Although philosophical semantics has become both a discipline in its own right and the source of the analytic techniques used in the rest of philosophy, its foundations have themselves been problematic. To provide a unified account of the field, John L. Pollock discusses issues including the nature of possible worlds, modalities, counterfactuals, and causation. Originally published in 1985. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These editions preserve the original texts of these important books while presenting them in durable paperback and hardcover editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.