  The term “naturalism” has been understood in various ways; we need to see what Quine’s naturalism comes to. At one point, he describes naturalism as “the recognition that it is within science itself, and not in some prior philosophy, that reality is to be identified and described” (1981, 21). Two points are important to note about the idea of “science” here. First, it is less restrictive than it may seem. Quine certainly takes the natural sciences, especially physics, as paradigmatic. As he says himself, however, he uses the word “science” broadly; he explicitly includes psychology, economics, sociology, and history (see 1995, 49). Second, Quine does not see scientific knowledge as different in kind from our ordinary knowledge; he sees it, rather, as the result of attempts to improve our ordinary knowledge of the world: “Science is not a substitute for common sense but an extension of it.” (1957, 229). The scientist, he says, “is indistinguishable from the common man in his sense of evidence, except that the scientist is more careful.” (1957, 233). We might add that the scientist is more narrowly focused on issues of truth and objectivity and, in the hope of contributing to these goals, clearer and more systematic.