In the evolution of living things two factors have been decisive, the development of brain power and the development of the social principle. We need scarcely add that the two are intimately connected, and further that the brain power of man is closely co-ordinated with his physical development. The supremacy of man is due to his brain power and to his readiness to associate for common ends, far more than to his strength or hardihood, in which he is greatly excelled by other animals. The entire history of civilisation bears witness to the potency of the two factors; for it is a truism to say that the communities and races that have excelled in brain power and in the family and social moralities have prevailed. A rational socialism might be defined as the mastery of associated human intelligence over the resources of nature for the general good. In this respect, also, the success of socialism would simply mark the continuous development of man along the tested and approved lines of progress. It is no doubt one of the many exaggerations of Lassalle, due partly to his function of agitator, that he laid excessive emphasis on the principle of community as the lever of progress, compared with the individual principle. Progress has always depended on the action and interaction of both principles. It is rather an idle question, which of the two is the more important; like that other question, whether the great man makes the age, or the age makes the great man. The man and the age make each other. We know the great influence often exerted in history by exceptional brain power or character, and both are often associated with a prominent individual. But high individual capacity is usually, if not always, found in an age and community with a high average of talent. Well-organised and well-endowed societies are most likely to produce the strongest and finest individuals, and it is only in such societies that the greatest individuals are likely to find adequate scope for their powers. We cannot form a just estimate of our subject unless we give due weight to both principles, but obviously the danger to society lies in the excessive development of the individual principle. History has too often witnessed the abnormal development of private selfishness, so overgrown as to weaken and finally dissolve the society in which it acted, thus accomplishing its own destruction. This is indeed the open secret of the ruin of most communities that have existed. We should seek in vain for an instance of a community ruined by excessive regard for the public good. A happy and wholesome individual development can be secured only by healthy relation and due subordination to society and the common weal.