Composition / Division
Assuming what's true of the parts must be true of the whole, or vice versa.
- informal
These twin fallacies wrongly transfer a property between a whole and its parts. Composition infers that the whole has a property just because its parts do; division infers that each part has a property just because the whole does. The inference ignores that many properties simply don't carry across.
Examples
- Composition: “Every musician in the orchestra is a brilliant soloist, so the orchestra as a whole must be brilliant.”
- Division: “Our company is the most profitable in the industry, so every department in it must be highly profitable.”
Why it works & how to counter
Persuasive because parts and wholes are so closely related. Counter it by asking whether the specific property actually transfers — a wall can be heavy while each brick is light.