A. Internal relevance
- Positively relevant: claim increases the probability of the conclusion.
- Negatively relevant: a statements truth counts against the truth of another statement.
- Irrelevant: a statements truth or falsity has no bearing on the other statement (conclusion).
Ways of being internally relevant:
1) Deductive entailment: anything which deductively entails the conclusion is relevant.
2) Analogy: When two things are similar in a number of respects, we may have reason for thinking that they are similar in other respects.
3) Inductive reasoning: relevance comes from the assumption that regularities that have been the case will persist. Past cases are relevant to future ones.
4) Normative relevance: premises are revelant to a conclusion about good or bad, about what we should or should not do.
B. Contextual relevance
The argument (including all premises and the main claim seperately) must be relevant to the issue at hand.
Problems in Contextual Relevance:
- Straw man/person: Misrepresenting an opponents position, usually to make it easier to deal with.
- Red herring: Diverting attention from the main point of an argument to a different point.
- Guilt by association: Linking a person or group with something else that is believed to be bad.
- Ad hominem arguments: An illegitimate attack on the person
- Appeals to ignorance: "We can find no evidence for the truth (or falsity) of X. Therefore X is false (or true)."
- Appeals to pity: Trying to support a conclusion by evoking pity in the listener.
- Jumping on the Bandwagon: Argument based on popularity.