Necessity and Propositions

Abstract

Some propositions are not only true, but could not have been otherwise, no matter how things had turned out. Under what conditions do propositions have this property of being necessarily true? This thesis examines some existing answers to this question and develops a new answer: a proposition is necessary iff it is, or is implied by, a proposition which is both true and inherently counterfactually invariant. The notion of inherent counterfactual invariance is introduced especially for the purpose of giving this answer. In support of this answer, an approach to a cluster of key issues in the philosophy of language is suggested.