The critical doctrine has performed its historical function, and the time has come for man to enter upon the Positive stage of his career. To enable him to take this step forward, it is necessary that the study of social phenomena should become a positive science. As social science is the highest in the hierarchy of sciences, it could not develop until the two branches of knowledge which come next in the scale, biology and chemistry, assumed a scientific form. This has recently been achieved, and it is now possible to found a scientific sociology. This science, like mechanics and biology, has its statics and its dynamics. The first studies the laws of co-existence, the second those of succession; the first contains the theory of order, the second that of progress. The law of consensus or cohesion is the fundamental principle of social statics; the law of the three stages is that of social dynamics. Comte's survey of history, of which I have briefly indicated the general character, exhibits the application of these sociological laws. The capital feature of the third period, which we are now approaching, will be the organisation of society by means of scientific sociology. The world will be guided by a general theory, and this means that it must be controlled by those who understand the theory and will know how to apply it. Therefore society will revive the principle which was realised in the great period of Monotheism, the distinction of a spiritual and a temporal order. But the spiritual order will consist of savants who will direct social life not by theological fictions but by the positive truths of science. They will administer a system of universal education and will draw up the final code of ethics. They will be able, more effectively than the Church, to protect the interests of the lower classes. Comte's conviction that the world is prepared for a transformation of this kind is based principally on signs of the decline of the theological spirit and of the military spirit, which he regarded as the two main obstacles to the reign of reason. Catholicism, he says, is now no more than "an imposing historical ruin." As for militarism, the epoch has arrived in which serious and lasting warfare among the ELITE nations will totally cease. The last general cause of warfare has been the competition for colonies. But the colonial policy is now in its decadence (with the temporary exception of England), so that we need not look for future trouble from this source. The very sophism, sometimes put forward to justify war, that it is an instrument of civilisation, is a homage to the pacific nature of modern society.