The ideal of liberty never entered the minds of the most advanced peoples of antiquity; their most enlightened political thinkers could not imagine a State which was not founded upon slavery. Yet it has become collectively accepted by all the leading nations, and the ordinary man has so entirely accepted it that he cannot be brought to reason about it. Facts and arguments tending to show that the greater part of the population of the world might be happier without liberty and under some form of slavery cannot touch or enter his mind at all. The ideal of political equality is of still later growth, and is in a sense derivative from that of liberty; it was in the main accepted as a means to liberty, but has become an end in itself. It is moulding national organisation everywhere; through its influence parliamentary government and universal suffrage are becoming the almost universal rule, and, through leading to their adoption, this ideal is in a fair way to wreck certain of the less firmly organised nations, and possibly our own also. But the ideal which, beyond all others, characterises the present age of almost all the nations of the world is the ideal of progress. Hardly anyone has any clear notion what he means by progress, or could explicate the idea; but the sentiment is very strong, though the idea is very vague. This idea also was unknown to the leading thinkers of antiquity and is of recent growth; yet it is so almost universally accepted, and it so permeates the mental atmosphere in every direction, that it is hard for us to realise how new a thing in the history of the world is the existence, and still more the effective dominance, of the idea. It is perhaps in America that its rule is most absolute; there the severest condemnation that can be passed by the average man upon any people or institution is to say that it is fifty years behind the time. The popular enthusiasm for flying-machines, which threatens to make life almost unlivable, is one of the striking illustrations of the force of this ideal. More recent still, and perhaps equally important, is the idea of the solidarity of the human race and of the responsibility of each nation towards the rest, especially towards the weaker and more backward peoples. We no longer cheerfully and openly exterminate an inferior people; and, when we do so, it is with some expressions of regret and even of indignation. But this moral idea is still in process of finding acceptance and illustrates well that process. It has been taught by a few superior minds and none dares openly repudiate it; hence, it gains ground and is now commonly accepted, verbally at least, and is just beginning to affect national action. The four ideas, liberty, equality, progress, and human solidarity or universal responsibility, seem to be the leading ideas of the present era, the ideas which, in conjunction with national sentiments, are more than any other, fashioning the future of the world.