This separation of the activities of life into several distinct processes having each a special function looks like a survival of the old faculty psychology, against which modern thought has protested as much as against anything whatever. The conception of the organic processes as separate in action has all the faults of a merely mechanical representation of consciousness. Doubtless some advantage is to be obtained, for purposes of investigation, by treating thought, appreciation, and affection separately; but it is a serious error to take this provisional distinction as real. It is a curious fact that Dewey, with all his opposition to such modes of procedure, himself falls into this abstract way of treating the 'functions' of experience, seeing not the beam that is in his own eye. It is this very form of treatment, strangely enough, which enables Dewey to call biology to the support of his interpretation of the function of knowledge. According to the Darwinian theory, survival of the species is dependent upon the development of special structures and capacities which enable the organism to adjust itself to its environment. Dewey finds, following a familiar argument, that the lower animals are adapted to their environment by special habits of reaction which are relatively fixed and inelastic. Man, on the contrary, has an exceedingly plastic nervous system, which enables him to meet changing conditions. Man is not only highly adapted, but highly adaptable. This trait of plasticity, or adaptability, Dewey believes, is a product of natural selection, and, of course, in the final analysis, this high degree of plasticity is the thought function. It is scarcely necessary to say that this treatment of thought is highly speculative. Dewey offers little concrete evidence to support his position; indeed, it would require the labor of a Darwin to supply the needed evidence. Instead of grounding his theories upon the results of science, Dewey adapts the ever elastic 'evolutionary method' (not really that of biological evolution, however indeterminate) to his own scheme of things. It would be hard to discover in philosophical literature a method more purely theoretical and even dialectical than that whereby Dewey gives his logical theory the support of evolutionary theory.