The Carnap-Quine debate in the first half of this century addressed nothing less than the very foundations of scientific truth. The central issue concerns the differing bases for asserting the truth of analytic versus synthetic statements in science. "Analytic" statements are those which are true a priori while "synthetic" statements are contingent and based on empirical evidence. Rudolf Carnap (1891-1970) argued that the axioms of arithmetic, logic and other bodies of a priori doctrine can be construed as implicit definitions of the terms they contain. Thus, in order to be justified in believing such axioms, we need only understand the meanings of the terms; no appeal to intuition is required. Because these claims and those which follow from them could become known through an analysis of meaning, Carnap called such claims analytic; all others were called synthetic. Around these central notions of meaning and analyticity, Carnap built a systematic theory of knowledge and that an approach to most of the other major problems of philosophy of science. This approach was the foundation of "logical positivism." W. V. O. Quine (1908- ) challenged this theory beginning in 1934. He went to the very foundations of logical positivism by rejecting outright any distinction between analytic and synthetic truths. He went on to develop an epistemology to replace Carnap's without retreating to a reliance on intuition, but instead justified the body of our beliefs as a whole based on the outcome of suitable processes of revision operating on antecedent totalities of belief. This debate between Carnap and Quine is one of the central episodes in the development of contemporary philosophy of science. Dr. Creath, under this grant, will examine this debate using a massive amount of documentary evidence which has only just recently become available. His purpose is to show that the debate is not merely of parochial semantic interest but concerns fundamental strategies in the theory of knowledge of central importance for our understanding of the nature of science. The project will contribute both to our historical understanding of philosophy of science and advance our systematic treatment of ongoing issues as well.