Ethical writers, like biologists, are no longer concerned with the mere fact of evolution. They are dealing with more specific questions of causes and methods. And, as with biology, two stages in the study may be expected. Biologists were at first interested in the historical question: What was the origin of species? They were temporarily satisfied with the answer: Natural selection, operating in conjunction with heredity and variation. Now, however, a clue to the specific method of heredity has been found in Mendelism, the causes operative in producing variation are being discovered by experimentation, and biology is entering upon a constructive stage which promises great results for agriculture, and perhaps also for human health and well-being. Ethics is as yet almost entirely in the descriptive stage. Perhaps we are staggered at the complexity of present problems, and timidly leave to the practical reformer or politician the responsible task of making positive suggestions. But, when the past evolution has been thoroughly analyzed, it may be hoped that social reform and moral education will be more intelligent. The interest of these problems for the student of religion is also obvious. For, to illustrate by one suggestion out of many, we ask: What causes the difference in the ideals of different ages and races? Is it religion, or philosophy, or economic needs and conditions solely? And shall the religious teacher who would hasten the Kingdom of God appeal to the conscience or to the legislature, or, in the conviction that neither of these avails, shall he stand still and wait for the inventor and the inevitable social revolution? It would be absurd to say that we are yet in a position to answer this old question conclusively, but it is not too much to say that no one can now afford to give dogmatic answers without first considering the complexity of the interaction which is increasingly coming into view between religious, political, economic, aesthetic, and ethical factors.