Definitions

from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun A false notion.
  • noun A statement or an argument based on a false or invalid inference.
  • noun Incorrectness of reasoning or belief; erroneousness.
  • noun The quality of being deceptive.

from The Century Dictionary.

  • noun Deceptiveness; deception; deceit; deceitfulness; that which is erroneous, false, or deceptive; that which misleads; mistake.
  • noun Specifically— A false syllogism; an invalid argumentation; a proposed reasoning which, professing to deduce a necessary conclusion, reaches one which may be false though the premises are true, or which, professing to be probable, infers something that is really not probable, or wants the kind of probability assigned to it.
  • noun The fallacy of accident, arising when a syllogism is made to conclude that, because a given predicate may be truly affirmed of a given subject, the same predicate may be truly affirmed respecting all the accidents of that subject.
  • noun The fallacy of speech respective and speech absolute, occurring when a proposition is affirmed with a qualification or limitation in the premises, but virtually without the qualification in the conclusion.
  • noun The fallacy of irrelevant conclusion, or ignoration of the elench, occurring when the disputant, professing to contradict the thesis, advances another proposition which contradicts it in appearance but not in reality.
  • noun The fallacy of the consequent, or non sequitur, an argument from consequent to antecedent, which may really be a good probable argument.
  • noun Begging the question, or the petitio principii, a syllogism, valid in itself, but in which that is affirmed as a premise which no man who doubts the conclusion would admit.
  • noun The fallacy of false cause, arising when, in making a reductio ad absurdum, besides the proposition to be refuted, some other false premise is introduced.
  • noun The fallacy of many interrogations in which two or more questions are so proposed that they appear to be but one: as, “Have you lost your horns?” a question which implies that you had horns.

from the GNU version of the Collaborative International Dictionary of English.

  • noun Deceptive or false appearance; deceitfulness; that which misleads the eye or the mind; deception.
  • noun (Logic) An argument, or apparent argument, which professes to be decisive of the matter at issue, while in reality it is not; a sophism.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun Deceptive or false appearance; deceitfulness; that which misleads the eye or the mind; deception.
  • noun logic An argument, or apparent argument, which professes to be decisive of the matter at issue, while in reality it is not. A specious argument.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun a misconception resulting from incorrect reasoning

Etymologies

from The American Heritage® Dictionary of the English Language, 4th Edition

[Alteration of Middle English fallace, from Old French, from Latin fallācia, deceit, from fallāx, fallāc-, deceitful, from fallere, to deceive.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Middle English, from Old French fallace, from Latin fallacia ("deception, deceit"), from fallax ("deceptive, deceitful"), from fallere ("to deceive").

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Examples

  • The main fallacy is that the tax does not acknowledge the largely static nature of short term energy demand.

    Oil: Marginal vs. Average Cost, Arnold Kling | EconLog | Library of Economics and Liberty 2009

  • A subset of this fallacy is the pervasive view that securities trading is a zero-sum game.

    Exuberance, Arnold Kling | EconLog | Library of Economics and Liberty 2009

  • The most common manifestation of this fallacy is the assumption that the artist begins with material that has already a recognized status, moral, philosophic, historical, or whatever, and then renders it more palatable by emotional seasoning and imaginative dressing.

    June 2010 2010

  • The most common manifestation of this fallacy is the assumption that the artist begins with material that has already a recognized status, moral, philosophic, historical, or whatever, and then renders it more palatable by emotional seasoning and imaginative dressing.

    Perfecting the Power to Perceive 2010

  • The most common manifestation of this fallacy is the assumption that the artist begins with material that has already a recognized status, moral, philosophic, historical, or whatever, and then renders it more palatable by emotional seasoning and imaginative dressing.

    John Dewey's *Art as Experience* 2010

  • The worst of the fallacy is the assumption that “worth” means only economic value, without any other factor interfering, and, as you note, that “worth” based on economic value in the current cultural environment somehow trumps any other consideration.

    Matthew Yglesias » Hispanics and Crime 2010

  • The most common manifestation of this fallacy is the assumption that the artist begins with material that has already a recognized status, moral, philosophic, historical, or whatever, and then renders it more palatable by emotional seasoning and imaginative dressing.

    The Reading Experience 2010

  • Franken also talks about what he calls the fallacy of liberal bias in the media which is interesting given my recent blog posts about that very issue.

    lies and the lying liars who tell them WENDEE HOLTCAMP 2008

  • Franken also talks about what he calls the fallacy of liberal bias in the media which is interesting given my recent blog posts about that very issue.

    Archive 2008-11-01 WENDEE HOLTCAMP 2008

  • When you say it like that, the fallacy is almost self-evident; we hardly need spell out the reductio ad absurdum.

    Dawkins the Meme-Daddy 2005

  • Such unmasking may contribute to what forensic experts call the sharpshooter fallacy: Someone fires a bullet in the side of a barn and then draws a circle around the bullet hole afterward to show they’ve hit their mark.

    Can We Identify a Person From Their Voice? Peter Andrey Smith 2023

  • Such unmasking may contribute to what forensic experts call the sharpshooter fallacy: Someone fires a bullet in the side of a barn and then draws a circle around the bullet hole afterward to show they’ve hit their mark.

    Can We Identify a Person From Their Voice? Peter Andrey Smith 2023

Comments

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  • There ain't no fallacy like a logical fallacy

    September 19, 2007

  • "5. The fallacy of irrelevant conclusion, or ignoration of the elench, occurring when the disputant, professing to contradict the thesis, advances another proposition which contradicts it in appearance but not in reality."

    --Century Dictionary

    September 29, 2010