The reasons why these games can produce love are subtle, but clear, once considered. The first reason is connected simply with pleasure, the second with human expression. When two people are responsible for producing inordinate mutual pleasure, it is natural for them to become deeply involved emotionally. Particularly is this the case when they realize that such a partner is almost unique. Such a partner is not simply another interchangeable unit, of which most of our marriages seem composed. Such a partner is a rarity. He, or she, is a jewel. The second reason is as honest as the first but, due to the lies we tell about ourselves, less likely to be accepted. It is that in all human beings there are exploitative elements, and elements of a desire to be the object of exploitation. In the crueler language of psychology in every human being there are certain sadistic elements and certain masochistic elements. These differ in amount and degree among human beings but they exist in all. Those with less of these elements are not, ipso facto, better than those with more. They may simply be more bland individuals, weaker, less alive, less deep. On the other hand, it is not the objective of these remarks either to commend or castigate these innate human tendencies. They are as natural as those of the cat and the wolf. The higher human being, if we must put people on ladders, is probably the deep, fierce, energetic individual, of high intelligence, who controls these powerful elements in himself. He rides mighty horses, but holds their reins in his hands. Morality for him is a victory, not the result of a slow metabolism. There is agreement that human beings should be kind, and moral and honest. There is also agreement that the human being is the sort of animal that often finds it hard to be these things. That he finds it hard to be these things is not the result presumably, of a prehistoric incident in a Middle Eastern garden, or of the temptation of devils. As Nietzsche recognized long ago, man does not need devils. He has his own. Man’s defense against himself has been love and rationality. It is still the best we have. They are all he has to pit against himself.

Few people today think much about evolution, but it holds the key to why certain complex aggregations of molecules survive and others do not.