taste for art is merely a disguised form of sexual desire. They might as well say that it is a disguised form of hunger, since artists are quite as notorious for being hungry as for being erotic, and artistic tastes are never found to exist in a man who takes no nourishment. Not only much modern psychology, but some other modern sciences such as comparative religion, are prone to a certain fallacy that may be called the fallacy of “explanation by origins”. This kind of explanation has been made popular by the theory of evolution, and the fallacy consists in supposing that to give the historical antecedents of a thing is to give an analysis of that thing. Thus, some authorities suppose that by showing that religion has developed from primitive magic rites, they have thereby proved that religion is nothing but a disguised form of magic. One might as well say that an oak-tree is a disguised form of an acorn, or that a man is a disguised form of an amoeba. But this error is too glaring to be committed by more than a small percentage of our modern “thinkers”. A much more insidious danger is that this type of explanation leads one to under-estimate the complexity of the thing to be explained. There is a tendency to neglect those factors in the final product which cannot be traced in its historical antecedents. This is one form of the widespread error of undue simplification. No human mind can deal exhaustively with concrete facts. Every natural entity, whether it be a flower or a nation, contains far too many factors for thought to grasp it completely. The art of human thinking is to make useful abstractions. Any man is a very complicated creature. All the artists and scientists of the world could not describe him exhaustively. But for the purposes of war every man under a certain military rank was regarded as a physical structure supporting weapons and a stomach on two legs. This abstraction was useful for the purposes for which it was invented. A somewhat different abstraction is required when a man is considered as a voter. When a man is considered as a “hand” or a “worker” it is found that slightly more complicated abstractions are required. In fact, the great fault of economic theory has been that its “economic man” was too simple an abstraction. The economist left out certain factors in his conception of man, with the result that his plans, when applied to real men, do not work. I am suggesting that the sciences which ape physics suffer, amongst other things, from inadequate abstractions. This is not surprising, for there is every reason to suppose that the extraordinary difficulties experienced by physics itself, at the present day, are due to the same cause. An analysis of this position will show us the direction of the probable future development of science and help us to see in what consists the importance of the arts. 5