The theory thus derived from the combination of this second or statical law with the dynamical law of the three stages, seems at first sight to include nothing but the intellectual movement. But my previous remarks will have shown that this is enough to guarantee its applicability to social progress also; since social progress has invariably depended on the growth of our fundamental beliefs with regard to the economy that surrounds us. The historical portion of my _Positive Philosophy_ has proved an unbroken connexion between the development of Activity and that of Speculation; on the combined influence of these depends the development of Affection. The theory therefore requires no alteration: what is wanted is merely an additional statement explaining the phases of active, that is to say, of political development. Human activity, as I have long since shown, passes successively through the stages of Offensive warfare, Defensive warfare, and Industry. The respective connexion of these states with the preponderance of the theological, then metaphysical, or the positive spirit leads at once to a complete explanation of history. It reproduces in a systematic form the only historical conception which has become adopted by universal consent; the division, namely, of history into Ancient, Mediaeval, and Modern. Thus the foundation of Social science depends simply upon establishing the truth of this theory of development. We do this by combining the dynamic law, which is its distinctive feature, with the statical principle which renders it coherent; we then complete the theory by extending it to practical life. All knowledge is now brought within the sphere of Natural Philosophy; and the provisional distinction by which, since Aristotle and Plato, it has been so sharply demarcated from Moral Philosophy, ceases to exist. The Positive spirit, so long confined to the simpler inorganic phenomena, has now passed through its difficult course of probation. It extends to a more important and more intricate class of speculations, and disengages them for ever from all theological or metaphysical influence. All our notions of truth are thus rendered homogeneous, and begin at once to converge towards a central principle. A firm objective basis is consequently laid down for that complete co-ordination of human existence towards which all sound Philosophy has ever tended, but which the want of adequate materials has hitherto made impossible. [By the discovery of Sociological laws social questions are made paramount; and thus our _subjective principle_ is satisfied without danger to free thought]