The only way to this feat lay for him through the conviction that beauty does not express anything absolute, but something that changes with circumstances and with men; that beauty, like everything that is subject to evolution, is constantly changing. Yesterday's beauty is not to-day's beauty. Beauty is no more opposed than anything else to that tendency to spiritualisation which is the most characteristic symptom ind result of all culture. Physiologists have proved that the physical strength of modern man is inferior to that of his ancestors, but that his nervous system is more developed, so that strength is more and more concentrated in the intellect. The Hellenic hero was the wrestler, the expression of a body harmoniously developed in every limb, the perfection of strength and skill; the hero of our time is the thinker, the ideal of intellectual strength and suppleness. And since our only way of estimating the perfection of things is by the ideal of our personal feeling, the form of beauty likewise has been transformed and become intellectual. And even when we seek it in the body, as, for instance, in the ideal woman's figure, we have grown accustomed to seeing perfection not so much in robustness and plumpness as in a noble, slender play of lines which mysteriously expresses the soul. Beauty is turning away more and more from the outer surface, from the physical, to the interior aspects, to the psychic. In proportion as motive forces hide themselves and as harmony becomes less obvious, beauty intellectualises itself. It is becoming for us not so much a beauty of appearance as a beauty of; aim. If we are to admire the telegraph or the telephone, we shall not be satisfied with considering the exterior forms, the network of wires, the keys, the receivers; we shall be impressed rather by the ideal beauty, by the idea of a vibrating spark leaping over countries and whole continents. A machine is not wonderful on, account of its rattling, rusty, iron framework, but by the idea, deep-seated in its body, which is the principle of its magical activity. A modern idea of beauty must be adapted not only to the idea of beauty of the past, but also to that of the future. And the future of æsthetics is a kind of ideology, or, as Renan expresses it, an identity with the sciences. We shall lose the habit of understanding things only by our senses, of seeing their harmony only on their exterior surface, and we shall have to learn how to conceive their intellectual aims, their inner form, their psychic organisation, as beauty.