Talk:Fallacy

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[edit] Is this a serious statement?

(highlights are mine to show questionable material)

Fallacy of Misplaced Concretion, identified by Whitehead in his discussion of metaphysics, this refers to the reification of concepts which exist only in discourse. This concept has been expanded by Hofer into political philosophy by his identification of a far more dangerous fallacy: The Fallacy of Misplaced Excretion. This occurs when individuals, through either failure of will or deliberate intention, misplace the excretion they're producing. This can result in huge cultural features made entirely from the same, including many prominent political figures.

I've taught philosophy/logic and never heard of this one! —Preceding unsigned comment added by 72.86.125.141 (talk) 01:37, 12 February 2008 (UTC)

Another dubious statement: Most common forms of fallacies are evident in political speeches. —Preceding unsigned comment added by 86.138.36.204 (talk) 14:53, 13 February 2008 (UTC)

[edit] Fallacy and Logical fallacy

The relation between these two articles is not clear. One would expect logical fallacy to be a subtype of fallacy, but in fact the longer "logical fallacy" article seems to deal with the same subject as this shorter "fallacy article". I think the relation should be explained or the two articles merged.--Georgius 23:14, 22 May 2005 (UTC)

Yes, the trouble is with technical versus common usage. Technically logical fallacy is a particular kind of fallacy in an argument. However, people not educated formally in logic usually call every fallacy in argument a logical fallacy. This is at least historically improper. (I wish to avoid the debate over the two approaches to usage).
The introduction of the "logical fallacy" article captures the distinction properly: "A logical fallacy is an error in logical argument which is independent of the truth of the premises. It is a flaw in the structure of an argument as opposed to an error in its premises..." After the first paragraph the article rapidly descends into "fallacy". I feel that most, but not all, of the content in "logical fallacy" should be merged into "fallacy"
Also, though fallacy is the shorter article; it's information density is 1) higher 2) more accepted in a technical sense.
--Pearlg 22:30, 23 May 2005 (UTC)
I am for merging. Logical Fallacy = a fallacy in logical argumentation (dictionary.com) = formal Fallacy and Fallacy with deductive reasoning (various wikipedia), invalid structure of argument (both). Problem is most articles about fallacies say "This is a logical fallacy" with a deductive logic argument and only its categories say if it's a formal or informal fallacy. Another problem is that informal fallacy redirects to logical Fallacy, defined as formal. The logical fallacy article looks unencyclopedic and poorly defined. I'll check more fallacies first. --Ollj 18:16, 11 October 2006 (UTC)

Merged Logical fallacy into Fallacy, more detailed reasons given here, dod not even mention this debate here --Ollj 20:29, 11 October 2006 (UTC)

As I was doing the Hungarian wiki for the specific examples of fallacies, I went through the English wiki pages and I found a lot of confusion and inconsistency here. Logical Fallacy is used sometimes in the strict (=formal), sometimes in the broad meaning (=all fallacies). My suggestions are the following:

  • The main article should be Fallacy; mentioning the term Logical Fallacy as an equivalent of Formal fallacies in a strict sense, however common usage today uses it as an equivalent of all Fallacies. Wiki should not take sides, but observe that both usages exist.
  • The categories, and references in the actual examples should avoid using the term Logical Fallacy for this reason: Fallacy in general, or specifically Formal or Informal Fallacy should be used instead. There is no confusion with these terms.

--Gligeti 08:37, 27 January 2007 (UTC)


Please read what you write on General examples:

  • Example 1 (Material Fallacy): a syllogism "is a kind of logical argument", it ABOUT LOGIC...and "James commits the logical fallacy of begging the question".
  • Example 2 (Verbal Fallacy): ok, the unique that not need logical analysis, but conclusions about an ambiguity, "sort of fallacy" and "fallacy of equivocation" are about logical field.
  • Example 3 (Verbal Fallacy): here more logic about "verbal", transitivity is algebrical logic, universal quantification is a technical term from predicate logic, and "fallacy of composition" is a inference.

ALL HERE IS ABOUT LOGIC (for a usual Wikipedia reader)! We can merge the articles, or review usual differences, or use a lead table to "join" all articles about fallacy.

[edit] fallacy and merging?

I believe the idea of merging two articles is not new. Ironically, I believe, the article motorized bicycle seems to have some fallicies (well at least the in the discussion). Perhaps someone would be interested in observing the merger that is currently happening with this article (and at the same time help out with our philosophical questions.)--CyclePat 01:02, 1 November 2005 (UTC)


[edit] Question about example 1 in general examples

In Example 1: Material Fallacy, it is stated in the end that, James commits the logical fallacy of begging the question. Can it be classified as False Premise/Questionable Premise? Thanks for anybody's kind explaination!

