The history of the development of Dewey's thought, set forth in the preceding chapters, does not pretend to furnish an adequate estimate of his philosophical system. The two questions, of origin and worth, are, after all, distinct. The genetic account of Dewey's theory of knowledge may serve to make its bearings and implications better understood, may reveal its deeper meaning and import, but the final estimate of its value as a philosophical hypothesis depends on other considerations. In this final chapter, it is proposed to deal with the question of the positive value of functionalism as a working hypothesis. This criticism may also serve to gather together the threads of criticism and comment which run through the previous chapters, and reveal the general ground upon which the writer's opposition to Dewey's theory is based. There can be no question that Dewey's theory of knowledge rests, finally, upon the doctrine of 'immediate empiricism;' upon his belief in "the necessity of employing in philosophy the direct descriptive method that has now made its way in all the natural sciences...."[281] This doctrine is clearly stated in the first essay reviewed in this study, "The Psychological Standpoint" (1886). To quote again from that essay: "The psychological standpoint as it has developed itself is this: all that is, is for consciousness or knowledge. The business of the psychologist is to give a genetic account of the various elements within this consciousness, and thereby fix their place, determine their validity, and at the same time show definitely what the real and eternal nature of this consciousness is."[282] The descriptive method here advocated does not differ, as an actual mode of procedure, from that of Dewey's later empiricism. It lies at the basis of all his speculation, earlier as well as later, and is undoubtedly the most important single element in his philosophical system. In "The Psychological Standpoint" Dewey ascribes the failure of the earlier empiricists to their desertion of the direct descriptive method (a criticism repeated frequently in later essays). Locke, for instance, instead of describing experience as it actually occurs, interprets it in terms of certain assumed simple sensations, the products of reflection. These non-experienced elements, Dewey believes, have no place in a purely empirical philosophy.