Theories of truth investigate truth as a property of one's thoughts and speech. We attribute truth and falsity to a wide variety of so-called truth-bearers: linguistic items (sentences, utterances, statements, and assertions), abstract items (propositions), and mental items (judgments and beliefs). What is the property we are attributing when we call a truth-bearer true? The question is crucial because of truth's involvement in central philosophical claims: For example, it is often said that truth is the aim of science, that the meaning of a sentence is given by the conditions under which it is true, that logical validity is the preservation of truth, or that ethical statements are neither true nor false. A proper understanding of truth promises to illuminate fundamental issues in metaphysics, the philosophy of language, logic, and ethics.

The two traditional theories of truth are the correspondence theory and the coherence theory. Further theories of...