text:
Talk:Genus–differentia definition

Example of Individual and Identity
This particular example: has come under attack for 2 reasons so far: Mfwitten (talk) 20:30, 11 February 2011 (UTC)
 * [the] Mfwitten: a Wikipedia user with the account name 'Mfwitten'.
 * 1) An embedded account name appears like vandalism. However, this just isn't a very good reason; either the example is useful or it is not. Of course, if someone were replacing existing examples as a vehicle for inserting his or her name, then that might be something worth undoing.
 * 2) It appears to be a poor example. In my opinion, it's a very good example because:
 * 3) * it relates these more formal definitions of 'individual' and 'identity' to the more common notions without relying on non-Wikipedia culture.
 * 4) * it hints at the thoughtful use of definite and indefinite articles used throughout the development of the concept of definition by genus and differentia (and it is also an allusion to those human languages in which it is permissible to use the definite article before somebody's name); the definition itself also follows the explicit 'a with ' pattern that has been frequently used.
 * Seems to me a bit odd to have a user name, and there's no good reason for it. There is nothing about WP users that make this particular example any better than any of countless other choices.  One might as well use a pet's name as the identifier for an individual and his species as the genus.
 * I'm afraid that your insistence on keeping the (your!) username as the example is not fundamentally motivated by a desire to improve the article. Wouldn't it be much simpler to give in and choose any other equivalent example?  There is absolutely nothing to be lost by doing so and at the least, we avoid more tedious debate over a fundamentally trivial point. Phiwum (talk) 14:12, 9 December 2011 (UTC)
 * Let me add that there is a good reason not to use an account name as the example. The name refers to at least two distinct entities: the account itself and the user who uses it.  Indeed, since sock puppets are common on the internet, and since the users of sock puppet accounts often try to speak with a distinct voice for each account, one is tempted to say that the account name most closely identifies the account, and not the user behind the account (whose identity is, for many purposes, unknown).  On the other hand, my (now dead) dog's name has no such ambiguity.  It was the name of my dog.  Phiwum (talk) 14:36, 9 December 2011 (UTC)

 * Firstly, it must be clearly stated that I've never insisted on using my account name (except, perhaps, for the choice to use it when the example was initially written). Of course, were someone simply to replace 'Mfwitten' in the example with some other account name, I think such an edit should be reverted, because it serves no purpose other than to insert an account name (note, though, that such an edit is not the nature of the edit that introduced my example).

 * By similar reasoning of your own, there is nothing better about the countless other choices for an example than the one that I chose when writing that section. Frankly, I think the tacit accusation of offensive vanity belongs not with me, but with those who contest the example based on the use of an account name.

 * I don't understand your point on ambiguity or even agree that such ambiguity exists. The term 'identity' is well defined in the article. Mfwitten (talk) 08:44, 10 December 2011 (UTC)

 * Well, let us set aside the point about ambiguity (though I'm puzzled why you don't understand that your account name names the account, and not you). Let's look at this in very simple terms.
 * There is no reason that a WP account name serves your purpose than literally any other name. A dog's name, the name of the President of the U.S., and so on, all work for this example just as well as your account name.  Correct?
 * Now, as you know, there exist small-minded, vain folk like me who think that the use of an account name is in poor taste in this example. Evidently, you've had to defend your choice repeatedly because of complaints.
 * Thus, the use of a WP account name is, it seems, not as good as many of the other choices, because it causes repeated discussions on its appropriateness. At least some editors (and surely some non-editing readers as well) think that it is inappropriate and thus distracts from the content of the article.
 * So tell me now why you are adamant that the example should not be changed. Why is a WP account name better than any of countless other examples of named objects/animals/persons, despite this evident deficit?  Phiwum (talk) 14:43, 10 December 2011 (UTC)

 * Actually, I've only been adamant that before altering the example, the real and only practical reason be given: A reader's puerile, baseless envy; your comment is about as close as I've gotten to extracting that admission from someone. Thank you for not cowering behind sterile, meaningless bureaucracy like some Vogon. Mfwitten (talk) 15:54, 10 December 2011 (UTC)

You didn't actually answer my question: is there any good reason to prefer the example as it stands, despite the repeated need to defend yourself? Please, just tell me: why do you insist that we should not change the example to something other than a WP account user name? (Be sure also to look at my questions regarding WP:OR at the bottom of this talk page, please.) Phiwum (talk) 16:12, 10 December 2011 (UTC)

 * I have only ever insisted on having a good reason for changing the example; a truthful reference to the reality of readers' primitive, cynical, petty emotions is good enough for me to replace the example, all else being equal. It's just that all the reasons have hitherto been either mistaken readings of the article or destructive bureaucratic mindlessness. Nevertheless, it would no doubt be a wearisome endeavor to defend against accusations of WP:OR, so here I present my rump to the inevitable destruction of useful information. Mfwitten (talk) 21:27, 10 December 2011 (UTC)
 * With all due respect, your answer suggests that this material should be removed because you evidently know that it is WP:OR. Please correct me if my interpretation is wrong.  In the meantime, I have removed the material because that's what WP policy is.  You may disagree with that policy, but that's how it goes. Phiwum (talk) 01:31, 11 December 2011 (UTC)

Issue tags
This article has been around since 2001. At this point it apparently has escaped notice.
 * Source or reference: There is only one source, an actual reference to a quote. The paragraph includes a purported "hackneyed example" (common, well-known, or customary), that is anything but common or well known. This bring into question;
 * Notability:Such profound and confusing writings should have reasoning for existence.
 * Incoherent: There are no section to reference but I tagged one example.
 * Wikify: Since there are no sections, thus no obvious lead, the article, providing some proof of notability and references, would need a serious rewrite. I read the article twice to see what needed improvements I could notice and just got more confused. From the beginning, since it is common that Wikipedia is touted as not being a dictionary, the title "Genus–differentia definition " seems to be inappropriate. Of course I am sure it can be explained why using the word "definition" is acceptable. An editor decided to use his/her own user name in an example in the article main space, and even gave an elaborate explanation for justification, that (before now) was not challenged. A host of reasons why this is not acceptable to include branding as ownership as the example was of a major contributor to the article. Otr500 (talk) 12:15, 10 November 2011 (UTC)
 * Having read through your qualms, it is my belief that your confusion is largely a fault of your own; in particular, the title "Genus–differentia definition" does not mean:
 * Definition of genus–differentia.
 * but rather:
 * An article discussing the concept of a "genus–differentia definition".
 * It is unavoidable for me to sound rude: If even that fact escapes you, then your opinion on the comprehensibility of the rest of this fundamental material is immediately suspect. For every reader of an encyclopedia, there is at least some material that is beyond that reader's immediate understanding; this simply means that the reader does not yet have a mature enough foundation for the subject. Should we scrap or otherwise mangle the article on the Jacobian matrix just because you, as a particular reader, have trouble understanding it? Should we disregard Principia Mathematica because you, as a particular reader, can't fathom why it would take around 400 pages of foundational logic to prove $$1+1=2$$?  Now, I grant that the lack of sectioning is cosmetically alarming at first blush, but the nature of the subject and the presentation of these concepts seem to require a rather tight coupling of the paragraphs throughout; it may just be the case that breaking the text into sections would only lead to contrived organization and further confusion. Of course, it's a task worth considering. Mfwitten (talk) 16:45, 10 November 2011 (UTC)
 * I introduced some sectioning and style enhancements. Mfwitten (talk) 18:47, 10 November 2011 (UTC)

Thank you for the sectioning. I do not see that adding sections degraded the article in the least and made it easier to read, study, refer to (as with links), and as a plus, which may or may not be important to some, follows policies and guidelines. Using one of your words I feel sections did offer "enhancements".

At times and in sundry places I have made light of my ignorance. For this I do not apologize as I have acquired some knowledge that rivals that of great minds. Since "ignorance", which can be defined by genus and differentia, is only a lack of knowledge, I imagine all are ignorant to some point. To present that one lacks the knowledge of a subject, we might suppose as ignorance, we could also presume this person to be unlearned. That might be true to some, but in reality may only be on a particular point or subject, thus one may still be learned and lack certain knowledge. It is highly probable that no one person (specifically speaking of the species Homo sapiens) knows everything. To determine if a subject (a lucky guess notwithstanding) does not have a "mature enough foundation" for understanding or is simply having trouble understanding, possibly because the way something is presented, is certainly debatable. In light of that, as with entertaining the thought of sections, it might be a good idea to consider the genus–differentia of the evidence presented. I assume that since words can be subjected to this method then certainly sentences and even paragraphs can.

As for understanding, or not understanding, the fault could lie on the person but could just as easily lie in the presentation of what is presented that is attempting to be understood. Since there is only one source, and nothing pertinent to the rest of the article, it is somewhat difficult to follow non-existent references to check facts. But this is only a fundamental Wikipedia criteria that to some is obviously not important. I can show another side of my foundational maturity regarding references should the need arise.

A method of defining terms would be the method used to determine the definition. In the context of the subject would this then not be a genus–differencia method? I found multiple references to this name and only one that corresponds with the current title.

I have read that there are limits of defining certain things by genus and difference. If this is so then a subsection, that would certainly enhance the article by presenting a neutral point of view, would be warranted.

