Talk:System

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The definition of system[edit]

1. A schematic representation of a closed system and its boundary
2. A schematic representation of a open system, with its boundary, input, through put and output.

The current definition of a system has been wrongfully altered by User:Anwar saadat from:

System (from Latin systēma, in turn from Greek σύστημα systēma) is a set of interacting or interdependent entities, real or abstract, forming an integrated whole.

To:

System (from Latin systēma, in turn from Greek σύστημα systēma) is a set of interacting or interdependent entities or inputs, real or abstract, forming an integrated whole or output.

Which I have referted, because in the systems approach.

  • A system is a whole of interacting entities in an environment
  • The interaction with this environment can be divided in a input and an output.

Anwar saadat is trying to state:

  • ... that the whole of interacting or interdependent entities is the input
  • and the whole is the output.

I think, he is mistaken here. The thing is:

  • The current definition applies both to an closed and an open system
  • Now there are a lot of definitions in of systems, by a lot of systems scientists.
  • However in general the first perception about a system is about its wholeness in it's environment.
  • The input and output are mostly part of the second or third part of the systems approach
  • One exception, I think, is with dynamical systems. Here, I think, the definition of Anwar saadat is right.

But this article is about system and not dynamical systems.

-- Marcel Douwe Dekker (talk) 10:55, 11 July 2008 (UTC)

I am racking my brains on how anyone can write a article about system without using the words "input" and "output". Absence of any of these two immediately signifies the absence of a system. I think you are confused between state and system. A singular hut is a state. When a chimney is added, it becomes a system. Anwar (talk) 13:07, 11 July 2008 (UTC)
I am merely representing science. You are speculating about some of your original thoughts, which don't make much sence, like your statement:
... Absence of any of these two immediately signifies the absence of a system
In systems science they talk about closed and open systems. A closed system hasn't got both.
Now the first definition of system, has to apply for both closed and open systems, so adding input and output in the general systems definition makes no sense.
-- Marcel Douwe Dekker (talk) 13:19, 11 July 2008 (UTC)
Are you telling me a closed system does not get inputs and/or give output? That is blasphemy. A flip-flop is a closed system where the output is the input is the output is the... and so on. Amoeba is a closed system. It reproduces without intercourse with a fellow species. A system will always have inputs and at least one output. In many cases, the inputs are not so obvious. So, we get the illusion that those systems are closed. Anwar (talk) 13:43, 11 July 2008 (UTC)
According to our own Wikipedia, a closed system is one that can exchange energy, but not matter; and isolated system has no interaction with the environment at all. So the concept of a system with no inputs or outputs is clearly in use. Even open systems -- like the solar system, for example -- are sometimes studied more for their internal interactions than for their inputs and outputs. Defining a system in terms of its inputs and outputs is common in systems engineering, but is a narrower use of the term. Spiel496 (talk) 13:55, 11 July 2008 (UTC)
Indeed there are all kinds of definitions of systems, an closed systems. For example:
Wikipedia states: A closed system is a system in the state of being isolated from the environment.
Michael Pidwirny states: Closed System - is a system that transfers energy, but not matter, across its boundary to the surrounding environment.
And Roland Müller gives and overview of more then 300 years of defining systems.
The point here is that not one defintion states, that:
  • the set of interacting or interdependent entities is called the inputs, and
  • the integrated whole is called the output output,
such as User:Anwar saadat has proposed. This is just nonsense. -- Marcel Douwe Dekker (talk) 15:13, 11 July 2008 (UTC)

@Anwar 13.07 11 July 2008. I agree that the notions of input and output should be introduced soon in the article, not only because it is useful operationally but also because "General Systems Theory/Science" needs it and uses it. A mathematical definition of SYSTEM calls for the use of 1) input, 2) output, 3) state and 4) system operator. And a mathematical definition is both useful and transdisciplinary. --pmagrass (talk) 11:58, 16 July 2009 (UTC)

The original problem I have experienced here was, that User:Anwar saadat with the change he made, explicitly states:
  1. the set of interacting or interdependent entities or inputs, and
  2. real or abstract, forming an integrated whole or output.
He seem to state that the set of interacting pasts is the input and the integrated whole is the output. In systems engineering I have learned a systems approach which states:
  1. A system is an integrated whole in a surrounding
  2. It consists of a set of interactie entities
  3. The interaction with the surrounding can he divided in an input and an output.
  4. And the dynamics of the whole of the interacting parts of the systems between the input and output is the throughput.
This is also expressed in figure 2. A schematic representation of a open system, with its boundary, input, through put and output. -- Marcel Douwe Dekker (talk) 18:30, 16 July 2009 (UTC)

The current definition, i.e. "System [...] is a set of interacting or interdependent entities, real or abstract, forming an integrated whole" is odd because it presents the words real and abstract as contraries. From the Discussion, I infer that the author(s) actually meantconcrete or abstract. The reason why I don't make the modification myself is that, as I explained elsewhere in this Discussion, I am against the futile specification of entities as concrete or abstract because entities can obviously be either. I warmly suggest we resist the temptation to philosophize (Techne ton technon, kai episteme ton epistemon...) and stick to the vocabulary definition at this stage of the article. Therefore, my next proposed modification will be to remove the "concrete or abstract" words altogether--pmagrass (talk) 09:03, 17 July 2009 (UTC)

Mathematical definition[edit]