[edit] To be added to the list?

Couldn't a teleological argument (argument from final consequences) be considered a fallacy in certain instances? Should it not be included in the list of fallacies?

what I mean here is an argument like this: "B could never have happened if A hadn't happened, therefore that B could happen is the reason A happened." In any system in which some intelligent entity wasn't instigating event A, or A has a more likely cause, this is a fallacious argument. For example: "I accidently stepped on the mouse trap I keep next to the fridge, and it snapped on my toe and hurt. When I bent over to get it off, I found the passport I'd been searching for lying underneath the cabinet. Therefore, the mouse trap grabbed me and hurt me so that I would find the passport." This is clearly a fallacy. . .the mouse trap would have done the same thing whether or not there was a passport. The stepping is the cause of the snapping rather than the final outcome of finding the passport. As you can see, such a fallacy is a different form of a Wrong Direction argument -- the effect is not supposed to cause the cause, but to be the reason for the cause, even though the cause had no reason or had a different (and perhaps better, by Occam's Razor) reason.

Any reasons why this should not be added to the list? --Quintopia 03:23, 3 August 2006 (UTC)

(1) We need to differentiate differing beliefs/premises from actual logical fallacies. If one for example accepts the premise that things don't appear ex nihil, then the apparent appearance of things logically implies an earlier cause. That things may always have been there is also a valid belief fo course. It is in fact an argument re specific basic premises, not about logical fallacies, and does not belong in the article, IMHO. (2) Likewise, the sentence: "This fallacy has been illustrated by ethical or theological arguments wherein the fear of punishment is subtly substituted for abstract right as the sanction of moral obligation." This example is not about logical fallacies but about basic premises. Some hold the premises that there is a God, who has communicated his thoughts on adultery and who will hold adulterers accountable. These people RATIONALLY conclude that adultery is not a good idea. Others hold the starting premise that there is no God or that if there is he never revealed him/herself, but their EQUALLY RATIONAL thoughts may well arrive at a similar conclusion about cheating on, or being cheated against by, their spouse. Both groups of people are rational. I would suggest that the specified sentence be removed, by reason of its fallacy. Petlif 02:02, 4 April 2007 (UTC)

[edit] Can the Conditional probability fallacy be added to the list?

The Conditional probability fallacy should be added. It is important because it often seems to underpin prejudice and racism, plus other mistakes in reasoning that are often made even by highly educated people in medical or legal situations. For example a bigot might support his racist beliefs by pointing out that there are a higher proprtion of black people in prison, and infer from this that black people are more likely to be criminal. In actual fact he is confusing p(black|criminal) with p(criminal|black). Taken to an absurd extreme, this is like saying that because most people in a Nunnery are female, therefore most females are Nuns, in other words p(female|nun) = p(nun|female)

That dosen't seem like it's the right way to apply the fallacy:
As i understood from rearding the page you linked: P(criminal|black) = P(black|criminal) * P(criminal) / P(black) is the relationship between the two probabilities. And P(criminal|white) = P(white|criminal) * P(criminal) / P(white) would be for white people.
But if P(black|criminal) > P(white|criminal) (more criminals are black) and P(black) < P(white) (there are more white people then black people) then: P(criminal|black) > P(criminal|white). So the argument is perfectly valid. The only problem may be in the premise (black people may be more likely to be arrested and caught rather then be criminal).
But maybe i misunderstand as i just read about this fallacy ? --Helixdq 11:15, 17 October 2007 (UTC)
The author Paulos - I forget his full name - discusses this fallacy in his book Innumeracy. There he uses the context of doctors misunderstanding the results of medical tests for disease. As I believe this fallacy is both common in real life and can have very serious results, then I think an article ought to be created please.


