11.1.3 Another Puzzle

Motivation of discourse phenomena: accessability of antecedents.

Before we propose a solution to deal with these unpleasant mismatches between natural language and first-order logic, let's have a look at a different, but somehow related, puzzle. Consider the following sentence:

``It's not the case that no woman walks.''

In first-order logic, this formula is equivalent with the translation for ``A woman walks''. However, although it is possible to continue this sentence with ``She smokes'', it sounds ungrammatical for

`` It's not the case that no woman walks. *She smokes. ''

This observation leads to the conclusion that describing meaning in terms of truth-conditions alone might be appropriate for sentences, but certainly it is not enough to capture the meaning of discourses. There seems to be something else going on that blocks anaphoric references - something that we are unable to capture with our simple first-order translations for discourse.