@MDD, I do not know where and when you received your qualification as he-who-represents-science ("I am [...] representing science", your own words above), but please understand that if that is your aim then it's going to be impossible to avoid a mathematical definition ("model") of a system, which is conspicuously lacking in en.wiki right now (even in the Systems science article!!). This is a major flaw. As it currently stands, the whole "systems" story in en.wiki does not sound a lot scientific. I'll readily admit that there are a million things (philosophical, historical, etc.) that can be said about the word system without venturing into the math realm. But, I am sorry to say, the overall impression right now it that en.wiki avoids a mathematical defition because its authors do not master it--pmagrass (talk) 12:18, 16 July 2009 (UTC)

You are right there is no maths in my work, as in a lot of regular articles about systems science. I am not pretending, nor aiming to represent all science. I am trying to represent the scientific sources that appeal to me. Now all that mathematical work indeed doesn't appeal to me. However, this is not my article, nor is the systems science article. If one feel some math definition should be added, everybody is free to add it.
I have the impression there is a similar difference in the whole systems sciences literature. I have found little math in article in the "General Systems Yearbook" and the "Systems Research and Behavioral Science" journal but then again, I pay little attention to those articles. Does that make me less a scientist...!? Untill now I haven't been considered to be a scientist at all. I am just a guy writing about systems science and modeling, and my main focuss is on visual/systems modelling. -- Marcel Douwe Dekker (talk) 12:53, 16 July 2009 (UTC)
P.S. My education is no secret here, see here
P.P.S. You will find no math in the chaos theory article neither. Is this a mayor flaw as well...??
I am not advocating mathematics everywhere. I'm just saying that sometimes a little formal definition saves a lot of ambiguous words. As to your credentials, it was never my intentions to question them. But if you write "I am representing science", then be prepared to carru the weight...:-)--pmagrass (talk) 14:52, 16 July 2009 (UTC)
Is there a mathematical definition of system? I don't think there is a standard one. — Arthur Rubin (talk) 14:03, 16 July 2009 (UTC)
Arthur, every undergraduate book on general systems theory begins with a mathematical model. Every system is given at least a "state equation" and "output equation". I know that most people are scared by math and stop reading as soon as it shows up, unless it is in a school book... However, math (formal langaues in general) is not only a perverse tool for tormenting students, or a mere technicality: it is the most powerful means Mankind possesses for formalizing concepts. In the case of systems, the added beauty of the math is that it is applicable to systems as diverse as those in biology, electronics, mechanics, sociology, economics, etc etc. I am not proposing that the Wikipedia article begins with a mathematical definition, but its lack altogether renders the whole article just odd. My two cents.--pmagrass (talk) 14:35, 16 July 2009 (UTC)
Uhm... let's see. I did not mean to sound that pedantic. I think you know all these thigs. But it's just that... all that useless philosophical discussion as to whether a system is "real" or an "abstraction", and zero operational definition of a system... I find it disturbing. Hope I'm making the point. Thanks.--pmagrass (talk) 14:42, 16 July 2009 (UTC)
You should have checked my user page; I am a mathematician, but I don't recall seeing a (mathematically) usable mathematical definition of system in the literature. As for chaos theory, it doesn't have a mathematical definition because it's a popularization of a (actually, more than one) mathematical concept, those concepts appearing in the article, and some of the mathematical development appearing in related articles. — Arthur Rubin (talk) 14:50, 16 July 2009 (UTC)
Excellent, since you are a mathematician, you will appreciate what I said even more: a little formula sometimes saves a thousand words, and without ambiguity. Somewhere in the article we should stick the STANDARD formal definition of system that can be found in any undergraduate book on systems theory. (In chaos theory that would be too tough a requirement, since no wikipedia reader would be happy to read the math for unstable nonlinear dynamical systems).--pmagrass (talk) 14:57, 16 July 2009 (UTC)
I agree with Arthur. Any system will admit many representations. I have never seen a formal definition of "system" and would appreciate if you could provide one that does not equate to that of "mathematical (algebraic) model". Because clearly to me, systemics is much more profound than modelling. Clauariel (talk) 21:55, 14 April 2016 (UTC)

I think the original definition is more accurate/appropriate. Not the least reason being that equating inputs with entities and outputs with "wholes" is a semantic/spatial/philosophical distortion that only serves to obfuscate and confusion. Kevin Baastalk 23:06, 16 July 2009 (UTC)

Who is equating inputs with entities and outputs with wholes? And what is "the original definition"?--pmagrass (talk) 08:20, 17 July 2009 (UTC)
Oh, I see now: you intended to comment to the "The definition of system" paragraph of the Discussion. Just an out of context comment.OK--pmagrass (talk) 09:05, 17 July 2009 (UTC)

Repairs[edit]

Devlin 25th november 2008: Article was vandalized, I repaired as much as possible. Admin: Please feel free to refert it back to its original state. —Preceding unsigned comment added by 82.215.32.139 (talk) 21:26, 25 November 2008 (UTC)

Abstractions of reality[edit]

I have a problem with this page. The introduction states as one of the characteristics that "Systems are abstractions of reality" - seems to me that the notion of system and the notion of model are confused here. Any objections on removing that line? Angeloh (talk) 14:04, 9 July 2009 (UTC)