Concerning the above mentioned article "Jacobian matrix"; there are issues there also. Maybe I am just better at mathematics than philosophy but that article does have better presentation and also has flaws. Neither article has a history section and some etymology would be beneficial. "Jacobian matrix" and Hessian matrix mention partial derivatives but "Jacobian matrix" states, "... is the matrix of all first-order partial derivatives of a vector- or scalar-valued function...", while "Hessian matrix" states, "...is the square matrix of second-order partial derivatives. Listed in the section "Jacobian matrix" of "Jacobian matrix and determinant":
 * In a sense, both the gradient and Jacobian are "first derivatives" — the former the first derivative of a scalar function of several variables, the latter the first derivative of a vector function of several variables. In general, the gradient can be regarded as a special version of the Jacobian: it is the Jacobian of a scalar function of several variables.

and:
 * The Jacobian of the gradient has a special name: the Hessian matrix, which in a sense is the "second derivative" of the scalar function of several variables in question.

Perhaps we could consider my "ignorance" or lack of "mature enough foundation" as to the reasons I feel there is confusion in discussing "second derivative" on one hand and "second-order" on the other as well as "first derivatives" as opposed to "first-order". I don't think it is just me, and the fact it may be above my "immediate understanding", that this is confusing. The Jacobian determinant has been confusingly referred to as "the Jacobian" so would this not be good information to be included an article?

"Partial derivative" explains, "The difference between the total and partial derivative is the elimination of indirect dependencies between variables in partial derivatives.", and this is hidden in the section Examples but, in my humble opinion, should be in the lead and in a noted section of that article.

I feel that my lack of any foundational understanding concerning a subject may be a reason not to try to get into a philosophical discussion on said subject but this does not mean that I can not see errors, things presented as to be confusing, or certain important things omitted.

Prima facie the article " Principia Mathematica" appears well laid out although there would probably be a great multitude of readers that do not need 400 pages to explain what was accepted before grade school. I would imagine there could be found some that could present some form of argument though.

Considering these discussions I have not forgotten that a user name is (to me) improperly used in the main space of Wikipedia. This was not addressed in replying comments nor in edits. Rational convincing arguments do not include suppositions, poor examples, personal opinions, non-Wikipedia culture, or hints as to reasoning. It was used and consensus by silence has allowed it to remain. "The world changes, and Wikipedia must change with it.", and I now object, so would you mind choosing a better example? I can pass this by the community to see if a particular example is justification (or not) or choose another avenue of dispute resolution. Perhaps my "immediate understanding" is just a lack of comprehensibility so maybe I should just go this route to see if there are minds more equipped to reach a more logical conclusion. Otr500 (talk) 10:20, 12 November 2011 (UTC)

 * With regard to the example about which you are so indignant:
 * [the] Mfwitten: a Wikipedia user with the account name 'Mfwitten'.
 * Would it still bother you if I had written the name of an account that does not exist? Upon reading such a variant, would you have bothered to ensure that the account does not exist? Why? Mfwitten (talk) 15:33, 12 November 2011 (UTC)
 * I did take the time to find out that the account was active but this is not relevant as there are several reasons why a user name should not be used in Wikipedia main space.

User name in main space
Placing a Wikipedia user name in an article main space, a real (current or past) user or even a fictitious user, would be covered by Wikipedia policies and guidelines concerning original research, blogs, notability, references, self promotion, indiscriminate collection of information, verifyability, and possibly more. The fact that a real and current user name is the subject, that also happens to be a major contributor, raises issues of conflict of interest. Otr500 (talk) 04:29, 13 November 2011 (UTC)
 * Please make a specific allegation and corresponding remedy; currently, it seems as though you are merely tilting at windmills. I have likely already provided a useful rebuttal here. Mfwitten (talk) 21:45, 13 November 2011 (UTC)
 * Thanks for the laugh concerning "make a specific allegation". WOW! that is funny. I will read the article again as I might have missed the other User name(s) in main space. Where's the cameras? I know, that is one of those "I can't hear you" comments.
 * I am not sure if the insinuations of your idiom are, 1)- that I think you are an enemy, 2)- that I am involved in  a futile battle, or 3)- that I  incorrectly perceived or misinterpreted something. It really doesn't matter as I am not going to continue circular discussions, and the "corresponding remedy" does not need to be suggested. I will bring this issue before the community for consensus. I feel I might as well seek a name change while I am at it to reflect actual references. Oh I'm sorry, there are no relevant references to the title or actually even to the subject. I did, however, find one reference to "genus–differentia definition", and several to "genus–differencia method". Otr500 (talk) 06:52, 16 November 2011 (UTC)
 * Just consider it a repayment for the laugh you gave me regarding:
 * The nature of your confusion over definition in the title.
 * Your aversion to even a fictitious user name in the example.
 * These two points and your literal interpretation of the law (as it were) color your opinions downright risible! Mfwitten (talk) 14:51, 16 November 2011 (UTC)
 * A good laugh never hurts anyone. I would like extend my cordial laugh back at you concerning my initial inquiry of the title name. I did not state or rationalize that using the word "definition" was indicative of meaning to lexically define genus–differentia. "My" interpretation may be just that, and it may or may not be shared, but my arguments are not without merit.
 * I hope that you will not confuse any lack of expertise with an inability to ascertain facts, explore and verify references, and determine relevance. I certainly hope you do not confuse the fact that I am not a Philosophy "expert" with a lack of knowledge of the English language and an ability to compare. It is interesting that you choose to relate what you feel is a "literal interpretation" with Biblical literalism.
 * While we might debate the article title, each other beliefs and interpretations, or other aspects, there are some things of which there is no doubt.
 * A history section is very important to the article and inclusion for some connection to Aristotelianism other than one reference. Considering this article has been elevated to B-class there needs to be a section for balance, which references do show there are certainly those that disagree.
 * With the addition of sections my concerns are specifically:
 * 1)-The title name; This is being discussed in the section below. I still feel that the term "method" is not inappropriate as there is no doubt that the title (and article) reflects only one of several known "methods" of defining. Surely you do not argue with this? "Genus and Differentia" might be an option depending on references.
 * 2)- User name (supposedly fictitious); You have stated that I am indignant and have an aversion over your use of a presented "fictitious" name when the fact is that I do not see a masked attempt ([the]) to conceal a user name as proper. You assert that by using [the] in front of a user name "Mfwitten", that specifically you identify with, this somehow portrays the user name as fictitious thus a justifiable reason for use as an "example". By using the brackets "the" is separated from "Mfwitten" and adding, "a Wikipedia user with the account name 'Mfwitten' ", it is made clear the name is not fictitious. Because an individual, with an account on Wikipedia, chooses not to have a "user page" (thus the red color), does not mean the name is fictitious nor that it is not an active account. After all, I am having discussions with someone that has an account and user talk page that certainly identifies with "Mfwitten". This does not even take into account the other above stated reasons why I feel the use is inappropriate. I have stated my intentions for resolution as I do not choose to get into edit wars and will work on this when time allows.
 * 3)- References; There is notability for content and this is being discussed in the section below as some of the many references surely can be used.
 * 4)- Tags; The article, as written, is "confusing or unclear to readers" and contains an "excessive amount of intricate detail that may only interest a specific audience". It had a context tag placed on it in 2009 but this was edited out. With a lack of references there is article content that appears to be synthesis and original research. Some of this can be resolved by including source and references related to content but with out clarification a lot of content will still be confusing. I do not mind debating but I hope resolution of the issues, being paramount to petty discussions, means improvements are more important than philosophical discussions. I will look at the references you provided. I would hope that you will include some of those in the article. Otr500 (talk) 19:55, 20 November 2011 (UTC)

The positions that you are representing are, in my opinion, unhelpful to Wikipedia.

Regarding confusion: I stand by my original statements.

Regarding a History section: I don't particularly care about the history, personally—I don't particularly care that someone thinks that we would be deprived of this concept (or at least this terminology) unless some guy named Boethius wrote about it. Of course, I don't mind if information about such history is introduced, but I think it's important to recognize that there are two approaches to this subject at play (I am concerned primarily with the latter):
 * Discussing accidents of our particular Universe, like Boethius.
 * Discussing inherent, fundamental, unchanging concepts (of a, say, mathematical nature).

Regarding notability: I personally feel that in general, the concept of "notability" is mostly a ridiculous one. The purpose of "notability" is found in the fact that resources are finite; if Wikipedia had infinite resources, nobody would care if I made one new article for each of my bowel movements.

Any debate about notability should really only be about the degree of interconnection with other articles that exist both outside and inside Wikipedia.

In this case, I think I have demonstrated even to you that this subject is notable, but quite frankly, I don't care one bit whether or not you (or anyone else) feels that this subject (or any other subject) can be called notable; what is notable to one person is not notable to another (for instance, Boethius is not notable to me in the slightest, but I imagine you'll definitely want him mentioned somewhere in the article—if only for the juicy reference).

Regarding references: I personally feel that references are only useful for resolving disputes. I don't think it's wrong to synthesize or even to produce original research on Wikipedia, because to me, the free‑flow of ideas and information is what is important—not whether some bloke said the same thing in some other medium.

For instance, let's assume that this article does perform a synthesis that cannot be attributed to some non‑Wikipedia source. What are you going to do with that synthesis? Remove it? To me, that would be a highly immoral destruction of useful information (as long as that synthesis is not in dispute). Ultimately, there is no, say, "journal" that is more peer‑reviewed than Wikipedia.

