Meaning postulate

In semantics, a meaning postulate is the notion that lexical items can be defined in terms of relations with other lexical items. The classic example (formulated by Rudolf Carnap) is: bachelor = unmarried male.

Meaning Postulate is a formula to express an aspect of the sense of a predicate. The formula is expressed with - so-called - connectives. The used connectives are:

  paraphrase ≡ "if and only if"
  entailment → "if"
  binary antonomy ~ "not"

Following examples will simplify this:

1. "If and only if X is a man, then X is a human being." In meaning postulate this would look like this:

  x MAN ≡ x HUMAN BEING

2. "If X is a girl, then X is female." In meaning postulate this would look like this:

  x GIRL → x FEMALE

3. "X is not awake, therefore X is asleep." In meaning postulate this would look like this:

  x ASLEEP → ~x AWAKE

See also

• List of logic symbols