Linguists, philosophers and computer scientists have for some time worked to produce more accurate and detailed models of meaning in natural language. Many have provided models that develop the idea that the meaning of a sentence is the set of situations in which the sentence is true. On the assumption that necessary truths are true in all situations, necessary truths all have the same meaning. But then, granted mathematical truths are necessary, all the truths of mathematics, being true in all situations, have the same meaning. My project looks at ways of distinguishing the meanings of sentences that are true in the same set of situations, so as to provide more accurate semantic models. In particular, I develop a semantic theory in which the notion of an individual’s perspective on the meaning of expressions in a sentence plays a vital role.