This paper has been written in the light of recent discussions on the relevance of the New Physics to Philosophy, and with particular reference to a symposium held at the Royal Institution on May 19, 1943. It seemed to me that, at the symposium, there was some misunderstanding both on the part of the scientists and on the part of the philosophers, mainly due to the fact that neither quite realized what the opposite side considered to be the function of science and philosophy. One of the few things that emerged clearly was that the scientists thought the new physics (by which was meant the developments in physics associated with the names Einstein, Planck, Rutherford, Bohr, Heisenberg, Schrödinger, Dirac) had very definite relevance for philosophy, while the philosophers thought that it had no relevance at all. It would seem that such disagreement could be due only to disagreement about what the new physics attempts to do, or to disagreement about what philosophy attempts to do. I shall consider each of these in turn.