This is an awesome fallacy, and I think it should be added! Kenmore17 19:02, 14 January 2007 (UTC)

This is NOT an inherent fallacy, but only if the basic premises are poorly distributed, e.g. it is rational to say, "frizzy hair is a feature found in most african americans with hair, therefore a hairy person who is an african american is more likely than not to have frizzy hair." It is irrational to say "there are more africans than whites in US penitentaries, therefore africans are more likely to be criminals", because the fallacy here is that one's basic premise is not wide enough to support this conclusion: it does not deal with a representative section of the US black populace. The essential problem is that one often argues "from some to all", i.e. drawing on observations from a sub-group and then applying them to a wider group. It is used widely, e.g. in pharmaceutical research and in voting surveys. For reliability and persuasiveness this argument depends on how representative the "some" are of the "all". It can be entirely persuasive, if it has cast-iron premises: "decapitated people are dead and guillotining decapitates, therefore guillotining is lethal". A theoretical objection that some decapitated people MIGHT be walking around somewhere with their heads under their arms does little to make the argument non-persuasive and it certainly does not make it illogical. Petlif 02:24, 4 April 2007 (UTC)

No, it IS a fallacy, exactly for the reasons that were just stated. Condititional probability is nothing more than a one-directional implication statement, dealing with probability. i.e. A→B. Clearly, from this we cannot deduce that B→A. However, if we set up our premises to ensure that A if and only if B... well then of course it's not a fallacy. But, with only the information that A→B, we cannot deduce that the converse is true. In conclusion, the probability of B given A does not imply the probability of A given B unless we are given enough information in the beginning to know that it's true... which is nothing more than a statement of equivalency in the first place, which could never be denied. Kenmore17 14:31, 12 April 2007 (UTC)

[edit] Identifying a fallacy

Here's a good one a friend of mine posed. Consider the following conversation:

Alice: "You're a liar and a thief."
Bob: "I'm not a liar."
Alice: "Ah, so you are a thief!"

What fallacy is Alice commiting? It's almost like the opposite of affirming a disjunct, but it's obviously wrong from a formal logic perspective. It only makes sense because if Bob isn't a thief one would have expected him to deny that part of Alice's assertion as well, and he didn't. (67.87.115.207 00:16, 29 July 2006 (UTC))

It's not a fallacy. Alice's first statement implies her last. The following argument is valid: (P & Q) --> Q. 128.200.6.147 22:02, 9 August 2006 (UTC)
It certaintly is a fallacy. Although Alice's first statement is consistent with her last statement, her last statement is not a correct conclusion from Bob's statement. Bob said that he is not liar, he did not say that he is a thief [thus it cannot be concluded by Alice]. 68.36.79.134 04:30, 28 December 2006 (UTC)
Yes, this is a fallacy. However, the fallacy does not reveal itself when considering what Bob said. What he stated is irrelavent. In fact, in certain cases Alice's last statement is a perfect conclusion from Bob's statment. For example, assume that her first statement is true. It then follows that whatever Bob says is the exact opposite; hence, his statement translates precisely to "I am a liar," and this does not contradict anything alice said. Nevertheless, assume that her statement is false. We know that ~(P&Q) --> ~P or ~Q, where P corresponds to "liar: and Q corresponds to "thief." We need only to look at one case to show that this is a fallacy. Consider that Q is true and ~P is true. Clearly ~(P&Q) is true, but the final assertion is that P is true. And, this is a contradition to ~P being true. In conclusion, we have an argument, in which a true statement implies a false statement, which is not even valid, much less true. So really what's going on here is the difference between formal fallacy and informal fallacy. If we just want to consider formal fallacies, then actually the argument (P&Q)-->Q is enough to say that this is, in fact, not a logical fallacy. However, when considering informal fallacies (which are much more applicable to real world situations), it is. Kenmore17 18:52, 14 January 2007 (UTC)
I think this fallacy could be classified as argument from silence. Bob speaks nothing about him being a thief. From his silence, Alice infers he is one. —The preceding unsigned comment was added by Ezadarque (talk • contribs) 21:03, 16 January 2007 (UTC).
            • I presently possess my own professional opinion to offer, though this clearly is not a manner of evidence which I can verify so I suppose this will be taken on trust, for purpose of adding to discussion only, or not taken in any way. Argumentation theory was in actuality, a mandatory part of training for a government position I held, many years ago. I had to take an extensive test at least twice a year to ensure my proficiency in evaluating as well as manipulating logic. Judging only by data read from other logic related articles, there does not seem to be any significant deviance from the rules of logic which I maintained a sharpness in for nearly a decade. Unless the "rules of the game" have been changed since I held that job (Which, considering that this position was my own over a decade ago, does not seem particularly unlikely) then I shall be of the opinion that this is not a fallacy. It is not a very sound argument, and it's just this side of invalid, but it's not, according to my understanding of argumentation theory, a fallacy. Note, of course, that this claim remains my opinion, and is not fact. MVMosin 20:45, 27 March 2007 (UTC)

[edit] A New Fallacy?

