Before we undertake a review of the thought of Hegel—to which the concluding paragraphs of the last chapter, with their insistence upon the dynamic character of historical development, are intended to form a kind of prolegomena—we must do something to resolve certain doubts that may be circulating in the reader’s mind as to the exact nature of the “presuppositions of science” about which we have been speaking. If, as we have insisted, all historical movements are engaged in constant struggle with counter-movements, with the result that the pattern of civilised life in any age is a dynamic pattern; and if this pattern of civilisation is a pattern of presuppositions entertained by the mind—what, it may well be asked, is the guarantee that these presuppositions that we hold, even if we do not consciously realise that we hold them, are valid? Out of the complex of presuppositions that have been held in the course of history, which should we select as most reliable? And finally, if presuppositions qua presuppositions are the foundation upon which our science is built, how can they be justified, seeing that science, by presupposing them, is automatically ruled out as an arbiter?