Quine's thesis of holism is justly regarded as the cornerstone of his naturalized epistemology. It is, to use Quine's own image, the crucial milestone in the development of post-Humean empiricism. Quine's holism constitutes a transition from the individual sentence to the organized system of sentences as the basic unit of empirical meaning. This system-centered approach allows him to dispense with theoretical reductions by dispensing not with the empiricist rejection of non-empirical facts, but with traditional assumptions concerning uniqueness and determinacy in matters of scientific theory. It allows the holist to affirm, rather than abandon, the empiricist commitment to science without having to secure this position on some a priori, neutral foundation.