I don't think so. I think the notion of a system is similar as the notion of a model. -- Marcel Douwe Dekker (talk) 14:12, 9 July 2009 (UTC)
Really? These definitions do not match: "A model is a pattern, plan, representation (especially in miniature), or description designed to show the main object or workings of an object, system, or concept."
"System (from Latin systēma, in turn from Greek σύστημα systēma) is a set of interacting or interdependent entities, real or abstract, forming an integrated whole."
The key is in the "real or abstract" bit of the systems definition: a real system is no abstraction of reality - the suggested general characteristic only applies to abstract systems (or models). Example: the solar system is a system, and definitely not an model - just like for example a computer system.
I feel backed here by sources like the Merriam Webster dictionary http://www.merriam-webster.com/dictionary/system and various books and other resources I am using right now while developing a course on systems design. Angeloh (talk) 14:24, 9 July 2009 (UTC)
Interesting argument. The article states "abstractions of reality" is one of the common characteristics of a system. I guess, I tend to believe a system, like a model, is always an abstraction of reality. And there are no real systems in reality. If you speak of a computer system, it is the whole you are refering to... !? Maybe you should give the Merriam Webster dictionary here so I can judge for myself. -- Marcel Douwe Dekker (talk) 14:42, 9 July 2009 (UTC)
I agree with MDD.
Furthermore, I contrast the notion that "the solar system is a [real-world] system". The solar system can be viewed as a system in itself or as a component of a galaxy: it depends on the point of view. One can treat Earth, Venus and Mars as a system. Another one will say that Earth, Moon and Sun are a system (such as in the famous 3-body problem of celestial mechanics).
Systems are not 'natural': they are representations of reality which we build --pmagrass (talk) 09:35, 28 July 2009 (UTC)
Interesting indeed ;-) Indeed in a computer system, the whole is the computer (e.g. your notebook), which consists of enties like the CPU, memory, screen etc. It's a very real system to me, and definitely not a model.
The Merriam Webster text was directy behind the link I provided. -- Angeloh (talk) 14:48, 9 July 2009 (UTC)
Making changes based on (own) interpretation of the Merriam Webster doesn't make sense to me here. I must say I am not absolutely sure here, and this seems to be and interesting oint of discussion. I guess in systems theory systems are most often seen as abstractions, but in regular science an other perception of systems is beeing used. In the Dutch Wikipedia for this reason whe created multiple articles about even more different kind of systems.
I guess it would be nice to investigate more about what systems scientists and other scientists state about the beeing and relationship between "systems" and "abstractions of reality"...!? -- Marcel Douwe Dekker (talk) 15:11, 9 July 2009 (UTC)
We could do that - or look a bit further at the sources at hand. The notion that 'systems are abstractions of reality' contradicts not only with Merriam Webster, but also with other materials I have at hand (books by Peter Senge, Derek Hatley, Eberhardt Rechtin as well as articles published by INCOSE - quotes can be provided if needed).
Closer to home, on the System page itself I see the following. What is written under the heading History in the System page itself, as well as the first item under the System Concepts heading - which states that "We then make simplified representations (models) of the system in order to understand it and to predict or impact its future behavior."
Thus, the Wikipedia item contradicts itself... Do as you see fit, I'm just a slightly involved visitor here, but I'd regret to see my students (and others) visit Wikipedia find something that contradicts what they find in other places. Angeloh (talk) 15:31, 9 July 2009 (UTC)
Systems Theory would be a good starting point for further investigation, it refers to some of the sources I indicated as well. Angeloh (talk) —Preceding undated comment added 15:36, 9 July 2009 (UTC).
There is a lot that can be improved, and your comment here is very much appreciated. I guess, again I just guess for now, that there is a double notion of a system, and that is why you can speak of a model of a system. Or maybe there is not even a double notion, because you can make an (simple) model of a (complex) model as well. I am not sure it is possible the other way around (to make a complex model of a simple model). That doesn't seem to make sence. But reducing complexity even more by making a model of a system could make sense to me. -- Marcel Douwe Dekker (talk) 16:05, 9 July 2009 (UTC)
P.S. Again it is not enough to interpret a contradiction. It would be nice to collect some text that really explains about the relation. Maybe we can even make a separate chapter in this article about it. For a start we do need those quotes from reliable sources.
Fair enough. I think some quotes that support your notion of "a system is a model" or "a system is an abstraction" would be useful as well. If these are not available, we might be attacking something that doesn't exist. I included some initial quotes below, attempting to get a view on systems and a view on models from the same author in both cases. I only failed in Dettmer's case, but I know that Goldratt's theory is based on models of systems so that can be ammended later. —Preceding unsigned comment added by Angeloh (talkcontribs) 18:11, 9 July 2009 (UTC)

collected quotes, starting point[edit]

"A system can be broadly defined as an integrated set of elements that accomplish a defined objective. People from different engineering disciplines have different perspectives of what a "system" is. For example, software engineers often refer to an integrated set of computer programs as a "system." Electrical engineers might refer to complex integrated circuits or an integrated set of electrical units as a "system." As can be seen, "system" depends on one’s perspective, and the “integrated set of elements that accomplish a defined objective” is an appropriate definition."

Source: INCOSE (2000) Systems Engineering Handbook
Context: Systems Engineering
Credibility: INCOSE is an international organisation of people working in the are of systems engineering

"Attempts to define "system" usually end up encompassing just about everything in the universe. The problem is that the univese itself is a system, so is an atom and so are most things in between. In the most general sense, a system is simply any organized set of components that work together in some defined way."

