Identical external events result sometimes in different human responses, and different external events produce sometimes the same human response. We do not know why. In the face of this state of affairs we cannot help withholding judgment on the essential statements of monism and materialism. We may or may not believe that the natural sciences will succeed one day in explaining the production of definite ideas, judgments of value, and actions in the same way in which they explain the production of a chemical compound as the necessary and unavoidable outcome of a certain combination of elements. In the meantime we are bound to acquiesce in a methodological dualism.
Human action is one of the agencies bringing about change.
It is an element of cosmic activity and becoming. Therefore it is a legitimate object of scientific investigation. It is true that the changes brought about by human action are but trifling when compared with the effects of the operation of the great cosmic forces. From the point of view of eternity and the infinite universe man is an infinitesimal speck. But for man human action and its vicissitudes are the real thing.