IN 1942 Jeans published a small volume entitled Physics and Philosophy, which I reviewed in Nature. In 1947 there was published posthumously a more substantial volume, entitled The Growth of Physical Science. (The proofs of this book had been revised by Jeans shortly before his death in September 1946.) The volumes to some extent overlap, since the one specifically dealing with philosophy includes sketches of the history of the progress in physics as the chapter sub-titles indicate: ‘The two voices of science and philosophy’ (Plato to the present); ‘How do we know?’ (Descartes to Kant; Eddington); ‘The passing of the mechanical age’ (Newton to Einstein);’ The new physics’ (Planck, Rutherford, Bohr); and ‘From appearance to reality’ (Bohr, Heisenberg, de Broglie, Schrödinger, Dirac); whilst the volume with the deliberately historical approach has chapters on the remote beginnings of science in Babylonia, Egypt, Phoenicia and Greece; science in Ionia and early Greece (including mathematics, physics, philosophy and astronomy); science in Alexandria, in the Dark Ages, in the Renaissance, in the century of genius (1601—1700), in the two centuries following Newton and in the modern era.

Jeans evidently took great pains over the latter book; it is well illustrated by reproductions of contemporary prints, paintings, etc., and it is indeed a more serious work. Physics and Philosophy is of a rather journalistic character, and has been much criticized by professional philosophers.

In my Nature review of Physics and Philosophy (from which I see no reason to differ today) I quoted Emerson's definition of philosophy as ‘the account which the human mind gives to itself of the constitution of the world’. Jeans in his preface modestly disavowed any acquaintance with philosophy other than that of an intruder, and disclaimed any intention to pose as an authority on questions of pure philosophy. Yet, on Emerson's definition of philosophy, no one had a greater right than Jeans to treat the subject of philosophy. Indeed, many of the great mathematical physicists of our generation, starting as mathematical technicians, have been compelled by their own researches to study the philosophy underlying them—Eddington, Planck, Einstein and Schrödinger.