presuppose

Everyday

1. (formal) To take something for granted as true before you start: «The plan presupposes that everyone will help.» tree →
2. (formal) To need something to be true or to exist first: «Reading presupposes knowing the letters.» tree →

In the lessons

In maths and logic it points to the hidden starting idea of a question or argument. In reasoning and olympiad puzzles it helps you spot a trick question: «When did you stop cheating?» presupposes that you cheated. Phrases: «presuppose that», «presupposes knowledge of».

Examples

• The question «Who broke the vase?» presupposes that somebody broke it. tree →
• Long division presupposes that you know your times tables. tree →
• His plan presupposes that the bus will be on time. tree →
• The story presupposes that dragons can talk. tree →
• Good teamwork presupposes trust. tree →
• Don't presuppose the answer before you check the facts. tree →

Note

Formal. Noun: presupposition. In logic, a loaded question presupposes something that may be false; you can answer by questioning the presupposition. Similar to «assume», but «presuppose» is about what must already be true for something else to make sense.