There is a widely held view that the expressions ‘necessary truth’, ‘a priori truth’ and ‘analytic truth’ either express the same concept or, at least, refer to all and only the same items. Philosophers who hold this view, and who are sometimes described as ‘empiricists’, often draw the conclusion that the truths of logic and mathematics, if necessary, are also a priori and are, in some important sense, empty or not about the world. The subject matter of these disciplines, then, (...) is said to differ in a philosophically important way from that of the empirical sciences, such as physics or chemistry. Rationalists, in contrast, have traditionally held that some a priori truths, either of logic or mathematics, are synthetic and, hence, non-analytic: i.e., there are synthetic a priori truths. (shrink)