I am sure I am not wrong in stating this result as one of the fundamental conclusions to which the entire drift of modern physiological investigation sweeps us. If asked what great contribution physiology has made to psychology of late years, I am sure every competent authority will reply that her influence has in no way been so weighty as in the copious illustration, verification, and consolidation of this broad, general point of view. I invite you, then, to consider what may be the possible speculative consequences involved in this great achievement of our generation. Already, it dominates all the new work done in psychology; but {115} what I wish to ask is whether its influence may not extend far beyond the limits of psychology, even into those of theology herself. The relations of the doctrine of reflex action with no less a matter than the doctrine of theism is, in fact, the topic to which I now invite your attention. We are not the first in the field. There have not been wanting writers enough to say that reflex action and all that follows from it give the _coup de grâce_ to the superstition of a God. If you open, for instance, such a book on comparative psychology, as der Thierische Wille of G. H. Schneider, you will find, sandwiched in among the admirable dealings of the author with his proper subject, and popping out upon us in unexpected places, the most delightfully _naïf_ German onslaughts on the degradation of theologians, and the utter incompatibility of so many reflex adaptations to the environment with the existence of a creative intelligence. There was a time, remembered by many of us here, when the existence of reflex action and all the other harmonies between the organism and the world were held to prove a God. Now, they are held to disprove him. The next turn of the whirligig may bring back proof of him again. Into this debate about his existence, I will not pretend to enter. I must take up humbler ground, and limit my ambition to showing that a God, whether existent or not, is at all events the kind of being which, if he did exist, would form _the most adequate possible object_ for minds framed like our own to conceive as lying at the root of the universe. My thesis, in other words, is this: that some outward reality of {116} a nature defined as God's nature must be defined, is the only ultimate object that is at the same time rational and possible for the human mind's contemplation. _Anything short of God is not rational, anything more than God is not possible_, if the human mind be in truth the triadic structure of impression, reflection, and reaction which we at the outset allowed.