Page:Philosophical Review Volume 15.djvu/155

137 results of brain physiology. In the meanwhile, there is no such science as is here spoken of, and it would be unreasonable to ask us to postpone the consideration of the problems of logic, ethics, metaphysics, and all other subjects rooted in psychology until we can deduce them from the mechanics of the brain. Professor Stout is right: "Such a demand is logically parallel to a demand that history or biography, or the practical estimation of character and anticipation of men's actions in ordinary life; shall come to a standstill until they have a sufficient physiological basis. On this view Carlyle should have abstained from writing his French Revolution, because he did not know what precise configuration and motion of brain particles determined the actions of the mob who stormed the Bastille."

We have said that so long as there is coherence in the mental world, uniformity of coexistence and sequence, psychology will have work to do. But, the objection is urged, the mental series does not form a continuous line, there are breaches in it, and you cannot therefore explain mental states by themselves. Unless you are willing to assume creation out of nothing, you must go to physiology for help. In the one case, you have no science at all; in the other, it becomes a branch of natural science. Not only can no uniformity be discovered in the psychical realm, there can be none in the very nature of things. For the cortical processes depend on the subcortical processes; therefore the excitations in the cortex do not form an unbroken causal series, because many of their causes lie in the subcortical region. And hence, since the subcortical activities are not accompanied by consciousness, the conscious processes of the cortex must show gaps. The mental world, in other words, does not form an unbroken causal nexus and cannot be understood without reference to matter. In external nature alone can there be a closed causal chain, here alone can there be true science. In order to be scientific psychology must become physiology.

The following answer may be given to this argument. The appeal of one science to another for aid is not equivalent to a surrender of its autonomy. By referring certain mental phenomena