The need of tolerance has been greatly increased by the rise of a social system which aims to be intelligent, recognizes change as rational, and seeks to guide it by discussion. Under an older régime, as in the Middle Ages, the prevalent doctrine was that there could be but one right way of thinking and that others must be suppressed. And in a society not organized for discussion there was more truth in this than the modern reader of history is apt to admit. A thousand years ago freedom of religious teaching, for example, would probably have resulted in doctrinal and moral anarchy. Innumerable conflicting sects would have sprung up, and there was no general organization of thought vigorous enough to keep them within limits or maintain a voluntary unity. In this, as in many other fields, we can dispense with a compulsory discipline because we have developed one which is spontaneous: formerly, if there was to be a moral whole it had to be authoritative. Even now this is more or less true of unenlightened populations, and it is only along with a campaign for enlightenment that we can safely demand freedom of speech. It is essential to the intelligent conduct of society that radical groups, however small and unpopular, should develop and express their views. Their proposals do good by forcing the discussion of principles and so leading to an illumination otherwise impossible. The large and moderate parties have a conforming tendency and usually differ but little in principles, if indeed they are conscious of these at all. But the radical programme is a challenge to thought, and can hardly fail to be educative. For some time past the Socialists have been of the utmost service in this way, and round their searching theories of human betterment discussion has largely centred. I have often been impressed by their value as a factor in clarifying the minds of college students. Such theories are like the occupation of an advanced post by a detachment of an army: they push forward the line of battle even if the position occupied does not, in the long run, prove tenable. We easily overlook the fact that an honest project is seldom wholly wrong, and that even if it is there may be profit in discussing it. The value of partial isolation as a factor in social intelligence is not often recognized in a democracy, where, under the sway of the brotherhood idea, we commonly assume that we cannot see too much of one another. But if we are to have a rich organization of thought, including many types of men, each good of its kind, we must have a corresponding diversity of environments in which these types of men may get their nurture. The culture of individuality, the need of which we are beginning to recognize, cannot go far except as we also foster distinctive groups. We need many kinds of family, of school, of church, of community, of occupational and culture associations, each with a tradition and spirit of its own.