What is "presupposition"

Presupposition \Pre*sup`po*si"tion\, n. [Pref. pre- + supposition: cf. F. pr['e]supposition.]

1. The act of presupposing; an antecedent implication; presumption.

2. That which is presupposed; a previous supposition or surmise.

1530s, from Middle French présupposition and directly from Medieval Latin praesuppositionem (nominative praesuppositio), noun of action from past participle stem of Latin praesupponere, from prae "before" (see pre-) + suppositio (see suppose).

n. 1 An assumption made beforehand; a preliminary conjecture or speculation. 2 The act of presupposing.

n. the act of presupposing; a supposition made prior to having knowledge (as for the purpose of argument)

In the branch of linguistics known as pragmatics, a presupposition (or ps) is an implicit assumption about the world or background belief relating to an utterance whose truth is taken for granted in discourse. Examples of presuppositions include:

• Jane no longer writes fiction.
  • Presupposition: Jane once wrote fiction.
• Have you stopped eating meat?
  • Presupposition: you had once eaten meat.
• Have you talked to Hans?
  • Presupposition: Hans exists.

A presupposition must be mutually known or assumed by the speaker and addressee for the utterance to be considered appropriate in context. It will generally remain a necessary assumption whether the utterance is placed in the form of an assertion, denial, or question, and can be associated with a specific lexical item or grammatical feature (presupposition trigger) in the utterance.

Crucially, negation of an expression does not change its presuppositions: I want to do it again and I don't want to do it again both presuppose that the subject has done it already one or more times; My wife is pregnant and My wife is not pregnant both presuppose that the subject has a wife. In this respect, presupposition is distinguished from entailment and implicature. For example, The president was assassinated entails that The president is dead, but if the expression is negated, the entailment is not necessarily true.

In epistemology, a presupposition relates to a belief system, or Weltanschauung, that is required for the argument to make sense. A variety of Christian apologetics, called presuppositional apologetics, argues that the existence or non-existence of God is the basic presupposition of all human thought, and that all people arrive at a worldview which is ultimately determined by the theology they presuppose. Evidence and arguments are only developed after the fact in an attempt to justify the theological assumptions already made. According to this view, it is impossible to demonstrate the existence of God unless one presupposes that God exists, with the stance that modern science relies on methodological naturalism, a myth, and thus is incapable of discovering the supernatural. It thereby fashions a Procrustean bed which rejects any observation which would disprove the naturalistic assumption. Apologists argue that the resulting worldview is inconsistent with itself and therefore irrational (for example, via the Argument from morality or via the Transcendental argument for the existence of God).

In linguistics, a presupposition of a statement is a proposition which must be true in order for the statement to make sense.

Presupposition may also refer to:

• Presupposition (philosophy), in epistemology, requirements for a belief system to make sense
• Presuppositional apologetics, argues that the existence or non-existence of God is the basic presupposition of all human thought