Consider, for example, the working of the idea of evolution, of the belief that the higher forms of life, including man, are descended from lower. A pregnant, widely related idea of this sort has a complex growth which is ever extending itself by selection and adaptation. We know that various lines of study had united, during the earlier half of the nineteenth century, to make it appear to bold thinkers that evolution from lower forms was not improbable. This idea found a point of fruitful growth when, in the thought of Darwin especially, it was brought into contact with the geological evidence of change and with the knowledge of heredity and variation accumulated by breeders of domestic species. Here it worked so vigorously that it drew the attention and investigation first of a small group and later of a great part of the scientific thought of the time. Other ideas, like that of Malthus regarding the excess of life and the struggle for existence, were co-ordinated with it, new researches were undertaken; in short, the public mind began to function largely about this doctrine and has continued to do so ever since. Just what is it that “works”? The idea implies that there is already in operation an active tendency of some sort which encounters the situation and whose character determines whether it will work there, and if so, how. In the case of the vine it is the pre-existing tendency of the tendrils to revolve in the air, to bend themselves about any object they may meet, and then to draw together like a spiral spring, which causes the vine to work as it does when it meets the wire. Indeed, to explain fully its working many other tendencies would have to be taken into account, such as that to grow more rapidly at the highest point attained, or where the light is greatest, and so on. In fact the vine has an organism of correlated tendencies whose operation under the stimulus of the particular situation is the working in question. When we speak of human life we are apt to assume that the existing tendency is some conscious purpose, and that whatever goes to realize this is “working,” and everything else is failure to work. In other words, we make the whole matter voluntary and utilitarian. This is an inadequate and for the most part a wrong conception of the case. The working of a man, or of any other human whole, in a given situation is much more nearly analogous to that of the vine than we perceive. Although conscious purpose may play a central part in it, there is also a whole organism of tendencies that feel their way about in the situation, reacting in a complex and mainly unconscious way. To put it shortly, it is a man’s character that works, and of this definite purpose may or may not be a part.