2. Another fountain-head of Pragmatic philosophy has been Darwinism. Indeed, the Pragmatic is the only philosophizing which has completely assimilated Evolution. The insight into the real fluidity of natural species ought long ago to have toned down the artificial rigidity of logical classifications. To know reality man can no longer rest in a 'timeless' contemplation of a static system; he must expand his thoughts so as to cope with a perpetually changing process. Since the world changes, his 'truths' must change to fit it. He is faced with the necessity of a continuous reconstruction of beliefs. This influence of Darwin has inspired the logical theories of Professor Dewey and the 'Chicago School' of Pragmatists. Thought in their writings is essentially the instrument of this readjustment. Its function is to effect the necessary changes in beliefs as economically and usefully as possible. It is an evolving process which keeps pace with the evolution of reality and the changing situations of mortal life. 3. It is not, however, entirely the reaction of science upon philosophy which has given birth to Pragmatism. Philosophy itself has been rent by internal convulsions. These have been emphasized in the work of Dr. F.C.S. Schiller, who has shown that already in the days of Plato the distinction between 'truth' and 'error' was baffling philosophy, that Plato's _Theaetetus_ has failed to establish it, and that the famous dictum of Protagoras, 'Man is the measure of all things,' distinctly foreshadows the 'Pragmatic,' or, as he calls it, the 'Humanist,' solution of the difficulty. Elsewhere Dr. Schiller has commented on the controversies raised by Hume's criticism of dogmatism. He has shown that Kant failed to answer Hume because he accepted Hume's psychology, and that no _a priori_ philosophers have since been able to devise any consistent and tenable doctrine. The idealistic theories of the 'Absolute' reveal their futility by their want of application to the genuine problems of life, and by the theoretic agnosticism from which they cannot escape. Hence the need for a new Theory of Knowledge and a thorough reform of Logic. 4. At this point he joins forces with Mr. Alfred Sidgwick, who has long been urging a radical criticism of the procedures of Formal Logic, and shown the gulf between them and the processes of concrete thought. Sidgwick has demonstrated that the belief in formal truth renders Logic merely verbal, and that the actual _meaning_ of assertions completely escapes it.