In the second place it must be pointed out that the _X_ factor, conceived as it is in this book, though Prof. Kellogg may call it ‘mystic’ if he likes, is certainly anything but ‘unknown.’ There is nothing more mystic than the human spirit—does not mysticism mean the attribution of spiritual significance to material things?—but there is nothing more real and certain. The very act of knowing, however material or mechanical may be the object of knowledge, is an act of the spirit, and we know the spirit itself better than anything else. How did this spirit come into active being? There are only two conceivable ways. Either it was at a certain moment projected into the universe from without by a Supreme Spirit, or it was, like everything else, evolved. If we accept the former view we may say good-bye to science. Miraculous interventions will explain anything, and if we admit them in one case they may be valid everywhere. But if we take the second view, as do practically all men of science, we are bound to admit that spirit had from the beginning some constant and natural relation to matter, for evolution does not work miracles—it cannot make something out of nothing. If, then, we regard Man not as an outside observer of the universe but as an organic part of it—and I believe no thinking about nature can be of any value until we have grasped and fully realized that position—then there can be nothing to surprise us if we find traces of a directive control in the elementary processes of life and development. It would be more surprising if we did not. If we reduce the whole universe, apart from the human spirit, to physico-chemical processes we are at once confronted with the problem of evolving the human spirit out of such processes; and that, on the face of it, is a sheer impossibility. All physical and all chemical phenomena as such are reducible to the movements and groupings of atoms and molecules. These movements and groupings can affect the spirit which finds itself mysteriously implicated in their activity, and the spirit can affect them. But that molecular movements can _create_ spirit is unthinkable by any one who realizes what spirit is and what movement. Rather should we say that in the power of movement, in action, change of any kind, we are to see the evidences of spirit.