Chapter · The idea
When reasoning breaks: first fallacies
Hasty generalization(Jumping to a pattern)Post hoc(After-so-because)Anecdotal evidence(One-story proof)
Definition
A fallacy is not a new kind of reasoning — it is a familiar kind of reasoning gone wrong. Hasty generalization is induction with too few cases. Post hoc is causal reasoning that mistakes sequence for cause. Anecdotal evidence is statistical reasoning that lets one vivid story outweigh the numbers. Because you can now recognize the healthy forms, you can recognize their failure modes.
Memory hook
“A fallacy is good reasoning's shape with the strength missing.”
What it sounds like
- I tried it once and it was terrible, so they all are. (hasty generalization)
- Right after we changed X, Y happened — so X did it. (post hoc)
- Forget the studies; my uncle smoked for sixty years and was fine. (anecdotal evidence)