"Most industries use models for purposes such as studying requirements for systems, examining feasibility and manufacturabilitym, and determining how to build an actual system. In the computer industry, models ar used for some parts of the development process (usually for software requirements or design, but no techniques are widely used for modeling the entire system"

"On the other hand, abstract models are just representations, omitting some aspects of real-world systems, at least temporarily, but mapping what we hope to understand into a form that we can understand. Different types of models answer different types of questions about the system they represent, but even if we build a hundred different models, they could not answer every possible question about the system. That can only be done by the final system itself."

Source: Process for Systems Architecting and Requirements Engineering; Derek Hately, Peter Hruschka, Imtiaz Pirbhai. Dorset House Publising (2000) ISBN 0932633412
Context: Systems Architecting
Credibility: System engineers and systems architects have build their discipline over the past 30 years based on amongst others the works of Hatley and Pirbhai.

""Systems" mean different things to different people. For our purposes here, the definition of "system" has two parts: 1) a system is a complex set of dissimilar elements or parts so connected or related as to form an organic whole 2) the whole is greater in some sens than the sum of the parts, that is, the system has properties beyond those of the parts. Indeed, the purpose of building systems is to gain those properties."

"Architecting usually begins with generating an abstract mental or paper description - a model - of the system and it's environment. There will be many steps and perhaps many years between this abstraction and the final evaluation. And well before that evaluation is complete, the system will encounter the "real world". [...snip...]. To complicate the architect's problems, the world in which the system will have to exist will probably change while the system is being built."

Source: Systems Architecting, Creating & Building Complex Systems, Eberhardt Rechtin. Prentice Hall (2000) ISBN 0138803455
Context: Systems Architecting
Credibility: Eberhardt Rechtin was a recognised expert in the are of systems engineering

"A cloud masses, the sky darkens, leaves twist upward, and we know that it will rain. We also know storm runoff will feed into groundwater miles away, and the sky will clear by tomorrow. All these events are distant in time and space, and yet they are all connected within the same pattern. Each has an influence on the rest, an influence that is usually hidden from view. You can only understand the system of a rainstorm by contemplating the whole, not any individual part of the pattern. Business and other human endeavors are also systems. They, too, are bound by invisible fabrics of interrelated actions, which often take years to fully play out their effects on each other. [...snip...] Systems thinking is a conceptual framework, a body of knowledge and tools that has been developed over the past 50 years, to make full patterns clearer, and to help us see how to change them effectively."

"That is why the discipline of managing mental models - surfacing, testing, and improving our internal pictures of how the world works - promises t be a major breakthrough for building learning organizations."

Source: The Fifth Disipline (Revised edition), Peter Senge, Currency Double Day (2006), ISBN 038551725
Context: Systems thinking
Credibility: Peter Senge is a recognized authority in the area of organizational learning and systems thinking

"A system comprised of a (usually large) number of (usually strongly) interacting entities, processes, or agents, the understanding of which requires the development, or the use of, new scientific tools, nonlinear models, out-of equilibrium descriptions and computer simulations." [Advances in Complex Systems Journal]" (1)

"The Complex Systems Modeling Research Area is concerned with basic and applied research on simulations of complex systems and development of applications to understand and control such systems. By complex system we refer to any system featuring a large number of interacting components (agents, processes, etc.) whose aggregate activity is nonlinear (not derivable from the summations of the activity of individual components) and typically exhibits hierarchical self-organization." (2)

Source: Luis Rocha, (1), (2)
Context: Complex systems modeling
Credibility: the univerisity of Indiana would not have started a scientific project based on these definitions if their was no recognised (scientific) basis for it.

""Appreciation for systems" - what does that mean? A system might be generally defined as a collection of interrelated, interdependent components or processes that act in concert to turn inputs into some kind of outputs in pursuit of some goal. Systems influence, and are influenced by, their external environment. Obviously, quality (or the lack of it) doesn't exist in a vacuum. It can only be considered in the context of the system in which it resides. So, to follow Deming's [AH: this is part of a text about W. Edwards Deming] it's not possible to improve quality without a thorough understanding of how that system works."

Source: Goldratt's Theory of Constraints, H. William Dettmer, ASQ/Quality Press (1997) ISBN 0873897300 Parameter error in {{isbn}}: Invalid ISBN.
Credibility: Dettmer is a recoginised author and quotes Deming, who in turn is recognised for his system of profound knowledge, which is based on considering the manufacturing process and everything related to it as a system.

Angeloh (talk) 18:07, 9 July 2009 (UTC)

Further comments[edit]

Very nice. To cut this discussion short, following the second quote you collected, I would say we could change that sentences into something like:

  • Systems are abstractions of reality, or part of reality (real-world systems)

Qoutes like "system" depends on one’s perspective from your first quote, proves to me people consider systems as an abstraction as well. So removing that sentence isn't an option for me. What do you think?

