The analytic-synthetic istinction (or dichotomy) is a conceptual distinction, used primarily in philosophy to distinguish propositions into two types: analytic propositions and synthetic propositions. Analytic propositions are those which are true simply by virtue of their meaning while synthetic propositions are not; however, philosophers have used the terms in very different ways. Furthermore, whether there is a legitimate distinction to be made has been widely debated among philosophers since Willard Van Orman Quine's critique of the distinction in the middle of the twentieth century.