Now, I recognize that this stance is diametrically opposed to the stance that some users of Wikipedia have. However, it is my opinion that those with the alternative view are unhelpful to Wikipedia; such people destroy value just to play some game with themselves (possibly because they are unable to help in creating real value in the first place).

Regarding the example:
 * I have never suggested that Mfwitten is a fictitious user name; I was merely trying to get you to see that the example does not inherently infringe on Wikipedia's guidelines (now, had I inserted Mfwitten into an existing example, then you might have a point).
 * Your misunderstanding of the purpose of [the] is baffling; it's use is meant for the following purposes:
 * To mirror the pattern of the other definitions, which are introduced with an indefinite article. However, the definite article is used to reflect the fact that an individual (as described in the article) is being defined.
 * To allude to those languages (such as German) in which a person (or individual) may be named with the use of a definite article; the word the is in brackets because it is unusual (particularly in English) to introduce an individual's name with a definite article.

Do you see the richness of this example? Perhaps you don't, but your reasons for removing this particular example are absurd, especially in the face of such richness. Mfwitten (talk) 02:25, 21 November 2011 (UTC)
 * The example is not only linguistically simple and consistent with the pattern of the other examples, but it also makes use of only Wikipedian culture in order to make a concrete illustration of the concept of inidividual (both as defined in the article and as understood in common usage).
 * You have taken a strange position to state that what I am representing is unhelpful to Wikipedia. I am not sure as to your position on Aristotelian ethics as your rhetorical theory does not contain any logic that follows the influence of Socrates.
 * You edit on Wikipedia but explain in detail how you disdain Wikipedia policies and guidelines and that your ideas are "diametrically opposed to the stance that some users of Wikipedia have.". You use the word "some" as if this was a minority of users. You make reference to "Boethius" and a comment about a "juicy reference" and delve into a discussion on synthesis and your ideology. The beauty of Wikipedia is that synthesis can be presented as long as it is not challenged. Sometimes it may be masked, sometimes overlooked thus allowed by silence, and sometimes not understood.
 * I am sorry but I do not see any richness in your example. Maybe it is like a joke, or maybe an insider joke, and I just do not see punch line. The fact that you refer to "an individual", that would be the genus, and a "specific individual", that would be the differentia (species) probably has something to do with your perceived "richness". Your reference that it is "...linguistically simple and consistent with the pattern of the other examples,...", would bring the question of  other examples. I would have settled for comments that would have given substance to the reasoning for use. I do not feel that you have proven anything concerning the article notability except the concept. The title does not agree with the majority of references provided below and certainly not with the one provided. The majority of the contents can not be verified and your comments give a hint that none will be located. You have made it clear this is not important to you.
 * Articles can survive as long as the are uncontested. They can then still survive if some argument is presented to justify existence that gains consensus and sometimes even with a lack of references.
 * Your comments are disturbing to me and are not in the spirit (as I perceive) of what Wikipedia stands for. In light of this an article for deletion request probably would be the best. That way you could argue your points, how the information in the article is relevant to the lack of references that you feel are not necessary anyway, and your disdain for Wikipedia and the majority of editors in the community. You seem to like a challenge so maybe this would be a good one? Otr500 (talk) 14:43, 23 November 2011 (UTC)

 * I find it difficult to understand the purpose of most of your reply. However, I have these responses:

 * For the record, I am not the one who chose the current title of the article, and I'm currently the only one who has made a suitable attempt at alternatives.

 * This statement of yours:
 * The fact that you refer to "an individual", that would be the genus, and a "specific individual", that would be the differentia (species)...
 * shows misunderstanding. To be concrete, consider the example:
 * [the] Mfwitten: a Wikipedia user with the account name 'Mfwitten'.
 * From the descriptions of the terms given in the article, it follows that:
 * The whole definition (to which one may refer with the term "Mfwitten" or "the Mfitten") is an individual; that is, Mfwitten is an individual.
 * The genus of Mfwitten (which is "a Wikipedia user") may be called synonymously the species of Mfwitten; that is, Mfwitten is an individual of the species "[a] Wikipedia user".
 * The differentia of Mfwitten (which is "with the account name 'Mfwitten'") may be called synonymously the identity of Mfwitten; that is, the individual Mfwitten is identified among other individuals of the same species by the fact that Mfwitten is the one that has "the account name 'Mfwitten'".
 * You are correct in what I perceive is your implication that the example in question doesn't quite match linquistically with the other examples; I believe I changed the other examples and then didn't extend that change to the example in question. I'll change that presently.
 * In any case, I don't [yet] perceive what value you think you're bringing to Wikipedia in suggesting a deletion or removal of material, especially since you have not brought up any particular dispute. Mfwitten (talk) 18:15, 23 November 2011 (UTC)
 * The purpose of most of my comments became superfluous with your last edit.
 * I tagged the article because it fails to meet Wikipedia standards through out. Although one issue was corrected this is just cosmetic in respect to the real underlying problems. "Any material challenged or likely to be challenged must be attributed to a reliable published source", per the burden of evidence section. There are other serious issues that you not only choose to overlook but defend. I have an incredulous disbelief that you trash Wikipedia yet edit articles. One instance could be accredited to many things but I feel you have shown contempt and total disregard with your edit. This apparently does not matter as your replies have been directed to the fact that you do not give much credit to Wikipedia standards, including the three core content policies, Your disdain, as well as disregard, is evidenced by the multiplication of one challenged entry to 14 instances.
 * I am not sure of your ultimate intention, as your edit was so obvious as to leave any doubt, so I would imagine that asking you to correct this would be a vain waste of time. I perceive your action as vandalism and it just may be possible that this will be a shared opinion.
 * You feel that my "positions" are "unhelpful to Wikipedia" and I feel this article as written does a disservice to Wikipedia. The notability of a topic or subject is not justification to create or edit an article with blatant original research. When information can not be corroborated, peer review can not be possible, so there is no proof of factual content. With more research I realize that this article can not be trusted. You might have noticed the little box in the lower corner of articles requesting the page to be rated. The first choice is Trustworthy and when a cursor is hovered over this selection the following is displayed;
 * "Do you feel this page has sufficient citations and that those citations come from trustworthy sources?".
 * It really does not matter what the name of the article title is, or that the information in the article does not agree with the title per common name, because as written and referenced the article has no place on Wikipedia. Any that may be concerned can try to solve this or take the position of "I stand by my original statements". In this instance I think I can build a pretty good case, according to those pesky little Wikipedia policies and guidelines, to involve editors that can effect proper changes.
 * Things I have written above, that are referenced, that I think worthy of consideration for inclusion, you haven't commented on. Another point for balance would be the opponents viewpoints. What about "form", "matter", "actuality" (actual substance), and "potentiality" (potential substance)? There is apparently a world of information that is relevant to definition by Genus and differentia, and from more than just Aristotle's view.
 * If there is no intention for correction, just verbiage in support of the status quo, then I feel it would be beneficial to Wikipedia and those that use it to seek deletion. I feel I can present overwhelming evidence to support this but then just maybe it won't be necessary. Otr500 (talk) 22:12, 4 December 2011 (UTC)

Seeking alternative avenues
I am listing comments on the project page at Wikipedia talk:WikiProject Philosophy. Otr500 (talk) 08:15, 9 December 2011 (UTC)

Article Title
Firstly, perhaps a compromise will do:
 * Genus and Differentia

In any case, the title Genus–differentia definition seems to be suitable:
 * Characterizing the definitions of anatomical concepts in WordNet and specialized sources
 * (Bodenreider and Burgun, 2002, whole document)
 * [11 or so uses of "genus-differentia definition"; note that they use a hyphen rather than an en-dash, which is what this Wikipedia article used initially.]

 * Genus and Differentia: Reconciling Unity in Definition
 * (Vogler, 2004, p.23)
 * Both the unequivocal and analogical theories have failed to explain how a genus-differentia definition is not two terms...

However, as another alternative, the article Definition has long had the section:
 * Definition by genus and differentia

Though a bit circuitous, it would be a decent article title:
 * It captures your notion of a 'method'.
 * It is a well-known phrase.
 * An Essay Concerning Human Understanding
 * (Locke, 1836, p.297)
 * ...defining by genus and differentia (I crave leave to use these terms of art, through originally Latin, since they properly suite those notions they are applied to)...

 * The collected writings of James Henley Thornwell, Volume 4
 * (Thornwell and edited by Adger and Girardeau, 1873, p.263)
 * Dr. Hodge affirms that there are two modes of defining—one by genus and differentia, the other by enumeration of attributes.

 * The principles of empirical or inductive logic
 * (Venn, 1889, p.310)
 * This was the time-honoured method of assigning a Definition 'by genus and differentia'.

 * Understanding Educational Research. An Introduction
 * (Van Dalen, 1962–1979, pp.182–183)
 * Definition by genus and differentia. Indicating its genus (the larger class of things in which the referent is included) and then how it differs from other subclasses of the same genus.

 * Definition in Jurisprudence (The Philosophical Quarterly)
 * (Hacker, 1969, p.343)
 * He argued that these concepts can be defined, but not by the traditional form of definition by genus and differentia.

 * Logic: The Essentials
 * (Manicas and Kruger, 1976, p.36)
 * ...acknowledge the importance of definition by genus and differentia.

 * Aristotle's Concept of Dialectic
 * (Evans, 1977, p.111)
 * ...which refers back to the discussion in Met. Z12 of definitions by genus and differentia.