-- Marcel Douwe Dekker (talk) 20:49, 9 July 2009 (UTC)

Sounds good! Angeloh (talk) 07:01, 10 July 2009 (UTC)
This is definitely in line also with what is written in the Cybernetica discussion below. I'd say make the change. Angeloh (talk) 09:34, 10 July 2009 (UTC)
I double checked. The term "real-world system" itself seems to be used in about 35 Wikipedia articles. Maybe we could/should even write an article about this term. Or write a section in this article about real-world systems...!? -- Marcel Douwe Dekker (talk) 11:01, 10 July 2009 (UTC)
How about making the change you suggested, and adding a section here on real-world systems vs. abstract systems? People looking for a definition of System will benefit from finding information about both. If we make real-world systems a separate page it only becomes harder to find for the large community of people working on real-world systems - who simply refer to these by the name "system". The other way, systems thinkers from the abstract point of view will be more aware of the other kind of systems this way.
Oopps - forgot to sign, once again. Angeloh (talk) 12:56, 10 July 2009 (UTC)
Ok I added the change suggested. I guess a section "real-world systems vs. abstract systems" can be added to the "types of systems" chapter. Would you like to give it a try? -- Marcel Douwe Dekker (talk) 10:38, 14 July 2009 (UTC)
Sure. I'll give it a shot, some time in the coming week. Angeloh (talk) 05:57, 15 July 2009 (UTC)
Forgot to mention this reference, which more or less puts the man-made subset of real world systems in direct relation to systems theory/systems thinking: System design Angeloh (talk) 11 will:32, 16 July 2009 (UTC)

The discussion as to whether a system is an abstraction or a "real" thing is philosophical and is active since at least 500 BC. It is unlikely to be resolved here. For each quotation -however authoritative- favoring one side, another quotation favoring the other can found. Therefore, I'd suggest we remove the sentence "Systems are abstractions of reality, or part of reality (real-world systems" altogether. Furthemore, the sentence is not at all useful in defining the word "system" in an encyclopaedia entry. --pmagrass (talk) 11:43, 16 July 2009 (UTC)

Equally futile and somewhat annoying are expressions such as the one in the very first sentence, that reads: "a set of interacting or interdependent entities, real or abstract, forming an integrated whole." REAL OR ABSTRACT is a useless specification and IMHO should be removed. --pmagrass (talk) 11:53, 16 July 2009 (UTC)

I do think it is important to mention and explain about the both of them. If there is a discourse as you say so, it is interesting to mention as well... For example in the history section.
I personally think this article could need a lot of work. If there are things unclear or questionable, there are two options in Wikipedia: remove it or improve it. You obviously favor the first option, I favor the second. -- Marcel Douwe Dekker (talk) 12:59, 16 July 2009 (UTC)
I undid the removal of the text by pmagrass, see here, as he suggested above.
  • Systems are abstractions of reality, or part of reality (real-world systems)
pmagrass gave the editsummary:
Removed specification on realism vs. idealism of systems (see Discussion, Section 3, July 28 2009): not useful (if meaningful) in this context
pretending there is some kind of agreement on this item here, which I think there isn't. So far he just gave his opinion and nobody agrees (so far). On the contrary there was an agreement here to put it like it was in the above discussion. -- Marcel Douwe Dekker (talk) 16:29, 28 July 2009 (UTC)
I had stated a view and no one disagreed to it during several weeks. I.e., I was not "pretending": I suggest you modify your language. Politeness and respect of others are essential prerequisites for participating in an intellectual discussion (in any discussion, actually). —Preceding unsigned comment added by Pmagrass (talkcontribs) 13:29, 29 July 2009 (UTC)
Now pmagrass removed the text again claiming: Nobody disagreed, either. Please provide an intellectual counterpoint to my position if you can.
I guess he forget to read the above sentence "I do think it is important to mention and explain about the both of them". or just didn't like the answer.
Earlier you can read that both Angeloh and me agreed on stating that particular sentence. If such a consensus is reached normally we accept it. If the next editor (here pmagrass) disagrees, I think it is only fair to change it again if a next consensus is reached. -- Marcel Douwe Dekker (talk) 12:26, 29 July 2009 (UTC)

i agree with pmagrass' position that it is useless and hardly meaningful to talk about "real-world" versus "abstract" systems at this stage. although in this discussion i do not see a lot of people argueing in favor of "real world" systems, should this ever become an issue, a link could be provided to a philosophical article in wikipedia. problem is, the same should be done for all words such as "object", "equation", "set", "group"... (i'm stopping to avoid creating a mess, but you see the point). --Gianburrasca (talk) 13:47, 29 July 2009 (UTC)

I am unaware of systems that exist by themselves, as opposed to systems created by human thought. Therefore, I favor the change proposed by pmagrass and supported by Gianburrasca.--Mariacanon (talk) 13:50, 29 July 2009 (UTC)

I have been asked to come and see. I read the article and all this discussion, and must say that I agree that the bulleted sentence "Systems are abstractions of reality, or part of reality (real-world systems)" should be removed. Thanks all!--Gionasz (talk) 13:53, 29 July 2009 (UTC)

OK folks: thanks for taking your time to look into this! Now, for those who think that Wikipedia is a democracy based on votes, we have enough votes for removing the sentence on realism vs. idealism.--pmagrass (talk) 14:00, 29 July 2009 (UTC)

i too agree with prof. pmagrass position. bye--Fergussa (talk) 14:07, 29 July 2009 (UTC)

Hi, it took me a while to read all this! I understand there has been debate concerning not onyl idealism and realism, but also systems and their models (which is, perhaps, the same issue). Ahead in the article, it says that "inclusion to or exclusion from system context is dependent of the intention of the modeler", seeming to assimilate model and system. I can see the issue, but I still believe the way to bring it up is not with a crude sentence claiming that systems may be concepts or real-word things. You could insert a little section that refers to that and points to the philosophical discussion in W articles where it belongs to: for example, I have noticed there is a decent IDEALISM article. In this sense, I agree with pmagrass.--Tinone (talk) 14:27, 29 July 2009 (UTC)

