The individual in his experiences is continually creating a world which becomes real through his discovery. In so far as new conduct arises under the conditions made possible by his experience and his hypothesis the world, which may be made the test of reality, has been modified and enlarged. I have endeavored to present the world which is an implication of the scientific method of discovery with entire abstraction from any epistemological or metaphysical presuppositions or complications. Scientific method is indifferent to a world of things-in-themselves, or to the previous condition of philosophic servitude of those to whom its teachings are addressed. It is a method not of knowing the unchangeable but of determining the form of the world within which we live as it changes from moment to moment. It undertakes to tell us what we may expect to happen when we act in such or such a fashion. It has become a matter of serious consideration for a philosophy which is interested in a world of things-in-themselves, and the epistemological problem. For the cherished structures of the metaphysical world, having ceased to house the values of mankind, provide good working materials in the hypothetical structures of science, on condition of surrendering their metaphysical reality; and the epistemological problem, having seemingly died of inanition, has been found to be at bottom a problem of method or logic. My attempt has been to present what seems to me to be two capital instances of these transformations. Science always has a world of reality by which to test its hypotheses, but this world is not a world independent of scientific experience, but the immediate world surrounding us within which we must act. Our next action may find these conditions seriously changed, and then science will formulate this world so that in view of this problem we may logically construct our next plan of action. The plan of action should be made self-consistent and universal in its form, not that we may thus approach nearer to a self-consistent and universal reality which is independent of our conduct, but because our plan of action needs to be intelligent and generally applicable. Again science advances by the experiences of individuals, experiences which are different from the world in which they have arisen and which refer to a world which is not yet in existence, so far as scientific experience is concerned. But this relation to the old and new is not that of a subjective world to an objective universe, but is a process of logical reconstruction by which out of exceptions the new law arises to replace a structure that has become inadequate.