 * Standardization of Technical Terminology: Principles and Practices - STP 806
 * (ASTM Committee on Terminology and edited by Interrante and Heymann, 1983, p.134)
 * The form of definitions, of course, remains a very important matter for ASTM. In that regard, Felber describes two important types: the intensional and the extensional. The first of these, also known as the definition by genus and differentia, is generally the preferred type in ASTM... straight forward example of definition by genus and differentia...

 * Conceptual Structures: Information Processing in Mind and Machine
 * (Sowa, 1984, p.13)
 * Definitions in terms of primitives ultimately derive from Aristotle's mode of definition by genus and differentia.

 * Substance and essence in Aristotle: an interpretation of Metaphysics VII-IX
 * (Witt, 1989, p.109)
 * An answer favored by Aristotle in many contexts is the definition by genus and differentia... The definition by genus and differentia places individuals into kinds...

 * John Philoponus' New Definition of Prime Matter
 * (Haas, 1996, p.186)
 * definition by genus and differentia

 * Reason Papers (Issue 21): Review Essay: Tara Smith, Moral Rights and Political Freedom
 * (Khawaja, 1996, p.61)
 * By contrast, Smith insists on the need for a definition by genus and differentia.

 * The pragmatics of defining religion: contexts, concepts, and contests
 * (edited by Platvoet and Molendijk, 1999, p.315)
 * Is a Definition by Genus and Differentia Specifica Possible?... definition by genus and differentia specifica is probably possible.

 * Aristotle: critical assessments, Volume 2
 * (Gerson, 1999, p.100)
 * This suggests that the notion of a what-is-it is not pegged to definition per genus et differentia... Aristotle's characterization of the method of division as definition per genus et differentia.

 * What Art Is: The Esthetic Theory of Ayn Rand
 * (Torres and Kamhi, 2000, p.375)
 * The most recent edition of Britannic (1997)... does include a reference to "definition by genus and differentia"...

 * Aristotle on Meaning and Essence
 * (Charles, 2000, p.247)
 * It's completed definitions by refer to differentiation through genus and differentia... So understood, there is no contrast or tension between definition by genus and differentia and definition by causally basic feature... Some have argued that Aristotle offers several distinct theories of definition, which fail to form a unified whole: definition by genus and differentia...

 * Essays on Definition
 * (Sager, 2000, p.243)
 * ...in mathematics the definition by genus proximum and differentia specifica...

 * Aristotle's Metaphysics
 * (Cohen, 2000, Substance and Definition)
 * This is a classic definition by genus and differentia.

 * A Concise Introduction to Logic
 * (Hurley, 2004, pp.106–108)
 * A definition by genus and difference assigns meaning to a term by identifying a genus term and one or more difference words...

 * The Blackwell dictionary of Western philosophy
 * (Bunnin and Yu, 2004, p.166)
 * Definition by Genus and Difference... from Latin genus et differentia... The most generally applicable form of intensional definition.

 * Concise Encyclopedia of Semantics
 * (Brown, 2009, p.200)
 * Porphyry's Eisagogē was translated into Latin by Boethius, and it is through Boethius that the tradition of defining by genus and differentiae has been transmitted to us.

 * Being, Nature, and Life in Aristotle: Essays in Honor of Allan Gotthelf
 * (Lennox and Bolton, 2010, p.94)
 * Aristotle says regarding definition by genus and differentia...

 * University of Washington:
 * The Form of a Definition by genus and differentia...

 * philosophypages.com:
 * Definition by Genus and Differentia... Copi and Cohen list five rules by means of which to evaluate the success of connotative definitions by genus and differentia...

 * Oregon State University:
 * [The information on the above page is copied verbatim for an introdcutory course; Oregon State's copy is not well formatted, suggesting it was copied and pasted.]

Mfwitten (talk) 20:04, 16 November 2011 (UTC)

The multiplicity section
Is this section WP:OR, or is there a reference to a discussion of this sort? Unless a reference can be given, I suggest it should be removed. It's not a particularly essential bit in any case. Phiwum (talk) 14:39, 9 December 2011 (UTC)

 * Similar comments apply to the structure section. Is there a good reference for the relationship between genus-difference and is-a?  If so, let's use it and if not, let's delete the section. Phiwum (talk) 14:43, 9 December 2011 (UTC)

 * As a general principle in any article, I would suggest that unless someone proposes conflicting information backed by greater credibility (to be decided by discussion), no existing information should be destroyed. Instead, it would make more sense to me to flag the information as explicitly unreferenced and leave it be for the reader's own consideration. Mfwitten (talk) 21:27, 10 December 2011 (UTC)

 * Did you add this information yourself? If so, then you surely know whether it comes from a reliable source or whether it is an original presentation on your part.  If it is the latter, then I'm afraid that policy states it should not remain in the article.
 * There's good reason for that, after all. The "structure" section seems pretty dubious in some of its claims.  At least as far as I can tell, it's fairly common for a difference to be expressed as "is-a", as in "A square is a rectangle which is also a rhombus".  The latter clause ("which is also a rhombus") plays the role of a difference, no?
 * But let's not take my word for the dubiousness of this passage! If a reliable source presents things as the article does, then we'll surely defer to the source.  If not, the material should be removed. Phiwum (talk) 00:08, 11 December 2011 (UTC)

Your thoughts are incomplete. Fortunately, the article, as it was written, can help you understand. In particular, now that you have removed the sections, the article ends with precisely your example:
 * In fact, the definition of a square may be recast in terms of both of the abstractions, where one acts as the genus and the other acts as the differentia:
 * a square: a rectangle that is a rhombus.
 * a square: a rhombus that is a rectangle.
 * Hence, abstraction is crucial in simplifying definitions.

At this point, though, you are left with 2 definitions for a square. Which definition is correct? Is a square a manifestation of a rectangle or is it a manifestation of a a rhombus? The section titled "Multiplicity" guides the reader's own thoughts toward an understanding in increasing generality:
 * When multiple definitions could serve equally well, then all such definitions apply simultaneously. Thus, a square is a member of both the genus  [a] rectangle  and the genus  [a] rhombus . In such a case, it is notationally convenient to consolidate the definitions into one definition that is expressed with multiple genera (and possibly no differentia, as in the following):
 * a square: a rectangle and a rhombus.
 * or completely equivalently:
 * a square: a rhombus and a rectangle.
 * More generally, a definition expressed as having $$n>1$$ genera can be recast as at least $$n$$ equivalent definitions, each of which has just one genus. Thus, the following:
 * a Definition: a Genus1 and a Genus2 and a Genus3 and a ... and a Genusn-1 and a Genusn that has some non-genus Differentia.
 * could be recast as:
 * a Definition: a Genus1 that is a Genus2 and that is a Genus3 and that is a ... and that is a Genus$n-1$ and that is a Genus$n$ that has some non-genus Differentia.
 * a Definition: a Genus2 that is a Genus1 and that is a Genus3 and that is a ... and that is a Genus$n-1$ and that is a Genus$n$ that has some non-genus Differentia.
 * a Definition: a Genus3 that is a Genus1 and that is a Genus2 and that is a ... and that is a Genus$n-1$ and that is a Genus$n$ that has some non-genus Differentia.
 * a Definition: a Genus$n-1$ that is a Genus1 and that is a Genus2 and that is a Genus3 and that is a ... and that is a Genus$n$ that has some non-genus Differentia.
 * a Definition: a Genus$n$ that is a Genus1 and that is a Genus2 and that is a Genus3 and that is a ... and that is a Genus$n-1$ that has some non-genus Differentia.
 * a Definition: a Genus$n$ that is a Genus1 and that is a Genus2 and that is a Genus3 and that is a ... and that is a Genus$n-1$ that has some non-genus Differentia.

In particular, that text directs the reader to consider when and how some differentiae may be transformed into genera, and that when this transformation is applied uniformly, one arrives at a structure that involves "is-a" and "has-a" relationships, which was described in the next section that you deleted.

Let me put this into a different light: Much of the text that you just destroyed is merely a recording of deductive logic and intellectual musings, the merit of which any reader is capable of considering on his own without any help from a blessed authority; requiring the citation of some authority imposes an extreme limitation on the free‑flow of this kind of information. Indeed, the article is now obviously less complete.

You are not improving Wikipedia by destroying content like this. Your destructive edit is no doubt an unintended consequence of the "policy" you cite. Mfwitten (talk) 03:25, 11 December 2011 (UTC)

 * It is not my opinion that differentia are intimately connected to some sort of "has-a" relationship. To take an example from Euthyphro, "Piety is that part of justice pertaining to service to the gods (paraphrased from faulty memory)."  The genus is (parts of) justice, and the difference is "pertaining to service to the gods".  That latter is not naturally rendered as a "has-a" relationship, near as I can figure — except in the sense that every adjective X can be more or less awkwardly turned into "has the property X", but this is true of is-a's too!  "This is a square" can be awkwardly reworded "This has the property of being a square", so I am still puzzled why you think that genus is to is-a as difference is to has-a.
 * To your latter point: the fact is that some of the OR was, as you claim, fairly simple and uncontroversial musings, but it's not at all clear that these musings ought to be presented here. It's not clear to me that the multiplicity section really presents an important observation about genus and difference that aids the reader in his understanding.  If I'm wrong, then surely some author somewhere has seen the wisdom in presenting essentially the same information, and we can cite him.
 * The structure section strikes me as a pretty good example of why we require citations. Your view that genus is tied to is-a is natural enough, but the connection between difference and has-a is not at all obvious to me and indeed seems false on the most natural interpretation.  In any case, this view (and the emphasis we see here) seems perfectly idiosyncratic and to my mind dubious.  Again, if I'm mistaken and this viewpoint is not only correct but natural, then surely we can cite an appropriate source.
 * I'm sorry that I've chopped out your contributions to this article. I'm sure that it took you time and thought to produce them, but they were not in line with WP policy and, I've got to say, I agree with the policy in this instance.
 * Nothing personal. Phiwum (talk) 05:08, 11 December 2011 (UTC)

Please note that the text that I wrote makes these two statements:

 * a genus of a definition provides a means by which to specify an is‑a relationship...
 * The non-genus portion of the differentia of a definition provides a means by which to specify a has‑a relationship...

