Now come the fallacies of weak induction: arguments whose premises give some support, but far too little. The first is the bad generalization.
Key idea
A hasty generalization draws a conclusion about a whole group from a sample that is too small or not typical of the group.
Why it works
A few cases can differ from the whole group by chance, and an unusual sample differs in a steady way. Two rude people from a town tell you about two people, not about the town.
Worked example: Too small
"The first ten pages of the book were slow, so the whole book is boring."
- Ten pages is a small and possibly untypical part of the book.
- Openings are often slower than the rest.
Answer: Hasty generalization.
Worked example: A fair sample
"The cook tasted a spoonful from the well-stirred pot of soup and it was too salty. So the whole pot is too salty."
- A well-stirred pot is the same throughout.
- So one spoonful is a typical sample.
Answer: Not a fallacy.
Two quick questions catch most hasty generalizations: how many cases were there, and how were they picked? A big, fairly chosen sample can support a general claim; a handful of cases picked by chance encounter cannot.
Common mistake
Confusing hasty generalization with accident (later in this unit). Hasty generalization goes up from a few cases to a rule. Accident goes down: it applies a good rule to a case the rule was not made for.