

I am not confusing the discussion, I am clarifying it. before we can answer the question at all we need to decide exactly what it means. This means deciding on the game rules and on what aspects of the question are significant. We have to make a decision that the words spoken by the host are not important. The question itself does not tell us that. Martin Hogbin (talk) 17:34, 16 August 2011 (UTC)

May be it clarifies thing for you. Nowhere in the problem statement it says that the way things go, depends on something else than the aspects I mentioned. Nijdam (talk) 22:13, 16 August 2011 (UTC)

You are quite right, but then the problem statement does not tell us anything at all about the way that things go. We have to decide for ourselves what events are significant before we can address the problem.

It is quite possible in a game show that the host would try to give clues as to what action the player should take by means of the language that he used. If we consider that this might be a possibility we must take it as a condition of our problem. In fact, this scenario seems more likely than that of a host having a bizarre and inexplicable preference for one door over another. Martin Hogbin (talk) 22:35, 16 August 2011 (UTC)

In this discussion I'm not interested in all kind of diversities. What do you think the average reader will (have to) understand as the MHP? Nijdam (talk) 07:02, 17 August 2011 (UTC)

To answer you question first, the average reader clearly understands the MHP as a problem where door numbers have no significance. In view of the fact that vos Savant added the door numbers to the problem it also seems clear that this was how Whitaker intended the problem to be understood. Of the thousands of letters from readers that vos Savant received there is no evidence that even one of them considered the door numbers, and more specifically the number of the door opened by the host, to be relevant. They may not all have used this language to describe their intuitive understanding but the average reader clearly understands the probability that the car is behind the originally chosen door to be independent of the door numbers in general and specifically of the door number opened by the host. It was some months before anyone (Morgan et al) proposed this dependence.

Regarding your interest, if you are going to arbitrarily ignore information in the problem statement then you cannot regard yourself as tackling the problem properly. The statement clearly tells us that the host says the word 'pick' before the player makes the decision on whether to swap or not. The statement does not tell us that the host always says this word so we must consider that case that the host might use another word or at least we must give a rationale for not doing so.

If course, I am being a little perverse, but so were Morgan et al. As a simple puzzle we regard the probability that the car is behind the originally chosen door to be independent of the door numbers and the specific door opened by the host, the words spoken by the host, and many other things. This is a perfectly reasonable and intuitive interpretation of the problem and it is the one that Whitaker intended and vos Savant responded to.

If you want to use this problem as a test for your students that is fine but it is unfair to expect them all to make the same decisions that you do. Most important is to make clear the decisions that have been made. Martin Hogbin (talk) 08:14, 17 August 2011 (UTC)

You seem to know the average reader well. And even then, what do you mean by: "have no significance"? It will be easily understood by the average reader that (with quite natural assumptions) that any aspect of the solution will be invariant under permutation of the door numbers. So what? Where does this lead us?

The probability distribution of the position of the car is NOT independent of the door opened by the host. And hence it is not obvious that the probability for the chosen door to hide the car has initially the same value as after the host opened the goat door. Notice that I'm very careful in formulating this. That's where the simple solution fails as a solution to the full MHP, as you have admitted yourself.

So again: please formulate the version of the MHP as you think the average reader will understand it. And add if you also think this is the MHP as you understand it. Nijdam (talk) 15:52, 17 August 2011 (UTC)

In the standard version of the problem the host chooses a goat-hiding door uniformly at random. The host's choice of door is therefore independent of the position of the car. Martin Hogbin (talk) 19:10, 17 August 2011 (UTC)

Do you mean to say that, if one introduces random variables for the position of the car and the door the host opens, these two variables are statistically independent? Nijdam (talk) 21:34, 17 August 2011 (UTC)

No, I mean that which of the goat-hiding doors the host opens is independent of the position of the car. Martin Hogbin (talk) 21:38, 17 August 2011 (UTC)

What then do you mean by "independent"?Nijdam (talk) 08:39, 18 August 2011 (UTC) Any chance on an answer? Nijdam (talk) 09:59, 19 August 2011 (UTC)

You are correct and I am wrong here. let me try to reformulate exactly what I mean. Martin Hogbin (talk) 10:34, 9 November 2011 (UTC)

(Editing)

"t will be easily understood by the average reader that (with quite natural assumptions) that any aspect of the solution will be invariant under permutation of the door numbers". Where does this leave us? It gives us the statement "Prob(other door hides car| numbers of doors chosen and opened) = Prob(other door hides car) = 2/3". It tells us to switch and that the probability of winning by switching is 2/3. It tells us that the specific door numbers can be ignored from the outset. Richard Gill (talk) 08:31, 6 November 2011 (UTC)

You finally admit, it is the conditional probability that counts? Nijdam (talk) 08:40, 6 November 2011 (UTC)

As I have said before, Nijdam, I have no objection to the use of the word 'conditional' if that makes you happy. We wish to calculate the probability of winning the car given all the significant conditions of the problem. It is a problem in conditional probability, as is every problem in Bayesian probability. However, as Richard say above we can easily deduce that the number of the door opened by the host is insignificant, along with many other things, and therefore we can ignore it in our calculations.

As I have said before, Martin, I have no objection not using the word 'conditional' if that makes you happy. As long as we wish to calculate the probability that governs the situation after we know which door is initially chosen and which one opened. The way this probability is calculated is irrelevant. Nijdam (talk) 17:01, 6 November 2011 (UTC)

Yes of course. That is the (conditional) probability that the player will win if they choose to swap. Ther are no other significant conditions. 17:32, 6 November 2011 (UTC)

No!!Nijdam (talk) 21:54, 6 November 2011 (UTC)

The host must open a door to reveal a goat. The sample space cannot be conditioned on this event, neither does it need to be. We knew at the start this would happen. Martin Hogbin (talk) 22:23, 6 November 2011 (UTC)

A sample space is never conditioned, so what do you mean? Of course we know at the start what is going to happen in general, but we do not know which door will be chosen and which will be opened. Nijdam (talk) 09:55, 7 November 2011 (UTC)

The urn again

If you remember, I have proposed a simple urn problem where you agree that you would do exactly the same thing, that is to say you would ignore unimportant facts and calculate the answer in the simplest manner possible.

I do remember, and also there he probability at stake was the conditional probability. Nijdam (talk) 17:01, 6 November 2011 (UTC)

Yes, but you were happy to calculated it in a simple manner, ignoring irrelevant conditions. Why will you not do the same for the MHP? Martin Hogbin (talk) 17:32, 6 November 2011 (UTC)

I also do with the MHP. But the way of calculation bears no significance, so why bother?Nijdam (talk) 21:54, 6 November 2011 (UTC)

I do not understand what you mean. I repeat a slightly modified version of the problem below. Perhaps you could answer my questions.

The urn problem restated

There are nine white balls in an urn numbered 1 to 9 and one black ball. Normal urn conventions apply. The first person takes a ball, which proves to be the white 5. The second person takes a ball which proves to be the white 7.

The third person is about to take a ball. How do you calculate the probability that they will take the black ball? What sample space do you start with. Do you need to explicitly calculate P(B3=R|B1=W5,B2=W7) or would you take an obvious short cut and just calculate P(B3=R|7 white balls and one red ball are left in the urn)?

The probability I have to calculate is P(B3=R|B1=W5,B2=W7), but I may reason it has the same value as P(B3=R|7 white balls and one red ball are left in the urn) (different experiment), and even simplify to reason that it is equivalent to an urn experiment with 7 white and 1 red ball. This only simplifies the calculation, but the relevant probability is the original P(B3=R|B1=W5,B2=W7). And it is obvious I can't say: it is the probability to draw the red ball, because this probability is 1/10 (in the experiment at stake). In this experiment it is clear that there is a difference between the probability to draw red in the original experiment and the conditioned experiment, because there is also a difference in numerical value. In the MHP however the values are the same, but as I explained several times, the nature of the probabilities differ. They also refer to different experiments. Nijdam (talk) 12:37, 7 November 2011 (UTC)

You say, 'the probability I have to calculate is P(B3=R|B1=W5,B2=W7)' but suppose now there are two urns containing identical sets of balls, a blue urn and a red urn. At the start you pick the blue urn. Do you now have to calculate P(B3=R|B1=W5,B2=W7,urn=blue)?

Of course. Also here, as in all the other situations, it is about the difference between the numerical value and the nature of the desired probability. As you understand, the reasoning is again, because of symmetry, or equivalence, the desired probability has the same value as a similar probability for one of the urns.Nijdam (talk) 22:30, 9 November 2011 (UTC)

What if your name was John? Would you now calculate P(B3=R|B1=W5,B2=W7,urn=blue,your name is John)? Martin Hogbin (talk) 00:27, 10 November 2011 (UTC)

Is my name in any way part of the experiment? If not, i.e. if my name is not relevant for any of the outcomes of the experiment, then my name does not have to appear in the sample space, and hence I can't condition on it. If, however, my name is part of the experiment, i.e. if for instance the experiment has to decide before the drawing is performed, which one of a set of people, among which I am, will do the drawing, and I'm the lucky one, then yes do I have to condition on my name. Nijdam (talk) 11:13, 10 November 2011 (UTC)

I agree with what you have written, especially, 'if my name is not relevant for any of the outcomes of the experiment, then my name does not have to appear in the sample space'. Would you not say the same is true for the host's choice of goat-door?

Well, you should know by now. The numbers of the doors are part of the problem. The player has a choice what door to pick, and the host in some cases also has a choice. Nijdam (talk) 15:14, 11 November 2011 (UTC)

Yes I do know, if you are interested in the the door number that hides the car or the number of the door that the player ends up with then the door number opened by the host is important but if you are only interested in whether the player ends up with the car or not the door number opened by the host is unimportant. Martin Hogbin (talk) 16:36, 11 November 2011 (UTC)

As elsewhere: unimportant for what? Nijdam (talk) 20:17, 11 November 2011 (UTC)

Answer??Nijdam (talk) 08:13, 13 November 2011 (UTC)

Unimportant for calculating the probability that a player who decides to swap will end up with the car or not. Martin Hogbin (talk) 09:37, 13 November 2011 (UTC)

A player always ends with the car or not, so this probability is 1. May be you mean something different. I suggest you specify the sample space and formulate exact what you mean. Nijdam (talk) 19:07, 13 November 2011 (UTC)

Yes, it was rather badly expressed, the probability of interest was the probability that a player who decides to swap will end up with the car. Martin Hogbin (talk) 10:05, 14 November 2011 (UTC)

On the other hand suppose you are presented with an urn containing one black ball and seven white balls marked 1,2,3,4,6,8,9. What probability would you now calculate? Martin Hogbin (talk) 10:21, 9 November 2011 (UTC)

Why should I calculate any probability? I might as well play some game with the balls. I mean, if I'm presented an urn without stating a probability problem, there is no need to do a probability calculation. Nijdam (talk) 22:30, 9 November 2011 (UTC)

As before, what is the probability that you will draw the black ball and how would you calculate it? Martin Hogbin (talk) 00:22, 10 November 2011 (UTC)

To make it instructive, I state the sample space, which is the urn itself, with a uniform probability law. Hence P(Black ball) = 1/8. No need for any calculation, as this probability is given. Nijdam (talk) 11:13, 10 November 2011 (UTC)

But is the uniform probabilty law (by virtue of the urn conventions) not equally applicable in the case where you have seen the W5 and W7 removed from the urn?

Conditionally yes. Nijdam (talk) 20:17, 11 November 2011 (UTC)

What do you mean by that? Martin Hogbin (talk) 01:09, 13 November 2011 (UTC)

In the case I've seen W5 and W7 being removed from the urn, this removal was part of the experiment. The original probability law, governing the urn, was a uniform distribution on the 10 possible outcomes. After the removal of W5 and W7, and stating that again a random draw has to be made, conditionally a uniform distribution governs this new situation. The point is not the uniform nature, but the conditional nature with respect to the original probability law. Nijdam (talk) 08:13, 13 November 2011 (UTC)

What would be your answer to the original urn problem stated at the top of this section if the balls were not numbered? Martin Hogbin (talk) 16:36, 11 November 2011 (UTC)

Then I calculate P(black | first draw was white and second draw was white). Nijdam (talk) 20:17, 11 November 2011 (UTC)

Just to be clear What sample space would you use? Are you saying that you would do the full conditional calculation? Martin Hogbin (talk) 01:09, 13 November 2011 (UTC)

You bring up an interesting question. Normally this is modelled by numbering the balls and taking the numbers as the outcomes. It raises a philosophical question about the distinguishability of the balls. Such problems play a role in physics as well. If the balls are indistinguishable, is it then possible to take one out, because it then is distinguished from the others? So my answer to your question will be, I number the balls. And then for the second part, you often ask about the calculation, which is unimportant. I just would point to - or prove - the equivalence with an urn with only one black and 7 white balls. Nijdam (talk) 08:27, 13 November 2011 (UTC)

It is an interesting point. Unlike bosons, which are fundamentally indistinguishable, all real macroscopic objects are distinguishable in principle. The question becomes one of whether we wish or need to distinguish between them and that depends on the question that we are asking and its context.

In the unnumbered ball urn question above I think you would agree that there is a strong case for treating them as indistinguishable. The interesting point is that there is a good case for treating the numbered balls as indistinguishable (even though we obviously can distinguish between them) because of the urn convention and the fact that we have no interest in the ball numbers in solving our problem. Martin Hogbin (talk) 11:12, 13 November 2011 (UTC)

Okay, indistinguishable of the white balls means, although we see different balls, once a ball has been drawn it is impossible to tell which one it was. The experiment consists of three successive draws of a ball without replacement. Possible outcomes are: BWW, WBW, WWB, WWW, as only the order of drawing and the colour matter. These four outcomes form the sample space. Probabilities are 1/10, 1/10, 1/10, 7/10, calculated in different ways. For instance; P(BWW)=P(WBW)=P(WWB)=P(The black ball is drawn)=1/10. Then P(3rd draw is B | 1st and 2nd draw are W)= P(WWB|WWB or WWW)=(1/10)/(1/10 + 7/10) = 1/8. Or equivalently by pointing to the remaining urn with 1 black and 7 white balls; P(3rd draw is B | 1st and 2nd draw are W)= 1/8. Nijdam (talk) 23:38, 13 November 2011 (UTC)

But the white balls are, in principle, distinguishable. Why have you chosen not to distinguish between then? Martin Hogbin (talk) 10:05, 14 November 2011 (UTC)

You asked what I would do if the balls weren't numbered, that's why. But it is irrelevant. The problem may be analyzed with or without numbering the balls. You're drifting away from the topic, which is the conditioning on what happened previously. Nijdam (talk) 11:43, 14 November 2011 (UTC)

A real problem

Nijdam, perhaps you would answer this question for me. Suppose you were employed as a probability consultant and a client came to you with a real-world version of the urn problem above.

9 white objects, numbered 1..9, and 1 black object are placed in an opaque container. You client has seen a person reach into the container without looking and remove white object number 5. They have then seen a second person do the same thing and end up with object number 7. Your client then asks you what the probability will be that they will end up with the black object if they reach into the container without looking and also how this probability should be calculated. What would you say to them? Martin Hogbin (talk) 16:48, 11 November 2011 (UTC)

Apparently he shows me an urn with 7 white and 1 black ball. The removal of the balls 5 and 7 were no part of the experiment. Piece of cake. Sample space {B,1,2,3,4,6,8,9}, random draw.Nijdam (talk) 20:31, 11 November 2011 (UTC)

This was meant to be a real-world problem. Is that what you would really say to your client? There are no urn conventions in the real world. Martin Hogbin (talk) 23:19, 11 November 2011 (UTC)

Well, I would have discussed all details with the client. But you gave me practically all the details, and as you said "urn problem", and asked for a probability, I assumed a random draw has to be made from the (remaining) content of the urn. Nijdam (talk) 17:11, 12 November 2011 (UTC)

I though I was being clear. This was meant to be an real-world version of the problem. The point I am making, however, is that there is a set of conventions that apply to urn problems that do not apply in the real world. In the real world you would have to discuss many things with your client, starting with asking exactly what they meant by 'the probability, and including many other things, such what the objects in the urn might be, whether thy might be distinguishable by touch, and many others that I am sure you could think of.

There are different conventions and rules for the same problem, depending on the context in which it is asked. In an examination question, for example, the student would be expected to assume that all the necessary information was given in the question and that all the information given was relevant to the answer in some way. But, as you have agreed above, in a real-world scenario you cannot assume that all the relevant information has been presented to you in the client's initial problem statement or that all the information given is relevant to computing the probability that the client actually wants to know. Would you not agree? Martin Hogbin (talk) 01:05, 13 November 2011 (UTC)

I thought I was being clear too. I said I would have discussed all details with the client. I did a lot of statistical consultation, and many times the client had to be helped in formulating what he wants. I.e. your client may just show me the urn and ask me "what is the probability of getting the black ball?" If I then would ask him if he would make a random draw from the urn, he may look puzzled at me, as he hardly understands what I mean. However if I ask him if he would shake the urn properly and then blindly takes out one of the balls - which by the way are all of the same weight and size and surface structure etc. - he would look at me and say "of course, what else could I do?" You see, for ordinary people such details are inherent connected to the situation with an urn, and implicitly assumed. Nijdam (talk) 07:58, 13 November 2011 (UTC)

Do you agree then that the way you would tackle a problem depends on the context in which it is presented? Martin Hogbin (talk) 10:43, 13 November 2011 (UTC)

This is too vague a question to be answered. Nijdam (talk) 23:46, 13 November 2011 (UTC)

Reduced probability space

To answer a question you ask elsewhere, my probability space would consist of two elements: the player initially chooses a car, the player initially chooses a goat, with probabilities 1/3 and 2/3 respectively. Everything else is certainty. Martin Hogbin (talk) 10:36, 6 November 2011 (UTC)

To repeat the question i asked several times: how do you describe the event door 1 is chosen and door 3 opened?Nijdam (talk) 17:01, 6 November 2011 (UTC)

I don't. There is no need to describe these events in the way you do. The player chooses a door and the host opens an unchosen goat-hiding door with certainty. Which doors these are are not important, just as the words used by the host are not important. The only question of importance is the whether the player swaps or not. This can be easily represented in my sample space. Martin Hogbin (talk) 17:32, 6 November 2011 (UTC)

You have to: the player knows which door she has chosen (I hope at least she does remember) and she sees the opened door. Or what? Nijdam (talk) 21:54, 6 November 2011 (UTC)

She may remember but she knows the door numbers make no difference, as do you. Martin Hogbin (talk) 22:23, 6 November 2011 (UTC)

No difference to what? Nijdam (talk) 10:08, 7 November 2011 (UTC)

To the probability that she will the car win by switching. Martin Hogbin (talk) 10:28, 9 November 2011 (UTC)

(outindented) Your sample space is (Car, Goat), with probabilities 1/3 and 2/3. What do you mean by the event "win the car by switching"?Nijdam (talk) 11:21, 10 November 2011 (UTC)

Exactly what I say, but I see what you are getting at. That event cannot be represented within my chosen sample space. On the other hand, is there any reason why it must be possible to represent that event within the sample space? Martin Hogbin (talk) 09:33, 11 November 2011 (UTC)

You're the one that brought it up.Nijdam (talk) 15:02, 11 November 2011 (UTC)

Yes, I do not doubt that the event occurred but why must it be represented in the sample space?

The occurrence of an event is nothing more than the occurrence of one of the outcomes, i.e. one of the elements of the sample space.Nijdam (talk) 11:23, 14 November 2011 (UTC)

If you want to by fussy then my sample space should really be Car-Stick,Car-Swap,Goat-Stick,Goat-Swap but we seem to have generally left out the swapping stage in out previous discussions. Martin Hogbin (talk) 23:28, 14 November 2011 (UTC)

Sorry Martin, you've lost me here. The extra aspect of swapping or not does not change a bit. And the whole discussion above applies as well.Nijdam (talk) 09:42, 15 November 2011 (UTC)

All I am saying is that my sample space should be (Car-Stick,Car-Swap,Goat-Stick,Goat-Swap) referring to the players initial choice and their subsequent action. This now allows all relevant events to be included. Nothing else makes a blind bit of difference. Whether the player sticks or swaps is important, whether the player initially chooses a car or a goat is important. We do not include the events that the host offers the player a swap or that the host opens a door to reveal a goat because these events occur with certainty. We do not include the door number that the player initially chooses, or the number of the door that the host opens or the name of the player or the name of the host because these events are not relevant to the probability of interest. Martin Hogbin (talk) 22:10, 15 November 2011 (UTC)

Just a question: What probabilities are assigned to the elements of your sample space? And another: Nothing else makes a blind bit of difference to what?? And a third: what is the probability of interest? Nijdam (talk) 22:32, 15 November 2011 (UTC)

See below

Nijdam, let me go back to my original sample space of just Car and Goat, I agree that the above space only works if we know the choice the player will make at the start. By "win the car by switching", I mean that the player will win the car if the choose the other available object. Martin Hogbin (talk) 21:05, 17 November 2011 (UTC)

I've no idea what this is about, But if you mean to perform an experiment with putcomes Car and Goat (probabilities ??), that's something different than the MHP. Nijdam (talk) 13:44, 23 November 2011 (UTC)

I guess that is where we disagree. If we mathematically formulate the MHP as a simple puzzle in which the number of the door originally chosen by the player and the door number opened by the host (within the rules of the game) are both considered independent of the probability that the player will win the car by switching then there is no reason not to use the simple (goat 2/3, car 1/3) sample space. We have no need in this interpretation of the problem to represent the event that the host opens an unchosen door to reveal a goat and the event that the player switches is represented by the player ending up with the opposite of their original choice. This makes the problem absurdly simple, which in fact it is when viewed properly.

If, on the other hand, you wish to treat the MHP as an examination question, where you will normally be expected to use all the information given but no other, then you must use the door numbers, because they are given to you. The sample space should therefore contain all possible combinations of producer door choice, initial player door choice and host door choice. For extra marks you might parametrise the producer's, player's, and host's door choice policies.