So, most importantly, you are making a straw man argument; you are fighting against a position that I do not actually take. In particular, the text that I wrote never states that any differentia can be regarded as a has‑a relationship (as you imply it does), but only that it is the differentia of a definition (namely, the non‑genus portion of the differentia) that may be used for expressing a has‑a relationship, which is discussed by the sections on multiplicity and structure (which you destroyed).

Your example is interesting (as I hope you'll see), but it does not help your case (in fact, it helps mine). For reference, here's the example:

 * Piety is that part of justice pertaining to service to the gods.

Now, I imagine that the term Piety is being defined, so let's place it in a more canonical form:

 * Piety: That part of justice pertaining to service to the gods.

There is an implied verb here:

 * Piety: That part of justice [that is] pertaining to service to the gods.

What does "pertaining to" mean? It's actually ambiguous language, but I would say it basically means "a manifestation of":

 * Piety: That part of justice [that is] [a manifestation of] service to the gods.

In terms of a definition by genus and differentia, when:

 * X is a manifestation of [a] Y.

then [a] Y is a genus of X, and it can simply be written:

 * X is [a] Y.

So, the example may be simplified further:

 * Piety: That part of justice [that is] [a] service to the gods.

Now, look at the form:

 * X: Y that is a Z.

As you can see, there is no non-genus portion of the differentia of this definition, so of course you cannot find a has‑a relationship. Your example doesn't express one! It is similar to the example presented in the Multiplicity section (which you deleted):
 * a square: a rectangle that is a rhombus.
 * a square: a rhombus that is a rectangle.
 * In such a case, it is notationally convenient to consolidate the definitions into one definition that is expressed with multiple genera (and possibly no differentia, as in the following):
 * a square: a rectangle and a rhombus.
 * or completely equivalently:
 * a square: a rhombus and a rectangle.
 * or completely equivalently:
 * a square: a rhombus and a rectangle.

That bit about "possibly no differentia" is referring to the fact that when there is no non‑genus portion of the differentia of a definition, then after the transformation, there will be no traditionally discernible differentia.

At this point, I've already exposed your example as being nonsensical with respect to your argument, but let's continue analyzing it. You stated:

 * "The genus is (parts of) justice"

That is not correct. Firstly, what does this portion of your example:

 * "That part of justice"

mean, anyway? It's a reference to a portion of an existing definition, namely the definition of "justice". That is, "That part of justice" is an abstraction; it is something that has been abstracted away from the definition of "justice" (fortunately, you haven't yet destroyed the part of the article that expounds upon abstraction). So, which portion has been abstracted away? Well, that portion pertaining to service to the gods, of course! So, your example is really a specification for how to abstract away a portion of the definition of "justice" (but not explicitly what that abstraction really is), and the term "piety" is simply the name given to that abstraction, and (as already shown) the genus of "piety" is:

 * "[a] service to the gods"

That is, "piety" is "[a] service to the gods", which certainly agrees with my understanding of "piety". Now, what about its relationship to "justice"? Well, "piety" could be employed in the definition of "justice" as one of two things:

 * A genus of "justice" (which includes a genus portion of the differentia of "justice", as described in the Multiplicity section, which you destroyed).
 * A non‑genus portion of the differentia of "justice".

We don't know which role it plays, though, because the portion of the definition of "justice" is never specified (and neither is an explicit definition of "piety"). However, my understanding of "justice" suggests that "piety" is in fact employed as a genus of justice: When justice is served, the gods are served; justice is a manifestation of piety; justice is piety. So, as you can see, all of the pieces fit nicely together.

In short, your point of contention does not exist; only your own confusion exists.

In further defense of the importance of the section on multiplicity, I firstly note that I am a reader who would be deeply troubled by the presence of multiple definitions for a single term, and having this kind of guiding text to focus my thinking would save me a lot of strife, personally; the presence of this text is something that you as a reader may shrug off as a triviality, but for me as a reader, it would save a great deal of mental anguish. So, in keeping the text, there's very little (if any) harm for some readers, and there's a great benefit for others.

In further defense of the importance of the section on multiplicity, I secondly note that it directly leads to thinking about the structure of not only a set of definitions, but also the structure of a single definition, and how is‑a and has‑a relationships can be mapped to genera and differentiae (and, at least to some large degree, vice versa). It is essential, in my opinion, to making a smooth transition to the subject of structure, a subject which is important for a number of reasons.

A large number of the readers of Wikipedia are no doubt people who are familiar with object‑oriented programming, a subject in which is‑a, has‑a, derivation (differentiation, extension, etc.), abstraction, and even multiplicity play fundamental roles in understanding the conceptual world and essentially the physical world; I think that making this connection will ignite an explosion of understanding in their heads, and it will perhaps lead others to these related subjects. For others, the development of the terms "species", "individual", "identity", and their connection to linguistic elements such as a pars pro toto synechdoche will trigger other understandings.

In any case, this makes sense: However, this almost always does not make sense: That rule only makes sense when resources are limited, such as when an article has become very lengthy, and it becomes worthwhile to reorganize or streamline it, etc. Put another way: That rule is only valuable because of our current limitations as humans, and I certainly don't think it can be said to apply in thise case.
 * Information should be destroyed when it is clear to many readers that the information has no value (or is harmful).
 * Information should be destroyed when it is unclear to some reader whether the information has value.

On the matter of citations, consider this: If a cited book states exactly what has been stated in this article, then you personally may remain just as confused and/or unswayed as you have been; what, then, does this book title do for you in this case that is so magical? Will you immediately be satisfied by what has been written? If so, then your approach to editing Wikipedia is unthinking and at a greater risk of being harmful (in fact, it has just been harmful). Let's say that I am the one who wrote that book; what in this situation has changed then? In this sense, the citation would corroborate not the reliability of what has been written on Wikipedia, but rather just my own determination to get the information on Wikipedia.

Look at all of this careful thought that is at the basis of what has been written. Look at how I've used what was talked about in the article (before you destroyed it) to help you understand your own example in great depth. Why are you so adamant about destroying this useful information when you offer nothing to contribute in its place? Clearly, the article was superior before your edit. Mfwitten (talk) 21:30, 11 December 2011 (UTC)

 * Clearly WP:NOT “destroyed”… unfortunately, still a WP:TL;DR wall of text. Per WP:REFACTOR, I've collapsed some of the copious WP:OR removed from the article (thus far), the protracted “defense” of an indefensible disregard for policy, and the deliriously optimistic self-assessments of same. In light of just recently ‘showing us his rump’, not in regard to WP:RS, but a similar “defense” of the contrived user name example (WP:SELF), it taxes WP:AGF to entertain a discussion which so quickly became no less WP:TENDENTIOUS. However information is welcome, (WP:V), such as the list provided in defense of the article's name. Thanks.—Machine Elf 1735  23:31, 11 December 2011 (UTC)

 * You have no right to censor my comments. I have restored them. Mfwitten (talk) 03:12, 12 December 2011 (UTC)
 * It is impossible, nay! totally impossible, to improve on original research other than by the original author. A problem is that other editors, wishing to abide by the principles of the vehicle wherein the the information is presented, can not make improvements without falling afoul of those principles. This subject is actually moot because no matter how well written an article is, that is based on original research, it is just that. You have shown more than once, in plain English, that references do not matter to you. The reason I placed (among others) a notability tag on the article is that only the idea has merit. WP:NOTABILITY states;
 * We require "significant coverage" in reliable sources so that we can actually write a whole article, rather than half a paragraph or a definition of that topic. If only a few sentences could be written and supported by sources about the subject, that subject does not qualify for a separate page, but should instead be merged into an article about a larger article or relevant list. (See the advice below.)
 * We require the existence of "reliable sources" so that we can be confident that we're not passing along random gossip, perpetuating hoaxes, or posting indiscriminate collections of information.
 * We require that all articles rely primarily on "third-party" or "independent sources" so that we can write a fair and balanced article that complies with Wikipedia's neutral point of view policy and that articles are not advertising a product, service, or organization.
 * We require the existence of at least one secondary source so that the article can comply with No original research's requirement that all articles be based on secondary sources.
 * We require multiple sources so that we can write a reasonably balanced article that complies with Neutral point of view, rather than representing only one author's point of view. This is also why multiple publications by the same person or organization are considered to be a single source for the purpose of complying with the "multiple" requirement.
 * Because these requirements are based on major content policies, they apply to all articles, not solely articles justified under the general notability criteria.
 * The precept is clear and if an editor took out all the information provided that was not directly supported by the sole reference, I assure you there would be less than a stub left as it is now written. This fact lends to questions of notability. I didn't expound on that fact as reasoning or there might have been debate before removal of the tag. None of this matters if you are not willing to acknowledge or understand (I tried to explain before I realized there was no use), that importance of information included in an article does not matter if the information does not have a source or reference.
 * I would challenge other involved editors to look at the source, the content provided in the article, and actually attempt to link the source to the content. The source provided is broken down into 14 chapters so this should not be too hard right?
 * What I have a serious problem understanding, considering the multitude of resources on "Genus and differentia", "Definition by genus and differentia", or "Definition by genus and difference" (anyone better than the current choice), is why would there be so much unreferenced material. An answer is that as written a large majority of the material in the article can not be matched to a source. I could not find any but if an editor can do this it would be a monumental improvement. Otr500 (talk) 06:30, 12 December 2011 (UTC)

