THE PHILOSOPHICAL AND PSYCHOLOGICAL PRESUPPOSITIONS The connection between social philosophy, on the one hand, and metaphysics and epistemology on the other hand, has always been a close one,--a fact not always adequately recognized by writers in the field of social science, in economics, especially. Scientists often "ignore" philosophy, holding that their concern is simply with the world of phenomenal "facts," and that the injection of philosophic considerations is illicit and unscientific. And this is often well enough in the field of the physical, chemical, and biological sciences, where the procedure is primarily inductive, and the data are got from sense observation. But in the social sciences, where the procedure is so largely deductive, and where the data are often principles of mind, whose truth is assumed as a starting point for investigation, and especially in economic theory, such an attitude cannot be justified. For philosophical assumptions _will_ creep in, and the scientist has no option about it. The only thing he can do is to be critical, and know definitely _what_ philosophical assumptions he is making,--and most of our treatises on economic theory do not bear evidence that this critical work has been done. There may be traced in the history of philosophy, in the ancient world, and also in the modern era, three main stages in philosophic thought, each accompanied by a distinctive set of ideas concerning the nature of society. In distinguishing these three stages, in showing the relation of each to social philosophy, and especially in tracing a parallel between the philosophy of the ancients and that of modern times, I recognize the grave dangers of giving a superficial treatment, and of distorting facts to make them fit a schematism. I recognize, further, that a host of details and a multitude of differences must be ignored in tracing the parallel I propose. Considerations of space, moreover, prevent such a detailed justification of the views here presented as would be required were this more than a minor phase of my subject. The need for this is lessened, however, by the fact that much of what follows is part of the commonplaces of the history of philosophy,--albeit a repetition of it seems needed in a criticism of economic theory. The three stages are: the dogmatic stage; the skeptical stage; and the critical stage. In Greek philosophy, the first stage is represented by the cosmological philosophers, as Thales, Anaximenes, and Anaximander, who, with perfect confidence in the power of their minds to solve the riddles of the universe, or rather, without questioning that point at all, proceeded to spin out poetical accounts of the origin and nature of things. The second stage is represented by the Sophists, who, struck by the manifold divergences in the philosophies of the earlier schools, and by the lack of harmony between the god-given laws and rules of morality which earlier tradition had handed down, and the needs of the