  The philosophers who most influenced Quine were the Logical Empiricists (also known as Logical Positivists), especially Rudolf Carnap. The distinction between analytic truths and synthetic truths plays a crucial role in their philosophy. Analytic truths might be characterized as those true solely in virtue of the meanings of the words they contain, or of the rules of the language, or something of the sort. Synthetic truths, by contrast, state matters of extra-linguistic fact, and are known by experience. The Logical Empiricists accounted for truths which do not seem to be answerable to experience, most obviously the truths of logic and mathematics, by saying that they are analytic. This position was very widely held by the 1940s. Quine, however, famously casts doubt on analytic-synthetic distinction, and rejects the use made of it by the Logical Empiricists and other philosophers from the 1930s on. (Notable among the others is C. I. Lewis, first a teacher and then a colleague of Quine; his influence on Quine has perhaps been underestimated. See Baldwin 2013, Ben-Menahem 2016, and Sinclair 2016.)