@Pmagrass. For someone who has been studying the way consesus is reached in Wikipedia, you should know there is no (as you call it) democratic consensus reached here. There is just a (temporary) democratic mayority here, as I see it. We normally give it some time for other editors to respond... (en we trekken niet gewoon een blik ja-knikkers open om je zin door te drukken/We normally don't bring in some new reinforcements, and claim victory at once). To my experience disagreements like this can last for weeks... But I understand this once sentence is in your way. I will leave it as it is for now, and wait and see. I think this article can use far more improvement. In compare to for example the German Wikipedia article about systems this whole article is rather POV. -- Marcel Douwe Dekker (talk) 14:54, 29 July 2009 (UTC)
P.S. I tend to agree with the last comment by Tinone that a new section could/would help
Right.... I felt bad promising to write something and not getting around to actually doing it. After reading this, I'm glad I didn't - the way this has gone in the past weeks is probably an example of why Wikipedia is not taken seriously by many people (whether or not that is just is a different discussion). Trying to get consensus in a project is the same as killing the project, and applies here as well, so this has to go one way or another. I'll see what my role in fixing this can be, after the flame war is over.
Systems have indeed been topic of discussion for many centuries, but I still stand by what brought me to this discussion originally: models and systems are different things (from a certain perspective models are systems, so maybe system is the more generic term). In my teaching material I now use the terms 'natural system' and 'man-made system' to distinguish between two obvious types of systems, and I'm considering whether 'model' could be a specific instance of the latter. If that is useful, I'm willing to contribute to adding an explanation anywhere in Wikipedia to explan the difference between these three and other terms.
Final note on the reference provided by Marcel: looks like the German Wikipedia page on System contains what I expected to find when I came to Wikipedia for some references on this topic. It might be that Germany has a pretty strong background in engineering that makes their page closer to home for myself and my students/collegues/... than the English page, but for me this definitely shows that I'm not alone in my views on what a system, natural system, man-made system, and model are.
Not sure if this helps the discussion, but I thought I'd share this anyway, instead of writing what is clearly not agreed on yet. Angeloh (talk) 08:13, 30 July 2009 (UTC)
PS. I am writing all of the above from the point of view that a site like WikiPedia should describe what people percieve in reality whenever possible, not the academic views only. The internet community is much broader than the group of people that used to buy the Encyclopdia Britannica and alike in the past 50 years.

Principia Cybernetica[edit]

This website is an excellent resource on systems thinking. See for example the Principia Cybernetica definition of System --RichardVeryard (talk) 18:49, 9 July 2009 (UTC)

could be, but the link is broken? Angeloh (talk) 19:00, 9 July 2009 (UTC)
If you want to have an overview of more then 500 years of systems definitions, you should check Definitionen von "System" (1572-2002) at Mueller science written partly in German and English. Just one or two of those definitions:
"By Systems I understand any numbers of men joined in one Interest, or one Businesse." (Thomas Hobbes , 1651)
"Zusammenhang miteinander verknüpfter Wahrheiten (nexus veritatum), wobei die Verknüpfung methodisch richtig und aus einem zugrunde liegenden Prinzip vollständig deduziert sein muss." (Christian Wolff, 1750)
"Ein System ist eine imaginäre Maschine, die erfunden wurde, um in der Vorstellung die verschiedenen Bewegungen und Effekte zu verbinden, die in der Realität tatsächlich schon ablaufen." (Adam Smith, um 1750)
In this latest definition Adam Smith practically states that a systems is an abstraction.
-- Marcel Douwe Dekker (talk) 21:02, 9 July 2009 (UTC)
P.S. This image is Roland Muller's synthesis of the historical development of the systems. In his perception the term evolved simultaniously in different directions.
The link to Cybernetics is fixed. It contains amongst others the following - perfectly related to what we're discussing:
2) Usually three distinctions are made:
  1. An observed object.
  2. A perception of an observed object. This will be different for different observers.
  3. A model or representation of a perceived object.
A single observer can construct more than one model or representation of a single object. Some people assume that 1. and 2. are the same. This assumption can lead to difficulties in communication. Usually the term "system" is used to refer to either 1. or 2. "Model" usually refers to 3. Ashby used the terms machine," "system," and "model" in that order for the three distinctions. (Umpleby) —Preceding unsigned comment added by Angeloh (talkcontribs) 06:10, 10 July 2009 (UTC)
1. Process of perception
I am afraid I don't see the connection (yet) in this distinction by Stuart Umpleby. I use to make a first distinction in (see image):
  • the observed objects, which are part of reality
  • the perception of those observed objects, which are part of the perception of the observer.
Now we agreed a systems can be a real-world system, part of reality, or imaginary cq. an abstraction, and part of the perception of the observer.
Both a system and a model, in combination a system model, can be a fundamental building block in the perception of the observer.
The observer can decide to construct a model, for example a simulation model, a physical model, or some kind of conceptual diagram. that it becomes part of the reality again. Do I make any sense? -- Marcel Douwe Dekker (talk) 11:55, 10 July 2009 (UTC)
Yikes, how to explain that... ;-) It's pretty much as you write, I guess. If you follow the systems thinking approach, the observed objects are (part of) a real-world system, the perception of the observer is a model (mental model, if you follow Peter Senge), and a conceptual diagram is also a model.
This latter model is part of the system where people work to understand the real-world system, and both are part of the system we call the real-world. This is part of the notion of system of systems, which is still an immature field of research. Angeloh (talk) 13:04, 10 July 2009 (UTC)
2. Approach mechanism in the process of perception
Ok, thanks. I guess I have a problem with automatically calling the perception of the observer a model. In my own work I have been trying to picture the elementary building blocks of the process of perception, and determine the place and role of models and systems in this process as well.
At first, see figure 1, models and/or systems are no obvious/direct part of the perception process. The start occuring if you use some kind of structured in the observation of a real-world situation, see figure 2. This approach will structure the observation and translate into a framework in which the perception is perceived. As you can see, the framework is an extra element added to perception of the observed objects. Now I guess you can question if a perception without any approach and perception framework, as pictured in figure 1, is even possible.
One way or an other, this framework could be called a model or a system? Do you think this and the illustrations make sense? -- Marcel Douwe Dekker (talk) 13:03, 14 July 2009 (UTC)
I'm not sure I get the picture, but I'll have another look later today - straight out of bed after a too short night it doesn't come across ;-). It reminds me of discussions with a collegue, who is very keen on the distinction between reality, observation and recording (or in Dutch 'waarheid, waarneming en waarlegging'). Angeloh (talk) 05:56, 15 July 2009 (UTC)
These illustrations are part of a visual meta-modeling language to express the elementaire building blocks and processes in the thinking process, I have been developing over the years. They have some similarities with the illustrations in Arbnor & Berke have been using in their "Methodology for Creating Business Knowledge". (see also here), but this is more advanced. I am actually testing them here if it makes any sense to use them here. I guess they are (still) of little help...!? I think the word "waarlegging" is a nice expression, but to my knowledge it is not used in Dutch. -- Marcel Douwe Dekker (talk) 13:23, 16 July 2009 (UTC)
I'm not suggesting to use waarlegging as a term - it's a term this person uses for lack of a fitting Dutch word. ;-) As for the diagrams: given the discussion going on above, I think they are not the solution right now. Angeloh (talk) 08:00, 30 July 2009 (UTC)

