|Cogito ergo sum|
Logic and rhetoric
Presupposition is not directly related to Presuppositionalism, which is a religious belief, although presuppositionalist beliefs are certainly full of presupposition.
A presupposition is a linguistic term for an implicit assumption in a phrase, usually a claim or a question.
Presuppositions can be used in a fallacious manner by playing on these assumptions, e.g., by asking a loaded yes-or-no question that will implicate the speaker in something disagreeable no matter which way he answers.
The appropriate answer to a question based upon a false presupposition is "mu".
- Phrase: "Have you stopped beating your wife?"
- Presupposition: 1) You, at some point, have at least one wife. 2) At some point you have beaten your wife (regardless whether that is the same wife as the first presupposition).
- Phrase: "I have quit smoking."
- Presupposition: I used to smoke.
And from Alice in Wonderland by Lewis Carroll:
"How am I to get in?" asked Alice again, in a louder tone.
"Are you to get in at all?" said the Footman. "That's the first question, you know."