Finally, if you want to treat the MHP as a real world problem, you need to ask many questions before you can even start to answer it.

I prefer the first approach, you take the second to be the only one possible, and anyone who wants to make the problem absurdly complicated can choose the third. Martin Hogbin (talk) 13:06, 26 November 2011 (UTC)

As you're saying, you're just guessing. It's not a matter of disagreeing: you're just mistaken. If you want to describe and solve the MHP with a proper sample space you're not free to take whatever you like. And then, what do you mean by saying: the number of the door originally chosen by the player and the door number opened by the host (within the rules of the game) are both considered independent of the probability that the player will win the car by switching? Words are patient and easy said, but the exact meaning is unclear, not to say incomprehensible. What could be the meaning of the player's choice being dependent of the probability of getting the car by switching???

The probability of winning the car by switching is 2/3, whether the player initially chooses door 1,2, or 3. Do you disagree?

Either you refer to different probabilities of winning the car by switching, with the same value for all choices of door, and then this value is independent of the door numbers (and not the other way around), or you just mean only one probability and then it is pointless to say it does not depend on the number of the chosen door. So, what do you mean? Nijdam (talk) 11:11, 27 November 2011 (UTC)

The MHP is not different for ordinary people, students in probability theory, me or you. It could as well be considered to be a real world problem.

The only thing you can do is give an exact formulation - eventually in words, if formula's are too difficult - of the problem and the, or your supposed, solution. As you said yourself: formulate the MHP mathematically as a simple puzzle. I'm looking forward.

Nijdam (talk) 18:00, 26 November 2011 (UTC)

Ther is no such thing as 'an exact formulation'. What is not exact about formulating the problem with the sample space (goat, car)? It gives the exact answer, and not by chance. Martin Hogbin (talk) 01:20, 27 November 2011 (UTC)

It will be best you mathematically formulate the MHP as a simple puzzle (your words). Please do. Nijdam (talk) 11:11, 27 November 2011 (UTC)

Formulating a natural language problem mathematically

Nijdam, our disagreement occurs when we convert Whitaker's natural language statement into some form that is open to mathematical analysis. There is no standard algorithm or fixed procedure for doing this. If you know of one, please state it.

We both know Whitaker's question, it does not actually ask for a probability but let us agree that we shall attempt to give one. In natural language, we want to know the probability that the player will win the car if they decide to accept the host's offer to switch, made after a door has been opened. We cannot formulate this mathematically yet because we have not yet decided how to formulate the entire question. Are you happy to take my natural language statement as the question that we both wish to answer?

Would you prefer to take a frequentist or a Bayesian interpretation of 'probability'? I do not much mind which (although I slightly prefer Bayesian) but do insist that we take one interpretation and stick with it for this discussion. Martin Hogbin (talk) 12:09, 27 November 2011 (UTC)

I do prefer the frequentist iterpretation, as being (more) objective, and easier to interprete. Whitaker's question is not directly for a probability, but the answer "switch", will quite natural be followed by the question "why?". And the trick of the problem is of course the surprising 2/3 (conditional) probability of getting the car by switching. Nijdam (talk) 00:40, 28 November 2011 (UTC)

OK, let us be frequentists. This leaves many unanswered questions. With what probability is the car placed behind each door? With what probability does the player initially pick each door? With what probability does the host pick each legally available door, given doors previously chosen by the producer to place the car and the player? What is your rationale for these probabilities? Martin Hogbin (talk) 00:57, 28 November 2011 (UTC)

Being a frquentist I assume the play is repeated, or at least repeatable. I also assume the formulation of the problem is not meant for exact mathematicians, otherwise it would be phrased more exact. If common people is given a choice out of three things, one with a price, they quite naturally assume the price is hidden with equal chances and they are unaware of the position of the price. So, the car is hidden uniformly and the initial choice is independent of the position of the car. The distribution of the initial choice is unimportant, hence does not need to be specified. This leaves us with the strategy of the host. It seems reasonable to assume he always offers the switch, and only opens a door with a goat. Other scenarios may of course also be analyzed. But the assumed one offers all the interesting aspects of the problem. What if the host has a choice between two goat doors. I guess most people would say: he flips a (fair) coin. There we are: the standard MHP.

We shall take it that the car is initially hidden uniformly and the host chooses uniformly between unchosen goat-hiding doors. That is all fine with me, except for one thing.

You say that the initial choice of the player is unimportant. Are you suggesting therefore that, although we know the player might have chosen door 2 or door 3 we only consider the case stated in the question. We need to calculate the probability that the player will win the car by switching. Why do you not consider the possibility that the player might have chosen a different door? 2.102.214.196 (talk) 18:23, 28 November 2011 (UTC)

Forgot to log in? Anyway, the answer will be the same whatever the distribution of the initial choice may be. Nijdam (talk) 20:59, 28 November 2011 (UTC)

So you consider it acceptable to reduce the sample space because you can see a simplification of the problem that obviously will not affect the answer? A representative sample of the whole sample space you might say. Martin Hogbin (talk) 22:12, 28 November 2011 (UTC)

On the contrary. There is no reduction of the sample space, and there is no reduction of the possible distributions.Nijdam (talk) 10:17, 29 November 2011 (UTC)

The whole sample space should surely contain all the outcomes allowed by the rules of the game. The player might have initially chosen door 3. Martin Hogbin (talk) 18:31, 29 November 2011 (UTC)

I do not completely follow you in your last two comments. I suggest you list all the possible outcomes of the experiment.Nijdam (talk)

Surely the full sample space should include all possible outcomes that are permitted by the rules of the game. For example, that the player initially chooses door 3 and the host opens door 1 to reveal a goat. Martin Hogbin (talk) 18:50, 29 November 2011 (UTC)

The fact that you speak of the "full sample space" strongly suggest there is another sample space. There is however just one sample space, the full one, if that's what you like to call it. And, as we've been there before, it consists of 18 outcomes with positive probability. Agree? Nijdam (talk) 12:50, 30 November 2011 (UTC)

You talk as if the sample space somehow presents itself to us when we read a natural language description. This is not the case. Before we can even talk about a sample space we have to consider which events are relevant to the probability of interest (that the player will win the car by switching) and which events are not important. Martin Hogbin (talk) 14:55, 30 November 2011 (UTC)

It does indeed, as the sample space is no more than a mathematical formulation of the possible outcomes. That's why I asked you to list the possible outcomes. Although you mentioned an example of an outcome, you did not list them all. I described the outcomes more or less. Perhaps it clarifies things if you describe all outcomes. Do bear in mind, i.e. that you have to describe the uniform distribution of the car. Nijdam (talk) 00:41, 1 December 2011 (UTC)

I have copied the original statement here for easy reference.

Suppose you're on a game show, and you're given the choice of three doors: Behind one door is a car; behind the others, goats. You pick a door, say No. 1, and the host, who knows what's behind the doors, opens another door, say No. 3, which has a goat. He then says to you, "Do you want to pick door No. 2?" Is it to your advantage to switch your choice?

So what are the possible outcomes? We cannot even begin to answer that question without making assumptions about things that are not explicitly stated. For example, it says, You pick a door, say No. 1. It does not explicitly say that you might have picked door 2 or door 3. This is not an unnatural assumption considering it is a game show but it is an assumption.

The same is true of the host's choice of door. Must he always open door 2?

Now I agree that these two particular questions are answered by the 'standard' rules of the game that are assumed by most people and that we have agreed to assume here but I mention them to show that, right from the very start, we must make some assumptions about what is important and what is not when we propose a sample space.

The host says "Do you want to pick door No. 2?" We are not told that the host might have used different wording but logic tells us that normal speech often uses different words to mean the same thing. Maybe the host sometimes says "Do you want to switch to door No. 2?" The standard rules tell us nothing about the host's choice of words although we are clearly told of one possible wording in the problem statement. Our sample space should therefore include every possible form or words that the host might have used, just as it includes the doors that the player might have originally chosen. Why do we not do this? Because we have to decide which are the important events before we set up our probability space. There is no procedure or algorithm that tells us how to do this; it is a matter of interpretation. Martin Hogbin (talk) 21:04, 1 December 2011 (UTC)

You seem to run around in circles. Remember you somewhere above said: Surely the full sample space should include all possible outcomes that are permitted by the rules of the game. For example, that the player initially chooses door 3 and the host opens door 1 to reveal a goat. What then is the status of this remark?

Anyhow, the problem statement says: ...you're given the choice of three doors... And the sentence: You pick a door, say No. 1, indicates that as an example of the possible three choices, the choice of door No. 1 is given. Etc. Nothing in the problem formulation indicates any dependance of the words of the host, the words of the host are not a part of the experiment, but of the question to be asked. Before the host offers the switch, it is possible to calculate the relevant probabilities, but we do not know which probability is asked for. And then, the problem being a natural language problem, no one except apparently you will come to such thoughts. And, last of all, your simple sample space is completely inadequate for your supposed possible outcomes.

Thus I repeat: please list the possible outcomes, not as you think they might be, but as common people, with natural language, think they will be. Nijdam (talk) 13:32, 2 December 2011 (UTC)

I understand that I am being a little perverse but I am trying to make the point that the sample space is not defined precisely by the problem statement but requires some thought. You say that, 'the words of the host are not a part of the experiment' but what exactly tells you this? It is quite conceivable that the host would try to help the player by giving them a the player a clue in the language that they use. Martin Hogbin (talk) 16:44, 2 December 2011 (UTC)

You are, and that's no problem. as far as it brings new insight. But you can't dwell there forever. Of course a natural language problem needs some reflection when formalizing it. Some problems may even fail there because of insufficient description. The formulation of the MHP however leads to a unique (up to equivalence) sample space. Concerning the words of the host, much is conceivable, but when there is no indication whatsoever in the formulation, of any difference the words may induce, it is not up to us, to speculate. As I said above, the words of the host only tells you about the question asked, but nothing about a possible outcome of the game. If you have a different pinion, please show me how the words of the host influence (not how they may influence) the outcome of the game. Nijdam (talk) 18:00, 2 December 2011 (UTC)

Can you show me how the host's choice of door (within the rules of the game) influence (not how they may influence) the outcome of the game? Martin Hogbin (talk) 21:47, 2 December 2011 (UTC)

Yes, no problem. And then it is your turn. If the host opens door 1, we see door 1 opened, if he opens door 3, we see door 3 opened, two different outcomes. It's that simple. Nijdam (talk) 11:16, 3 December 2011 (UTC)

If the host the host says 'pick' we hear 'pick', if the host says 'choose' we hear 'choose', two different outcomes. As with the host's door choice neither affects the probability of interest. Martin Hogbin (talk) 12:28, 3 December 2011 (UTC)

Where in the problem statement did you read that the host says, or may say, "choose"? Nijdam (talk) 18:31, 3 December 2011 (UTC)

Where in the problem statement does it say that the host may open door 2? Martin Hogbin (talk) 22:58, 3 December 2011 (UTC

Here: " opens another door". And now your answer to my question, straightforward.Nijdam (talk) 21:02, 4 December 2011 (UTC)

There is no mention of door number 2 specifically, the only door mentioned is 3. Martin Hogbin (talk) 21:14, 4 December 2011 (UTC)

Why specifically? Do I have to spell it out for you? There are three (3) doors. Door 1 is chosen by the contestant. The host opens another door. Which door might that be? Not No. 1 as that is the same door. The other doors are door No. 2 and door No. 3. The host opens one of these other doors. He may open No. 2 or he may open No. 3. (As an example door No. 3 is chosen in this instance of the game.) Would you prefer a picture for easier understanding? Nijdam (talk) 23:53, 4 December 2011 (UTC)

You still seem to be viewing the problem like an exam question where information that is given is normally given because you are expected to use it and all the information required to solve the problem is given in the problem statement. In other situations it is quite possible that you might be given information that is not required to solve the problem and that some of the information required to solve the problem will not be given. I have given a fairground example at the end of this talk page for ease of editing. Martin Hogbin (talk) 12:53, 4 December 2011 (UTC)

It has nothing to do with an exam question. You keep mentioning this, as if you need to convince yourself. Nijdam (talk) 21:05, 4 December 2011 (UTC)

I an trying to convince you that the way a natural language statement is turned into a mathematical question and a sample space depends on the context. In an exam you assume that all the information you need to answer the question in the way intended by the examiner is contained within the question and that only necessary information is given.

You have already agreed that if this were a real life problem you would start by asking many questions. Do you not agree that in another context, such as the consultancy context we discussed earlier, you might want to enquire if there was any more relevant information and whether some information, such as the door numbers, was considered significant? Martin Hogbin (talk) 21:14, 4 December 2011 (UTC)

Some relevant info we deduced from the formulation. If it was a consultancy I would have asked my client to be sure. What more information do you want to know? And there we are again: to what should the door numbers be considered significant?? It's time you give a straightforward and precise answer. Nijdam (talk) 23:43, 4 December 2011 (UTC)

The way you put a question into mathematical terms depends on what question you think the questioner is asking. That is a basic point of statistics. In a real life situation we agree that you would need to ask many questions to find out what the questioner really wanted to know. In an exam question we would naturally assume that all information given was significant and necessary. However, the MHP was none of these it was a simple puzzle, proposed as a question to a column in a popular, general-interest magazine. We happen to know that the door numbers were never intended to be part of the question and that they were added by vos Savant to try to clarify the question. There is no doubt in my mind that Whitaker was not intending to distinguish between the 'conditional' and 'unconditional' interpretations of the problem and that it was intended to be a simple brain teaser in which the door number opened by the host played no part. Therefore, whenever the player makes their choice, {goat 2/3, car 1/3} is a perfectly adequate sample space to describe the intended question. Martin Hogbin (talk) 22:46, 7 December 2011 (UTC)

The MHP is a simple puzzle, a simple probability puzzle. I do not know who "we" are and how they happen to know something, but it is time, and I asked this several times, you clarify your ideas about the door numbers. This time you say they were not intended to be a part of the question. When the player chooses a door, will there be a number on that door, or if you hate numbers, will it be the left, the middle or the right door? And I have no idea about Whitaker's intentions; whatever they were, it is unavoidable to speak of conditional probabilities. To ease the discussion, answer the following question: Which door do you, as the player, choose? Nijdam (talk) 16:50, 8 December 2011 (UTC)

Let me start by supposing that Whitaker did not specify doors in his original question. The host opens any door not originally chosen by the player that hides a goat. We cannot identify the doors in any way. Martin Hogbin (talk) 21:03, 8 December 2011 (UTC)

This makes no sense. Whitaker does not explicitly speak about the numbers, but he mentions three doors. You're the player, you're on stage, do you see the three doors? Just answer yes or no.Nijdam (talk) 10:52, 9 December 2011 (UTC)

The problem statement does not tell me. I need to interpret the statement according to its context. I this was a real life situation I would see three doors along with many other things that might or might not be relevant. As this is a simple puzzle I do not see any doors, as I know they are irrelevant to the intended question. Martin Hogbin (talk) 17:39, 9 December 2011 (UTC)

Is this a yes or is this a no?Nijdam (talk) 18:02, 9 December 2011 (UTC)

That depends on the context, which is my whole point. I am not avoiding the question, just pointing out that your question is ambiguous. In reality, I can see nothing of the events. Do you mean:

Would I expect a person on a real game show to see which doors were opened? Yes.

Do I think Whitaker considered it important that I should imagine specific doors being opened? No. Martin Hogbin (talk) 18:19, 9 December 2011 (UTC)

You seem to know Whitaker well. I do not care what Whitaker might have considered important or not, fact is he introduced three doors, and no one doubts the fact that the player makes a choice from these doors. It is impossible for the host to open a door if not the choice of the player is made. I suggest you describe me how the game proceeds through the different stages. Nijdam (talk) 00:04, 10 December 2011 (UTC)

But you must care what Whitaker considered important if you are to answer his question properly. As Seymann said, Without a clear understanding of the precise intent of the questioner, there can be no single correct solution to any problem. Thus, with respect to the three door problem, the answer is dependent on the assumptions one makes about the intent of the one who originally posed the question. In this case, the intent of the questioner is made clear by the forum in which he chooses to ask it; a column on a popular magazine. Martin Hogbin (talk) 11:21, 10 December 2011 (UTC)

Yes, what he considered important, but not what he might have considered important. It is not up to us to speculate. Anyway, whatever he might have had in mind, he mentioned three doors to choose from. That's a fact, or do you have doubts? That's why (almost, I may have to exclude you) everyone pictures three doors, and for the sake of simplicity numbers them 1, 2 and 3. But again, and this time no other questions, remarks, etc., just describe how the game proceeds according to you. Nijdam (talk) 14:07, 10 December 2011 (UTC)

We have to use our consider, in Seymanns words, what the 'precise intent of the questioner' is before we can even formulate an answer. That is my main point.

Whitaker mentioned three doors but he did not distinguish between them.

Regarding how the game goes, the player chooses a door, which has either a car or a goat behind it. The host opens a different door to reveal a goat. The player then decides whether to swap or not. If he originally chose the car and swaps he gets a goat, if he originally chose a goat and swaps he gets the car, if he originally chose the car and sticks he gets the car, if he originally chose a goat and sticks he gets a goat. That is it.

We do not care what the number of the door is that the player originally chooses, which goat the host reveals or which door the host opens. Martin Hogbin (talk) 14:27, 10 December 2011 (UTC)

It suffices that you say: Whitaker mentioned three doors. I cannot imagine what you possibly could mean by saying: but he did not distinguish between them. Three doors are three doors. One door, another door and the third door. Does the player see three doors or what? If you have the idea the player does not see three doors, what then does she see?? Before continuing, just tell me what the player sees, and for the moment no more, just this. Nijdam (talk) 22:42, 10 December 2011 (UTC)

I'll make it easy for you. Logically, one of the following possibilities must be true.

1. She does not see any door
2. She just sees one door
3. She sees exactly two doors
4. She sees exactly three doors
5. She sees more than three doors

Just mention the number of the possibility you think is true. Nijdam (talk) 22:56, 10 December 2011 (UTC)

The problem statement does not tell us how many doors the player sees so I cannot answer your question. Martin Hogbin (talk) 00:05, 11 December 2011 (UTC)

Okay, then does she know how many doors there are? Nijdam (talk) 17:38, 11 December 2011 (UTC)

Yes. Martin Hogbin (talk) 12:49, 16 December 2011 (UTC)

How many? Nijdam (talk) 12:07, 20 December 2011 (UTC)

Three. Martin Hogbin (talk)

What difference would it have made, if you had said: she sees three doors?Nijdam (talk) 07:05, 21 December 2011 (UTC)

It might imply that the doors themselves might have some significance. The point is that if someone, before the start of the show, swapped all the door numbers (or any other identifying features) round it would not affect the outcome. Martin Hogbin (talk) 22:06, 24 December 2011 (UTC)

I can't follow you here. If the player knows there are three doors and she is on stage near the doors, she sees them (I do not consider her to be blind).Nijdam (talk) 09:44, 25 December 2011 (UTC)

Do you prefer to play the role of the player or of one of the audience?? Nijdam (talk) 19:19, 24 December 2011 (UTC)

Of course it is very reasonable to assume that the player could see the doors but it is, nevertheless, still an assumption. Martin Hogbin (talk) 10:59, 25 December 2011 (UTC)

I am answering based only on information given in the (Whitaker's) question. Martin Hogbin (talk) 22:06, 24 December 2011 (UTC)

In that case - read the problem formulation - you're the player. So, which door did you choose? Do not say something like: it doesn't matter which one, etc, just answer the question! I'm anxious to hear your answer. Nijdam (talk)

Whitaker's original question did not tell us which door the player chose. Vos Savant added 'say door 1' to the statement but this was just intended to be an example of one of the doors that the player might have chosen.

If you are asking me to follow Whitaker's suggestion and imagine that I am a player on a show then I have not imagined a door number, although I do wonder if there is a car or a goat behind my chosen door. Martin Hogbin (talk) 10:59, 25 December 2011 (UTC)

Doors

You choose to be the player. Following Whitaker's scenario, you're on stage now. Let us assume you're not blind. Because, as you said, you know there are three doors, you must be able to see them. Do you see them? Tell me how you like to distinguish them. A, B, C or 1,2,3 or left, middle right, anyway you like. You're asked to choose a door. As Whitaker wrote: "you pick a door" etc. See, nothing problematic. just tell me which door it is you've chosen?Nijdam (talk) 21:56, 28 December 2011 (UTC)

If this information is not given in the question we cannot use it in the solution. I pick a door. That is all. You may assume that I am not blind, that I see the door that I pick, that I can remember which one it was, and that I do not spot the obvious symmetry that makes it irrelevant but the information is not given in the question.

If you do not want to reveal which door you've chosen, you may solve the problem by calling it the door with the number x. And I presume you know very well how this continues.

It has nothing to do with my wishes. I am responding based only on the information given in the original question, as Morgan entreat us to do. The original question does not tell us which door was opened.

Let me ask you this question, 'Which goat does Monty reveal when he opens a door?'. Martin Hogbin (talk) 10:02, 29 December 2011 (UTC)

That's easy: The goat behind the door he opens. Nijdam (talk)

But which goat is this? Monty knows where the goats are, we presume that he can see them and that they are different goats, distinguishable in principle. Shall we call it goat number x?

You see my point? There is no more reason to include door numbers in our sample space than there is to include goat numbers. Martin Hogbin (talk) 11:55, 30 December 2011 (UTC)

Maybe the host always reveals the white goat (whichever door it is behind) when the player has initially chosen the car. Martin Hogbin (talk) 12:00, 30 December 2011 (UTC)

You're trying to make a point where there is none. If you would like to distinguish the goats, go ahead, it doubles your outcomes. However nowhere in the problem formulation anything is said about the difference of the goats, like "the host opens one of the closed doors and shows a goat, say goat nr. 1" or something like that. In fact anyone understands the goat doors could as well be empty. On the other hand it is said the player choose a door. And that means the chosen door is known. Nijdam (talk) 17:46, 1 January 2012 (UTC)

So, if the problem statement did say, 'the host opens a door to reveal the white goat', would it make any difference to your solution and sample space? Martin Hogbin (talk) 18:23, 1 January 2012 (UTC)

Yes, of course, it would mean another condition. Nijdam (talk) 19:11, 1 January 2012 (UTC)

What about if it said,'...and behind the other doors distinguishable goats'? Martin Hogbin (talk) 19:13, 1 January 2012 (UTC)

Well, it doesn't. And if, then look at what I said above. Nijdam (talk) 23:21, 1 January 2012 (UTC)

When must we distinguish?

