The philosophy of language can be viewed as a branch of the theory of knowledge. It concerns itself with a special case in epistemology, linguistic knowledge, and the questions

The philosophy of language can be viewed as a branch of the theory of knowledge. It concerns itself with a special case in epistemology, linguistic knowledge, and the questions about such knowledge that it tries to answer have the form of classical epistemological questions, namely, what do we know about a natural language and how do we come to know it. It is no surprise, then, to find that theories about linguistic knowledge, like theories about knowledge in general, are either rationalist or empiricist. Rationalist theories like Chomsky's claim that acquisition of the complex competence of a fluent speaker must be explained as a process in which innate schemata expressing the general form of a grammar become differentiated and realized as hypotheses about the character of the particular grammar underlying a sample of speech. On a rationalist theory, the primary role of a linguistic environment is to stimulate such differentiation and to confirm or disconfirm the hypotheses resulting from these schemata. Rationalism also claims that the principles expressing these innate schemata are synthetic a priori because they constitute the framework within which environmental stimulation can be interpreted as evidence bearing on the learner's hypotheses about the grammar. 1 Empiricist theories like Quine's claim that an explanation of language acquisition needs nothing more complex or sophisticated in the way of an assumtion about innate capacities than a system of inductive procedures for forming generalizations from the limited regularities in the learner's linguistic experience. On an empiricist theory, experience plays the central role that innate schemata play on a rationalist theory. Experience teaches the language learner both the form and content of grammatical rules. Accordingly, for the empiricist, even the principles that express the invariant form and content of grammars, the linguistic universals, are synthetic a posteriori. They could have been otherwise and would have