On any view, much remains to be done before the statement of historic causation can reach scientific thoroughness; and it may well be that some of my theories will incur modification. All I claim for them is that they are made in the light of a study of the concrete process; and I am satisfied that fuller light is to be obtained only in that direction. In the end, doubtless, conflicts of historical interpretation will turn upon problems of psychology. A contemporary German expert of distinction, Prof. Lamprecht, in his able lectures on the problem _What is History?_ (Eng. trans. 1905), lays it down that the main problem of every scientific history of mankind is the "deducing from the history of the most important communities of men the evolution of the breadth of consciousness"; and again that "the full historical comprehension of a single change or of a single phenomenon, with their historical significance, can only be acquired from the most general principles; that is to say, from the application of the highest universal-historical categories." If I understand Prof. Lamprecht aright, he here means simply that we properly understand the motivation of men in the past in terms of our own psychosis, conceived as in touch only with their data. This seems to me substantially sound. But on the other hand I doubt the utility of his apparent purpose of explaining modern historic developments in terms of special psychic changes or movements in communities, considered as forces. That way seems to lie reversion to the old and vain device of explaining the course of nations in terms of their "characters." In any case, however, we have Prof. Lamprecht's avowal that "It would be a study of great value to establish, by comparative work in universal history, what are the constantly recurring economic factors of each period which are so uniformly followed by the development of other higher intellectual values." That is as full a recognition of the "economic factor" as I am concerned to contend for, if it be understood that economic motives are on the one hand recognised as affecting social action in general, and on the other that varying forms of social machinery react variously on intellectual life. Upon such hypotheses the following inquiry proceeds; to such conclusions it leads. Obviously all critical exposition, historical or other, is an attempt to influence the psychic processes of the reader, to make him "feel" this and "think" that; and in this sense any resulting change of conduct means the play of "the psychic factor." But that is only another way of saying that the psychic factor is conditioned by material circumstances, by knowledge, and by ignorance. To insist on the perpetual social significance of all three is the general aim of this book. _September, 1912._ PART I POLITICAL FORCES IN ANCIENT HISTORY CHAPTER I THE SUBJECT MATTER § 1