A while back you were arguing that even if the doors were not numbered and the door numbers were not given in the problem statement it would still be necessary to include the door opened by the host as an event in our sample space. Your reasoning was that the player would undoubtedly be able to see the doors and distinguish between them.

Why then must the sample space not also include the ID of the goat that is revealed? We know that the host can see the goats and that goats are, in principle, distinguishable. Martin Hogbin (talk) 09:55, 2 January 2012 (UTC)

Would you be able to distinguish between two almost identically looking goats?Nijdam (talk) 11:42, 13 January 2012 (UTC)

I cannot say. I am not an expert on goats. Whether I or any specific person could actually distinguish between the two goats is not important. The goats are in principle distinguishable. There are two goats, not one goat moved from door to door. It is quite possible that the goat that Monty chooses to reveal depends on the location of the car. Must we include goat-number in our sample space? Martin Hogbin (talk) 12:05, 13 January 2012 (UTC)

Sorry, didn't know you were a layman with goats. Let's first solve a MHP with one door with a car and two empty ones. See where this leads us. Nijdam (talk) 20:01, 13 January 2012 (UTC)

But goats are an integral part of the MHP. The problem statement clearly tells us that there are two goats and the host reveals one of them. How can you ignore thee information in the specific goat that the host reveals? Martin Hogbin (talk) 20:05, 13 January 2012 (UTC)

Just do it. Nijdam (talk) 23:05, 14 January 2012 (UTC)

Of course you can ignore this information if you like but it is quite possible that the answer to the problem depends on it. It is possible to envisage a situation where the host prefers the white goat to the black goat and only reveals the black goat when he has to, just as Morgan envisage the situation where the host prefers door 3 and only opens door 2 when he has to. Neither possibility is stated in the problem statement so why do you insist on including door numbers in your sample space but not goat numbers? Martin Hogbin (talk) 00:42, 15 January 2012 (UTC)

Please Martin, do as I asked.Nijdam (talk) 10:47, 15 January 2012 (UTC)

Sorry, I am not sure what you want me to do when you say 'Just do it'. Martin Hogbin (talk) 18:59, 15 January 2012 (UTC)

Solve a MHP with one door with a car and two empty ones. See where this leads us. Nijdam (talk) 19:45, 15 January 2012 (UTC)

This leads me to one of the simple solutions but maybe it leads you to Morgan's solution. I do not see the point of this, the MHP has goats behind the loosing doors. One goat is revealed to the player but the other is not. Why do you not want to take this into account in your probability calculation. Martin Hogbin (talk) 16:40, 16 January 2012 (UTC)

Please Martin, spell it out. Nijdam (talk) 09:45, 20 January 2012 (UTC)

One car, two empty doors

My solution is to start with the sample space {C,E} so initially P(C)=1/3 P(E)=2/3.

A player who swaps gets the opposite of his original choice, so P(C|swap)= 2/3), a player who sticks gets his original choice, so P(C|stick)=1/3. Martin Hogbin (talk) 09:54, 20 January 2012 (UTC)

I think you will not be surprised when I ask: How do you describe the event "'the car is behind door No. 1'"? (That's where we started some while ago.) Nijdam (talk) 08:07, 25 January 2012 (UTC)

And I guess that you will not be surprised if I ask you in return how you would describe the event that the host says the word 'pick'. Both events undoubtedly occur but neither is relevant to the probability of interest (which is that the player wins the car given the conditions of the problem).

I think you do not realise that you are applying a set of rules or conventions to the way that you answer the problem. You know that the door numbers are important because a specific door number is mentioned in the (vos Savant's version of Whitakers's question) problem statement. You assume all the information given is important, so your sample space must include door numbers, and you assume information not given explicitly, such as the fact that there must be two different goats, is not relevant, so must not be included in your sample space. Would you agree? Martin Hogbin (talk) 09:42, 25 January 2012 (UTC)

First your answer, then other details. Nijdam (talk) 00:06, 26 January 2012 (UTC)

My answer is that I do not describe that event. Martin Hogbin (talk) 09:22, 26 January 2012 (UTC)

Seemingly too difficult for you. Then a simpler question: Which door did the player choose? Nijdam (talk) 00:13, 27 January 2012 (UTC)

We do not know. Vos Savant (but not Whitaker) superfluously gave door 1 as an example of a door that he might have chosen but it is pretty obvious that in makes no difference which door the player chooses if the car is hidden uniformly at random. Martin Hogbin (talk) 10:00, 27 January 2012 (UTC)

Difference to what?Nijdam (talk) 12:00, 27 January 2012 (UTC)

The probability that the player has originally chosen the car and the probability that a player who swaps will win the car. Martin Hogbin (talk) 15:13, 27 January 2012 (UTC)

Martin, you haven't learned much from our discussion. As I explained before, the probability that the player has originally chosen the car is 1/3. How in the world can anything make any difference to this?? And similarly, what difference could it make to the probability that a player who swaps will win the car? Normally your thoughts show more logic. Nijdam (talk) 23:03, 27 January 2012 (UTC)

Yes, you are quite right about the original probability but I cannot see what is wrong with 'the probability that a player who swaps will win the car'. Perhaps I should make it 'the probability that a player who participates in the game as described and who, after the host has revealed a goat, decides to swap will win the car'. Martin Hogbin (talk) 00:18, 28 January 2012 (UTC)

Well, try to formulate the event you mention "a player who swaps will win the car" in terms of your sample space. And then make clear where there is no difference. I'm lost actually. Nijdam (talk) 10:31, 30 January 2012 (UTC)

That is quite easy. The original sample space is {C,E} with probabilities 1/3 and 2/3 respectively. If the player's original choice is E (that is to say an empty door) and the player swaps they will end up with the car, so the probability that a player who swaps will win the car is 2/3. Whether the player initially chooses door 1, 2, or 3 does not alter this probability. The door number that the host opens, within the rules of the game, also makes no difference, neither does the name of the host or the words that he says.

Not as easy as you think. Indeed is E the event I asked for, with probability 1/3. Where could it make any difference which door the player chooses? There are only, in your model, the doors E (empty) and C (car), and it makes a considerable difference which one the player chooses. Please explain. Nijdam (talk) 10:54, 31 January 2012 (UTC)

The door number, or indeed any other distinguishing feature of the door, is irrelevant to the probability of interest which, as stated above is the probability that a player, who conforms to the rules of the game and who on being shown and empty door switches, will win the car.

Do you mean P(E)?? Show me how the door number is irrelevant to P(E)?

What do you mean by P(E)? Is it the probability that the player has chosen originally nothing? The door number is clearly irrelevant to this probability. Unless you think the player is more likely to have chosen nothing if they initially pick a specific door number, in which case perhaps you could tell me which door number. Martin Hogbin (talk) 22:22, 31 January 2012 (UTC)

You shouldn't ask me, it's your sample space. Indeed is it, as you stated, the probability the player's first choice is an empty door. In your sample space P(E)=2/3. In what way may a door number influence this? Please show me. Nijdam (talk) 11:45, 1 February 2012 (UTC)

The door number does not influence this. That is why I do not care about door numbers. Martin Hogbin (talk) 15:07, 1 February 2012 (UTC)

That's not an answer. Give me the correct formulation, best in formula, of your statement that the door number does not influence P(E). Nijdam (talk) 15:48, 2 February 2012 (UTC)

I cannot do that; it is done before the formal formulation of the problem. How do you show from your preferred sample space that the goat revealed or the words the host says is not relevant. Martin Hogbin (talk) 16:07, 2 February 2012 (UTC)

If you disagree, perhaps you can tell me which door is most likely to be a winner. Is it 1,2, or 3? We agree that the car is placed behind the doors uniformly at random.

What does it mean that the car is placed randomly? Use your sample space. Nijdam (talk) 22:09, 31 January 2012 (UTC)

The random placement of the car is used to assign the probabilities 1/3 and 2/3 to the elements in my sample space.

How do you know this? Nijdam (talk) 11:45, 1 February 2012 (UTC)

On car, two empty doors, uniform placement. Martin Hogbin (talk) 15:07, 1 February 2012 (UTC)

Can you show me in your sample space that the car is placed randomly? Nijdam (talk) 15:48, 2 February 2012 (UTC)

No, this is not necessary. See may answer aboveMartin Hogbin (talk) 16:07, 2 February 2012 (UTC)

You have not answered my question. Which door is most likely to be a winner. Martin Hogbin (talk) 22:22, 31 January 2012 (UTC)

You still seem to be missing my main point, which is that, on reading a natural language problem, a sample space does not automatically present itself to us. We have to decide what elements we need to include in our sample space in order to determine the probability of interest. Martin Hogbin (talk) 16:07, 2 February 2012 (UTC)

The doors do not need to form part of the problem, they are an irrelevance, a distraction. All that matters is what is behind the doors.

You have not (seriously) answered my question below. I agree that it is not exactly in the game show format but is clearly shows that the doors are not essential to the game; they merely play the role of the blindfold in my problem. Martin Hogbin (talk) 15:30, 31 January 2012 (UTC)

Ten doors, one car

Nijdam, I hope that by rational discussion we will eventually be able to come to a common understanding of this subject. In order to help clarify your views I would be interested to hear how you would deal with the following problem.

A car is placed uniformly at random behind one of ten doors, numbered 1 to 10. A player is allowed to pick any five doors. What is the probability that one of the chosen doors hides the car? How would you calculate this? Martin Hogbin (talk) 10:17, 2 February 2012 (UTC)

Firstly we have to assume the choice of the player is independent of the position of the car. Then we may reason that any choice of 5 doors will hide the car with probability 1/2, so all the conditional probabilities we're looking for have the value 1/2. This may also be calculated formally with sample space etc. We may also establish the equivalence with an urn with one black and 9 white balls and 5 successive drawings without replacement. To see clearly how this has to be solved, consider the car to be hidden with probabilities p1,p2,...p10. What then?Nijdam (talk) 16:07, 2 February 2012 (UTC)

I guess I should have mentioned that the random car placement was secret so, yes, the choice of the player is independent of the position of the car.

As you say, we could consider the car to be placed behind each door with probability 1/10 and then consider the large sample space in which the player picks every combination of 5 doors and eventually find the probability that the player will pick the car. On the other hand you say, 'we may reason that any choice of 5 doors will hide the car with probability 1/2'. You seem to be suggesting that we do not absolutely need to set up our vast sample space to do this and there I completely agree with you. Would you therefore agree with me that to assign the probability of picking a car from 3 doors we do not absolutely need to include the doors in our sample space? Martin Hogbin (talk) 00:19, 3 February 2012 (UTC)

No, I think you misinterpret me. My reasoning is just to ease the calculations, just as we may use symmetry in the MHP. Nijdam (talk) 17:06, 7 February 2012 (UTC)

So what sample space do you say is the minimum necessary to solve this problem. Martin Hogbin (talk) 17:12, 8 February 2012 (UTC)

Gerhard's comment

pardon again, but the characteristic and specific feature of the MHP is the correct decision to be made, the correct answer to be given, and never any forever unknown supposable additional hint that  "(im)potentially  could eventually be expected",  arising from any peculiar behavior of the host or of the guests, the color of the doors or the illumination. You "can" suppose anything whatsoever you like, if you just like, but it is not necessary and not helpful for the correct decision, and it never will affect this correct decision to be made and the correct answer to be given. As you do and forever will know nothing about any such influence, all of this is a pure mathematical issue for undergraduates, that's where it belongs, not affecting the only correct answer to be given in the MHP.  Gerhardvalentin (talk) 15:32, 10 December 2011 (UTC)

One car, two goats

Now one for you, Nijdam.

The player is blindfolded and asked to point at the stage, where there are there are two goats and a car. The object closest to where the player is pointing is then removed from the stage and put in another room as the players original choice. The host then takes the player to a different room and then brings the white goat, from the stage, into that room with the player. The player is then given the choice between having their original choice or taking the item left on the stage. How would you answer that one? Martin Hogbin (talk) 10:03, 20 January 2012 (UTC)

With the help of a friend the player manages to climb on to the stage, and stumbles over the black goat, which in anger, pushes the player off the stage. The host then removes the black goat from the stage and puts it in a chair amongst the audience. The player then enters the stage again, and points to the white goat, making the black goat furious. The black goat rushes from his seat on to the stage and stumbles over the player, who in anger shoves the black goat from the stage. The host the removes the player from the stage and puts het in a chair among the audience where she becomes at rest finally. For her cooperation she receives the car. Nijdam (talk) 08:16, 25 January 2012 (UTC)

I guess that is why the goats are kept behind closed doors. But do the doors really make such a difference to the probability calculation? Martin Hogbin (talk) 09:30, 25 January 2012 (UTC)

You speak of "the white goat". what does this mean?Nijdam (talk) 11:48, 1 February 2012 (UTC)

It means that goat is revealed and that it is white. We do not know the colour of the other goat but we can surely assume that it is not the same one as the one that has been shown. We are therefore free to refer to it as the black goat, purely for our own convenience. Martin Hogbin (talk) 14:42, 1 February 2012 (UTC)

The problem statement did not mention a white goat, nor a black one. Do I have to add this? Nijdam (talk) 16:09, 2 February 2012 (UTC)

Yes is does, 'The host then takes the player to a different room and then brings the white goat'. Martin Hogbin (talk) 00:09, 3 February 2012 (UTC)

Well it just says: the white goat, from the stage, which leaves as interpretations: on the stage has remained a white goat and another one, not white, or a white goat and the car, leaving the colour of the other goat unexplained. Let me assume there is a white goat (W) and a black one (B).The original choice then takes the values C(ar), W or B, and for good reasons with equal probabilities. As we are informed that W is still on stage, the first choice wasn't W. The question now is about the conditional probabilities, given the first choice wasn't W, which are P(CW|first not W) and P(BW|first not W), being both equal to 1/2. Nijdam (talk) 16:56, 7 February 2012 (UTC)

Nijdam's solutions

You seem to be stating objections to my proposed solutions that would apply equally to the solutions presented in the article and by you. To save us going round in circles, perhaps you could give me your solutions, with clearly identified sample spaces in the following two cases, where the standard rules apply: Martin Hogbin (talk) 09:46, 16 November 2011 (UTC)

Your statement is incorrect.Nijdam (talk) 11:32, 16 November 2011 (UTC)

The player initially chooses door 1 and the host opens door 3

As you know one description is in terms of the three random variables C (position of car), X (choice of player)n and H (door opened by host). any other description is equivalent to this. The relevant probability is P(C=2|X=1, H=3).Nijdam (talk) 11:37, 16 November 2011 (UTC)

The player chooses a door and the host opens another door

Do you mean: The player will choose a door and the host will open another door? Or do we see what happens? Description of course as above. If the player chooses door x and the host opens door h, the relevant probability is P(C<>x,C<>h|X=x. H=h).Nijdam (talk) 11:44, 16 November 2011 (UTC)

No, I mean that we only know that the player has chosen a door and the host has opened another door but we do not know which. Martin Hogbin (talk) 15:07, 16 November 2011 (UTC)

And it's us who have to decide? We then will base our advise on the overall probability of getting the car by switching, being 2/3. In the MHP, as an extra aspect, we know that all conditional probabilities of winning the car by switching have the same value 2/3. So the advise off switching will also be best in all specific cases. In other problems however the decision to switch may be the wrong one in some cases. Nijdam (talk) 21:49, 16 November 2011 (UTC)

Let me explain what I mean by quoting this version of the problem, 'You will be offered a choice of three doors, and after you choose, the host will open a different door, revealing a goat. What is the probability that you will win if your strategy is to switch?'.

What is your sample space and solution? Martin Hogbin (talk) 21:11, 17 November 2011 (UTC)

Well, you didn't explain what you mean. But anyway, apparently there are three doors, and I call my choice X, with values the door numbers (or letters, or whatever to identify them). The door opened by the host I call H. I do not understand the role of the goat. I assume this problem is not stated in a strict formal context, so I put P(X=x)=1/3, for all x. As the host in any situation has a choice of two doors, it seems reasonable to take P(H=h|X=x)=1/2 for all h<>x. Is this of any help?? Nijdam (talk) 13:54, 23 November 2011 (UTC)\ BTW, I didn't answer the question about the probability, as I have no clue what I might win. The goat? And does switching means, like in the MHP, finally choose the remaining closed door? Nijdam (talk) 22:31, 23 November 2011 (UTC)

Another sample space

Nijdam, would you prefer this space then? C, G1, G2 each with probability 1/3. What matters is the object behind the door, the door and the number on it are unimportant.

The player initially chooses one of the objects. The host the reveals either G1 or G2, neither we nor the player know which, then the player, after receiving this 'information' decides whether to stick or swap. How would you tackle that problem? Martin Hogbin (talk) 10:15, 14 November 2011 (UTC)

No, I don't. A sample space is no more than a model of the situation. It reflects the essential aspects of the problem. Any relevant detail of the situation will be reflected in the sample space. In this way the problem is better accessible for formal treatment. So, list all relevant things that may happen in the MHP and construct a sample space. The player entering on stage is no relevant detail. Nor is the host sneezing, as nowhere is any indication that something depends on this. The choice of one of the doors by the player however is, as this choice may for instance be the door with the car. Etc.Nijdam (talk) 11:36, 14 November 2011 (UTC)

'Unconditional' solution

Nijdam, to make discussion easier, perhaps you could show me how you would do the calculation for the case where the player decides his strategy before the host opens a door. Martin Hogbin (talk) 07:24, 18 August 2011 (UTC)

Does the contestant have a strategy? And even then, the contestant argues that in the case she picks door No. x and the host opens door No. h, she has to calculate the conditional probability, or alternatively the odds, to base her decision on. Nijdam (talk) 08:39, 18 August 2011 (UTC)

The player's strategy is to always swap. Martin Hogbin (talk) 09:06, 18 August 2011 (UTC)

What does she base this strategy on?Nijdam (talk) 16:24, 18 August 2011 (UTC)

I have no idea but she comes to the show with the intention to swap. What is your solution to this problem? Martin Hogbin (talk) 19:06, 18 August 2011 (UTC)

Another contestant has the strategy to stick to her first choice. Also a solution? Nijdam (talk) 21:29, 18 August 2011 (UTC)

If you like. Martin Hogbin (talk) 22:32, 18 August 2011 (UTC)

This does not seem a very constructive approach, don't you think? Nijdam (talk) 09:59, 19 August 2011 (UTC)

I do not understand, all I am asking is for you to show me the way that you would do the calculation for what is commonly called the 'unconditional' case. Martin Hogbin (talk) 12:08, 19 August 2011 (UTC)

Did you read what I write above? If the "unconditional case" is to be the situation in which the audience has on forehand to decide what the contestant's decision has to be, the I gave you my calculations. But again: the audience argues that in the case the contestant chooses door x and the host opens door h, the conditional probability on the car behind the remaining door, given x and h will be (under the usual assumptions) 2/3, for all values of x and h. Hence she better switches. Understood? Nijdam (talk) 16:46, 19 August 2011 (UTC)

I was asking for how you do this calculation. What sample space would you start with for the unconditional case? Martin Hogbin (talk) 21:25, 19 August 2011 (UTC)

The "unconditional" case. as you call it, may need a more extensive way of solving, but further it needs the same sample space as any other form of the MHP. And you know what that is. Nijdam (talk) 22:16, 19 August 2011 (UTC)

I do not call it the 'unconditional' case, that is what others call it. You seem to have changed your mind on how to solve it. Your opinion was, in common with all the sources on the subject, that the simple solutions were perfectly correct for the unconditional case and that a sample space consisting of only two elements (G and C) was all that is required to solve it. What is your reason for this change. ? Martin Hogbin (talk) 09:08, 20 August 2011 (UTC)

I did indeed change my opinion. The simple solution, the one that says: The chance you first hit the car is 1/3, hence when switching you get it with chance 2/3, is only an answer to the question: what is the probability the average player who always switches will get the car? Even for this case the sample space should be rich enough to describe all that may happen. The only thing is, that for the calculation of the answer (in the symmetric situation, of course) we may use an equivalent simpler sample space, as you suggest. Nijdam (talk) 20:00, 20 August 2011 (UTC)

So what sample space do you consider necessary for the question, 'what is the probability the average player who always switches will get the car?'? Martin Hogbin (talk) 22:52, 20 August 2011 (UTC)

To describe the problem we need the well known sample space with 18 elements. The average player who always switches may have chosen door 1, door 2 or door 3 and then switches to the remaining door. The position of the car is also important, and the independence of choice and car position. We may reason that hitting initially a goat, gets the car after switching, so we may leave the host out and look at a sample space of 9 elements: {(c,x)|c,x=1,2,3}, etc. Nijdam (talk) 22:26, 25 August 2011 (UTC)

Why do we need to start with a sample space of 18 elements? Why not more, to include every possibility, such as the host's choice of words? Why not fewer, because we can work out, as you say above, that some elements are not required. Why not the sample space G1,G2,C? The doors and door numbers are irrelevant, all that matters is what is behind the door. Martin Hogbin (talk) 08:33, 26 August 2011 (UTC)

We have been here before. You may "complicate" the outcomes, for instance by adding some words the host says, like the outcome: the car is behind door 2,contestant chooses door 1, the host opens door 3, the host says "hello", and it is raining, You then have to add also the combinations with the host not saying "hello", and with not raining. It enlarges the sample space, but does not change the analysis. To describe the event that the car is behind door 2, you have to combine all the outcomes where the car is behind door 1, so with the host not saying "hello" and with the host saying "hello" etc. If you want to describe the situation in which the host says "hello", you have to condition on this event. And guess what, as nothing depends on this "hello", the conditional probabilities have the same values as the original probabilities. The same holds for the host not saying "hello", so why bother. The point is that nowhere in the problem statement it says that anything depends on the host saying "hello", A smaller sample space however with less elements is not capable of describing the essential events that may happen. You say: the door numbers are not relevant, but not relevant to what? Presumably you mean, not relevant in the sense that for every combination of door numbers the desired conditional probabilities have the same value? Nijdam (talk) 17:58, 27 August 2011 (UTC)

You say, 'nowhere in the problem statement it says that anything depends on the host saying "hello"', actually I would prefer to say 'pick' because we are told in the question that the host says 'pick'.