 * I do not agree that what I have written is WP:OR; it is merely synthesis that is appropriate and valid as per the supplemental essay WP:SYNTHNOT, which was no doubt written as a response to people who abuse policy (WP:BURO). Please note Wikipedia policy WP:IGNORE:
 * If a rule prevents you from improving or maintaining Wikipedia, ignore it.
 * as well as the associated WP:WIARM, specifically:
 * The spirit of the rule trumps the letter of the rule. The common purpose of building a free encyclopedia trumps both.  If this common purpose is better served by ignoring the letter of a particular rule, then that rule should be ignored. (See also The rules are principles.)
 * Despite its name, "Ignore all rules" does not sabotage the other rules. Its purpose is to keep them from sabotaging what we're doing here: building a free encyclopedia. Rules have zero importance compared with that goal. If they aid that goal, good. If they interfere with it, they are instantly negated.
 * A rule-ignorer must justify how their actions improve the encyclopedia if challenged.
 * I have adequately justified how what I have written improves Wikipedia as an encycolopedia. In this case, if you think that more references are necessary, the proper and reasonable response is not to censor information, but to mark it with that fact explicitly; after all, why else would templates such as template:citation needed exist?

 * You are not improving Wikipedia. You are harming Wikipedia. Mfwitten (talk) 07:15, 12 December 2011 (UTC)

 * I don't think that this talk page is the appropriate venue to discuss whether "pertaining to service to the gods" "really" is a genus or not, so let me just say that I'm underwhelmed by your response, and we can continue this discussion by user talk page if you'd like. Nor am I familiar with any presentation of genus-difference that makes a point of treating the difference-as-genus case as distinct from other cases of difference, as your own, personal presentation does so, which is good reason to avoid your own, personal research.  Finally, while your discussion of abstraction on this talk page seems utterly confused to me, let's instead discuss the corresponding section in the article.  You raise a good point: is it an instance of WP:OR?  If so, I'm afraid that it should be removed, too.  Perhaps, however, we can find a source that actually discusses the relation between abstraction and difference.  That seems a perfectly natural topic.  Have you looked? Phiwum (talk) 13:08, 12 December 2011 (UTC)

 * If you doubt that the removal was correct, perhaps you can discuss it at Original research/Noticeboard. Maybe the deletion was hasty, after all.  They would know better than I. Phiwum (talk) 13:50, 12 December 2011 (UTC)

 * Surely you mean long overdue…
 * A duplication of the user's WP:OR from Definition:
 * It would be welcome if the user were to make inquiries at the noticeboard. I don't see why he wouldn't if someone were trying to “censor” his “comments”. Never mind I simply collapsed the text he repeatedly copies from the article history that we've already read. His “comments”, they are indeed—no argument about that—but I wasn't aware of the right to repeatedly spam talk pages with tired WP:OR. I'll try to bear that in mind. In fact, I'd almost forgotten what Phiwum “just destroyed is merely a recording of deductive logic and intellectual musings, the merit of which any reader is capable of considering on his own without any help from a blessed authority”.
 * Or rather   every reader   is required to  … no fair helping. Irrational straw animals are a hoot, but the WP:OR noticeboard is a tough crowd: I'm not sure how someone who ignores all feedback can be persuaded? Really, it goes without saying that following the rules, any of them, might be too much to hope for… But perhaps I'm being too cynical, by all means, let bygones be bygone—“poetry” has a place, and this article will too. Make way, building an encyclopedia is mostly harmless. Were it not buried under a pile of tl;dr… “no doubt” readers of this talk page would agree: open flame does not “ignite an explosion of understanding in their heads”.—Machine Elf 1735   20:23, 12 December 2011 (UTC)
 * A duplication of the user's WP:OR from Definition:
 * It would be welcome if the user were to make inquiries at the noticeboard. I don't see why he wouldn't if someone were trying to “censor” his “comments”. Never mind I simply collapsed the text he repeatedly copies from the article history that we've already read. His “comments”, they are indeed—no argument about that—but I wasn't aware of the right to repeatedly spam talk pages with tired WP:OR. I'll try to bear that in mind. In fact, I'd almost forgotten what Phiwum “just destroyed is merely a recording of deductive logic and intellectual musings, the merit of which any reader is capable of considering on his own without any help from a blessed authority”.
 * Or rather   every reader   is required to  … no fair helping. Irrational straw animals are a hoot, but the WP:OR noticeboard is a tough crowd: I'm not sure how someone who ignores all feedback can be persuaded? Really, it goes without saying that following the rules, any of them, might be too much to hope for… But perhaps I'm being too cynical, by all means, let bygones be bygone—“poetry” has a place, and this article will too. Make way, building an encyclopedia is mostly harmless. Were it not buried under a pile of tl;dr… “no doubt” readers of this talk page would agree: open flame does not “ignite an explosion of understanding in their heads”.—Machine Elf 1735   20:23, 12 December 2011 (UTC)
 * Or rather   every reader   is required to  … no fair helping. Irrational straw animals are a hoot, but the WP:OR noticeboard is a tough crowd: I'm not sure how someone who ignores all feedback can be persuaded? Really, it goes without saying that following the rules, any of them, might be too much to hope for… But perhaps I'm being too cynical, by all means, let bygones be bygone—“poetry” has a place, and this article will too. Make way, building an encyclopedia is mostly harmless. Were it not buried under a pile of tl;dr… “no doubt” readers of this talk page would agree: open flame does not “ignite an explosion of understanding in their heads”.—Machine Elf 1735   20:23, 12 December 2011 (UTC)

The discussion that we are having is part of your argument; your argument for a destructive edit is based (at least partially) on it. Therefore, the discussion belongs here.

Firstly, I address the continuing qualms surrounding the example on which you base your argument. Secondly, I address the accusations of WP:OR.

With regard to abstraction, first take a look at the discussion on abstraction. For reference, here is one of the definitions of a square that is presented: Now consider this definition: As with your example of "piety", this is a vague specification for an abstraction; the definition of a rectangle given here is specifying that something is being abstracted away from the definition of a square. As with the treatment of your example: Because we are actually given the definition of a square (unlike with "justice"), we can surmise which part of a square is actually meant by the abstraction specification, thereby allowing for an explicit definition: Just as "service to the gods" in your example is a genus of "piety", so it is that "a quadrilateral with certain interior angles" is a genus of "a rectangle".
 * a square: a quadrilateral that has interior angles which are all right angles, and that has bounding sides which all have the same length.
 * a rectangle: that part of a square pertaining to a quadrilateral with certain interior angles.
 * 1) a rectangle: that part of a square pertaining to a quadrilateral with certain interior angles.
 * 2) a rectangle: that part of a square [that is] pertaining to a quadrilateral with certain interior angles.
 * 3) a rectangle: that part of a square [that is] [a manifestation of] a quadrilateral with certain interior angles.
 * 4) a rectangle: that part of a square [that is] a quadrilateral with certain interior angles.
 * a rectangle: a quadrilateral that has interior angles which are all right angles.

By substituting the definition of a rectangle into the definition of a square, one gets: Just as "piety" in your example is (likely) a genus of "justice" (and certainly not the other way around), so it is that "a rectangle" is a genus of "a square" (and certainly not the other way around); a square is a manifestation of a rectangle; a square is a rectangle.
 * a square: a rectangle that has bounding sides which all have the same length.

As for WP:OR, I think that WP:SYNTHNOT is instructive:

 * When you look at a case of putative SYNTH, apply the following test. Suppose you took this claim to a journal that does publish original research.  Would they (A) vet your article for correctness, documentation, and style, and publish it if it met their standards in those areas?  Or would they (B) laugh in your face because your "original research" is utterly devoid of both originality and research, having been common knowledge in the field since ten years before you were born?  If you chose (B), it's not original research -- even if it violates the letter of WP:SYNTH.

Have I really expanded human knowledge rather than just thoughtfully present it? Please tell me if I have, and tell me which journal of note would accept my article.

The only thing going for the detractors of what I have written is the lack of citations. To that, I think the very first footnote of WP:OR is instructive:
 * By "exists", the community means that the reliable source must have been published and still exist—somewhere in the world, in any language, whether or not it is reachable online—even if no source is currently named in the article. Articles that currently name zero references of any type may be fully compliant with this policy—so long as there is a reasonable expectation that every bit of material is supported by a published, reliable source.

