The Fallacy Zoo

In my various debates on the net and elsewhere, I find that often when I accuse an opponent of fallacious reasoning he is either entirely unfamiliar with the fallacy I mention, isn't thoroughly convinced the fallacy is a bad thing, or thinks he knows what the fallacy is but is mistaken. I don't know how many times I have been told that an ad hominem argument is not really ad hominem because the author of the gem didn't mean to hurt someone's feelings, or that the fact that some analogy I just used was not identical in every respect to the case at hand somehow made it a false analogy. To combat this kind of thing I have captured here for your enjoyment and edification a fine collection of classic fallacies known for their error throughout the ages. I plan to make extensive use of them in my other writings so that if I want to point out that someone is posing a false dilemma for example, I can avoid having to yet again explain what that is and why it is wrong. You are certainly welcome to do that same.

So enjoy the show, please stay behind the ropes, and for god's sake don't feed the fallacies!

Fallacies of Distraction

*False Dilemma: two choices are given when in fact there are three or more options
*From Ignorance: because something is not known to be true, it is assumed to be false
*Slippery Slope: a series of increasingly unacceptable consequences is drawn
*Complex Question: two unrelated points are conjoined as a single proposition

Appeals to Motives in Place of Support

*Appeal to Force: the reader is persuaded to agree by force
*Appeal to Pity: the reader is persuaded to agree by sympathy
*Consequences: the reader is warned of unacceptable consequences
*Prejudicial Language: value or moral goodness is attached to believing the author
*Popularity: a proposition is argued to be true because it is widely held to be true

Changing the Subject

*Attacking the Person:
(1) the person's character is attacked
(2) the person's circumstances are noted
(3) the person does not practise what is preached
*Appeal to Authority:
(1) the authority is not an expert in the field
(2) experts in the field disagree
(3) the authority was joking, drunk, or in some other way not being serious
*Anonymous Authority: the authority in question is not named
*Style Over Substance: the manner in which an argument (or arguer) is presented is felt to affect the truth of the conclusion

Inductive Fallacies

*Hasty Generalization: the sample is too small to support an inductive generalization about a population
*Unrepresentative Sample: the sample is unrepresentative of the sample as a whole
*False Analogy: the two objects or events being compared are relevantly dissimilar
*Slothful Induction: the conclusion of a strong inductive argument is denied despite the evidence to the contrary
*Fallacy of Exclusion: evidence which would change the outcome of an inductive argument is excluded from consideration

Fallacies Involving Statistical Syllogisms

*Accident: a generalization is applied when circumstances suggest that there should be an exception
*Converse Accident : an exception is applied in circumstances where a generalization should apply

Causal Fallacies

*Post Hoc Ergo Propter Hoc: because one thing follows another, it is held to cause the other
*Joint effect: one thing is held to cause another when in fact they are both the joint effects of an underlying cause
*Insignificant: one thing is held to cause another, and it does, but it is insignificant compared to other causes of the effect
*Wrong Direction: the direction between cause and effect is reversed
*Complex Cause: the cause identified is only a part of the entire cause of the effect

Missing the Point

*Begging the Question: the truth of the conclusion is assumed by the premises
*Irrelevant Conclusion: an argument in defense of one conclusion instead proves a different conclusion
*Straw Man: the author attacks an argument different from (and weaker than) the opposition's best argument

Fallacies of Ambiguity

*Amphiboly: the structure of a sentence allows two different interpretations
*Accent: the emphasis on a word or phrase suggests a meaning contrary to what the sentence actually says

Category Errors

*Composition: because the attributes of the parts of a whole have a certain property, it is argued that the whole has that property
*Division: because the whole has a certain property, it is argued that the parts have that property

Non Sequitur

*Affirming the Consequent: any argument of the form: If A then B, B, therefore A
*Denying the Antecedent: any argument of the form: If A then B, Not A, thus Not B
*Inconsistency: asserting that contrary or contradictory statements are both true
*Stolen Concept: using a concept while attacking a concept on which it logically depends

References

Barker, Stephen F. The Elements of Logic. Fifth Edition. McGraw-Hill, 1989.
Cedarblom, Jerry, and Paulsen, David W. Critical Reasoning. Third Edition. Wadsworth, 1991.
Copi, Irving M., and Cohen, Carl. Introduction to Logic. Eighth Edition. Macmillan, 1990.
Rand, Ayn Introduction to Objectivist Epistemology. Second Edition. Penguin, 1990.
Special thanks to downes@adminnet.assiniboinec.mb.ca for much of the research on which this stuff is based.

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