pitfalls to scientists. Most are deductive pitfalls, but a couple of inductive pitfalls (e.g., hasty generalization) are included here because of their similarity to deductive pitfalls.
The list of fallacies that follows is loosely based on the compilation of Hurley [1985]. Other logicians lump or split these fallacies differently and describe them with different jargon. For our purposes, the names applied to these fallacies have limited usefulness; instead, our goal is to recognize when an argument is fallacious. Practice with a variety of examples is the key, and logic textbooks have a wealth of examples.
Most fallacies fall into one of four types: problems in a premise, extraneous extra evidence, faulty link between premises and conclusion, or case-dependent relationship between parts and whole. Table 10 gives an overview of these different kinds of fallacy, and the remainder of this chapter examines these fallacies in more detail.
Table 10. Varieties of fallacious argument.
Problems in a premise:
| Fallacy | Premises | other ‘evidence’ | ⇒ | Conclusion |
|---|---|---|---|---|
| false dichotomy | 2 choices assumed | other choices omitted | ||
| suppressed evidence | weakness ignored | |||
| ambiguity | ambiguity | misinterpreted | ||
| false cause | noncausal, yet assumed causal | |||
| slippery slope | unlikely chain of events | flawed links |
Extraneous other evidence:
| Fallacy | Premises | other ‘evidence’ | ⇒ | Conclusion |
|---|---|---|---|---|
| appeal to authority | experts say . . . | |||
| personal attack | fools say . . . | |||
| mob appeal | rest of group says . . . | |||
| might makes right | accept or suffer consequences | |||
| extenuating circumstances | extenuating circumstances | |||
| red herring | smoke-screen distraction |
