On the Individuation of Fregean Propositions

ABSTRACT: My aim is to sketch a principle of individuation that is intended to serve the Fregean notion of a proposition, a notion I take for granted. A salient featur e of Fregean propositions, i.e. complexes of modes of presentation of objects (individuals, properties), is that they are fine-grained items, so fine-grained that even synonymous sentences might express different Fregean propositions. My starting point is the principle labelled by Gareth Evans the Intuitive Criterion of Differ ence for Thoughts, which states that it is impossible coherently to take different mental attitudes to the same proposition. As a logical truth (a consequence of Leibniz’s Law), this is a synchronic principle, the appli cation of which is restricted to attitudes held at a single time. I argue that such a restriction might be reasonably lifted and, on the basis of an adequate notion of attitude-retention, I propose an admissible diachronic extension of the principle