The lowest kind of sexual drive is concerned solely with finding, by any means and through any person, momentary release and physical satisfaction. It is biological, what man shares with the animals for continuing the race; yet it is often rendered obscene in him by its combination with cunning or fancy. In a superior kind of drive, it is mingled with emotional, aesthetic, and romantic feelings and begins to free itself from confinement to the crude animal attraction alone. This is the specifically human stage of sex life, where not any kind of woman, but only certain kinds, allure: love of two human beings for each other, emotional response between them, now complements the lust of two animals for each other. In the sexual union of two human beings who have reached this second level, each is called upon to receive the other into himself or herself, that is, to fall in love once again and quite afresh. The experience may be and usually is quite a fleeting one. But it will always arouse much ecstatic feeling and tender conduct. It is egoistic, and therefore subject to the vacillations and selfishnesses, the illusions and exploitations which the personal ego shows in its social relations generally. With evolutionary growth, the third stage marks a further change in the kind of satisfaction the sexual drive desires. Intellectual, moral, and cultural affinity is the attraction at this level. The highest aims of the egos must harmonize.
-- Perspectives > Chapter 5: The Body > # 32