It will be remembered that Kant's criticism had denied the human mind all knowledge of things in themselves, and that the post-Kantian systems had been so many efforts to get at the Absolute in its despite. But none had stated the question at issue so clearly as Schopenhauer put it, or answered it in such luminous terms. Like theirs, his solution is idealist; but the idealism is constructed on new lines. If we know nothing else, we know ourselves; only it has to be ascertained what exactly we are. Hegel said that the essence of consciousness is reason, and that reason is the very stuff of which the world is made. No, replies Schopenhauer, that is a one-sided scholastic view. Much the most important part of ourselves is _not_ reason, but that very unreasonable thing called will--that aimless, hopeless, infinite, insatiable craving which is the source of all our activity and of all our misery as well. _This_ is the thing-in-itself, the timeless, inextended entity behind all phenomena, come to the consciousness of itself, but also of its utter futility, in man. {120} The cosmic will presents itself to us objectively under the form of the great natural forces--gravitation, heat, light, electricity, chemical affinity, etc.; then as the organising power of life in vegetables and animals; finally as human self-consciousness and sociability. These, Schopenhauer says, are what is really meant by the Platonic ideas, and they figure in his philosophy as first differentiations of the primordial will, coming between its absolute unity and the individualised objects and events that fill all space and time. It is the function of architecture, plastic art, painting, and poetry to give each of these dynamic ideas, singly or in combination, its adequate interpretation for the æsthetic sense. One art alone brings us a direct revelation of the real world, and that is music. Musical compositions have the power to express not any mere ideal embodiment of the underlying will, but the will itself in all its majesty and unending tragic despair.