# Talk:Informal logic

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Field: Foundations, logic, and set theory

## You can't prove anything using only informal logic

It seems to me that you can't prove anything using only informal logic, but I may be wrong. Doesn't it take an appeal to formal logic to prove informal logic's statements? I'll look for references later if I have time. Jules LT 22:12, 23 September 2005 (UTC)

## Sections don't mention logic

The two sections, Social sciences and Law and politics don't mention logic at all. It felt to me as they somehow aren't quite connected to the article. __meco 08:07, 5 July 2007 (UTC)

## Serious?

Is this article serious, or a spoof? 84.9.92.9 (talk) 21:19, 12 June 2008 (UTC)

This are serious article. We are serious editing it. --Gwern (contribs) 14:55 29 June 2008 (GMT)
I agree with (what I take to be the intent of) the original query - this page should be almost entirely re-written. The intro paragraph might be serviceable and could stand as a stub. Cathalwoods (talk) 20:27, 11 July 2008 (UTC)

## Origination of Informal Logic

The statement:

"Informal logic emerged in North America in the early 1970s as an alternative approach to the teaching of introductory logic courses to undergraduate students."

Is not correct, Informal logic emerged well before the 1970's. An entire chapter is dedicated to Informal Logic in Introduction to Logic[[1]] by Irving M. Copi, Macmillan company, 2nd ed., seventh printing, 1964. As such I'm omitting the above quotation from the article. Gerald Roark (talk) 00:39, 6 January 2009 (UTC)

## Overhaul: Overview section; Example section?

I have overhauled the first two sections of this page. Major changes so far:

Overview section: I removed the first definition in favor of the one from Johnson & Blair. The first (that informal logic concerns arguments in everyday discourse) was inconsistent with remarks elsewhere in the article that Johnson & Blair expanded their definition beyond arguments in everyday discourse (I moved this text to footnote 1). Perhaps the first definition should be retained and the footnote scrapped. But I think J&B's definition, applied to both everyday and non-everyday discourse, is better.

Having picked this definition, however, the next section needs major revision, as it focused on the "everyday discourse" aspect of the (now-removed) definition.

The first paragraph (about Socrates' mortality) was removed.

There then were two examples of arguments - Harper's argument about Windsor, and the ontological argument. Since the ontological argument was intended to demonstrate the difference between everyday and non-everyday discourse, it is no longer needed. (Anselm's argument could be evaluated formally or informally.)

Similarly, I removed Harper's argument about Windsor and the remarks following, since it and they do not illustrate informal logic (that is, they do not illustrate the definition offered in the Overview.)

What is badly needed for this section is an example (Harper's argument which I removed might be of service) followed by a treatment using (as the definition puts it) "non-formal standards, criteria, procedures".

Cathalwoods (talk) 02:38, 13 January 2009 (UTC)

I inserted an example, along with a very brief informal treatment (please expand!) and a brief formal treatment, for comparison. From the "(Further) Theory" section I retained the paragraphs about Massey's objection and about the "focus" of informal logic and moved them into this (Example/Formal Logic) section, though I am not happy with either of them. Cathalwoods (talk) 18:31, 13 January 2009 (UTC)

## Overhaul: Theory section

I'm not familiar with the Barth and Krabbe, but I'm having a hard time seeing the value of these three paragraphs. Anyone else have an opinion?

I think the last paragraph (Massey) is good and would follow nicely from (or could even be included with) a good example of an argument evaluated using informal criteria & procedures.

Cathalwoods (talk) 02:43, 13 January 2009 (UTC)

I have kept the Barth and Krabbe as a separate section "Further Theory". I moved the paragraph on Massey and the paragraph about the "focus" of informal logic into the Example/Formal Logic section. Cathalwoods (talk) 18:27, 13 January 2009 (UTC)

## Overhaul: Fallacies (new section needed)

One section this page will need is a section on (informal) fallacies. Agreed?

Cathalwoods (talk) 03:00, 13 January 2009 (UTC)

## Overhaul: Formalism (new section needed?)

Do we think this page needs a section (or some treatment) against the idea that by inserting as "hidden" or "missing" propositions any argument can be given a form (which will be either valid or strong), thus making informal "logic" about only the interpretation and truth of the premises and not about the connection between premises and conclusion?

E.g. argument from authority can be formalized (Speaker says "p", speaker is an expert, in a relevant field, is unbiased, and is making an uncontroversial claim within the expert community). If all these are true, then p.

Cathalwoods (talk) 03:16, 13 January 2009 (UTC)

I treated this problem very lightly - in the footnote about abstraction in the "Bush says it will rain" argument. Cathalwoods (talk) 18:28, 13 January 2009 (UTC)

## From the other side of the pond...

the rhetoricians aren't every pleased with this field, and sound a bit dismissive: [2]. Tijfo098 (talk) 13:39, 24 April 2011 (UTC)

## Removed napoletano.net article

Not only its relevance is only tangential to the main topic here, but it also contains this gem: "Formal logic, on the other hand, does not concern itself with the meaning or content of an argument, and assesses its correctness solely by form of the propositions. " Apparently they've never heard of model theory. Tijfo098 (talk) 15:51, 24 April 2011 (UTC)