Hasty Generalization
Blanket Statement · Overgeneralization · Fallacy of Insufficient Statistics
Drawing a broad conclusion from too few instances or an unrepresentative sample, ignoring that the evidence is insufficient to support the generalization.
Origin
Aristotle first catalogued this class of reasoning error around 350 BCE in his Sophistical Refutations, describing the fallacy of secundum quid — drawing universal conclusions while ignoring necessary qualifications. The modern concept broadened to encompass conclusions drawn from insufficient evidence or unrepresentative samples. The English term "hasty generalization" developed through centuries of logic and rhetoric, becoming a standard entry in informal fallacy taxonomies by the 20th century.
Everyday Use
"I met two rude people from that city, so everyone there must be rude." We do this constantly — drawing sweeping conclusions from a tiny sample. One bad meal and a restaurant is "terrible"; one good review and a product is "amazing." The fewer data points we have, the more confidently we tend to generalize from them.