Citations are not necessary if there is a reasonable expectation that every bit of material is supported by a published, reliable source. This, combined with the spirit of acceptable synthesis makes what I have written acceptable, and WP:IGNORE makes what I have written essential. Mfwitten (talk) 16:44, 12 December 2011 (UTC)

 * I am honestly bumfuzzled as to why you think I have said anything that suggests a rectangle is suitably defined thus:
 * a rectangle: that part of a square pertaining to a quadrilateral with certain interior angles.
 * You seem to misunderstand the definition of piety as "that part of justice pertaining to service to the gods". What it means is this: Justice concerns at least two different kinds of service.  The first is service to fellow men (some translations use "attention" rather than "service", which may make more sense) and the other kind is service to the gods.  Piety is a part of justice, namely that part concerning service to the gods.  Thus, we define piety as a kind of justice, which strikes me as a typical genus-difference definition.
 * We do not (in the context of Euthyphro) abstract from piety to come to a notion of justice. Nor is piety an abstraction of justice at all.  This is an example where we are trying to define piety, and we do so with reference to a genus that is taken here as more or less given.  In this respect, it is not an example in which the genus can be had by abstraction from the species.  (Please, see Euthyphro if you want to pursue this line.)
 * But I do think that there's a sense in which differentiation is naturally represented as dual to abstraction. I think it would be good to find references saying as much and I think we can do so.  Let's do that, so that we don't have to strike the current discussion as uncited.
 * All of your discussion of rectangles as "parts of square pertaining to" this or that is based on a misreading of my example. Piety is a part of justice, and so my idea is that piety is to (a part of) justice as square is to rectangle.  The primary reason that this example isn't as clear as I'd like is that piety is a part of a whole, rather than a subset of a genus (hence my parenthetical "part of").  But let's not get hung up on that.  If you don't like the example from Euthyphro, let me offer another.
 * Before I do so, let me recall the reason for the example. You claimed (uncontroversially) that, in genus-difference definitions, the genus "provides a means by which to specify an is-a relationship."  I agree.  You also claimed that "the differentia of a definition provides a means by which to specify a has-a relationship."  This is, as far as I can tell, false, unless interpreted to trivialize the claim.  Consider the following genus-difference definition:
 * A sequence is a tree in which each node has exactly one child.
 * The property "each node (of the tree) has exactly one child" does not express a has-a relation as near as I can figger. Of course, I may be wrong and you may be right and even in this case, perhaps, the difference does indeed "provide a means by which to specify a has-a relationship."  How to reliably settle the question?  WP policy has answered for us: we refer to a reliable source saying so.Phiwum (talk) 19:31, 12 December 2011 (UTC)
 * NOTE: I once again invite you to bring the matter up at an appropriate noticeboard if you think I've misapplied WP policy. I'm not a particularly active editor, so I might misunderstand what WP:OR means.  Please, feel free to overrule my judgment. Phiwum (talk) 19:39, 12 December 2011 (UTC)
 * I am assuming you meant "Please, feel free to overrule my judgment", as pertaining to if there is consensus to make such an overrule. If that is not what you meant that is perfectly alright as I will be the proverbial thorn in the side. The only way that I can tell if information contained in articles is trustworthy or plain old BS is by references. I have the backing of hundreds, if not thousands, of editors to corroborate this which has been applied by consensus over time. "If" someone wishes to "override" my judgement concerning original research or synthesis, I will simply "do the right thing" which will be to politely bring this to the appropriate location for resolution. If that is not the purpose of the process, to ensure more accurate and factual article content, then there is no purpose. "If" information is not verifiable per policy I intend to start on the talk page and if that fails I have no choice but to climb the latter to resolution. I am glad that others have so far gotten involved as it make my time worthwhile. Otr500 (talk) 23:03, 12 December 2011 (UTC)
 * I would also like to state that I will have no qualms bringing any instance where an editor thinks or assumes that WP:IGNORE overrides Wikipedia's core content policies. I will add these in case there may be confusion;

 * While it is true consensus can change I will be more than happy to extend the courtesy of testing some theory an editor might have as to if it has at this point. What is printed above may actually be outdated and not have community support so I will suggest that, if there is confusion, we put it to a test. Statements like, "Articles that currently name zero references of any type may be fully compliant with this policy—so long as there is a reasonable expectation that every bit of material is supported by a published, reliable source.", can be justified until any such information is challenged. At this point the introduction of one of Wikipedia's core policies takes precedence which can not be "...superseded by other policies or guidelines, or by editors' consensus.". While one of the five pillars of Wikipedia is certainly Wikipedia does not have firm rules, it is followed by, " Rules in Wikipedia are not carved in stone, and their wording and interpretation are likely to change over time.".
 * When any editor feels instruction creep has rendered a policy or guideline obsolete then there are many options to seek to change this. One thing to remember is that the policy no original research includes, "If no reliable third-party sources can be found on a topic, Wikipedia should not have an article about it. If you discover something new, Wikipedia is not the place to premiere such a discovery.". Jimbo Wales stated, "If your viewpoint is held by an extremely small minority, then — whether it's true or not, whether you can prove it or not — it doesn't belong in Wikipedia, except perhaps in some ancillary article. Wikipedia is not the place for original research.
 * Until such time that the policies change, which will only be at such time when consensus changes, please do not disrupt Wikipedia with contemptible circular discussions that serve no purpose. Please follow the link for examples of disruptive editing. It is still my position that this article is full of original research. Otr500 (talk) 04:53, 13 December 2011 (UTC)

Genus of "Piety"
Your "piety" example has been confusing, because you conflate the notions of intensional and extensional definitions. Basically, the language for your definition of "piety":
 * piety: that part of justice pertaining to service to the gods.

is meant to be interpreted in the context of an extensional definition of "justice" rather than an intensional definition by genus and differentia; the term "justice" is very silently assumed to be written something like this:
 * justice: service to fellow men OR service to the gods [OR ...]

Here, the term "justice" is being defined by listing all members of the genus "justice", and thus the words "that part of justice" actually mean "a member of the genus justice" (or, as I've been using in other comments, "a manifestation of justice"), which can simply be reduced to "justice" and employed as the genus of a definition of "piety" by genus and differentia: Perhaps an expanded system of definitions by genus and differentia might look like the following: Mfwitten (talk) 23:46, 17 December 2011 (UTC)
 * 1) piety: [a manifestation of] justice pertaining to service to the gods.
 * 2) piety: justice pertaining to service to the gods.
 * 3) piety: justice [that is] pertaining to service to the gods.
 * 4) piety: justice [that is] [a manifestation of] service to the gods.
 * 5) piety: justice [that is] service to the gods.
 * service: justice that involves a beneficiary.
 * humanity: service where the beneficiary is a man.
 * piety: service where the beneficiary is a god.

 * With due respect, you're plumb wrong in thinking that Socrates implicitly defined justice by listing its parts. This notion is simply foreign to the project at hand: finding the "form" for terms such as piety.  Have you read Euthyphro?  He's trying to figure out what piety means.  He suggests that one can do so by figuring out what part of justice piety is.  It is nonsensical to think that justice is implicitly pre-defined as a disjunction of parts as you say.
 * But I don't see any reason to continue this off-topic discussion. Let's discuss the article, not Euthyphro. Phiwum (talk) 04:06, 18 December 2011 (UTC)

 * I'm discussing the confusion that you introduced with the language "that part of". In any case, I agree that it's not completely on topic; I'm only trying to clarify what has been going on for the sake of completeness. Mfwitten (talk) 05:19, 18 December 2011 (UTC)

Has-a Relationships
You are arguing against a statement that is not there, and thus ALL of your examples are wasted.

The text I wrote for the article states that the differentia of a definition (namely, the non‑genus portion of the differentia of a definition) is simply a place where a has‑a relationship may be specified.

What I wrote for the article is indeed a weaker statement than that against which you are arguing (and which does not exist in what I wrote), but that does not render it as having no value; in fact, the value comes from simply mentioning has‑a relationships along side is‑a relationships. Mfwitten (talk) 23:46, 17 December 2011 (UTC)

 * What you wrote (per your quoted material above) was
 * a genus of a definition provides a means by which to specify an is‑a relationship...
 * The non-genus portion of the differentia of a definition provides a means by which to specify a has‑a relationship...
 * Surely, the second statement is just as strong as the first, and seems naturally interpreted as "Every differentia provides a has-a relationship". Maybe you didn't mean this, but I can only read what you write.  If you weaken it to "Some differentia provide has-a relationships," then the whole structure bit is weakened to triviality.  All genus membership claims are is-a claims (obviously) and some differentia claims are has-a claims, some are is-a claims and some are something else.  Not too interesting.
 * But why should we argue over whether what you wrote is noteworthy? If you think that it shouldn't have been deleted, then take it up with the Original Research noticeboard.  Phiwum (talk) 04:17, 18 December 2011 (UTC)

 * Apparently you cannot read what I write, because you are filling in the gaps with your own words. The text does not anywhere state "Every differentia provides a has-a relationship." It states that the differentia of a definition (namely the non‑genus portion of the differentia of a definition) provides a means by which to specify a has‑a relationship. That is interesting, and it complements and completes the discussion about is‑a statements. Mfwitten (talk) 05:28, 18 December 2011 (UTC)

Definition of a Sequence
While I've already made my point, I'll entertain the example you provided, which is:

 * a sequence: a tree in which each node has exactly one child.

With regard to that example, you stated:

 * The property "each node (of the tree) has exactly one child" does not express a has‑a relation as near as I can figger.

Let's do some abstraction to make the example clearer:

 * ''a SequenceNode: a node that has exactly one child.
 * a sequence: a tree in which each node is a SequenceNode.

