In inquiring into the reason which has made the theory of evolution seemingly so barren in its ethical consequences, the first point which requires attention is that the characteristics of Unity, Variety, and Continuity are treated by it not as principles involved in development, but as theories inferred from, or superinduced upon, the facts of development. We are led by facts to suppose certain hypothetical laws--namely, that organisms tend to harmony with their environment, but that there are certain causes promoting variation, and, consequently, that the history of all life is that of a continuous process towards more comprehensive uniformities, passing always into more intricate variations. Additional facts are compared with these hypothetical causes, and, by their ability to explain such facts, the hypotheses are raised to the position of laws of nature, and are confidently applied to account for new phenomena of the same kind. But when we pass beyond facts lying immediately on the plane of those from which our laws have been gathered, it is to follow an insufficient analogy if we interpret them by theories only shown to belong to the former order. And this becomes still more obvious when the change is not merely to a different order of facts, but to a different way of looking at facts, as is the case in the transition from the point of view of knowledge to that of action. [Sidenote: not as depending on a principle implied in experience;] But there is another way in which the principles of Unity, Variety, and Continuity may be regarded. Instead of being simply generalisations gathered from experience and depending upon it, they may be founded on a principle which is itself the basis of the possibility of experience. Of course, no one would think of denying that it is to the accumulated mass of experienced facts that these laws owe their prominence in modern scientific opinion, and their acceptance by the judgment of the best scientists. But the process by which a man has been led to lay hold of such principles is one thing; their logical position in relation to experience quite another. Our definite recognition of the laws may very well be the result of experience, at the same time that the principle of Continuity is presupposed in our having experience at all. As long as we kept to the ground from which we started, and did not attempt to get beyond the categories of causality and reciprocity, our progress might seem to be easy enough. Although their logical relations may be misconceived, the laws are, of course, actually there, in experience: their application to the successive phenomena of nature remains the same, and may be duly apprehended. The extension of facts into laws is explained by the scientific imagination, and we do not stay to inquire into the conditions on which the scientific imagination works and has applicability to experience. But, when we try to pass from efficient cause to the notion of purpose or of morality,