Nowhere in the question does it say that anything depends on the door number opened by the host. It is exactly the same. We are told that the host says 'pick' and that the host opens door 3. We know the host could have used a different word and could have opened a different door.

Why then must we include the door opened by the host in our sample space but not the words said by the host? Martin Hogbin (talk) 23:09, 27 August 2011 (UTC)

Well, it is also a matter of common understanding of language. But, anyway, the best is you show me the sample space you have in mind, with an essential role for the host saying "pick". Nijdam (talk) 22:16, 28 August 2011 (UTC)

Suppose we decide before formal mathematiziation that the symmetry of the situation means that door numbers may be ignored. We are only interested in the relation between the manifest and the hidden roles of the doors. Manifest roles are: door chosen by player, door opened by host, door left closed. There is one hidden role: the door hiding car. There are only two possible relations between these two sets of roles: car is behind door chosen by player, and car is behind door left closed by host. So if we insist on being pedantic and introducing a sample space etc etc we only need a sample space with two points. The two points are "car is behind door chosen by player" and "car is behind door left closed by host". Since the first of the two points has probability 1/3 the second must have probability 2/3. This is a completely respectable complete mathematical solution of MHP which coincides with most people's intuitive understanding of the problem and moreover the way it was introduced and solved by Steve Selvin and Marilyn vos Savant. The specific mention of door numbers in the usual statement of the problem is intended to confuse the listerner by giving them a clear visual picture of a certain stage of the game, forgetting the past. This leads people to jump to the wrong solution. MHP can be thought of as a joke: you carefully set up the listener so that they suddenly experience a conflict between what they expect and what you say. Most brain teasers are in fact jokes in this sense, two envelopes problem is a good example. In order to solve the paradox one has to make a sideways mind-jump - see the problem in another way. For instance, realise that door numbers are irrelevant and solve the problem by noticing that 2/3 of the time, your initial choice of door hides a goat.

The solution in the probability class where we painstakingly construct a sample space containing 27 or so points, a heap of random variables, carefully fill in all the probabilities, and then laboriously compute a particular conditional probability by going back to first principles, is useful for students learning about probability. It's not useful for solving MHP. Richard Gill (talk) 08:31, 6 November 2011 (UTC)

ArbCom Request for clarification

I understand the Arbcom ban on certain users to apply to this discussion and any comments from banned editors will be immediately removed from my user space

Do you have time to make a Request for Clarification about the sanctions against Blackash, Slowart, and SydneyBluegum today? I would do it myself but I am crazy busy and should not even be writing this. I will second the request if you make it. Colincbn (talk) 05:22, 17 August 2011 (UTC)

I will try to do that. I cannot believe that Arcom wanted what has happened. Martin Hogbin (talk) 07:48, 17 August 2011 (UTC)

from Arbcom has put a tag on the page for closing admins. I think this is the best we will get. Martin Hogbin (talk) 14:27, 17 August 2011 (UTC)

Well that is not good enough for me. ArbCom made a ruling in plain English that is not being upheld. Either they need to reword it or stop the violations. I will make the request when I get the time. Colincbn (talk) 01:51, 19 August 2011 (UTC)

What do you think would be a better wording? --Elonka 01:54, 19 August 2011 (UTC)

I think the current wording makes their intention fairly clear. Arbcom were considering a complete ban on Blackash and Slowart but decided that, because of their expertise in the subject, they should be allowed to outlay proposals and background rationale at the commencement of the discussion (my bold). This seems fairly clear to me. In order to facilitate this process, I asked for contributions from both banned expert editors at the start of the discussion but got no response. What they have done, initiated by Blackash, is to try to game the system by using their 'one free hit' not to outlay proposals but to have the maximum impact on the closing admin. John Brandenburg's notice may go some way to reducing this impact but I agree with Colin that it does not really go far enough.

It is quite clear from Blackash's latest comments on the talk page that her only objective is to prevent the name 'arborsculpture' from being used. This reaction is not based on any WP policy but on her own commercial and personal rivalry with Slowart. Martin Hogbin (talk) 08:33, 19 August 2011 (UTC)

If you would like to file a Request for Clarification, that is your choice. --Elonka 23:57, 19 August 2011 (UTC)

Overreacting

I doubt some silly image of Mr. Breivik is going to result in more people dying. Breivik or no Breivik, image or no image, sicko's excist and commit their atrocities regardless. The article should be properly illustrated, and images of Breivik are available. So we shall use them untill a better image is found, licensed and uploaded. Maybe we should also consider protecting the page. Polozooza (talk) 15:41, 18 August 2011 (UTC)

You are no expert. Have you seen the video? That is the word by an expert on these things.Martin Hogbin (talk) 15:55, 18 August 2011 (UTC)

As it just so happens, I am an expert. I am not going to base my entire opinion on a single video, and neither should you. Polozooza (talk) 16:00, 18 August 2011 (UTC)

Who are you trying to kid? Experts do not write "sicko's excist", or "I doubt some silly image of Mr. Breivik is going to result in more people dying". Martin Hogbin (talk) 16:06, 18 August 2011 (UTC)

Not every "expert" is speaks English as a native language, brother. :) Polozooza (talk) 16:12, 18 August 2011 (UTC)

I do have a sense of humour but if you want to make joke, please do it with something less serious. Martin Hogbin (talk) 16:17, 18 August 2011 (UTC)

3RR

Watch out for it on Anders Behring Breivik. causa sui (talk) 16:11, 18 August 2011 (UTC)

I have asked the admins to intervene. This is far more serious that a simple edit war. Martin Hogbin (talk) 16:19, 18 August 2011 (UTC)

I see you are one. You have a duty to intervene and prevent WP form becoming possible promoter of mass murder. These people do this kind of thing because they want fame and glory, we must not give it to them. Martin Hogbin (talk) 16:23, 18 August 2011 (UTC)

consistency of argument?

Why don't you oppose the inclusion of the image at Jared Lee Loughner, for which an equal consideration would seem to apply as to Breivik's? That is the problem I have with such an argument, if its to be made it should be made at a systemic level, not picking and choosing were it applies - unlike other editorial considerations which indeed should be case-by-case. --Cerejota (talk) 14:22, 19 August 2011 (UTC)

One major difference is that Loughner's image is a standard mugshot not a staged self-promotion photo. I am not against having an image of Breivik but not one that shows him how he sees himself, as some kind of hero. This represents an extreme minority POV and could pose a significant danger of promoting copycats.

In my opinion even the image of Loughner is not ideal as there is a degree of glamour attached by some to a criminal mugshot. Just a picture to show what he looks like would be better.

I agree that these things should generally be considered at a systematic level just as is the case with BLPs but in this case we do not appear to have a system to cover it. No system can cover every possibility and just occasionally a little common sense is required. When the dust has settled on this case I am going to suggest that we work on some sort of policy, probably as an extension to the BLP policy. I agree vehemently that WP should not be censored so the policy needs to distinguish cases like this from people who want to censor for personal, or POV reasons. It is a complex subject that needs to be discussed carefully, but not while ther might be a significant risk of promoting mass killings. Martin Hogbin (talk) 15:05, 19 August 2011 (UTC)

Thank you very much

Thank you very much for your hysteria. Much appreciated. Not. :) Polozooza (talk) 17:40, 19 August 2011 (UTC)

Canvassing

I'd like to hear what you think at Talk:Anders_Behring_Breivik#Proposed_compromise. causa sui (talk) 21:17, 19 August 2011 (UTC)

I think it is quite wrong to have the self promoting image anywhere in the article. I see no reason for a compromise, why not just use another picture? Martin Hogbin (talk) 21:45, 19 August 2011 (UTC)

Editing comment

Martin Hogbin, I have slightly edited your comment at Talk:Tree shaping (removed bolding, and made it its own section),[11] since it might have confused other editors into thinking that the RM was closed, when it was not. Please let an uninvolved administrator handle the close and the determination of consensus, thanks. --Elonka 06:11, 20 August 2011 (UTC)

That is fine with me, thanks for clarifying. I did not mean to create the impression that the RfM was closed but I see no reason why I should not try to clarify and summarise the facts. Any non-banned editor who disputes my summary is, of course, welcome to comment as well. We are coming to the end of a very long dispute involving an Arbcom decision and to end it on a snap decision by a passing admin, as nearly happened, would not be right.

I am concerned that a passing admin may not have the time to study the history properly and might make a quick decision based on what, at first sight, might seem to me a lack of consensus. This is why I suggested that you would be better to close this RfM. You have not stated any opinion on the naming dispute but have remained only to help maintain good order on the page. In my view that makes you uninvolved but informed. Alternatively, might we ask a member of Arbcom, who will also be familiar with the history of the dispute, to either close the case personally or to propose someone who they know will give the matter the attention which it deserves. Martin Hogbin (talk) 08:58, 20 August 2011 (UTC)

I understand the concerns. However, there are extremely qualified administrators who patrol WP:RM, and given the nature of the move discussion at Talk:Tree shaping, since it's clear that it's part of an ArbCom case, I am pretty confident that no one is going to come in and make a snap judgment. In fact, I think that anyone who doesn't have the time to really read and digest the discussion, is going to steer well clear of the article! The close is probably going to be left to someone who has experience with closing "one of the tough ones". Of course, if the close is way off-base, there will be ways to challenge it (as we did with SilkTork). My own general read of the discussion is that it could close one of two ways: The article is either moved, or the RM is closed as "no consensus". But instead of playing "what if" at this point, I recommend patience for at least another week, and then we'll see what happens. Sound good? --Elonka 15:08, 20 August 2011 (UTC)

I am baffled as to how anyone could say there is no consensus. What do you understand by a consensus? Martin Hogbin (talk) 22:57, 20 August 2011 (UTC)

Patience... --Elonka 23:15, 20 August 2011 (UTC)

Advice taken. Martin Hogbin (talk) 08:17, 21 August 2011 (UTC)

Please keep comments at Talk:Tree shaping focused on the topic, and not on other editors. If you would like to refute a statement about the subject, that's fine. But attacking the motivations of another editor is not. --Elonka 00:22, 29 August 2011 (UTC)

Which bit are you referring to and which editor am I attacking? Martin Hogbin (talk) 08:30, 29 August 2011 (UTC)

Request

Is this [12] the link you were looking for from AFDhero ?Slowart (talk) 15:53, 25 August 2011 (UTC)

Thanks. I was interested to see what diff Afd hero would give me. The whole thing seems quite mysterious to me. AFD hero says '...move arborsculpture to a neutral name like Tree Shaping (as MgM suggests)' but I can find no suggestion from MgM. Can you shed any light on this? Martin Hogbin (talk) 16:34, 25 August 2011 (UTC)

Er, is this discussion related to the naming issue, or something else? If the naming issue, we may be running afoul of ArbCom restrictions, since Slowart is banned from discussing it in userspace, as well as on article talkpages. Martin, could you please clarify? Is Slowart responding to a query you asked somewhere? --Elonka 16:46, 25 August 2011 (UTC)

It was in response to a question that I asked in replying to a post by AFD hero. Although I did not ask the question specifically of Slowart I would have thought that just providing an asked-for diff was pretty much what Arbcom had in mind when they allowed the banned editors to respond. If you are now interpreting things more strictly that is fine with me.

You might like to look at the link yourself and see if you can work out exactly who suggested 'Tree shaping' and on what basis. Martin Hogbin (talk) 16:56, 25 August 2011 (UTC)

It gets even weirder. This comment:

*Comment Tree shaping (especially bonsai) and Tree trimming should be looked into as alternative less secret topics. - Mgm|^(talk) 11:34, 8 January 2009 (UTC)

was made the day before AFD hero made his comment above but it shows 'Tree shaping' as wikilinked, and the article mas moved at: 05:15, 10 January 2009. Martin Hogbin (talk) 18:32, 25 August 2011 (UTC)

It was probably a red link at the time, like "Tree trimming"? Johnuniq (talk) 08:52, 29 August 2011 (UTC)

Yes, AFD hero has confirmed this. It is still rather a cryptic comment though and it represents the entirety of the discussion concerning the move to 'tree shaping' . I remain completely baffled as to why some editors support this random and unsuitable title. Martin Hogbin (talk) 09:01, 29 August 2011 (UTC)

A barnstar for you!

The Original Barnstar

Martin, I enjoyed reading your comments on the discussion page to the Wiki article on reactive centrifugal force. In my view you are completely correct. This is a bogus concept and should not be given legitimacy like this. But it is a difficult subject as you can see from the discussion that I started on physicsforums.com at http://www.physicsforums.com/showthread.php?t=523212 AMSask (talk) 23:24, 31 August 2011 (UTC)

Thank you!

Yes, it is a complicated subject, made more complicated by people who do not understand it. The problem is that historically the term 'centrifugal force' has been used with a variety of meanings, including the reactive force mentioned in the article. The reasons for this were originally that the subject was not fully understood, although by the 18th century I think mathematicians and physicists had a good grip of the subject. There is also no 'correct' meaning of the term. I has been made up by humans and it is up to us to decide what we want it to mean.

The problem has also been complicated by teaching of the subject. In the early 20th century some teachers, especially at in engineering subjects, considered that the concept of a rotating reference frame and was too hard for their students but still wanted an easy explanation for why., for example, turbine blades burst and they therefore put forward a, rather vague, concept of centrifugal force. Since the focus was on the engineering, the rigour of the physics was not considered that important. What then seems to have happened, in my opinion, is that some people were embarrassed by the fact they they were essentially wrong in their description of CF and invented, or maybe dragged up from the past, the correct but pointless definition of CF as the reaction to the centripetal force.

Later thinking on teaching the subject was that, at an elementary level, it is best to use Newton's laws in inertial frames only and therefore not to mention centrifugal force at all. The force is later introduced properly as the inertial force required in a rotating frame. I think there is general agreement that this approach causes the least confusion.

The problem is that there are still a few sources giving the reactive description of CF and some editors seem to think that we should therefore give this description equal exposure to the inertial force description. On the other hand there are many sources which support the idea of not mentioning CF at all in inertial frames and very few or none which say this is a good idea. Martin Hogbin (talk) 13:33, 1 September 2011 (UTC)

I think you make it more complicated that it is. I'm pretty sure I understand it completely, and I'm not asking that reactive centrifugal force be given equal weight with the fictitious force. But it's an actual and distinct different concept of centrifugal force, and should not be ignored. It is not incorrect, and though deprecated, not totally gone even from twenty-first-century literature. I don't understand the desire to pretend it doesn't exist. Dicklyon (talk) 22:43, 17 September 2011 (UTC)

Good to hear from you Dick. I welcome the opportunity to discus this subject in a civil and logical manner.

I do not want to say that the term RCF does not exist, as you say, there are undoubtedly some modern books that use the term. On the other hand its usage is deprecated, which is something we should take note of in writing our own encyclopedia. I therefore think we should move RCF into a section at the end of the article called 'Alternative and historical meanings' or the like. Let us first talk about sources:

Sources

I think you must agree that the considerable majority of modern sources use CF for the inertial force only (I prefer this term as I do not like to call something responsible for hurricanes 'fictitious').

More important though is what sources say about the two usages. I do not have any sources to hand (although I am sure I could find some if required) but there certainly are sources that strongly advise against the use of the term CF to mean anything other than ICF. On the other hand I do not believe that there are any sources at all which state that RCF is a better way to use the term.

As the main purpose of WP is to convey information to our readers, I think we should take the advice of sources dealing with the way this subject is taught.

Physics

As you know, if we want to do Newtonian physics in a rotating frame in exactly the same way as we do in an inertial frame, we need to invent a number of forces that have never previously existed. As these forces simply do not exist in an inertial frame it is very convenient to give them special and unique names. 'Centrifugal force' nicely describes one such force, which always acts away from the center of rotation.

As you also know, Newton's third law tells us that every force has an equal and opposite reaction force. So for example: the bullet on a gun exerts a reaction on the gasses to the force the expanding gasses exert on the bullet; the floor exerts an upward reaction force to the downward force that your shoes exert on the floor; and an accelerating mass exerts an equal and opposite reaction force on the object that is providing the accelerating force. This is standard Newtonian physics and although we could give each instance of a reaction force a special name, there is no advantage in doing so, in fact it would make the subject very cumbersome.

To give the RCF, which is just an instance of my last example, a special name suggests that this force has a special significance or that it is somehow different from other reaction forces but, as you know, this is not the case. Also, as has been pointed out, in the Newtonian case of two mutually orbiting bodes the reaction to the centripetal force exerted by one body on another (the RCF) is, in fact centripetally directed; very confusing. Martin Hogbin (talk) 09:55, 18 September 2011 (UTC)

Athletics

I'm beginning to feel vaguely uneasy about this discussion. Specifically with your last reply. There's a difference between being conservative about what can go into the article and bare-faced lying to readers. Noym (talk) 03:24, 23 September 2011 (UTC)

What lie are you referring to? Martin Hogbin (talk) 08:23, 23 September 2011 (UTC)

"[N]obody apart from those involved in the tests, does know. Quite rightly, the results of a persons medical tests were not made public. This means that we cannot answer the question of what physical condition Caster might or might not have."

Um... what?

For one thing, Semenya's condition is openly named and discussed in a fairly large number of refereed scientific publications, in journals including Int J Sport Comm, Int J Sport Physiol Perform, J Genet Couns, or J Med Ethics. These journals are not exactly exotic; they are among the leading publications in their respective fields. Every life science department on the planet subscribes to these journals. Everybody with a browser and a credit card can order reprints of these articles.

Semenya's condition is also named and discussed in refereed humanities journals, for example the Duke journal of Lesbian and Gay studies and the Wellington journal of World Affairs. It is discussed in articles in law journals, for example Zaccone 2010 in the Brooklyn Law Review, Larson 2011 in the Pace International Law Review, and Adair 2011 in the Sports Lawyers Journal. There is a book by now, Krijnen et al. 2010, and there are at least two review articles, Tucker 2010 in the Int J Sport Physiol and Perf, and Martinez-Patino 2010 in the J Human Sport Exerc.

For another thing, there is the 2010 International Conference on Sexual Differentiation Disorders, which was convened by the IAAF specifically to discuss the Semenya disaster and the lessons to be learned from it. Of course this was not an open junket you could have simply walked in to, but they did solicit input from every endocrinology group in the known universe with a working knowledge of English and a listed phone number. The proceedings of this thing are not exactly secret either.

For a third thing, even if we didn't have the actual publications we'd still know what Semenya has simply from official statements by the IAAF. One the one hand the IAAF has confirmed the veracity of the leak in two separate interviews - perhaps not verbosely enough to pass BLP, but still. One the other hand the Berlin statement didn't leave a lot of questions unanswered anyway. We all know what specific tests they did in what specific order; it's spelled out pretty explicitly in the IAAF's official regulations. We all know that the fact the matter was not settled either after the imaging or after the karyotyping can mean only one thing.

I'm not going to edit the article. I respect BLP, even though I don't understand why leading geneticists writing in leading peer-reviewed genetics journals are somehow not reliable sources. I can live with the fact that BLP can occasionally cause articles to be inaccurate; I accept that BLP is more important than the absolute, perfect accuracy of any one single article. I do, however, find it disconcerting that we should lie. If you are uncomfortable with answering the question truthfully you could have simply not answered at all. It would have cost you nothing.

Noym (talk) 16:44, 23 September 2011 (UTC)

I am no expert in the subject but this is all news to me and has not been presented by anyone editing the Semenya article before. Is any of that information accessible online or can you post the relevant excerpts here? Martin Hogbin (talk) 17:11, 23 September 2011 (UTC)

Sure, I can post excerpts. The full text of most of the scientific papers is behind their respective publisher's paywalls. You'd need to either buy these papers or get someone in a research hospital or in a bio department to download them for you. Some of the legal stuff and the humanities essays are on the open web. You realize, of course, that if I post detailed citations here then people with agendas could try to use them to get the medical specifics into the article, right? Noym (talk) 06:55, 24 September 2011 (UTC)

Just to be clear, are you saying that there are publications in which Caster Semenya is clearly stated to have a specific medical condition? Martin Hogbin (talk) 08:29, 24 September 2011 (UTC)

Yes. There are publications that specifically state which kind of gonads Caster Semenya has. There are publications that specifically name the reason she would look the way she looks in spite of having these gonads, the inability of a certain nuclear receptor protein to bind and retain a certain steroid hormone. There are many publications that do not directly identify the type of gonads or the pathenogenesis but that do use either the MeSH or the IDC-10 name for the class of conditions. Noym (talk) 19:29, 24 September 2011 (UTC)

There would seem to be a serious breach of medical ethics involved somewhere. Surely it is not usual for patients to be named in scientific papers. Martin Hogbin (talk) 21:58, 24 September 2011 (UTC)

The IAAF felt free to disclose the diagnosis because of the waivers that Semenya had signed. Scientists generally feel free to discuss things that are general public knowledge anyway. Looking at the timeline, first the IAAF trumpets the exam results in their Berlin statement, then all kinds of activists and humanities people use the diagnosis in all kinds of essays and proclamations, the we have the leak, then the IAAF confirms the leak, then finally the scientific papers begin to appear. I don't think that, say, Dr Martinez-Patino of the University of Vigo in Pontevedra committed an egregious violation of anything when he began writing his review article two years after Berlin. Noym (talk) 03:51, 25 September 2011 (UTC)

Thanks for your informative response, you seem to know a lot about this. My comments were based only on the sources quoted by others here. I completely agree that WP should not misinform but it should, on the other hand, respect individual privacy.