So, the non-genus portion of the differentia of the definition of "a sequence" that you provided does indeed provide a means by which to express a has‑a relationship, namely:

 * a SequenceNode has exactly one child.

Similarly, the definition you provided expresses a constraint on an existing has‑a relationship:

 * a tree has one or more nodes

The constraint is that each node be a SequenceNode. So, the non‑genus portion of the differentia of the definition of "a sequence" that you provided does express new has‑a relationships:

 * A sequence has one or more SequenceNodes.
 * A sequence has only SequenceNodes.
 * If a sequence has 3 nodes, then that sequence has a SequenceNode that has a SequenceNode that has a SequenceNode.
 * etc.

As an aside, even a genus provides the means by which to express a has‑a relationship; after all, just expressing that a sequence is a tree is enough to express that a sequence has one or more nodes, for instance. Note that what I wrote for the article does not preclude such thinking (however, I would argue that such thinking is not worthy of prominence given that such a has‑a relationship depends on the existence of an is‑a relationship). Mfwitten (talk) 23:46, 17 December 2011 (UTC)

 * Again, a brief discussion, but, no, the non-genus portion of the definition of sequence does not define a has-a relationship in the normal manner discussed previously.
 * But who cares? You have admitted that not every differentia defines a has-a, so why should we argue over this?  (Example: define conservative as "aged liberal" — not a very clever definition, I know, but it serves the point — "aged" does not yield any obvious, natural has-a statement.)
 * One last time: I don't see any reason you and I should have to discuss the correctness of this stuff. If it was cited, then my opinion wouldn't matter.  If it was allowable synthesis because it was obvious, then you wouldn't have to convince me of anything.  If you feel compelled to write paragraph after paragraph in order to persuade me that this stuff is important and correct, but there is no citation to be had, then it violates WP:OR.
 * I implore you: don't take my word for it. Ask for a second opinion at an appropriate noticeboard.
 * I don't think I'll bother replying to any more discussions on this matter at this time. It's all beside the point and off-topic for a talk page. Phiwum (talk) 04:17, 18 December 2011 (UTC)

 * The problem is that you read what's not there, you don't read what is there, you put words in a person's mouth, and you communicate carelessly with ambiguous language. Your allegations of WP:OR are but a copout for discussion. You are correct that further discussion is worthless, but not because of the reasons you cite. Mfwitten (talk) 05:40, 18 December 2011 (UTC)

 * We are agreed then. No point continuing this.  Now, if you really think that my use of WP:OR is a cop-out, because I'm a bad, knowledge-destroying arch-villain, then why not bring it up with an appropriate noticeboard as I've repeatedly suggested?  It's not a trick suggestion.  I could be wrong in my judgment.  Present your case elsewhere and you won't have to try to convince me of anything. Phiwum (talk) 14:19, 18 December 2011 (UTC)

A golden oldie?
Hey ho.

I was looking through some old revisions of this article, and I saw this one. There are some things I like about it, and I wondered whether others would agree.

First, the introduction explicitly mentions "species", which is an essential term in traditional presentations of genus-difference, but is currently omitted until the "human being" example (where "species" could well mean the biological classification, not the term usually meant in this context).

Second, I really like the tables that break down the examples clearly into genus and difference — and make no special consideration for the cases in which the difference involves membership in a genus. Those look very clearly presented.

I don't mean to kick Mfwitten while he's down, and I know that he's the reason we've lost the old intro and the table presentation of definitions, but it seems to me that these losses were a mistake. Any opinions? Phiwum (talk) 14:26, 13 December 2011 (UTC)
 * I realize it was a pun but I am not trying to kick anyone. While I do like (far better) the way the older version is presented, but there are 14 chapters in the source so I am still wondering if someone could actually assign some of those chapters to the article content?
 * My involvement began because I could not attribute the source to the article as written. It is still my opinion that such a subject should have far more resources available than is presented. Would that not be a position that is shared? I only know that when I first saw the article, in my opinion, it was a wreck. When something is that bad it is hard to figure out where to start. The title name, the contents, the reference? At least there would be a layout that would make some sense. Would you please look at the older version and see if the sole source could be attributed to some of the sections instead of a blanket source?
 * I get confused (as to reasoning) when an article is totally rewritten and the source stays the same. At least the older version is presented more on the line of Wikipedia standards. If there is a starting point then improvements can be made but there absolutely must be more references. I will have to look back but I presented a link, that was ignored, but I have to go to work so can't look now. Aristotle did have critics so this would be a great thing to show for NPOV.
 * As it stands (of course with more references) I support the older version. We can change versions all day long but in the end that is only what we will have accomplished with no actual referenced improvements. I am so glad that others are looking into this. Otr500 (talk) 11:22, 14 December 2011 (UTC)
 * Let's not be WP:UNDUE for the sake of WP:NPOV on a farily straight-forward topic… embrace the Aristotle.—Machine Elf 1735  12:31, 14 December 2011 (UTC)
 * (EC) Surely, we all agree that the current article is woefully undersourced, but Aristotle is referenced here only for the example. I'm not sure why you think that criticism of this particular source would be relevant in the least.  We don't care whether man is aptly defined as "rational animal" or not.  We only care that this is an example of definition by genus-difference.
 * So, let's see what references we can find. I think I can dig up a book or two which mentions this concept. There is also slight mention at SEP.  Phiwum (talk) 12:38, 14 December 2011 (UTC)
 * Exactly, it needs much more than an example, which had been editorialized as “hackneyed” until recently. More like, a golden oldie… one might even say, he wrote the book on it.—Machine Elf 1735  13:24, 14 December 2011 (UTC)
 * Yes, we need that reference. Can you add it to the article? Phiwum (talk) 13:36, 14 December 2011 (UTC)
 * It's worth mentioning that Part 6 of the above work includes ways to evaluate such definitions, just as I mentioned in Copi's and Layman's work. Also, one might point out that the same part speaks of the "true" genus of a species.  The idea that a species has a "true" genus conflicts, at least in spirit, with Copi's comments that genus and difference can be interchanged, logically speaking (though Copi acknowledges that there may be non-logical reasoning for preferring one as the genus and the other as difference, consistent with Aristotle's comments). Phiwum (talk) 13:41, 14 December 2011 (UTC)

NOTE: The SEP refers to Book V (Zeta) of Aristotle's metaphysics, not the Topics. I think that this book may be more relevant for us, since it seems to deal more explicitly with differentia. Phiwum (talk) 16:59, 14 December 2011 (UTC)

Some notes about references.
From my own shelves, I've found the following references.
 * Copi's "Introduction to Logic", The Macmillan Company, 1961, pp. 118-127.
 * Includes a discussion of "human" as "rational animal" and makes the point that, from a logical viewpoint, we could just as well take "rational" as the genus and "animal" as the difference. (Grammatically, there is a slight difference not mentioned by Copi, namely that a genus is a class, while a difference is a predicate, but this is trivially fixed by saying the genus is "rational thing" and the difference "is an animal".)
 * Also includes rules for writing a good definition by genus-difference.

 * Copi and Cohen's "Introduction to Logic", Pearson Prentice Hall, 2009, pp. 105-109. A much more recent descendant of the above.
 * Includes rules for writing a good definition. I haven't checked whether they are the same rules as the above.
 * Omits both the discussion of "rational animal" and the claim that the choice of genus and difference is arbitrary (in the sense mentioned above, that we could take the difference as the genus and vice versa).

 * Hurley, "A Concise Introduction to Logic", 10th edition, Thomson Wadsworth 2008, pp. 101-102
 * Includes a claim that "Definition by genus and difference is the most effective of the intensional definitions for producing the five kinds of definition discussed in Section 2.3." The five kinds of definition discussed are stipulative, lexical, precising, theoretical and persuasive.  The other kinds of intensional definitions discussed therein are synonymous definition, etymological definition and operational definition.

 * Layman, "The Power of Logic", 3rd edition, McGraw-Hill, 2005. pp. 101-106
 * Again, includes criteria for evaluating such definitions.

These are four of the first six books I grabbed off of my shelf. The only two which do not discuss genus-difference are Baronet's Logic and Washburn's The Vocabulary of Critical Thinking (which is not so focused on logic per se). It should be very easy to add references to this article.

We should probably also refer to Aristotle's treatment of such definitions. I don't know where that occurs offhand. Phiwum (talk) 13:22, 14 December 2011 (UTC)
 * Thanks Phiwum for your edits and seeking assistance at Wikipedia talk:WikiProject Philosophy. This is as much, and more, as one could ask for. I am also not familiar with the aspects you mentioned but know that in the previous form the article should have been titled "Aristotle's view on Genus–differentia", or some other such name, except the article still did not reflect the contents of the reference. I have been working very long hours so have not had time to devote to such a profound subject so thanks again. Otr500 (talk) 10:19, 20 December 2011 (UTC)

Definition by abstraction then speciation?
I was just wondering if this method of definition includes those which start by (perhaps implicitly) abstracting from an existing definition to create a genus, and then becoming more specific again with different differentia - or if there is a different term for such a process.

As an example of what I mean I offer the definition of "Scotch Chess": It's chess, but after White's first move, each player makes several consecutive moves, namely one more than the number of moves made by the previous player.

The abstraction made is "chess, except that the order in which the order of play remains unspecified", followed by differentiation by specifying an order of play that is different to that of chess. — Preceding unsigned comment added by 202.162.181.145 (talk) 20:51, 30 September 2013 (UTC)

title: Talk:Genus–differentia definition