While reading various blogs about differences between humans, the mention of a particular fallacy arose. That is:

A and B overlap, therefore A equals B. eg, some women are taller than some men, therefore men and women are the same height on average.

From the original writer (gc on the blog Gene Expression), follows an explanation and (unpolitically correct) examples: "That is...virtually every single leftist (and pseudo-rightist) argument re: race, religion, etcetera can be reduced to the following form:

A and B have some overlap, hence A and B are equal.

The argument is deployed virtually every time someone wants to cover up an inconvenient truth. It's so mind numbingly frequent that it's easy to miss it as *the* canonical show-stopper of modern discourse, even more so than the whole Nazi/racist/Godwin's Law thing, which is kind of domain specific. It's as slippery as "God did it" and has the advantage of being secular.

Some examples:

1) some women are better at math than some men, hence men and women have the same mathematical ability distribution.

2) Some whites commit more murders than some blacks, hence blacks and whites murder at the same rates.

3) Some fundamentalist Christians commit religious terrorism (e.g. bombing abortion clinics), hence fundamentalist Muslims and Christians commit terrorism at equal rates.

4) Some Christians are just as liberal as some Jews, hence Jews are no more liberal than Christians

5) Some wealthy people are lazy and dumb, hence the wealthy are just as likely to be lazy and dumb as the poor (and so postnatal luck rather than a heritable characteristic is the primary cause of wealth inequality)."

There are ample (ab)uses of this fallacy, necessitating a citation or two.

[edit] Remove General list of fallacies

The general list of fallacies "neither exhaustive nor mutually exclusive" and "traditionally recognized and discussed in works on critical thinking; others are more specialized" lacks in criteria. Just klick Category:Logical fallacies for a complete and sorted list and remove the general list of fallacies after merging their comments into theitr articles. I sorted the list of common logical fallacy, "common" elements make sense to list. --Ollj 18:52, 11 October 2006 (UTC)

[edit] Half-truth logic.

Half-truth flawed logic.

The entire concept of half-truths is a new field of discovery, many forms have yet to be identified, although the book, The Jesus Christ Code. will expose them.

Here is one type. (correct me if this is already mentioned)

"Stop violence against women". Logical statement used: "Most victims of physical violence between spouses are women. (infers men are the abusers)

Half-truth #1 - The real issue is abuse, and some types of violence are self defense. Abuse includes financial, psychological, and passive forms. Selective isolation of one form of abuse.

Half-truth #2 - The person who suffers the greater physical harm is assumed to be the victim. (maybe not a half-truth, just a false conclusion)

Half-truth #3 - They both might be abusive.

Half-truth #4 - The model silently suggests that the abusers are male, while in the case of same gender couples, ie lesbians, the victim and abuser is always a woman.

Half-truth #5 - The model ignores children, of both sexes, that may abuse mother or father.

Half-truth #6 - In general society, most of the victims are male, in altercations with other males.

This type of logic is 'black and white' generalized logic.

There is also the logical error of generalized logic. That is most does not mean all. We cannot create stereotypical models that are based on generalizations.

The other more important logical flaw used within these models is to assume that people are perfect, and this is normally not the case, so when applying a label of abuse, the term can almost apply to all of us, at one time or another.

--Son of Maryann Rosso and Arthur Natale Squitti 04:02, 9 January 2007 (UTC)

How on earth do these examples refute any notion of bivalence or tertium non datur? --Knucmo2 17:39, 12 September 2007 (UTC)

[edit] Paralogism

The term paralogism redirects here, only for no definition of the term as used in the Critique of Pure Reason to be given in the article. Any offers, otherwise I'll give it a shot sometime. --Knucmo2 17:39, 12 September 2007 (UTC)

[edit] Conservapedia

Is there a logical fallacy in Conservapedia's statement that it is "A Conservative Encyclopedia You Can Trust." - and if so what? Jackiespeel 18:11, 18 September 2007 (UTC)

Well, its sort of question-begging, is it not, viz. It presupposes you can can't trust the other encyclopedias. And also, it might be interpreted as founding its truth-claims upon its political viewpoint, which again might be begging the question a little.--Knucmo2 19:54, 20 September 2007 (UTC)

[edit] WikiProject class rating

This article was automatically assessed because at least one WikiProject had rated the article as stub, and the rating on other projects was brought up to Stub class. BetacommandBot 03:59, 10 November 2007 (UTC)

[edit] Lead

I wouldn't say it's too long in terms of text, but eight paragraphs is a bit much; I think around four would be better. Richard001 (talk) 06:44, 26 January 2008 (UTC)