Authoritative Definitions[edit]

I removed the following section:

There are many definitions of what a system is. Below are a few authoritative definitions of system:
  • ANSI/EIA-632-1999: "An aggregation of end products and enabling products to achieve a given purpose."[1]
  • IEEE Std 1220-1998: "A set or arrangement of elements and processes that are related and whose behavior satisfies customer/operational needs and provides for life cycle sustainment of the products."[2]
  • ISO/IEC 15288:2008: "A combination of interacting elements organized to achieve one or more stated purposes."[3]
  • NASA Systems Engineering Handbook: "(1) The combination of elements that function together to produce the capability to meet a need. The elements include all hardware, software, equipment, facilities, personnel, processes, and procedures needed for this purpose. (2) The end product (which performs operational functions) and enabling products (which provide life-cycle support services to the operational end products) that make up a system."[4]
  • INCOSE Systems Engineering Handbook: "homogeneous entity that exhibits predefined behavior in the real world and is composed of heterogeneous parts that do not individually exhibit that behavior and an integrated configuration of components and/or subsystems."[5]
  • INCOSE: "A system is a construct or collection of different elements that together produce results not obtainable by the elements alone. The elements, or parts, can include people, hardware, software, facilities, policies, and documents; that is, all things required to produce systems-level results. The results include system level qualities, properties, characteristics, functions, behavior and performance. The value added by the system as a whole, beyond that contributed independently by the parts, is primarily created by the relationship among the parts; that is, how they are interconnected."[6]
  1. ^ "Processes for Engineering a System", ANSI/EIA-632-1999, ANSI/EIA, 1999 [1]
  2. ^ "Standard for Application and Management of the Systems Engineering Process -Description", IEEE Std 1220-1998, IEEE, 1998 [2]
  3. ^ "Systems and software engineering - System life cycle processes", ISO/IEC 15288:2008, ISO/IEC, 2008 [3]
  4. ^ "NASA Systems Engineering Handbook", Revision 1, NASA/SP-2007-6105, NASA, 2007 [4]
  5. ^ "Systems Engineering Handbook", v3.1, INCOSE, 2007 [5]
  6. ^ "A Consensus of the INCOSE Fellows", INCOSE, 2006 [6]

I removed this section because these definitions are all from the field of (systems) engineering, and I think this gives a whole wrong impression. Systems are used in all fields of science and a thousands of (very notable) scientists have given a own definition of a "system". -- Marcel Douwe Dekker (talk) 21:52, 9 July 2009 (UTC)

