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Fallacy Information

In logic and rhetoric, a fallacy is usually an improper argumentation in reasoning resulting in a misconception or presumption. By accident or design, fallacies may exploit emotional triggers in the listener or interlocutor (appeal to emotion), or take advantage of social relationships between people (e.g. argument from authority). Fallacious arguments are often structured using rhetorical patterns that obscure any logical argument.

Fallacies can be used to win arguments regardless of the merits. Among such devices, discussed in more detail below, are: "ignoring the question" to divert argument to unrelated issues using a red herring, making the argument personal (argumentum ad hominem) and discrediting the opposition's character, "begging the question" (petitio principi), the use of the non-sequitur, false cause and effect (post hoc ergo propter hoc), bandwagoning (everyone says so), the "false dilemma" or "either-or fallacy" in which the situation is oversimplified, "card-stacking" or selective use of facts, and "false analogy". Another favorite device is the "false generalization", an abstraction of the argument that shifts discussion to platitudes where the facts of the matter are lost. There are many, many more tricks to divert attention from careful exploration of a subject.[1]

Fallacies can generally be classified as informal (premises fail to support the proposed conclusion, but the argument is structured properly) or formal (logical structure is flawed).

Contents

Material Fallacies

The taxonomy of material fallacies is based on that of Aristotle's body structure Organon (Sophistici elenchi). This taxonomy is as follows:

Fallacy of accident or sweeping generalization

Converse fallacy of accident or hasty generalization

Irrelevant conclusion

Affirming the consequent/Denying the antecedent

Begging the question

Fallacy of false cause

Fallacy of many questions

Straw man

Verbal Fallacies

Verbal fallacies are those in which a conclusion is obtained by improper or ambiguous use of words. They are generally classified as follows.

Equivocation

Example Argument: All heavy things have a great mass; Jim has a "heavy heart"; therefore Jim's heart has a great mass.
Problem: Heavy describes more than just weight. (Jim is sad.)

Connotation fallacies

Apophasis and argument by innuendo

Amphiboly

Example: The position of the adverb "only" in a sentence starting with "He only said that" results in a sentence in which it is uncertain as to which of the other three words the speaker is intending to modify with the adverb.

Fallacy of composition

Example Argument: All the musicians in a band (constituent parts) are highly skilled, therefore the band itself (composite item) is highly skilled.
Problem: The band members may be skilled musicians but lack the ability to function properly as a group.

Division

Example Argument: "The university (the whole) is 700 years old, therefore, all the staff (each part) are 700 years old".
Problem: Each and every person currently on staff is younger than 700 years. The university continues to exist even when, one by one, each and every person on the original staff leaves and is replaced by a younger person. See Theseus' Ship paradox.
Example Argument: "This cereal is part of a nutritious breakfast therefore the cereal is nutritious."
Problem: Simply because the breakfast taken as a whole is nutritious does not necessarily mean that each part of that breakfast is nutritious (unless the definition of a nutritious breakfast requires all parts to be nutritious).

Proof by verbosity

Accent

Figure of Speech

Example: The sailor was at home on the sea.
Problem: The expression 'to be at home' does not literally mean that one's domicile is in that location.

Fallacy of misplaced concreteness

Example 1

Timmy argues:

  1. Billy is a good tennis player.
  2. Therefore, Billy is 'good', that is to say a morally good person.

Here the problem is that the word good has different meanings, which is to say that it is an ambiguous word. In the premise, Timmy says that Billy is good at some particular activity, in this case tennis. In the conclusion, Timmy states that Billy is a morally good person. These are clearly two different senses of the word "good". The premise might be true but the conclusion can still be false: Billy might be the best tennis player in the world but a rotten person morally. However, it is not legitimate to infer he is a bad person on the ground there has been a fallacious argument on the part of Timmy. Nothing concerning Billy's moral qualities is to be inferred from the premise. Appropriately, since it plays on an ambiguity, this sort of fallacy is called the fallacy of equivocation, that is, equating two incompatible terms or claims.

Example 2

One posits the argument:

  1. Nothing is better than eternal happiness.
  2. Eating a hamburger is better than nothing.
  3. Therefore, eating a hamburger is better than eternal happiness.

This argument has the appearance of an inference that applies transitivity of the two-placed relation is better than, which in this critique we grant is a valid property. The argument is an example of syntactic ambiguity. In fact, the first premise semantically does not predicate an attribute of the subject, as would for instance the assertion

Nothing is better than eternal happiness.

In fact it is semantically equivalent to the following universal quantification:

Everything fails to be better than eternal happiness.

So instantiating this fact with eating a hamburger, it logically follows that

Eating a hamburger fails to be better than eternal happiness.

Note that the premise A hamburger is better than nothing does not provide anything to this argument. This fact really means something such as

Eating a hamburger is better than eating nothing at all.

Thus this is a fallacy of equivocation.

Deductive Fallacy

Main article: Deductive fallacy

In philosophy, the term logical fallacy properly refers to a formal fallacy: a flaw in the structure of a deductive argument which renders the argument invalid.

However, it is often used more generally in informal discourse to mean an argument which is problematic for any reason, and thus encompasses informal fallacies as well as formal fallacies.

The presence of a formal fallacy in a deductive argument does not imply anything about the argument's premises or its conclusion (see fallacy fallacy). Both may actually be true, or even more probable as a result of the argument (e.g., appeal to authority), but the deductive argument is still invalid because the conclusion does not follow from the premises in the manner described. By extension, an argument can contain a formal fallacy even if the argument is not a deductive one; for instance an inductive argument that incorrectly applies principles of probability or causality can be said to commit a formal fallacy.

