Page:Popular Science Monthly Volume 73.djvu/237

Rh necessarily in consciousness, and, in so far forth, is not causal at all. For, of nervous states as such we do not know anything, and never can know anything. Accordingly, the other side proffers its claim, which, in the light of this agnosticism, is very far from being modest. This point was admirably taken by Professor Cattell, in his vice-presidential address to the Anthropological Section of the American Association for the Advancement of Science, in 1888:

Much is being written just now regarding the relation of consciousness to the brain. The question is: Do perceptions, thoughts, feelings, volitions, stand in causal interaction with the brain, or are they an epiphenomenon, accompanying changes in the brain but not influencing them? Are our ordinary actions complex reflexes due to physical stimuli and the structure of the nervous system, or are the changes in the brain that precede movements initiated and directed by consciousness? The question is one of facts that should be settled by scientific methods; and the solution will by no means concern psychology alone. The two greatest scientific generalizations of the present century are the conservation of energy and evolution by the survival of the fit. Now, if consciousness alters, however slightly, the position of molecules in the brain the fundamental concept of physical science must be abandoned. If consciousness have no concern in the actions of the individual we have one of the most complex results of evolution developed apart from the survival of useful variations, and the Darwinian theory has failed.

We conclude then with the startling reflection that psychology is the keeper of a tremendous oracle. And, on the whole, the oracle keeps silence still.