I am no expert on medical papers but is still seems wrong to me that someone should publish a medical review paper in which living individuals are named, even if it was a case that 'everybody knows'.

You say 'The IAAF felt free to disclose the diagnosis'. Where did they do this and is it possible to see what they published online? Martin Hogbin (talk) 09:03, 25 September 2011 (UTC)

 ?oygul's contributions

These diffs represent the sum total of ?oygul's contributions to WP apart from subjects directly related to the arguments concerning Tree shaping.

[13] [14] [15] [16] Martin Hogbin (talk)

A barnstar for you!

	The Barnstar of Diligence
	I award this Barnstar to Martin Hogbin for highlighting and taking a stand against premature and selective archiving of discussions despite having no strong view on the actual material in question. Shakehandsman (talk) 20:57, 26 September 2011 (UTC)

Request from Sydney Bluegum

Martin I feel your summary on the tree shaping change of name move was unnecessary. You have constantly misconscrewed the truth regarding myself. Your comments are perpetuating the untruths that were expoused by Ellen of the Roads when she did a terrible job of handling the Arbcom case and made up evidence against me eg made up the story where I supposedly stated that certain editors cut down trees with chainsaws. My whole comment was taken out of context, twisted and used against me.I believe none of the Editors read the evidence given or this would have been noticed and acted upon. You can jump up and down all you like and spruck on about whatever but stop spreading untruths.You have waged a campaign against any new editors that come to the tree shaping page that dont agree with your point of view eg Sockpuppet allegations against myself and oygul. There is absolutly NO evidence that we are linked. I do not know who this person is. It seems we live in the same city or area. 3 million people live my area. Helloannyong had feelings that we were linked but no real evidence. Also stop acting like an Administrator. Woo be the day that you made the grade,It will be a sad day for Wiki. Perhaps you could spend time outing the sockpuppets that you know. Ohh sorry they support your point of view.Sydney Bluegum (talk) 02:13, 28 September 2011 (UTC)

Tree shaping AE

Why don't you place your case on WP:AE? KillerChihuahua^?!?Advice 20:53, 28 September 2011 (UTC)

Thanks. If nothing is done, I will. Martin Hogbin (talk) 21:10, 28 September 2011 (UTC)

Martin Hogbin, you are skating the edge of restrictions yourself, because you keep bringing up the same issues.[17] This has already gone through multiple checkuser requests and an ArbCom clarification request. It is understood that you do not agree with the decision, but please, let it go. It is not appropriate to be starting sections with headers such as, "My worst fears have been realised,"[18] or to call naming discussions, "absurd".[19] In the future, please keep your comments on the talkpage civil, conservative, and focused strictly on the article content. If you have new concerns about an editor, you are welcome to bring them to my talkpage, but the decision on the older issues (who can participate, how they can participate) has been made. It is final, so please stop bringing it up. --Elonka 05:00, 29 September 2011 (UTC)

Thanks for policing the situation, but what is needed is investigation of the issues—one of Wikipedia's most prolonged COI cases. Do you have any suggestions for dealing with that? Johnuniq (talk) 07:16, 29 September 2011 (UTC)

Put it on AE, which is the appropriate venue for this. Seriously. Its not "if nothing is done" - its where you go to get it taken care of. When you see a vandal, you report the vandal on AIV, you don't post on an admin's talk page and say "here is a vandal", do you? I don't understand why you aren't doing this, you are choosing a highly ineffective approach and placing the procedure provided as a last ditch resource instead of using it as it is intended. Can you explain why you're doing it this way? I'm deeply puzzled. KillerChihuahua^?!?Advice 13:04, 29 September 2011 (UTC)

Elonka. You are right that I should not have commented on the actions of other editors on the talk page. If any new issues arise I will bring them up in the appropriate venue. Martin Hogbin (talk) 15:20, 30 September 2011 (UTC)

Sounds good, thanks! --Elonka 05:50, 1 October 2011 (UTC)

---

Hi Martin, just to be clear: The Requested Move for Tree shaping to Arborsculpture has been closed as "no consensus". This discussion went on for several weeks, and had the input of multiple editors and administrators. Since there is clearly no consensus for that title, editors are going to discuss possible alternative titles for the article. If you would like to engage in the discussion for alternate titles, you are welcome to do so. However, if you continue with the stance of "There is only one title I can support",[20] then you may risk having your access to the talkpage restricted. The choice at this point is yours, so I hope that you will give careful thought to possible compromises, before returning to the naming discussion. Thanks, --Elonka 14:59, 5 October 2011 (UTC)

Martin, regarding your recent comments on my talkpage:[21] You have been told clearly, on multiple occasions, that the RM is closed as "no consensus", and that multiple administrators have reviewed the situation. I realize you don't agree with the decision, but you've made your arguments, and now it's time to stop arguing about it and get back to working on Wikipedia. If you continue protesting the RM closure, then you may risk having your name added to the list of editors who are banned from discussing the naming issue. So please, let it go. There are plenty of other things to do on Wikipedia, thanks. --Elonka 10:57, 7 October 2011 (UTC)

The Arbitration Committee has permitted administrators to impose discretionary sanctions (information on which is at Wikipedia:Arbitration Committee/Discretionary sanctions) on any editor who is active on pages broadly related to Tree shaping. Discretionary sanctions can be used against an editor who repeatedly or seriously fails to adhere to the purpose of Wikipedia, any expected standards of behavior, or any normal editorial process. If you engage in further inappropriate behavior in this area, you may be placed under sanctions, which can include blocks, a revert limitation, or an article ban. The Committee's full decision can be read in the Wikipedia:Arbitration/Requests/Case/Tree shaping#Final decision section of the decision page. Please familiarise yourself with the information page at Wikipedia:Arbitration Committee/Discretionary sanctions, with the appropriate sections of Wikipedia:Arbitration Committee/Procedures, and with the case decision page. No sanctions are being placed at this time, this is just a notice to ensure that you are aware of the procedures. Thanks, --Elonka 01:13, 8 October 2011 (UTC)

Elonka, I have looked at the links you have posted above and I am hard pushed to see what I am doing wrong. Perhaps you could enlighten me. I have not posted on the Tree shaping talk page since 5 October when I said that I would support any of Colin's suggestions. As far as I can see that is in line with your request to consider alternative titles.

Regarding my comments on your talk page, I understand and accept that the RfM has closed. I was responding mainly to your attack on my editing style. You said, it is being noted that in your own contribution history, Martin Hogbin (talk · contribs), you seem to be spending nearly all of your time jumping from dispute to dispute. This has nothing to do with Tree shaping or discretionary sanctions it was a personal attack on the way that I choose to do my editing. You do not state exactly who has noted my contribution history or where it has been noted and you have not responded to my requests to answer these questions. I would therefore ask you to withdraw your comment. Is there some off-wiki discussion going on about me and, if so, who is involved and why is the discussion not in public?

As I said on your talk page, different editors have different ways of contributing to WP. Some add good information, which I have done on many occasions, some remove bad information because this damages the reputation of WP. As I also explained, I do respond to Requests for comment because that is what people want to happen, they ask for outside opinions. On the Harriet Harman article, for example, where there are good reliable sources supporting both sides of argument and no sources stating a preference for either side, I am pushing politely but firmly for a compromise. Martin Hogbin (talk) 08:39, 8 October 2011 (UTC)

Hi Martin, like I said, no sanctions have been placed. This was just a followup to the earlier informal warning, to make sure that the notification was correctly issued and logged. You hadn't done anything new over the last 24 hours that escalated the issue or anything, so I wouldn't worry about it. As long as your future participation in the Tree shaping dispute remains constructive and helps the debate move towards a compromise or consensus that the participants can support, then all will be well. --Elonka 12:19, 8 October 2011 (UTC)

Actually all is not well Elonka, you have still not explained what you meant by your remark about my editing style. Who has noted things about me, where have they been noted, and why? Martin Hogbin (talk) 12:49, 8 October 2011 (UTC)

I think you're putting too much emphasis on the word "noted". The phrase "It has been noted" simply means, "I have noted", it's nothing more than that. Any formal notes or logs are all public here on-wiki, as you've seen. --Elonka 13:26, 8 October 2011 (UTC)

Thank you for clarifying that, I am surprised that you consider it acceptable to comment on my general editing style in such a way considering the strong stand you generally take against personal attacks. Martin Hogbin (talk) 13:45, 8 October 2011 (UTC)

Stop harassing me

Martin, I'm not a "near SPA" your diff doesn't show all my edits on different articles unrelated to tree shaping unless you are saying articles like FP-45 Liberator are related? Ever since I went near pleaching you have continually called my editing, and who I am into question. It appears to me that you are trying to bully me away from tree shaping. I have looked at your contributions on other articles and it appears this is your style. You seem to make only token edits to the main article, you like getting into arguments and pushing your POV. I believe you need to stop focusing on other editors' behavior and start focusing on content. The way you edit, you are a disruptive editor. ?oygul (talk) 23:30, 29 September 2011 (UTC)

Hello, Martin Hogbin. You have new messages at Noleander's talk page.
You can remove this notice at any time by removing the {{Talkback}} or {{Tb}} template.

NPOV noticeboard - speed of light

There is a section here[[22]] you may be interested in. 이방인 얼라이언스 (talk) 11:25, 3 October 2011 (UTC)

power structures

with respect to this: [23].

You know I've brought these kinds of issues up in a number of different places (AN, ANI, ArbCom, personal talk page, project pages), and the upshot is that there does not seem to be an appropriate place to talk about this on wikipedia. Whenever and wherever I try, I run into the following flak:

• Editors/admins who dominate a particular topic area and are angered by any suggestion that might loosen the stranglehold they have over content.
• Editors/admins who want to dominate a particular topic area and are angered by any suggestion that might keep them from doing so.
• Editors/admins who are hung up on the concept of unrestrained liberty and fearful that any rules whatsoever will turn the project into an autocratic nightmare.

The project is perhaps the purest form of dystopian liberalism I've ever seen: everyone is so fearful that others will impinge on their rights that they are unwilling to do anything will preserve the rights of the people they distrust. It's the world's first post-apocalyptic encyclopedia. Fascinating, in an aggravating sort of way. --Ludwigs2 15:40, 6 October 2011 (UTC)

We may disagree about content but I do agree with you about some principles. Important decisions in the democratic world are made in two ways, by votes and by courts. With votes, everybody gets one vote and every vote counts, it may be imperfect but nobody has found a better way. Countries in which the validity of some votes is assessed by an administrator before they are counted are generally not considered good ones by the rest of the world. In the pregnancy dispute it is quite obvious that if I closed the discussion by considering the weight of argument on each side, the 'oppose' side would win but if you were to close it the 'support' side would win. If you have votes, the admin should just count them. In another dispute, I am being chastised for objecting to a 8:4 vote being overturned by the closing admin. In the Pregnancy dispute, despite losing, I am happy to give in gracefully. I may not like the result but at least it was arrived at by a recognised procedure.

If WP is not a vote then we need a way of settling protracted content disputes, along the lines of a court or perhaps Arbcom. Unfortunately Arbcom refuse to decide on content. The current method whereby a passing 'uninvolved' admin quickly sums up the weight of argument on both sides is unsatisfactory and is like no other precess in the free world. Martin Hogbin (talk) 16:50, 6 October 2011 (UTC)

Well, let's set aside the fact that I disagree with your assessment of the arguments. If I were to summarize the arguments without all the crapfest, there are good arguments on both sides. I happen to think the support-the-change arguments are stronger, but of course I'd think that (just that way that you'll naturally think your side's arguments are better). The closing admin (if s/he's doing what s/he's supposed to be doing) is simply supposed to examine different discussion points, look at general support, and evaluate policy considerations: it's essentially the same role that the supreme court hold in the US (a guardian role that ensures fair compliance with core principles). It's a bit screwy that it's just a random admin - part of why I tried to get a particular person to commit to doing the task - and it has some practical limitations since admins don't have any specialized knowledge or skills for the role, but it's not a bad system inherently, and it's currently necessary because the other decision processes on project are so piss-poor. If our discussions didn't get so consistently tangled in their own crap, we wouldn't need an outsider to come in and dictate common sense to us. but they do, and we do. --Ludwigs2 17:23, 6 October 2011 (UTC)

The idea, or assumption that any admin is "uninvolved" is not certain. Many will indicate they are, but that is debatable. For example, ArbCom outside contributors. Comparing such mostly anonymous internet people to sworn officers of the highest court in the US is not valid. 76.205.67.182 (talk) 21:25, 6 October 2011 (UTC)

not comparing the people; comparing the social roles. --Ludwigs2 21:48, 6 October 2011 (UTC)

The comparison is still invalid. 76.205.67.182 (talk) 22:07, 6 October 2011 (UTC)

suit yourself. --Ludwigs2 23:19, 6 October 2011 (UTC)

I think 76.205.67.182 has a better idea of what I am getting at. There is no system in the free world where disputes are discused at length by the interested parties then a random person turns up quickly assesses the weight of argument on both sides and makes a decision. We have two main ways:

1) The interested parties discuss the issues at length and then a vote of the interested parties is taken. The majority vote decides.

2) The interested parties put their case to some kind of independent panel/tribunal/court/committee the members of which are chosen in some specified and understood way. There are procedures to try to ensure both sides are allowed to make their points clearly and all the points are understood by members of the panel who will then make a decision, normally based on some recorded policy. That is roughly how Arbcom works here.

Neither of the above works perfectly but they are the two models that have evolved over centuries to solve disputes in the free world. Martin Hogbin (talk) 08:40, 7 October 2011 (UTC)

Martin, the intention (which is spelled out quite clearly in the in the Pillars) Is that Wikipedia is supposed to be a pure consensus system - one in which editors discuss article content and come to reasonable decisions collectively. This is a very good system if you can get it to function correctly, but it is a very difficult system to get functioning correctly. Consensus systems are not voting systems (though they may vote on some things); consensus systems do rely on committees or tribunals (though they may use them on occasion); consensus systems do exist in the real world (but usually only in small, homogenous, highly educated groups). The nice thing about consensus systems for wikipedia is that it places power where it ought to be for an encyclopedia - on reason and informative sources. Other systems place power elsewhere and are open to abuse. You want to change the power system because the current power system is not doing what you want you think is right. That's perfectly valid, but try to raise you perspective - shift the power system to twhat's good for the encyclopedia, not just to a system where you think you will have more power. --Ludwigs2 14:01, 7 October 2011 (UTC)

Whatever it claims to be dispute resolution is WP is not consensus based system. There was no consensus in the Pregnancy article there was still close to a 50/50 split of opinion. A random admin made the decision, based mainly on their own assessment of the arguments, and the vote.

I am not trying to get more power. I support the vote system even though I lost out on the Pregnancy article. I would like everyone to be able to see where the power lies, whether it is with everyone and we vote, or it is with a select panel of editors. At present, regardless of the discussion, an random admin can close the discussion any way they like. Martin Hogbin (talk) 16:23, 7 October 2011 (UTC)

RfC at Talk:List of sovereign states/Discussion of criteria

Since you participated in the last one, I'd appreciate your opinion in this final one aswell. Thanks, Nightw 12:56, 10 October 2011 (UTC)

Archiving assistance

Hi Martin, I noticed your talkpage is getting quite long. If you'd like, I could setup an archive bot which would automatically archive older threads (older than 90 days), and then you wouldn't have to worry about it anymore? Let me know, --Elonka 13:33, 11 October 2011 (UTC)

Elonka, is extraordinarily kind of you to offer to help me tidy my room but I thing I would prefer to do it manually. Some threads go on for a long time. Thanks again for the offer it is appreciated. Martin Hogbin (talk) 13:11, 13 October 2011 (UTC)

If you would like, I could easily change the date threshold to something else. For example, there are some threads here that have had no activity since January 2010. Just let me know where you'd like the cutoff to be (no activity in 6 months?) and I can set the bot accordingly. Another option is to manually post an advance date in some threads that you'd like to permanently "stick" to the page, and then the bot will leave those alone. --Elonka 15:26, 13 October 2011 (UTC)

comment on Tree Shaping Talk

Martin I have made a comment on the tree shaping talk page.?oygul (talk) 13:24, 7 November 2011 (UTC)

Talk:Pregnancy#RfC: Which photo should we use in the lead?

You are invited to join the discussion at Talk:Pregnancy#RfC: Which photo should we use in the lead?. You participated in the previous RFC on the lead image, Talk:Pregnancy/Archive 4#Lead image RfC. Nil Einne (talk) 15:00, 17 November 2011 (UTC)

Singular "they"

Thanks; that was interesting. Haven't decided whether to keep working on the issue or not. -- Jo3sampl (talk) 01:20, 26 November 2011 (UTC)

The problem is that most people have a concept of 'correct' English which is based on what they were taught between the ages of 5 and 18. Language is not as simple as that. Much of the grammar we were taught was manufactured by the Victorians and has never formed part of written or spoken English. Martin Hogbin (talk) 12:41, 26 November 2011 (UTC)

Vacuum

Hi Martin: I wonder what your opinion is about vacuum as specified by BIPM? Do you have doubt that they mean it to be the reference medium with electromagnetic properties dictated by c, c₀, ε₀, μ₀? I agree that this reference medium can be described in other units as well, for example units where the relative permittivity and relative permeability are identically unity for all frequencies and wavelenghts. But even in such units that means that the reference medium still has no capacity to recognize vacuum fluctuations or virtual particles, which lead to relative permittivity and relative permeability that depart from unity to a degree, and to observed behaviors like the Casimir effect and the Lamb shift. Whatever the system of units, the reference state is there with defined properties that render it distinct from quantum vacuum, don't you agree? Brews ohare (talk) 19:17, 3 December 2011 (UTC)

I do not think it is for us to say what BIPM mean by vacuum if they choose not to say themselves. The whole subject is complicated and bulk properties such as μ₀ and even speeds are not well defined in the quantum domain. When there is a real and practical need to specify what is meant by a vacuum in order to better define the metre, I an sure that the relevant standards bodies, guided by experts in the subject, will do so. Martin Hogbin (talk) 21:45, 3 December 2011 (UTC)

Hi Martin: I don't think that is quite the point: Of course the standards organizations will adapt to whatever comes along. But for the moment they have settled upon a reference state defined by parameters c, c₀, ε₀, μ₀. For any experimental vacuum, including whatever turns out ultimately to characterize a "quantum vacuum", the present approach would be the same as for, say, air. You just measure the actual permittivity and permeability and present it relative to the standard reference vacuum. That is, there is no need to worry whether the reference vacuum is obtainable experimentally (it is not realizable even in principle, though at the moment any difference between the reference vacuum and quantum vacuum is found only indirectly through the Lamb shift or the Casimir effect, which don't exist even theoretically in the reference vacuum). It seems likely to me that the only thing that would cause a shift to a new standard is if it were found that some realizable vacuum were actually easier to use than making the corrections to refer to the present c, c₀, ε₀, μ₀ standard. Don't you think that is so? Brews ohare (talk) 23:36, 3 December 2011 (UTC)

Do you have any evidence that the EM constants are measured or calculated when making allowance for the refractive index of the actual medium used for realisations of the metre. I would have thought that the refractive index would have been used directly. Martin Hogbin (talk) 12:48, 4 December 2011 (UTC)

Martin: The refractive index of air is found using an input vacuum wavelength and then calculating the various contributions that introduce a departure from ideal vacuum, based upon measured partial pressures of CO₂, H₂O, and so forth. Here is how NIST does it. However, this topic appears to me to be a digression, no? Brews ohare (talk) 13:13, 4 December 2011 (UTC)

That is more or less as I thought. The digression is the involvement of the EM constants; they seem to play no direct part in the calculation. Whether the ideal vacuum is considered a classical vacuum or a quantum vacuum is irrelevant; there are no quantum theories which suggest an abrupt change in bulk refractive index when an ideal vacuum is approached. Martin Hogbin (talk) 14:06, 4 December 2011 (UTC)

Martin: From an experimental approach, the refractive index is not the best way to decide whether experimentally one can distinguish between the c, c₀, ε₀, μ₀ vacuum and a field-theoretic vacuum. These effects are very small: see John F. Donoghue, Eugene Golowich, Barry R. Holstein (1994). Dynamics of the standard model. Cambridge University Press. p. 47. ISBN 0521476526. http://books.google.com/books?id=hFasRlkBbpYC&pg=PA47#v=onepage&q&f=false.  The distinction is based more clearly upon the prediction of the Casimir effect, or the Lamb shift, or other such experiments. If one uses a model of c, c₀, ε₀, μ₀ vacuum the prediction is that these effects do not exist, because the c, c₀, ε₀, μ₀ vacuum does not allow for virtual particles or vacuum fluctuations. Thus, the c, c₀, ε₀, μ₀ vacuum does not agree with these experimental observations. On the other hand, the vacuum of quantum electrodynamics does predict these effects. Thus, the c, c₀, ε₀, μ₀ vacuum is an idealization not observed in experiment, but still useful as a reference state because theory is able to calculate corrections to this reference state that allow experimental observations to be predicted. Brews ohare (talk) 15:01, 4 December 2011 (UTC)

As you say, the practical difference between the two vacua is very small and in terms of the speed of light and the realisation of the metre it is insignificant compared to current experimental uncertainties. When metrology reaches the state where the difference in vacua starts to become important then the standards authorities will have to agree in exactly what vacuum they mean, just like they may have to specify other factors that turn out to be important. You may have an opinion on what would be the best choice but until the type of vacuum is specified by the standards authorities we cannot specify one in WP. Martin Hogbin (talk) 17:18, 4 December 2011 (UTC)

Well Martin, maybe we have to leave things like this. However, I don't understand your position, and it is unsourced. It appears to me that when the BIPM and NIST have specified that the electromagnetic properties of what they call "vacuum" are c, c₀, ε₀, μ₀ there is simply no room for a more precise specification. That also is the view of Weiglhofer & Lakhtakia, who take the reference state of classical vacuum as one with ε₀, μ₀ and state further "It is important to realize that the vacuum is the only "medium" for which this identity in form holds" referring to the constitutive relations that use ε₀, μ₀. Other sources that agree are Cardarelli, Fleisch and many more. You may be a minority of only one person. Brews ohare (talk) 20:21, 4 December 2011 (UTC)

On the contrary,it is your view that is unsourced, unless you can find a source that says specifically that the vacuum mentioned in the BIPM definition of the metre is a classical vacuum, in those actual words. Martin Hogbin (talk) 22:02, 4 December 2011 (UTC)

Martin, you choose to ignore the BIPM and NIST postings at c, c₀, ε₀, μ₀ which clearly refer to what they call vacuum, and what Weiglhofer & Lakhtakia call "classical vacuum" , which also has of course the properties c, c₀, ε₀, μ₀. The adjective "classical" is appended, not to describe something different, but to separate it from QCD vacuum and the like, as you well know. Weiglhofer & Lakhtakia also say in their section The classical vacuum as reference medium "It is important to realize that the vacuum is the only "medium" for which this identity in form holds", referring to the constitutive relations involving ε₀, μ₀.

