Copyright © Stephen Downes, 1995-2000
stephen.downes@ualberta.ca
Taken from http://www.intrepidsoftware.com/fallacy/toc.htm
Ø False Dilemma: two choices are given when in fact there are three options
Ø From Ignorance: because something is not known to be true, it is assumed to be false
Ø Slippery Slope: a series of increasingly unacceptable consequences is drawn
Ø Complex Question: two unrelated points are conjoined as a single proposition
Ø Appeal to Force: the reader is persuaded to agree by force
Ø Appeal to Pity: the reader is persuaded to agree by sympathy
Ø Consequences: the reader is warned of unacceptable consequences
Ø Prejudicial Language: value or moral goodness is attached to believing the author
Ø Popularity: a proposition is argued to be true because it is widely held to be true
Ø Attacking the Person:
1. The person's character is attacked
2. The person's circumstances are noted
3. The person does not practice what is preached
Ø 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
Ø Anonymous Authority: the authority in question is not named
Ø Style Over Substance: the manner in which an argument (or arguer) is presented is felt to affect the truth of the conclusion
Ø Hasty Generalization: the sample is too small to support an inductive generalization about a population
Ø Unrepresentative Sample: the sample is unrepresentative of the sample as a whole
Ø False Analogy: the two objects or events being compared are relevantly dissimilar
Ø Slothful Induction: the conclusion of a strong inductive argument is denied despite the evidence to the contrary
Ø Fallacy of Exclusion: evidence which would change the outcome of an inductive argument is excluded from consideration
Ø Accident: a generalization is applied when circumstances suggest that there should be an exception
Ø Converse Accident : an exception is applied in circumstances where a generalization should apply
Ø Post Hoc: because one thing follows another, it is held to cause the other
Ø Joint effect: one thing is held to cause another when in fact they are both the joint effects of an underlying cause
Ø Insignificant: one thing is held to cause another, and it does, but it is insignificant compared to other causes of the effect
Ø Wrong Direction: the direction between cause and effect is reversed
Ø Complex Cause: the cause identified is only a part of the entire cause of the effect
Ø Begging the Question: the truth of the conclusion is assumed by the premises
Ø Irrelevant Conclusion: an argument in defense of one conclusion instead proves a different conclusion
Ø Straw Man: the author attacks an argument different from (and weaker than) the opposition's best argument
Ø Equivocation: the same term is used with two different meanings
Ø Amphiboly: the structure of a sentence allows two different interpretations
Ø Accent: the emphasis on a word or phrase suggests a meaning contrary to what the sentence actually says
Ø Composition: because the attributes of the parts of a whole have a certain property, it is argued that the whole has that property
Ø Division: because the whole has a certain property, it is argued that the parts have that property
Ø Affirming the Consequent: any argument of the form: If A then B, B, therefore A
Ø Denying the Antecedent: any argument of the form: If A then B, Not A, thus Not B
Ø Inconsistency: asserting that contrary or contradictory statements are both true
Ø Fallacy of Four Terms: a syllogism has four terms
Ø Undistributed Middle: two separate categories are said to be connected because they share a common property
Ø Illicit Major: the predicate of the conclusion talks about all of something, but the premises only mention some cases of the term in the predicate
Ø Illicit Minor: the subject of the conclusion talks about all of something, but the premises only mention some cases of the term in the subject
Ø Fallacy of Exclusive Premises: a syllogism has two negative premises
Ø Fallacy of Drawing an Affirmative Conclusion From a Negative Premise: as the name implies
Ø Existential Fallacy: a particular conclusion is drawn from universal premises
Ø Subverted Support: The phenomenon being explained doesn't exist
Ø Non-support: Evidence for the phenomenon being explained is biased
Ø Untestability The theory which explains cannot be tested
Ø Limited Scope The theory which explains can only explain one thing
Ø Limited Depth The theory which explains does not appeal to underlying causes
Ø Too Broad The definition includes items which should not be included
Ø Too Narrow The definition does not include all the items which should be included
Ø Failure to Elucidate The definition is more difficult to understand than the word or concept being defined
Ø Circular Definition The definition includes the term being defined as a part of the definition
Ø Conflicting Conditions The definition is self-contradictory
For Educators
Stephen Downes Guide to the Logical Fallacies
Copyright © Stephen Downes, 1995-2000
stephen.downes@ualberta.ca
Taken from http://www.intrepidsoftware.com/fallacy/toc.htm