(I removed a comment I made here - because I missed your earlier suggestion) Angeloh (talk) 07:01, 10 July 2009 (UTC)
Yes, there are now three different talk items open for debate, and you can respond to either one of them. -- Marcel Douwe Dekker (talk) 08:52, 10 July 2009 (UTC)
I'm not sure about this confusion, but these definitions definitely fit better in the systems engineering page - if anywhere Angeloh (talk) 09:33, 10 July 2009 (UTC)
Ok, good idea. I have added the section to the systems engineering page. -- Marcel Douwe Dekker (talk) 10:16, 10 July 2009 (UTC)
Thanks! Maybe I should consider contributing to WikiPedia myself - instead of just making suggestions and providing you with work. —Preceding unsigned comment added by Angeloh (talkcontribs) 13:06, 10 July 2009 (UTC)
You are welcome to join us in editing. There is enough to improve, and no better way of learning more, then to contribute to articles yourself. But when it comes to making these mayor kind of changes, better continu proposing these things, and wait for comments by experienced editors. -- Marcel Douwe Dekker (talk) 19:50, 10 July 2009 (UTC)
P.S. In the field of systems science here, there is a big change I will respond because I initiated the Wikipedia:WikiProject Systems and follow most of the articles and discussions. Your are invited to join the project if you like. Eevery person who is developing a course on systems design is more then welcome.
Thanks. I'll think about it. In the mean time - need a hand on that additional paragraph related to real-world systems? 88.159.212.37 (talk) 09:43, 13 July 2009 (UTC)Angeloh (talk) 12:14, 13 July 2009 (UTC)
Let me think about that. I will get back on this soon. -- Marcel Douwe Dekker (talk) 01:55, 14 July 2009 (UTC)

I wrote the section and concur. Thanks. Sidna (talk) 15:54, 19 July 2018 (UTC)

Ok thanks.-- Marcel Douwe Dekker (talk) 01:51, 14 July 2009 (UTC)

Copy-paste registration[edit]

-- Mdd (talk) 23:10, 6 November 2009 (UTC)

A wish[edit]

The intro is good, bordering to very good. It is what I would like to read, but I already had an idea of what a system is. <mood class="humbleness">Maybe however,</mood> the intro could profit from a few examples of what has been analysed as systems to serve the needs of less knowledgeable persons. F.ex. a computer system, the human nervous system as a biofeedback system, a chemical factory as a system. Just something short, so that the reader gets an idea what application areas are common. ... said: Rursus (mbork³) 09:33, 11 November 2009 (UTC)

Fair idea Angeloh (talk) 10:21, 15 November 2009 (UTC)
I agree. This article does have a section "type of systems" which gives just a start, and the systems/systems science template at the bottum lists some more main types of systems. I even created a List of systems with 2000+ systems mentioned in Wikipedia. If you want to explain some more about the most common systems I would start with the systems listed in the template. -- Mdd (talk) 00:00, 16 November 2009 (UTC)

Boundary of the System[edit]

Why should there be a need to define this? A system is a collection of elements conneceted together so that they nmay interact. There is no system without the connections which themselves specify the extent of the system. Hence no need for boundaries.

Kenneth Boulting was not very clear when he wrote:

            A system is a big black box
            Of which we can't unlock the locks
            And all we can find out about
            Is what goes in and what comes out.
            Perceiving input-output pairs,
            Related by parameters,
            Permits us, sometimes, to relate
            An input, output, and a state.
            If this relation's good and stable
            Then to predict we may be able,
            But if this fails us heaven forbid!
            We'll be compelled to force the lid!

Yet it seems that this still applies! Macrocompassion (talk) 13:49, 9 May 2012 (UTC)

Definition of a system (Oct 31, 2012)[edit]

Hi, the current (Oct 31, 2012) definition of a system is given as: "A system is a set of interacting or interdependent components forming an integrated whole or a set of elements (often called 'components' ) and relationships which are different from relationships of the set or its elements to other elements or sets." I've seen the following discussion on this but I have a more basic (or stupid) question - what is the property that distinguishes a composite component from a "system"? A composite component has a set of elements as well and relationships among these. BTW, I miserably fail to understand the "relationships which are different from relationships of the set or its elements to other elements or sets." - do you mean "relationships among the elements of the set"? In the first part of the definition, what exactly does "integrated whole" mean? Is a composite component an "integrated whole"? If not, how can one judge if something is an "integrated whole"? I find the expression a bit too vague.

Separate point: I believe that the (Greek) etymology of the word "σύστημα (systēma)" is "συν (syn)" (with, along with, together, at the same time) + "ιστημι (istēmi)" (to stand), i.e., its literal meaning is co-standing. http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0057%3Aalphabetic+letter%3D*i%3Aentry+group%3D32%3Aentry%3Di%28%2Fsthmi

138.40.68.42 (talk) 21:27, 31 October 2012 (UTC)Christos

You are right. But this is a profound question. Most system "definitions" focus on the whole/parts duality (which we can, I think now, speak more clearly in terms of emergence these days). Some other definitions will focus on the intrinsic/extrinsic duality (system vs environment). I don't think theres a closed answer to a "definition", hence I totally disagree with trying to provide a definition for a concept of "system". That is very childish Clauariel (talk) 21:59, 14 April 2016 (UTC)

change lead illustration[edit]

To be "arrow compatible":

--Krauss (talk) 07:43, 11 October 2014 (UTC)

Networking service[edit]

Networking service isp license Roufique Hossain 20:11, 7 January 2017 (UTC)

System (Mathematics)[edit]

I came to this article from reading the articles Time-invariant system, Causal system and Linear time-invariant theory. This article does not contain enough mathematics to be useful for the reader of the mentioned articles. I would like a proper mathematical definition of a system here in this article and some examples. E.g. a system is a function that maps functions (called input signals) to functions (called output signals), i.e. the domain and codomain of a system are function spaces. I propose adding a section 'System (Mathematics)' to this article. Another option would be to create a new article 'System (Mathematics)'. This would have the advantage that we could treat important system properties like linearity, stability, ... there. Fvultier (talk) 16:16, 18 July 2017 (UTC)