Formalisms and frameworks used to understand fallacies

A different approach to understanding and classifying fallacies is provided by argumentation theory; see for instance the van Eemeren, Grootendorst.[3] In this approach, an argument is regarded as an interactive protocol between individuals which attempts to resolve a disagreement. The protocol is regulated by certain rules of interaction, and violations of these rules are fallacies. Many of the fallacies in the list above are best understood as being fallacies in this sense.

Other systems of classification

Of other classifications of fallacies in general the most famous are those of Francis Bacon and J. S. Mill. Bacon (Novum Organum, Aph. 33, 38 sqq.) divided fallacies into four Idola (Idols, i.e. False Appearances), which summarize the various kinds of mistakes to which the human intellect is prone. With these should be compared the Offendicula of Roger Bacon, contained in the Opus maius, pt. i. J. S. Mill discussed the subject in book v. of his Logic, and Jeremy Bentham's Book of Fallacies (1824) contains valuable remarks. See Rd. Whateley's Logic, bk. v.; A. de Morgan, Formal Logic (1847) ; A. Sidgwick, Fallacies (1883) and other textbooks.

See also

Logic portal
Thinking portal
Psychology portal

References

  1. ^ Ed Shewan (2003). Applications of Grammar: Principles of Effective Communication (2nd ed.). Christian Liberty Press. pp. 92 ff. ISBN 1930367287. http://books.google.com/books?id=22s9JWeHJbAC&pg=PA92.
  2. ^ Damer, T. Edward (2008). Attacking Faulty Reasoning: A Practical Guide to Fallacy-free Arguments (6 ed.). Cengage Learning. pp. 130. ISBN 9780495095064.
  3. ^ F. H. van Eemeren and R. Grootendorst, Argumentation, Communication and Fallacies: A Pragma-Dialectical Perspective, Lawrence Erlbaum and Associates, 1992.

Further reading

Historical texts

External links

Look up fallacy in Wiktionary, the free dictionary.
Formal fallacies
Masked man fallacy · Circular reasoning
In propositional logic Affirming a disjunct · Affirming the consequent · Denying the antecedent · Argument from fallacy · False dilemma
In quantificational logic Existential fallacy · Illicit conversion · Proof by example · Quantifier shift
Syllogistic fallacy Accident · Affirmative conclusion from a negative premise · Converse accident · A dicto simpliciter · Exclusive premises · Existential · Necessity · Four-term fallacy · Illicit major · Illicit minor · Negative conclusion from affirmative premises · Undistributed middle
Other types of formal fallacy · List of fallacies
Informal fallacies
Absence paradox · Begging the question · Blind men and an elephant · Cherry picking · Complex question · False analogy · Fallacy of distribution (Composition · Division) · Furtive fallacy · Hasty generalization · I'm entitled to my opinion · Loaded question · McNamara fallacy · Name calling · Nirvana fallacy · Rationalization (making excuses) · Red herring fallacy · Special pleading · Slothful induction
Correlative-based fallacies False dilemma · Denying the correlative · Suppressed correlative
Deductive fallacies Accident · Converse accident
Inductive fallacies Sampling bias · Conjunction fallacy · False analogy · Hasty generalization · Misleading vividness · Overwhelming exception
Vagueness and ambiguity Amphibology · Continuum fallacy · False precision · Slippery slope
Equivocation Equivocation · False attribution · Fallacy of quoting out of context · Loki's Wager · No true Scotsman · Reification
Questionable cause Animistic · Appeal to consequences · Argumentum ad baculum · Correlation does not imply causation (Cum hoc) · Gambler's fallacy and its inverse · Post hoc · Prescience · Regression · Single cause · Slippery slope · Texas sharpshooter · The Great Magnet · Unknown Root · Wrong direction
List of fallacies · Other types of fallacy
Fallacies of relevance
General Dicto simpliciter ad dictum secundum quid (Accident) · Ad nauseam (Argument from repetition) · Argumentum ad ignorantiam (Argument from ignorance) · Argumentum e silentio (Argument from silence) · Argumentum ad temperantiam (Argument to moderation) · Argumentum ad populum (Appeal to the people) · Base rate · Compound question · Evidence of absence · Ignoratio elenchi (Irrelevant conclusion) · Invincible ignorance · Loaded question · Moralistic · Naturalistic · Non sequitur · Proof by assertion · Special pleading · Straw man · Two wrongs make a right
Appeals to emotion Fear · Flattery · Nature · Novelty · Pity · Ridicule · Children's interests · Invented here · Island mentality · Not invented here · Repugnance · Spite
Genetic fallacies Ad hominem · Ad hominem tu quoque · Appeal to accomplishment · Appeal to authority · Appeal to etymology · Appeal to motive · Appeal to novelty · Appeal to poverty · Appeals to psychology · Argumentum ad lapidem (Appeal to the stone) · Appeal to tradition · Appeal to wealth · Association · Bulverism · Chronological snobbery · Ipse dixit (Ipse-dixitism) · Poisoning the well · Pro hominem · Reductio ad Hitlerum
Appeals to consequences Appeal to force · Wishful thinking
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Noun

fallacy (plural fallacies)
  1. Deceptive or false appearance; deceitfulness; that which misleads the eye or the mind; deception.
  2. (logic) An argument, or apparent argument, which professes to be decisive of the matter at issue, while in reality it is not.
Derived terms
from: Wiktionary: fallacy,
Mon Apr 23 10:41:38 2012