So, Martin, the situation is very clear: you haven't entertained the above facts, and you haven't any sources to support your view that there is ambiguity in whether BIPM and NIST have adopted vacuum as the c, c₀, ε₀, μ₀ vacuum, or may have deliberately left unspecified whether the reference medium is QCD vacuum or some other field-theoretic vacuum. In other words, according to your view, we don't know whether the reference vacuum today is one that does not allow the Lamb shift, namely the c, c₀, ε₀, μ₀ vacuum, or a different reference state that does allow the Lamb shift. In your view, NIST and BIPM have left this decision to await later developments. The Lamb shift has been known for over 50 years so, from your viewpoint, one might query what the standards agencies are waiting for.

However, the BIPM and NIST in actual fact have indeed made the choice of the c, c₀, ε₀, μ₀ vacuum, as indicated on their web sites by the choice of electromagnetic properties for their vacuum of c, c₀, ε₀, μ₀, and the secondary property Z₀, "the characteristic impedance of vacuum". Various secondary sources make the same identification.

It's my suggestion that you reconsider this matter: if you have doubts, you might ask yourself what is the meaning of the c, c₀, ε₀, μ₀ postings, and why do Weiglhofer & Lakhtakia refer to a vacuum with c, c₀, ε₀, μ₀ as a reference medium? Brews ohare (talk) 19:04, 7 December 2011 (UTC)

You have missed the point Brews. Whatever you think ought to be the name used by BIPM is not important. The name they do use is 'vacuum'. Indeed only one, rather obscure, source even mentions the term 'classical vacuum'. Martin Hogbin (talk) 22:35, 7 December 2011 (UTC)

←outdent Martin, sorry if I misunderstood you. I thought your remark "When there is a real and practical need to specify what is meant by a vacuum in order to better define the metre, I am sure that the relevant standards bodies, guided by experts in the subject, will do so." indicated that you felt the term "vacuum" was somehow vague. But apparently you have no problem with the BIPM and NIST term "vacuum" referring to the medium with c, c₀, ε₀, μ₀. That being so, we agree. Brews ohare (talk) 23:58, 7 December 2011 (UTC)

My point was simpler than that; BIPM and NIST just use the term 'vacuum', so we should use exactly the same term in WP. Any ambiguity or imprecision (which I am sure is incredibly small) caused by the use of the unqualified term 'vacuum' is currently inherent in the standard. In is not up to us to interpret what they really meant or to try to reduce any ambiguity which we may see in the terms used.Martin Hogbin (talk) 16:54, 8 December 2011 (UTC)

Martin, while in common usage the term "vacuum" is vague indeed, the imprecision in the BIPM and NIST usage of the word "vacuum" is zero. They have specified to infinite precision (by using definitions) the values c, c₀, ε₀, μ₀ as the electromagnetic properties of their "vacuum", and there isn't any room to wonder what they "really mean", or struggle to "reduce any ambiguity". In any event, assuming you agree that their vacuum uses c, c₀, ε₀, μ₀, we don't need to argue over the implications of these choices. Brews ohare (talk) 16:12, 9 December 2011 (UTC)

Because the word "vacuum" in everyday use (for example, as understood by many WP readers) is vague, the link vacuum should not be used when vacuum in electromagnetism really is meant, as is the case in defining the metre. So I am happy you have agreed to use of the latter link. Brews ohare (talk) 16:33, 9 December 2011 (UTC)

You may wish to read this discussion. I find it odd that you would change the links on the page metre without any Talk page comment there, when we actually agreed about this earlier. And why no engagement here in this discussion on your Talk page, which you seemingly have abandoned? Brews ohare (talk) 16:48, 10 December 2011 (UTC)

Martin, what happened to agreement about links? Brews ohare (talk) 14:23, 11 December 2011 (UTC)

Sorry Brews (I also apologised in my edit summary) but I did not notice that you had linked to a specific section of the Vacuum article. Martin Hogbin (talk) 16:51, 11 December 2011 (UTC)

Fairground MHP

You are at a fairground where a game is played for small prizes you are asked this question:

Suppose you're on a game show, and you're given the choice of three doors: Behind one door is a prize; behind the others, nothing. You pick a door, say No. 1, and the host, who knows what's behind the doors, opens another door, say No. 3, which has a goat. He then says to you, "Do you want to pick door No. 2?"

The host has an assistant who plays the game occasionally to drum up business but he wins every time. I have some inside information and I am told that the prize is placed randomly and the host chooses which door to open, within the rules, randomly. I have also been told that the the assistant has no information about the placement of the prize. How does he win every time? Martin Hogbin (talk) 13:23, 4 December 2011 (UTC)

I hope this will not distract you from the above discussion. Anyway: you did not say whether the assistant swaps choice every time? And, you say you've been told he ha no info. Does he indeed, at the moment of decision, have no information about the position of the price, other than within the game rules? If yes, then it is sheer luck, because I then exclude him being clairvoyant or tipped off in some way, i.e. by some secret agreement with the host about the way he wears his spectacles, or the words he uses when offering the switch, etc,Nijdam (talk) 21:14, 4 December 2011 (UTC)

You obviously know what I am getting at, which is that the words spoken could easily, in some circumstances, be used to give information about the location of the prize. You consider this unlikely, or at least not justified by the wording of the question, but you must agree that it is a possibility that might, in some circumstances need to be taken into account. Martin Hogbin (talk) 21:21, 4 December 2011 (UTC)

Yeah, yeah. And may be Whitaker was just lying about the car, or there were in fact 20 doors, or just one door. Or his aunt just had her period, and so on. This all has nothing to do with the MHP. Nijdam (talk) 23:35, 4 December 2011 (UTC)

Yes indeed, those any many other questions might need to be answered in a real life problem. An over-simplistic, 'mathematics-tells-us-so' approach to real life problems can have serious consequences. Martin Hogbin (talk) 22:53, 7 December 2011 (UTC)

Exam question

There are three boxes, numbered 1,2 and 3. One of the boxes contains a price, the others are empty. The price is put at random (uniformly, to avoi any misunderstanding) in one of these three boxes. You are unknown with the position of the price and you may choose one of the boxes and have what's in it. After you choose one of the boxes but before you open it, I open one of the not chosen boxes, showing it is empty. This game may be repeated, and I will always open an empty box after you have made your initial choice. If There are two empty boxes for me to choose from, I open one of them at random (uniformly ...).

1. Give a relevant sample space.
2. What is the probability the price is in box No. 1?
3. If you did choose box No. 1, what then is the probability the price is in box No. 1?
4. If you did choose box No. 1 and I opened box No. 3 showing it is empty, what then is the probability the price is in box No. 1?

In each case not only give the desired answer, give the derivation as well and the relation with the sample space.

Please Martin, care to solve it?Nijdam (talk) 10:32, 5 December 2011 (UTC)

That looks like the question we answered at User:Martin_Hogbin/Monty_Hall_analysis

I don't know, I'm looking forward to your solution. Nijdam (talk) 16:53, 8 December 2011 (UTC)

As you describe this as an exam question and the doors are numbered, I imagine that I am expected to chose a sample space with 18 elements of the type (PHN) where P is the door number hiding the prize, H is the door I choose and N is the door you open, with the elements not permitted by your rules being excluded.

The probability that the prize is behind door 1 is 1/3, whether or not I choose box 1. Am I on the right track? Martin Hogbin (talk) 00:13, 11 December 2011 (UTC)

I presume you mean box, where you say door. It's not about what I expect, but what you think. I take your answer to point 1 to be your mentioned 18 elements. Your answer to point 2 is, I guess; P(P=1)=1/3. Please formulate how you arrive at this conclusion and formulate the answers to the other points; use the sample space. Nijdam (talk) 17:50, 11 December 2011 (UTC)

It might be easier if you explained what you are getting at. The important point from my perspective is that you described this as an exam question, this means that I make certain assumptions. Martin Hogbin (talk) 21:01, 11 December 2011 (UTC)

Which assumptions did you make? And as this is supposed to be an exam question, it's up to you.Nijdam (talk) 22:01, 11 December 2011 (UTC)

Because you call it an exam question, I assume that all the information given is relevant and expected to be used in the answer and that no important information is missing.

To clarify P(P=1) = 1/3 at the start

I then set up the sample space, as described, using the given uniform distributions then condition it for the box originally chosen and the box you opened and conclude that

P(P=1|H=1) = 1/3

P(P=1|H=1,N=3)=1/3

I have calculated a conditional probability just the way you would like me to (I presume). Martin Hogbin (talk) 22:19, 11 December 2011 (UTC)

How precisely does this problem differ from the MHP?Nijdam (talk) 08:57, 12 December 2011 (UTC)

In the context, as I gave said all along. As I say above, I have chosen to assume, 'all the information given is relevant and expected to be used in the answer and that no important information is missing', because you described this as an exam question. Because this is an exam question I can determine the precise intent of the questioner. In other contexts this might not be so easy.

Here are the sentences one by one, and numbered for your convenience:

1. There are three boxes, numbered 1,2 and 3.
2. One of the boxes contains a price, the others are empty.
3. T he price is put at random (uniformly, to avoi any misunderstanding) in one of these three boxes.
4. You are unknown with the position of the price and you may choose one of the boxes and have what's in it.
5. After you choose one of the boxes but before you open it, I open one of the not chosen boxes, showing it is empty.
6. This game may be repeated, and I will always open an empty box after you have made your initial choice.
7. If There are two empty boxes for me to choose from, I open one of them at random (uniformly ...).

Mention the numbers of the sentences which in your opinion differ form the MHP, and motivate your answer.

Let me ask you about Whitaker's question. Do you believe that Whitaker was interested in specific doors? Do you believe that he wanted vos Savant to consider the case that the host opens door 2 to reveal a goat to be somehow different from the case where the host opens door 3? What exactly do you think Whitaker wanted to know? Do you bilieve that Whitaker was not aware of the obvious symmetry with respect to door number? Martin Hogbin (talk) 22:23, 12 December 2011 (UTC)

A lot of questions again, but first it is your turn to respond to the question above. Nijdam (talk) 22:40, 12 December 2011 (UTC)

I have responded to your question. The way this question differs from the MHP is the context in which the natural language question is asked. Asked by you as an 'exam question' I am happy to formulate it mathematically in the way that you think correct. When the same, or a rather more vague, natural language question is asked in a popular magazine, I would formulate it differently (using the sample space {car, goat}). Martin Hogbin (talk) 14:40, 13 December 2011 (UTC)

Nijdam, you have not responded to my comment above. Are you overwhelmed with my stupidity or are you just taking a break? Martin Hogbin (talk) 10:35, 16 December 2011 (UTC)

Please Martin, mention the numbers where you think the MHP differs from my exam question. Nijdam (talk) 12:13, 20 December 2011 (UTC)

The question asked by Whitaker differs considerably from your question, which is far less vague (I can indicate them all if you wish) but that is not my main point, which is that even the same question may be understood differently depending on the context. Martin Hogbin (talk) 19:31, 20 December 2011 (UTC)

I do not wish you indicate them all, however, is it your opinion they all differ? Nijdam (talk) 07:09, 21 December 2011 (UTC)

There probably is some kind of difference between every one of your statements and the statement of Whitaker. This is to be expected as Whitaker was not an expert on the subject and did not make clear exactly what he wanted to know. You statements, on the other hand, are clearer and in the given context I have a much better idea exactly what question you require me to answer. Martin Hogbin (talk) 10:03, 21 December 2011 (UTC)

Tell me the difference, pointwise. Nijdam (talk) 23:27, 22 December 2011 (UTC)

Nijdam, you are missing my point. Even if the two descriptions were exactly the same I might formalise them differently according to their contexts. Martin Hogbin (talk) 23:31, 22 December 2011 (UTC)

Okay, tell me which points have the same formulation and what the difference is in the context.Nijdam (talk) 10:56, 23 December 2011 (UTC)

If the problem was an exam question (in particular one written by you) in which door numbers chosen and opened were given, I would assume that the door numbers were intended to be significant and therefore to be used in the mathematical formulation of the problem. I would therefore use the 18-element sample space.

If, on the other hand, door numbers were not given, or were given just to clarify how the game worked, and the context was that of a simple mathematical puzzle, I would assume that the door numbers were not significant and use the {Goat, Car} sample space. Martin Hogbin (talk) 11:53, 23 December 2011 (UTC)

That's not an answer. And what's more. it's meaningless what you say. You said such before, and couldn't explain to what the door numbers were not significant. That's why i go point for point through the experiment. So Martin, take point 1 for a start and tell me the difference, if there is one. Nijdam (talk) 21:18, 23 December 2011 (UTC)

Sorry Nijdam but I have got a little lost here.

This is the setup?

1. There are three boxes, numbered 1,2 and 3.
2. One of the boxes contains a price, the others are empty.
3. The price is put at random (uniformly, to avoi any misunderstanding) in one of these three boxes.
4. You are unknown with the position of the price and you may choose one of the boxes and have what's in it.
5. After you choose one of the boxes but before you open it, I open one of the not chosen boxes, showing it is empty.
6. This game may be repeated, and I will always open an empty box after you have made your initial choice.
7. If There are two empty boxes for me to choose from, I open one of them at random (uniformly ...).

What question do you want me to answer? Martin Hogbin (talk) 22:35, 23 December 2011 (UTC)

I will answer this one:

If you did choose box No. 1 and I opened box No. 3 showing it is empty, what then is the probability the price is in box No. 1?

As an exam question set by Nijdam

I have just been studying sample spaces and have been advised to start with a sample space that includes all the facts given in the question. I assume that all that is required to give an answer is provided in the question.

1 As the boxes are numbered I shall use the box numbers to set up my sample space. 3 The probability that the prize is in box 1 is 1/3, and boxes 2 and 3. My sample space must include the event that the prize is in each box.
4 My sample space must include the event that I choose any of the boxes.
5 My sample space must include the event that you open an unchosen empty box.
7 I can assign equal probability to all the above events.

I therefore set up a sample space with 18 elements and condition it appropriately, greatly pleasing by teacher.

As a simple puzzle

Maybe some of the data given is irrelevant. Perhaps there are some valid shortcuts that make the puzzle easier to explain. Symmetries perhaps, they are very powerful and intuitive.

1 There are three boxes. Do the numbers matter. Let us see.
3 The probability that the prize is in any given box is 1/3
4 So far the problem is symmetrical with respect to box number. There is nothing to distinguish any box from any other thus the box numbers are thus far irrelevant.
5 Nothing still distinguishes the boxes. The only important thing is what is in the box.
7 Box number is confirmed to be unimportant.

I therefore set up a simple sample space containing everything that matters, what is in the box I initially pick. It contains only two elements {Prize -1/3, Nothing - 2/3} Martin Hogbin (talk) 15:14, 24 December 2011 (UTC)

As the original question

Please concentrate on the question. Let me spell it out again. I take point 1: 1 There are three boxes.

Does this make a difference whether you consider this an exam question or as the simple MHP puzzle?? that's the simple question I like you to answer. Is it that difficult?Nijdam (talk) 19:16, 24 December 2011 (UTC)

Clarity of the term 'vacuum' in electromagnetism

Transcription from Talk:Metre:

To Martin: I agree that BIPM and NIST have deliberately not "qualified" their use of the term 'vacuum', I suspect because the historical usage of 'vacuum' in the context of SI units will define it by implication. One might, however, inquire whether a general reader of WP will understand that very specific context without a little guidance. Although it is possibly uncharitable of myself, I do subscribe to the (possibly erroneous) idea that you are resisting changes here less because of the espoused reasons than because you fundamentally wish to avoid any indication that vacuum in the context of SI units refers to Vacuum#In electromagnetism. If I am mistaken about this, please tell me so. Brews ohare (talk) 17:00, 11 December 2011 (UTC)

If there were any ambiguity in NIST's and BIPM's use of the unqualified term 'vacuum', their use of the term is made crystal clear with their web-site postings of c, c₀, μ₀ and the subsidiary derived properties with the exact values ε₀ and Z₀. Do you agree? Brews ohare (talk) 17:12, 11 December 2011 (UTC)

However clear you may think it is that BIPM meant something different from that which they wrote I think we must use the actual words they used in the standard.

My reasons for this are not so much that I actually disagree with you but that I think you are jumping to conclusions. I am happy to discuss this on my talk page. Martin Hogbin (talk) 21:18, 11 December 2011 (UTC)

Continued discussion: Martin: Can you spell out for me (i) the statements I've made that you do agree with me about, and also (ii) my statements that amount to "jumping to conclusions"? Brews ohare (talk) 21:59, 11 December 2011 (UTC)

We seem to agree that BIPM and NIST have deliberately not "qualified" their use of the term 'vacuum'.

OK Brews ohare (talk) 00:58, 12 December 2011 (UTC)

I disagree with you that BIPM intend to specify any particular type of vacuum. The reason for this is that the expected difference between the SOL in different vacua is insignificant compared to current experimental uncertainties. They do not need to address what might turn out to be the very difficult question of which kind of vacuum to use because they simply do not need to.

I agree that they do not have to specify any real vacuum, but that is because they chose a different path. They have defined, instead of a realizable vacuum, an ideal reference state, not realizable even in principle, to which measurement of any real vacuum's properties may be referred by measuring its refractive index (for example) or its relative permeability (for example). Consequently, no matter what is discovered about the vacuum of electrodynamics or QCD vacuum, those discoveries can be related to the reference vacuum, which remains aloof from all that. All this is exactly the same as for a medium like air, and is done the same way. You will recall the NIST calculator for refractive index of air, which takes as input the vacuum wavelength, c₀/f. Brews ohare (talk) 00:58, 12 December 2011 (UTC)

The EM values you mention are based on the SOL in vacuum so your reference to a vacuum in which these constants have particular values is a tautology not physics or metrology. Experimentally c and the EM constants are the same in all vacua.

I agree that the speed of light in Vacuum#In electromagnetism is not physics. It refers to a idealized reference state, unobtainable in the laboratory, even in principle. For one thing, Vacuum#In electromagnetism has defined properties, not measured ones. For another, Vacuum#In electromagnetism fails to agree with some observed phenomena, for example, all realizable vacua must allow for vacuum fluctuations and virtual particles. These behaviors have verified experimental consequences, like the Lamb shift, and lead to electromagnetic properties of all real vacuums (whatever else may be discovered about them) that differ from the defined ones of Vacuum#In electromagnetism. These differences are experimentally small, but the point isn't their size but that they exist in real vacua, while even in principle they play no role in Vacuum#In electromagnetism.

I do not agree that metrology plays no role, and would say in contrast that metrology is the primary concern of BIPM and NIST and so is the underlying objective in their choice of definition for a reference state. That is, this reference state is intended to make measurements simpler and easier to compare with one another by basing them upon the departure of the measured system from the universally recognized reference state of 'vacuum'.

The final statement that "c and the EM constants are the same in all vacua" is incorrect, and really beyond debate. For example, you may recall that the speed of light in a medium is c/n, and n is not identically one for all wavelengths and all frequencies and all field strengths and all polarizations and all directions in any medium other than the reference state of Vacuum#In electromagnetism. If you need references on this subject, check the ones out I have provided elsewhere.

When QM starts to become significant in the realisation of the metre the standards authorities will have to use the best theory of the day to decide exactly which vacuum they wish to use. This is how things work in metrology. Until it matters it does not matter. Martin Hogbin (talk) 22:34, 11 December 2011 (UTC)

This idea is not properly framed. The definition as the distance light travels in 'vacuum' in 1/299,792,458 seconds is independent, of quantum mechanics, of course. The realization of the second may change with advances in atomic physics, like frozen atoms and so forth. That changes the metre, but not the reference vacuum which remains a medium with defined electromagnetic properties that have no relation to measurement.

