[T]he theory of meaning is the fundamental part of philosophy which underlies all others. Because philosophy has, as its first if not its only task, the analysis of meanings, and because, the deeper such analysis goes, the more it is dependent upon a correct general account of meaning, a model for what the understanding of an expression consists in, the theory of meaning, which is the search for such a model, is the foundation of all philosophy, and not epistemology as Descartes misled us into believing.