In his works the American philosopher Willard van Quine constantly rejects the analytic/synthetic distinction claiming that it is not justified. This happens because, in his opinion, human statements about the external world face the tribunal of experience not individually but as a corporate body, which implies that the judgment on their validity ultimately rests on experience itself. Many problems arise at this point, since even language plays a fundamental role in the Quinean view, and it must be accommodated into the picture if the picture itself means to be coherent. Conceptual scheme and external world are both necessary, but language does not seem to be a factor whose ultimate legitimacy relies on something outside the conceptual sphere, and this means in turn that we face a dualistic situation. Conceptual schemes or world-views, like the ones provided by Newtonian mechanics or quantum theory, are the primary bearers of truth, and the truth of a statement strictly depends from the particular conceptual scheme one currently adopts.