To avoid meandering about between the many topics above, I propose a series of sub-headers where individual discussions can be segregated. Here is an example starting point: Brews ohare (talk) 16:58, 12 December 2011 (UTC)

To begin

I'd suggest that we can lay to rest quite quickly the statement "c and the EM constants are the same in all vacua", so that might be a good starting point. The relative permeability and permittivity of field-theoretic vacuums is described in Kurt Gottfried, Victor Frederick Weisskopf (1986). Concepts of particle physics, Volume 2. Oxford University Press. p. 389. ISBN 0195033930. http://books.google.com/books?id=KXvoI-m9-9MC&pg=PA389.  and more recently in John F. Donoghue, Eugene Golowich, Barry R. Holstein (1994). Dynamics of the standard model. Cambridge University Press. p. 47. ISBN 0521476526. http://books.google.com/books?id=hFasRlkBbpYC&pg=PA47#v=onepage&q&f=false.  and also R. Keith Ellis, W. J. Stirling, B. R. Webber (2003). QCD and collider physics. Cambridge University Press. pp. 27-29. ISBN 0521545897. http://books.google.com/books?id=TqrPVoS6s0UC&pg=PA27. "Returning to the vacuum of a relativistic field theory, we find that both paramagnetic and diamagnetic contributions are present."  Brews ohare (talk) 16:44, 12 December 2011 (UTC)

My conclusion is simply that the beginning statement is incorrect. If you wish, it can be revised to say "c and the EM constants are nearly the same in all vacua". Brews ohare (talk) 17:01, 12 December 2011 (UTC)

Please note that I said, ' Experimentally c and the EM constants are the same in all vacua'. In other words there are no experiments that can determine the difference in c and the EM constants over a distance of a metre. By how much do you think c varies between different vacua, measured over a distance of a metre? Martin Hogbin (talk) 22:30, 12 December 2011 (UTC)

Fine, Martin. This point is settled. Let's go on with the next one. Brews ohare (talk) 23:12, 12 December 2011 (UTC)

You have not answered my question. Martin Hogbin (talk) 09:25, 13 December 2011 (UTC)

BIPM does not need to specify a particular vacuum because of small experimental differences between them

This is an interesting discussion. In my mind, experiment plays no role, whether the differences are large or small. Now vacuum#In electromagnetism very clearly uses defined electromagnetic properties, which clearly indicates experiment is not a factor. Quite simply, although definitions can be changed under practical duress, so long as a definition is in place, the properties are determined to infinite decimal points, unlike any measured quantity. So the above header appears to suggest that, in your view, the 'vacuum' of BIPM used to define the metre is in fact not vacuum#In electromagnetism, although, in your view, their 'vacuum' applies to any vacuum that is compatible with vacuum#In electromagnetism until better experiments come along. Is that your view? Brews ohare (talk) 17:12, 12 December 2011 (UTC)

A somewhat different version is that 'vacuum' in the BIPM definition of the metre is a stand-in that is expected to survive any future developments, but for the moment it is provisionally selected to be a defined entity vacuum#In electromagnetism, but without any unyielding commitment to this form of vacuum. Thus, although today there is no difference between 'vacuum' and vacuum#In electromagnetism, the term 'vacuum' is used in a more inclusive sense that envisions the possibility that one day 'vacuum' will not be vacuum#In electromagnetism. Possibly a change will be motivated by advances in measurement techniques, but of course, metrology has to weigh a variety of practical considerations (for example, reproducibility and availability of the standard), so experimental advances are not the only thing entering a decision to change. How's that? Brews ohare (talk) 17:20, 12 December 2011 (UTC)

The first formulation has to address what is the role of the postings of c, c₀, μ₀ and the subsidiary derived properties with the exact values ε₀ and Z₀. The second formulation has no problem with these postings, as they are the 'vacuum' of the moment. Brews ohare (talk) 17:27, 12 December 2011 (UTC)

The problem is that there may be an infinite number of things that might affect the speed of light most of them, as yet, undiscovered so if your objection is the purely philosophical one that we have defined an exact speed in an inexact medium then this is a problem that we will always be stuck with. Nevertheless, if you do agree to have an exact speed in an inexact medium, nothing bad happens.

When experimental uncertainties become comparable to the theoretical differences in c between different vacua over a distance of a meter then we will need to define our vacuum more precisely. Until that time, I take the BIPM wording to mean 'any kind of vacuum you like'. This is how standards have always worked. For example, when the temperature of the caesium atoms used to define the second started to become a significant aspect of measurement uncertainty, a defined temperature was added to the standard. In fact it was a theoretical and unobtainable temperature.

It is the same with the vacuum. When we can measure the difference over a distance of a metre, we will need to specify exactly what kind of vacuum we mean. It might be one of several types of unobtainable theoretical vacuum depending on what is considered to be the most fundamental according to the theory of the day. Martin Hogbin (talk) 22:50, 12 December 2011 (UTC)

Martin, this discussion of measurement seems to suggest you are adopting the first of the two choices I outlined above. Is that correct? If so, why not the second one, which seems to me the simpler of the two because it avoids all this discussion entirely? Brews ohare (talk) 23:15, 12 December 2011 (UTC)

You seemingly will not address the question of what role is played by the postings of the exact values c, c₀, μ₀ and the subsidiary derived properties with the exact values ε₀ and Z₀. It seems to me that if BIPM wished to suggest that any vacuum with properties within ±Δ of these properties is 'vacuum' within their definition, then they would have done that. What is your explanation for using definitions in these postings: how are they supposed to be used in practice? Brews ohare (talk) 03:48, 13 December 2011 (UTC)

I assume, like you, that the exact values of the EM constants might be considered to apply to the same notional type of vacuum as the exact value of c but BIPM have not specified what type of vacuum this is. We could do our own OR and by looking at other references make our own decision as to what type of vacuum this ought to be but that, in my opinion would be wrong.

When we are close to being able to measure a difference between different vacua over a distance of a metre the standards authorities, along with theoretical experts, will have to decide on the best treatment for the whole subject. We cannot predict what this may be. It could be, for example, that Maxwell's equations need to change. Maybe an additional constant will be added, breaking the strict relation between the current EM constants and c or maybe a more complex change will be required.

At the moment we have some exact constants defined in inexact circumstance. Let us leave it like that until the experts decide it needs to change. Martin Hogbin (talk) 11:57, 13 December 2011 (UTC)

You have said that one might "assume" that the posted μ₀ and the subsidiary derived properties with the exact values ε₀ and Z₀ apply to "the same notional type of vacuum" as that in which the defined value c, c₀ applies. Is that an assumption you make yourself, or do you feel there is some alternative, equally likely assumption? If so, what is it? Brews ohare (talk) 15:35, 13 December 2011 (UTC)

You have said that " BIPM have not specified what type of vacuum this is", which I would take as meaning that they haven't spelled out just how one might prepare this "notional vacuum" in a laboratory. My stance on this, which is not OR at all, is that any laboratory vacuum will exhibit such experimentally established observations as the Lamb shift and spontaneous emission. Such phenomena result from interactions with virtual particles and vacuum fluctuations that cannot occur in the "notional vacuum" because its specified parameters ε₀ and μ₀ are incompatible in theory with these phenomena. These experiments cannot be explained using the "notional vacuum". In other words, the "notional vacuum" is fictitious, or differently described, ideal. Brews ohare (talk) 15:43, 13 December 2011 (UTC)

The "notional vacuum" is not useless, even though it is not realizable in a laboratory, because it can be used as a reference state. So, for example, one can calculate a "vacuum wavelength" as c₀/f using a measured frequency, even though this vacuum wavelength is in principle not observable in a laboratory. Then one can calculate an observable wavelength by putting in the properties of a realizable vacuum, in the manner of the NIST calculator. Brews ohare (talk) 15:58, 13 December 2011 (UTC)

The electromagnetic properties of a medium, such as air, are related to the reference state using various formulas. These in turn are established by an extended process of verification, for example, the polarizability and permeability of molecules, which are verified by a host of experiments, such as optical absorption spectra, chemical behavior, etc. This smorgasbord of experiments establishing a formula is not restricted to measurements of the speed of light. Brews ohare (talk) 16:55, 13 December 2011 (UTC)

I have not traced the steps behind the formulas in the NIST calculator, although references are provided. In any event, any theoretical attempt to arrive at these formulas for comparison of theory and experiment will introduce the reference state because all the theoretical models are based upon Maxwell's equations with source terms that are taken to indicate the departure from the reference state. Brews ohare (talk) 17:05, 13 December 2011 (UTC)

There seems to me to be the possibility that there exist two reference states: (i) the "experimental" reference state underlying the experimental procedure establishing that (for example) the formulas in the NIST calculator indeed describe a departure from the reference state (maybe, for example, an assumption that the reference vacuum corresponds to zero partial pressure), and (ii) the "theoretical" reference state established by the theoretical procedure employing Maxwell's equations with sources that cause departure from their reference state. Maybe that concern is what you are worried about? So far as I can tell, this possible incompatibility of "experimental" and "theoretical" versions of the reference vacuum is not a concern of physicists. Brews ohare (talk) 17:26, 13 December 2011 (UTC)

In any event, for the moment the vacuum#In electromagnetism is taken as the reference state for experiment and for theory. Maybe one day, as you may already have said, a theoretical connection between vacuum#In electromagnetism and the experimental procedure for establishing departures from this state will be elaborated and will introduce corrections to a simple assumption that the reference state corresponds experimentally to (for example) zero partial pressure. Brews ohare (talk) 18:12, 13 December 2011 (UTC)

Martin, please excuse me if the above reads like a lecture. I have difficulty in conveying a conversational tone on a Talk page. In any event, I do appreciate your willingness to engage in such an extensive back and forth. Brews ohare (talk) 18:27, 13 December 2011 (UTC)

You seem to go in to a lot of pointless detail. The fact is that we have exact values in an inexact medium. The reason the medium is not defined any more exactly is because it makes no measurable difference. Martin Hogbin (talk) 23:29, 13 December 2011 (UTC)

Disappointed that you find the above pointless, Martin, possibly a simple consequence of not reading it carefully? I made a concerted effort to explain matters from what I see as an accurate standpoint. That is, the "fact" is that we have an exactly defined but not physically realizable reference vacuum with defined electromagnetic properties c, c₀, μ₀ and the subsidiary derived properties with the exact values ε₀ and Z₀. Measurement of these properties is not a consideration, inasmuch as they are defined. I think your dismissal of the points described above is cursory, and unfortunate. Brews ohare (talk) 01:56, 14 December 2011 (UTC)

Your notion that "we will need to define our vacuum more precisely" on the occasion "when we can measure the difference [between different choices for vacuum] over a distance of a metre" is not correct. Improvements in measurements might establish that (for example) QCD vacuum was a good model for a vacuum prepared in some fashion, but that development would not force a change from the present reference vacuum, because any advance in the measured properties of real vacuum is easily expressed as an improved accuracy in measuring its departure from the reference vacuum. Theoretical descriptions of QCD vacuum and other field-theoretic vacuums already are expressed in this fashion, relative to the reference vacuum. Brews ohare (talk) 15:16, 14 December 2011 (UTC)

To elaborate with an example, reference vacuum is independent of frequency and wavelength. Thus, any measurement of a real vacuum that demonstrates such a dependence of that vacuum can be described as a frequency-and-wavelength dependent departure from the featureless reference vacuum. The use of a departure from reference vacuum is exactly how media that are not vacuums are described today, both theoretically and experimentally. Such theoretical and experimental departures are the basis of relative permittivity and relative permeability, which are identically unity by definition in the reference vacuum. Brews ohare (talk) 15:43, 14 December 2011 (UTC)

If you are saying that the vacuum in which c and the EM constants have their defined exact values could be defined as 'that vacuum in which c and the EM constant have their defined and exact values' then I would be hard pushed to disagree with you but this is not physics, it is just a tautology. Exactly what else this should be taken to imply about the vacuum is not clear.

A similar case has already occurred in relation to the definition of the meter. How gravitation should be taken into account was not clear at one time. This was clarified not by specifying a type of vacuum but by consideration of the meaning of the word length' itself. As it happens the necessary theory and terminology was already in existence and the issue was resolved by defining the metre to be a unit of proper length.

In the case of QM effects we do not yet have the necessary theory to fully resolve this issue but luckily the practical effects are well below current measurement uncertainties. My point is that you are preempting decisions that may need to be made at some time in the future but which have not, in fact, yet been made. Martin Hogbin (talk) 10:34, 15 December 2011 (UTC)

Martin: These remarks of yours are not pertinent to anything I have said above. My remarks seem to have passed you by in their entirety. Your commentary about measurements and their progress are not relevant to the use of vacuum#In electromagnetism as the reference vacuum for electromagnetic properties of all media, including whatever may be learned about particular vacuum states and the effects of gravity upon them. And speculations about what future choices of reference state might be made by the BIPM or its related agencies are simply speculations: what is in hand is the understanding of what is done today. Brews ohare (talk) 16:38, 15 December 2011 (UTC)

To make a crude analogy about the role of a reference state, the Ten Commandments can be used as a basis for judging human behavior, regardless of one's particular beliefs about their status or origin in the scheme of things. All that is necessary is to be able to judge whether a particular behavior is consonant with the standard or not, or, in the case of the reference medium, to be able to make an estimate of how far and in what way any particular medium departs from the standard. Brews ohare (talk) 16:49, 15 December 2011 (UTC)

Brews, I cannot really understand what you are getting at. All I can say is that there is disagreement (at least between you and me) about the meaning of the term 'vacuum' in the BIPM definition of the meter so we are best to stick closely to the wording used in the definition rather that to try to interpret it however obvious you may think your interpretation is. Martin Hogbin (talk) 10:06, 16 December 2011 (UTC)

I wouldn't characterize your incomprehension of my remarks as disagreement exactly; maybe as disconcerting. Brews ohare (talk) 16:06, 16 December 2011 (UTC)

In any event, a WP reader is very likely to find reference on WP to the posted c, c₀, μ₀ and the subsidiary derived properties with the exact values ε₀ and Z₀ and can draw the obvious conclusion that this is what BIPM and NIST think of as the properties of what they term 'vacuum'. If they have doubts about this connection they have multiple secondary sources, for example, that draw this conclusion for them. Brews ohare (talk) 16:37, 16 December 2011 (UTC).

My only clue to your reservations in this matter seems to be a belief of yours that the vacuum in which the standard metre is measured has to be real (which is undoubtedly true) and that vacuum has to be the 'vacuum' referred to by the BIPM (which is not true, this 'vacuum' is a reference state and is not a real vacuum at all). The standard meter can be measured as wavelengths in air, if one wishes, and the departure from the reference state is then calculated using the NIST refractive index calculator. Or, it could be measured in partial vacuum and the corresponding corrections for that medium could be used. (These corrections will evolve, of course, as measurement techniques improve.) In any event there is no need at all for the standard metre to be measured in the reference vacuum and, in fact, that is an impossibility as the reference vacuum is a fictitious unrealizable ideal reference. Brews ohare (talk) 17:14, 16 December 2011 (UTC)

Another example of an unrealizable reference datum is absolute zero which is the starting point for the Kelvin scale and shares with reference vacuum the similarity that it is unobtainable. Brews ohare (talk) 17:25, 16 December 2011 (UTC)

Brews, I have stated my opinion as clearly as I can and you do not seem to understand what I am getting at. You have stated your opinion as clearly as you can and I do not understand what you are getting at. I do not see any point in continuing. Martin Hogbin (talk) 17:50, 16 December 2011 (UTC)

Am I to understand that my assessment that you wish to have the metre measured in 'vacuum' is incorrect? I understand that the "standard metre" as established in some medium is found only to within a measurement error, described by NIST as dominated by errors in finding partial pressures, and not to errors in the theoretical formulas used. So, if you like, the "standard metre" is itself unrealizable, because any attempts to reproduce it are subject to measurement errors in characterizing the medium, and to various errors of interferometry. Brews ohare (talk) 17:55, 16 December 2011 (UTC)

In any event, if you feel we cannot identify what the differences between us actually are, so be it. Brews ohare (talk) 18:55, 16 December 2011 (UTC)

My thoughts and opinions

You have said here on Talk:Metre that "I am not going to get involved in an edit war but it looks to me as though Brews is adding his own personal thoughts and opinions to this article (despite the citations)."

You may recognize that this comment lacks any specifics about exactly what constitute my "personal thoughts and opinions" that I have added to this article, "despite the citations".

Frankly, I find this kind of oblique approach to criticism in the vaguest of terms to be reprehensible. It is accusation from the shadows without exposure to fact. If you have something to say, say it clearly and specifically! Brews ohare (talk) 17:29, 17 December 2011 (UTC)

Brews, I do not want to have this discussion all over again on the Metre article talk page. You seem to want to make some point about the speed of light definition of the metre but I cannot understand what it is. I can see no encyclopedic purpose in the material that you have added but rather than us arguing endlessly about it let us see what others think. Martin Hogbin (talk) 18:19, 17 December 2011 (UTC)

Martin, how can we expect others to express their ideas about what you think when you have not said what it is you object to, but have only registered an nonspecific vague reservation? Basically, you are asking others to come up with and crystallize objections that you cannot formulate yourself. Or, maybe you are rallying the troops?

In contrast to your remarks immediately above, I am making no comment whatsoever about "some point about the speed of light definition of the metre". In my opinion, this notion of yours is a fixation that causes any comment to be refracted through this prism: it is an idée fixe of yours. Brews ohare (talk) 19:39, 17 December 2011 (UTC)

What has been said about the metre is simply that its definition in BIPM vacuum can be related to laboratory approximations of the metre that employ real media, interferometers, and frequency measurements. All these real world impediments introduce measurement uncertainties in any laboratory attempt to fashion the standard metre, and thus an exact version of the ideal standard metre of the definition cannot be verified in a lab. I'd say that the description of these practical uncertainties is in no way a commentary upon the nature, value, or advisability of the definition of the metre, despite your reaction to the contrary. Brews ohare (talk) 19:56, 17 December 2011 (UTC)

Realisations (or delineations) of the metre will always imperfect and subject to uncertainties and if that is what you want to say that is fine with me but why not use the standard metrological terminology rather that inventing your own terms like the 'standard metre' and 'laboratory approximations of the metre'. Martin Hogbin (talk) 21:52, 18 December 2011 (UTC)

Martin: I am glad we are now on the same page. I made some changes to play down the term "standard metre" as you have suggested. Brews ohare (talk) 17:41, 19 December 2011 (UTC)

I have made some further changes to simplify and used more standard terminology. Martin Hogbin (talk) 11:54, 23 December 2011 (UTC)

Hi Martin. These changes seem OK. Now you have entertained the notion of realization of the metre, which involves use of a real medium. I believe that concept involves recognition that any realization of the medium with defined electromagnetic properties c, c₀, μ₀ and the subsidiary derived properties with the exact values ε₀ and Z₀ will involve uncertainties, which involve among other problems the impossibility of avoiding vacuum fluctuations and virtual particles. I'd guess you are OK with that too? Brews ohare (talk) 14:16, 23 December 2011 (UTC)

A concomitant of the uncertainties in realizing this idealized medium with defined properties is that no realization of the defined speed of light c₀ is free of uncertainty either. Brews ohare (talk) 14:28, 23 December 2011 (UTC)

I am sorry but I do not understand what you are getting at. If you are happy with what I have don so far I will make some more changes, mainly to avoid repetition if the same facts. Let me know what you think. Martin Hogbin (talk) 17:28, 23 December 2011 (UTC)

←outdent Hi Martin: I was wondering whether the notion of "realization" might illuminate our discussion of the medium with defined electromagnetic properties c, c₀, μ₀ and the subsidiary derived properties with the exact values ε₀ and Z₀? That is, we might discuss this medium from the stance of trying to effect its realization.

In particular, the specification of this medium is a matter separate from its realization. Hence, the discussion of a reference state with defined properties is released from some of our digressions, which in this light now appear to be a discussion of the realization of this state, and not a discussion of the reference state itself. Brews ohare (talk) 17:20, 24 December 2011 (UTC)

To pick one point in particular, the defined speed of light c₀ is one characteristic of this ideal medium. Then realizations of the metre, or observations of the measured speed of light in some real medium, can be discussed in terms of that real medium being an approximate realization of this ideal medium. Brews ohare (talk) 17:30, 24 December 2011 (UTC)

You are back to your tautology again. The medium in which the light has the defined exact speed in metres per second is indeed a medium in which light has a defined exact speed on metres per second. I cannot see what other point you are making. Martin Hogbin (talk) 22:14, 24 December 2011 (UTC)

Martin: try to look at things from a different angle, the angle that the properties of any real medium can be related to that of an idealized medium with defined c, c₀, μ₀ and the subsidiary derived properties with the exact values ε₀ and Z₀. This comparison is effected through the relative permeability μ ⁄ μ₀ and relative permittivity ε ⁄ ε₀ of that medium. That can be done for partial vacuum, for example, a medium with c=c₀/n, n the refractive index. If one is deliberately trying to reduce n to n=1 by pumping down the partial vacuum, one may view the sequence of partial vacuums at any particular stage of pumping down as better and better realizations of an ideal medium, an ideal medium where it is actually the case that c=c₀. I take this as a pretty conventional viewpoint.

What may appear less conventional to you is that this viewpoint sets up the idealized medium with defined c, c₀, μ₀ and the subsidiary derived properties with the exact values ε₀ and Z₀ as a "reference" medium, and removes any requirement that this medium be "real": it is just a reference point, like absolute zero, perhaps. Consequently, our previous discussion in which you speculated that BIPM chose this standard only because experiment was too inaccurate to tell the difference between this medium and, say, QCD vacuum becomes unnecessary: this reference medium need not be closely related to any real vacuum, any more than, say, it is related to a ferroelectric, because the real vacuum and the ferroelectric both can be characterized relative to the standard medium via their particular values for the ratios μ ⁄ μ₀ and ε ⁄ ε₀. Improvements in measurement do not affect the standard's μ₀ and ε₀. Rather, the more accurate numbers show up as better values of μ ⁄ μ₀ and ε ⁄ ε₀. Brews ohare (talk) 23:08, 24 December 2011 (UTC)

Idealised 'medium' in which the speed of light has its defined speed

I agree that there is an idealised 'medium' in which the speed of light has its defined speed and that this medium is practically unobtainable but, at the moment, BIPM refer to this medium just as 'vacuum'; so should we. Do you not agree? Martin Hogbin (talk) 11:07, 25 December 2011 (UTC)

I agree that any quote from BIPM or NIST should use their wording, which in the case of their definition of the speed of light refers to 'vacuum'. I don't think we have ever disagreed about this point.

I am happy that you agree that there is an idealized medium where c=c₀, which I would refer to a bit differently, maybe, as being "unobtainable in principle", rather than "practically unobtainable".

