Outward manifestation of instinct can be best observed in animals, where the part it plays is most significant; but it is in ourselves alone that we can get to know its internal process, as of everything internal. It is true, it is thought that man has scarcely any instinct at all, or at any rate has only sufficient instinct when he is born to seek and take his mother's breast. But as a matter of fact man has a very decided, clear, and yet complicated instinct--namely, for the selection, both earnest and capricious, of another individual, to satisfy his instinct of sex. The beauty or ugliness of the other individual has nothing whatever to do with this satisfaction in itself, that is in so far as it is a matter of pleasure based upon a pressing desire of the individual. The regard, however, for this satisfaction, which is so zealously pursued, as well as the careful selection it entails, has obviously nothing to do with the chooser himself, although he fancies that it has. Its real aim is the child to be born, in whom the type of the species is to be preserved in as pure and perfect a form as possible. For instance, different phases of degeneration of the human form are the consequences of a thousand physical accidents and moral delinquencies; and yet the genuine type of the human form is, in all its parts, always restored; further, this is accomplished under the guidance of the sense of beauty, which universally directs the instinct of sex, and without which the satisfaction of the latter would deteriorate to a repulsive necessity. Accordingly, every one in the first place will infinitely prefer and ardently desire those who are most beautiful--in other words, those in whom the character of the species is most purely defined; and in the second, every one will desire in the other individual those perfections which he himself lacks, and he will consider imperfections, which are the reverse of his own, beautiful. This is why little men prefer big women, and fair people like dark, and so on. The ecstasy with which a man is filled at the sight of a beautiful woman, making him imagine that union with her will be the greatest happiness, is simply the _sense of the species_. The preservation of the type of the species rests on this distinct preference for beauty, and this is why beauty has such power.