Logical Fallacies Index






Index

Fallacies of Distraction

  • False Dilemma: two choices are given when in fact there are three 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

    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: 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 the truth of the conclusion is assumed by the premises
  • Straw Man: the author attacks an argument different from (and weaker than) the opposition's best argument
  • Fallacies of Ambiguity

  • Equivocation: the same term is used with two different meanings
  • 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
  • Syllogistic Errors

  • Fallacy of Four Terms: a syllogism has four terms
  • Undistributed Middle: two separate categories are said to be connected because they share a common property
  • 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
  • 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
  • Fallacy of Exclusive Premises: a syllogism has two negative premises
  • Fallacy of Drawing an Affirmative Conclusion From a Negative Premise: as the name implies
  • Existential Fallacy: a particular conclusion is drawn from universal premises
  • Fallacies of Explanation

  • Subverted Support (The phenomenon being explained doesn't exist)
  • Non-support (Evidence for the phenomenon being explained is biased)
  • Untestability (The theory which explains cannot be tested)
  • Limited Scope (The theory which explains can only explain one thing)
  • Limited Depth (The theory which explains does not appeal to underlying causes)
  • Fallacies of Definition

  • Too Broad (The definition includes items which should not be included)
  • Too Narrow (The definition does not include all the items which shouls be included)
  • Failure to Elucidate (The definition is more difficult to understand than the word or concept being defined)
  • Circular Definition (The definition includes the term being defined as a part of the definition)
  • Conflicting Conditions (The definition is self-contradictory)