The unaddressed question, where we might have some residual disagreement, is as to the electromagnetic properties of this hypothetical (or maybe inaccessible is better) ideal medium, which I would take as the defined c, c₀, μ₀ and the subsidiary derived properties with the exact values ε₀ and Z₀. What is your view of this point? Brews ohare (talk) 21:08, 25 December 2011 (UTC)

I gather from the lack of any response to this query that your interest in this matter has lapsed? Brews ohare (talk) 15:57, 30 December 2011 (UTC)

Not quite, but I am trying not to argue unnecessarily. The relation between the EM constants and the speed of light is based on Maxwell's equations. These may not always be the appropriate equations to use. Martin Hogbin (talk) 17:05, 30 December 2011 (UTC)

Martin: While the speed of light in any medium can be determined from Maxwell's equations if the medium's permittivity and permeability are known, that fact is separate from the observation that the BIPM has defined c₀ and μ₀, and has also specified that ε₀ is given an exact value by the definition ε₀≡1 ⁄ (μ₀c₀²). Of course, this relation follows from classical electromagnetism, but the adoption of this formula by the BIPM is nowhere identified by them as a consequence of Maxwell's equations, and they have nowhere endorsed classical electromagnetism. Rather, the relations between the EM constants is a choice of definitions made by a standards committee based upon metrology, not upon a theory . Brews ohare (talk) 17:34, 30 December 2011 (UTC)

To follow up, the utility of the relation ε₀≡1 ⁄ (μ₀c₀²) as a property of a reference 'vacuum' depends upon many factors. Any philosophical stance regarding the "physical significance" of the standard is secondary. Brews ohare (talk) 17:52, 30 December 2011 (UTC)

BTW, the reference to the formula ε₀=1 ⁄ (μ₀c₀²) can be found in Table 1, p. 637 and following the equation for the fine structure constant here. Brews ohare (talk) 18:16, 30 December 2011 (UTC)

Metrology

Martin: Perhaps it would be interesting to explore the metrological aspect a bit. Why would the standards committee elect to choose a reference state with exactly defined properties, and why these particular properties?

My notion is that you and Steve Byrnes think this was done out of expediency on a provisional basis that will be abandoned should it evolve that we can measure the electromagnetic properties of vacuum more accurately. More than that, you both wish to read some deliberate ambiguity into the mention of 'vacuum' in the official definition of the metre and the speed of light, despite the posting of its exactly defined electromagnetic properties. You imagine that the goal is to avoid any change in wording as measurement advances, because 'vacuum' can be retained in these definitions, even though its meaning will have changed.

I'd suggest that when measurement evolves to the point that some very elaborate and expensive laboratory procedure allows very precise determination of the departure of a realizable vacuum from the reference 'vacuum' in a few highly specialized labs in a very few locations, it will have no effect whatsoever upon the adopted properties of the reference. There will be in fact absolutely no advantage in setting up a reference based upon a realizable vacuum and comparing against it, compared to comparing against the present unobtainable reference 'vacuum'. Just as there is no point today in comparing two wavelengths instead of two frequencies because wavelength comparisons are less accurate, comparison of a medium against a realizable vacuum only will introduce additional errors and expense. In contrast, by retaining the ideal reference, advances in measurement will find expression in a more accurate determination of the departure of any medium (including realizable vacuum) from the reference. Brews ohare (talk) 18:49, 30 December 2011 (UTC)

Sorry Brews but I do not know what to say because I cannot see what you are driving at. I think we should leave it and just stick to the wording used by BIPM. Martin Hogbin (talk) 18:35, 2 January 2012 (UTC)

Martin: I simply parroted your comments of 12 December and reasoned above that they are baseless from the view of metrology. Perhaps you could clarify what you do not understand? Brews ohare (talk) 15:18, 3 January 2012 (UTC)

Martin, are you unable to identify what statements of mine you are unable to follow? Brews ohare (talk) 15:24, 6 January 2012 (UTC)

Brews, I have no objection to the use of an unobtainable reference vacuum, it is your insistence of distinguishing between different kinds of ideal vacuum that I object to. Martin Hogbin (talk) 16:16, 6 January 2012 (UTC)

Martin: I have not referred to different kinds of ideal vacuum. Brews ohare (talk) 01:34, 7 January 2012 (UTC)

I have referred to an unobtainable reference vacuum as "an idealized medium with defined c, c₀, μ₀ and the subsidiary derived properties with the exact values ε₀ and Z₀." Brews ohare (talk) 01:57, 7 January 2012 (UTC)

This is a mere tautology. Of course c has its exact value in the medium in which the speed of light is exactly c. The same applies to the EM constants. Martin Hogbin (talk) 10:14, 7 January 2012 (UTC)

Yes, Martin, you have stated a tautology. I thought the question here was that you felt I had distinguished between multiple "ideal vacuums". Has that idea been put to rest? Brews ohare (talk) 15:36, 7 January 2012 (UTC)

You do not seem to be proposing anything that I disagree with. Martin Hogbin (talk) 00:03, 8 January 2012 (UTC)

Your recent answers

Hi Martin: I see you have replied to a query by a reader as to why the speed of light is an exact number. It seems to me another question is: If this is explained so clearly in the article, why are people asking questions about it? Of course, one can adopt the view that some readers can't read, or that the subject is basically beyond clear explanation. But it seems likely to me that the problem is not insoluble, it just has not been solved. The underlying difficulty is that the speed of light seems like a real thing, something measurable like the speed of a car, and a defined value seems to be something else. How will WP fix this problem? Brews ohare (talk) 04:27, 15 January 2012 (UTC)

I see the bee in your bonnet has started buzzing again. I do agree with you, however, that questions from readers can be taken as some indication that an article is not as good as it could be. I have the same view about the Centrifugal force article, where I think readers are confused by too much discussion of the historical usages of the word and the Monty Hall problem article, which I believe concentrates too much on a irrelevant complication, but let us leave those for the moment and concentrate on the Speed of light.

So far we have had just one 'complaint'. I often try to draw 'complainants' into discussion to try to find out exactly where there problem lies so that we can consider how the article might explain things better. Unfortunately may of them sense that they are being drawn into a hornets nest and do not respond.

What do you think of the replies given? Do you like the 'light-year' answer? Do you agree that the peed of light in light-years per year is exactly 1?

What would you suggest to improve the article? Not loads of stuff about EM constants and classical vacuums I hope. Martin Hogbin (talk) 10:05, 15 January 2012 (UTC)

Hi Martin: No, I don't think those things would be a clarification. It might help if it were pointed out that : Yes, the speed of light is a real speed and it can be measured, but not in SI units. So the discussion might take this form:

In SI units, the meter is not expressed as the length of some physical thing, but as the distance light travels in a given time of 1/299*** seconds. Consequently, the speed of light becomes 299*** m/s by definition. That opens the question of what can be done to determine the real speed of light? That has to be done using units of length that are not defined in terms of that speed, but are independent. For instance, it can be measured in wavelengths traveled per second for some particular wavelength of the light, as was once done, or in terms of electron wavelengths for a particular electron energy, or in terms of the spacing of atomic layers in a crystal. If it should happen by some as yet unknown mechanism that the speed of light actually changed in value, the speed we measured in wavelengths/s or atomic layers/s would change, but the speed in m/s, being defined, would not change but remain at 299*** m/s. Of course, this hypothetical change in the real speed of light would change how far the light traveled in 1/299*** s, so the real length of the metre would change too. One might reasonably ask why a unit of length is defined in terms of the speed of light this way, instead of the old-fashioned way. Those practical decisions made by standards organizations pertain to the field of metrology, and involve questions of reproducibility, measurement errors, availability, and utility of the standard. This particular decision on how to define the metre is discussed at length in the article metre.

Brews ohare (talk) 17:28, 15 January 2012 (UTC)

Oh dear, this really is the same bee. You ask '...what can be done to determine the real speed of light?' What do you mean by 'real speed'? Martin Hogbin (talk) 18:05, 15 January 2012 (UTC)

Martin: Methinks you are not trying too hard to understand. The 'real speed' is the speed that is measured in wavelengths/s or crystal layers/s that can (in principle) change if the second changes or if the speed of light changes, as opposed to the speed of 299***m/s which cannot change in principle even if the second changes or the speed of light changes. Brews ohare (talk) 18:16, 15 January 2012 (UTC)

What is not 'real' about the defined speed of light? We just accept that the length of the metre is subject to (very small) change. Martin Hogbin (talk) 18:23, 15 January 2012 (UTC)

Martin: This discussion is not about what 'real' means. It is about there being two different things: the speed of light in units where the speed of light can change in principle, and 299*** m/s that cannot change in principle. They have different behavior, so they are different from each other. Brews ohare (talk) 18:34, 15 January 2012 (UTC)

This matter is not resolved by noticing the metre can change (as is discussed in the sample paragraph); the changes that may occur in the metre do not affect the speed of light as 299***m/s. Brews ohare (talk) 18:47, 15 January 2012 (UTC)

Brews, you were the one who brought up the 'real speed' of light. Of course there are different ways of defining the speed of light with important differences in principle between them, but the way BIPM has chosen is to define the metre such that the speed in metres per second is a fixed constant. What is your objection to this? Why is it not the 'real' speed of light. Martin Hogbin (talk) 18:57, 15 January 2012 (UTC)

Martin: Again, you are changing the subject. First, I have no objection at all to the BIPM choice. It is based upon many practical matters that they are eminently qualified to weigh. That is not the subject here. The subject here is the clarification to the non-technical reader of a distinction between a system of units where the speed of light is defined as 299***m/s and the speed of light in other systems of units where length is not defined in terms of the speed of light. The present exposition of this difference at Speed of light is not clear to many readers. I've proposed what may be an improvement. You seemingly have not read it yet. Brews ohare (talk) 19:07, 15 January 2012 (UTC)

Brews, this is what you wrote just above, 'In SI units, the meter is not expressed as the length of some physical thing, but as the distance light travels in a given time of 1/299*** seconds. Consequently, the speed of light becomes 299*** m/s by definition'.

So far that is absolutely fine with me, although words to that effect already appear in the article, but perhaps it could be made clearer.

You follow with this with (my emphasis), 'That opens the question of what can be done to determine the real speed of light?'. What point are you trying to make here? Martin Hogbin (talk) 19:32, 15 January 2012 (UTC)

Martin, I see that this wording bothers you. So maybe a substitute is needed. Let me rewrite that phrase: 'That opens the question of the relation of the defined speed of light, which is exactly 299***m/s, to a measurement. That has to be done using units of length that are not defined in terms of the speed of light, but are independent.' ... and so forth. Brews ohare (talk) 19:55, 15 January 2012 (UTC)

I think that phrasing is better, so here is the proposal with this change:

In SI units, the meter is not expressed as the length of some physical thing, but as the distance light travels in a given time of 1/299*** seconds. Consequently, the speed of light becomes 299*** m/s by definition. That opens the question of the relation of the defined speed of light, which is exactly 299***m/s, to a measurement. That has to be done using units of length that are not defined in terms of the speed of light, but are independent. For instance, the speed of light can be measured in wavelengths traveled per second for some particular wavelength of the light, as was once done, or in terms of electron wavelengths for a particular electron energy, or in terms of the spacing of atomic layers in a crystal. If it should happen by some as yet unknown mechanism that the speed of light actually changed in value, the speed we measured in wavelengths/s or atomic layers/s would change, but the speed in m/s, being defined, would not change but remain at 299*** m/s. Of course, this hypothetical change in the speed of light would change how far the light traveled in 1/299*** s, so the length of the metre would change too. One might reasonably ask why a unit of length is defined in terms of the speed of light this way, instead of the old-fashioned way. Those decisions made by standards organizations pertain to the field of metrology, and involve practical questions about measurement errors, reproducibility, availability, and utility of the standard. This particular decision on how to define the metre is discussed at length in the article metre.

Brews ohare (talk) 20:04, 15 January 2012 (UTC)

Why not just say, 'The speed of light can be experimentally measured in units of length that are not defined in terms of the speed of light, but are independent, for example astronomical units. Martin Hogbin (talk) 20:07, 15 January 2012 (UTC)

Again I have no objection to, 'One might reasonably ask why a unit of length is defined in terms of the speed of light this way, instead of the old-fashioned way'. But, 'Those practical decisions made by standards organizations pertain to the field of metrology, and involve questions of reproducibility, measurement errors, availability, and utility of the standard' is only part of the story there are also good theoretical reasons why length is defined in this way. Martin Hogbin (talk) 20:11, 15 January 2012 (UTC)

Hi Martin: OK, you can add to the list of length units that don't depend upon the speed of light. One can argue why a.u.'s are a better example than the use of wavelengths of light as used today in interferometry, or electron wavelengths, used today in smaller dimensions, or crystal lattice spacings, used today to relate these two wavelengths. One can add to metrological considerations theoretical reasons (if you can think of any that can be explained in the context of an introductory exposition). But it appears that you accept the proposal, and are offering some suggestions for improving it? Brews ohare (talk) 20:19, 15 January 2012 (UTC)

The point about astronomical units is that they are a defined unit which I believe is still in current usage but any other unit that is actually used would be fine with me. Martin Hogbin (talk) 20:56, 15 January 2012 (UTC)

Wavelengths of light and of electrons are used extensively. For example, the BIPM maintains a listing on their site of recommended wavelengths, and the article length measurement provides some limited discussion. Brews ohare (talk) 21:06, 15 January 2012 (UTC)

I'd add that metrology is not above employing theoretical reasons in their decisions, but clearly the adoption of the definition is not primarily a theoretical matter, but one of commerce. Brews ohare (talk) 20:23, 15 January 2012 (UTC)

That is not my understanding so you would need a good secondary source for that. Martin Hogbin (talk) 20:56, 15 January 2012 (UTC)

We could discuss this later, but there is no need in the present context. My understanding as to the main impetus for this definition was the commercial need for a standard that was more reproducible and more precise than the old wavelength definition, and a definition independent of wavelength that wouldn't have to be changed every time a source with better frequency stability and narrower linewidth was invented. Brews ohare (talk) 21:06, 15 January 2012 (UTC)

Another factor was the need for a variety of measurements under very different circumstances, as in surveying vs. microchips, and practicality demanded use of different sources in different applications, and freedom from comparison of wavelengths with that of some standard source was achieved simply by relying upon their frequency. Brews ohare (talk) 21:25, 15 January 2012 (UTC)

Incidentally, the article astronomical unit is not written in a way that makes its independence from the SI units clear. It mentions the mean Earth-Sun distance, but abandons that as archaic and suggests that it is defined only as the theoretical orbital radius of an infinitesimal orbiting mass. It does say that the speed of light is 173.144 632 6847(69) AU/d, and suggests this was found by a comparison of ephemerides, a concept foreign to me, and to most people, I'd guess. I'd classify this choice of example as arcane, and this article as obscure. Brews ohare (talk) 20:47, 15 January 2012 (UTC)

I think they are still used by astronomers. Martin Hogbin (talk) 20:56, 15 January 2012 (UTC)

No doubt, but the quality of the article astronomical unit doesn't recommend its use here. Brews ohare (talk) 21:06, 15 January 2012 (UTC)

Maybe you know an intuitively simple and accepted definition of the astronomical unit of length that anyone can understand? Otherwise, it is hard to see that it is more understandable to the non-technical reader than, say, the spacing of atomic planes in crystal, or the wavelength of light? Brews ohare (talk) 21:33, 15 January 2012 (UTC)

Brews if you look at the article under the 'Astronomical measurements' you will see that it mentions that the speed of light can be measured in astronomical units and gives a very precise value for the result. I do not see the need to add any more. Martin Hogbin (talk) 23:46, 15 January 2012 (UTC)

Martin: The issue is not whether 173.144 632 6847(69) AU/d is a "precise" value or an "accurate" value, say compared to other values based upon interferometry, but whether stating the speed in AU/d is understandable to a non-technical person who has no idea what the AU is or whether it is based on the SI units or whatever. The article on AU isn't much help in figuring that out. Wavelengths of light or crystal lattice spacings are intuitively more obvious units for length, and are clearly not based upon SI units.

What strikes me more to the point, however, is whether you even would consider revising the speed of light article to make it clearer to the non-specialist how a defined speed differs from a measured speed? Maybe just by pointing out there is a difference? Brews ohare (talk) 00:20, 16 January 2012 (UTC)

One person has had trouble understanding why the speed of light is exact. There is therefore a case for making it clearer why this is so but I would suggest that one sentence is sufficient. On the other hand most people expect to be able to measure the speed of light in some independent units so I am not sure that an explanation for that is needed at all. I we had one we could just refer back to the earlier metal bar metre definition of the metre. Personally I would not want to devote more than a sentence or two to explaining all this succinctly. I am sure that the other regulars on the article will not support the addition of a long and rambling paragraph on the subject. Perhaps we should wait for some feedback from our original questioner. Martin Hogbin (talk) 00:48, 16 January 2012 (UTC)

Martin: Your remarks about the "other regulars" make me chuckle. The fact is that any attempt to change even a comma on that page will embroil one in a weeks-long battle over the way that added comma has completely altered the meaning of an absolutely perfect exposition arrived at only after painstaking negotiation among what should be acknowledged as world experts on the topic. However, I am gratified that we two have (in my view) managed to come to a pretty similar view of the subject. Thanks for the conversation. Brews ohare (talk) 01:17, 16 January 2012 (UTC)

Centrifugal force

By the way, on centrifugal force, I left a note for you about that on the Talk:Centrifugal force page. The gist of it is that the content of the page is not just about exposition and due weight for different subtopics. It also is about maintenance of the page. Where readers of an article hold a variety of views, they naturally want to see their views presented. A subset of readers actually think their view is the correct view, and the others are mistaken superstition and should be removed. These factors mean the page will be under assault to reflect these realities, and survival with limited warfare means it has to have content that is battle ready. That is, it has to anticipate the changes a hodge-podge of readers may attempt, and present matters so that readers will come to a wider appreciation of the subject, and feel accordingly that their views are reasonably represented. In particular, reactive centrifugal force may be a minor topic, but WP history shows that many readers think it is the whole story and are willing to fight about it. Brews ohare (talk) 17:27, 15 January 2012 (UTC)

In fact, I feel that this issue of designing a page to be battle-ready is the basic reality underlying WP and the mechanism that ultimately determines its content. For any stability of content, by definition the article must be persuasive enough to keep dissent to a minimum. It is misconception to think that an on-line encyclopedia subject to attack from all comers has the same criteria for content as a Britannica. Brews ohare (talk) 17:39, 15 January 2012 (UTC)

In this context, for example, one may query how the struggle for concise articles pursued with diligence by DickLyon, for example, plays into survivability. On the one hand, a very brief article may be interpreted by a reader as an unambitious presentation, and so not one to seriously dispute. On the other hand, a more extended article may be more useful or clearer but also has more detail that may raise opposition. That means a longer article demands a more careful exposition to survive without continuing dispute. Brews ohare (talk) 17:46, 15 January 2012 (UTC)

I appreciate your aim in trying to make pages more stable but I think it will not work, and at the expense of including more fringe views. Martin Hogbin (talk) 18:00, 15 January 2012 (UTC)

It might be that Centrifugal force is an interesting experiment in this respect. For reasons unknown to me, it is a subject very popular among a large cross-section of readers including some fanatics. In the old form as one article it was subject to unending controversy. Today it is in several pages of different scope. It seems to be less controversial this way. Brews ohare (talk) 18:10, 15 January 2012 (UTC)

To a degree, I can understand this improvement: if an article is clearly an overview, then debate over details is properly directed at a page devoted to that subtopic. If a page is a particular facet, then debate over other facets is properly directed elsewhere. On the page for a specific aspect, there is greater likelihood of a narrow debate, and less likelihood of wandering into generalities that cannot be decided. So the natural tendency of Talk pages to wander off into the desert of digression is curtailed, and a real resolution of opinions becomes more likely. Brews ohare (talk) 18:44, 15 January 2012 (UTC)

Traffic statistics show Centrifugal force has about 2000 hits/month, while Reactive centrifugal force has about 80 and Centrifugal force (rotating reference frame) and Fictitious force about 180. Inertial frame of reference about 350. On the basis that the general overview Centrifugal force is not the right place to argue details, it appears that breaking up the articles may reduce controversy because not many readers are interested enough to pursue the other pages. So they seldom look at the venue where their disputes could be argued. Other related topics are even less looked at: Absolute rotation, Rotating spheres: 20 Bucket argument: 50 . Of far more interest is the Coriolis effect at 3000. Brews ohare (talk) 16:23, 16 January 2012 (UTC)

What is this "struggle for concise articles pursued with diligence by DickLyon" of which you speak? I don't recall pursuing anything like that. As far as I can recall, the only editor that I routinely push back against for unrestrained article bloat is Brews ohare. Dicklyon (talk) 16:18, 17 January 2012 (UTC)

Astronomical unit

Hi Martin: I've made some additions to the article Astronomical unit, mostly some added sources. It appears the AU is based upon setting a length scale so the measured positions of an assembly of solar system objects is best described theoretically using a very particular value for the gravitational constant. Because the measurements involve sensing light signals or echoing radar bounces the speed of light enters into the measurements. The article Astronomical unit makes no serious attempt to document what goes into the extraction of the speed of light from this comparison of theory and measurement, and the whole subject of where 173.144 632 6847(69) AU/d comes from is left to the imagination. Are you interested in fixing this discussion? Brews ohare (talk) 19:21, 16 January 2012 (UTC)

BTW, it appears that a wrinkle in this is that the metre is not well-defined for large distances because of unspecified (so far) relativity corrections, so the subject of converting an AU to metres could be interesting. Brews ohare (talk) 19:24, 16 January 2012 (UTC)

From this document (Chapter 1, Table 1.1 p. 18) it appears that the speed of light in IAU units is in fact defined to be c₀ of the SI units, and the error bar in the speed of light in AU/d is due to uncertainty in the AU, not due to any actual measurement of the speed of light itself. The AU is a length unit defined independently from the speed of light, but its length in meters is calibrated so the time of transit across an AU forces the speed of light to be exactly c₀ by definition. Brews ohare (talk) 22:33, 16 January 2012 (UTC)

That is, the transit time of light across 1 AU, τ_A, is set so that c₀τ_A = 1 AU. Brews ohare (talk) 22:38, 16 January 2012 (UTC)

Hi Martin: I'd thought that you felt the speed of light in AU was a measured value, and would be a bit surprised that in AU the speed of light is not measured at all, but defined to be the same c₀ used in SI units. Guess not, eh? Brews ohare (talk) 03:57, 25 January 2012 (UTC)