Page:Philosophical Review Volume 15.djvu/154

136 the symptoms of hidden brain action, it would seem rational to study the symptoms in order to get at the underlying causes; indeed, that would seem the only possible way. In short, the brain physiologist cannot take a step in the construction of his hypotheses without a knowledge of mind, that is, psychology. If his psychology be crude, his brain theories will be crude: they must needs conform to his psychological beliefs. One of the most glaring examples of this truth is the theory of phrenology. To quote from Professor Höffding's recent book on the Problems of Philosophy; "If it is desired to supersede psychological definitions by physiological, it is evidently presupposed that psychological definitions are already in existence. The creation of these definitions must be the part of psychology; and if it can itself make no clear-cut definitions, assuredly physiology cannot ascertain for it what it should seek in the brain an explanation for. If what is to be superseded be vague and uncertain, then what supersedes it will likewise be vague and uncertain. And we cannot derive certainty from the fact that we have actually discovered the brain states which correspond to psychical manifestations observed in the act. The independence of psychology must be recognized in any event, since it prescribes—like a kind of symptomatology—the work of physiology. It is a long and difficult task to find adequate definitions in any experimental science; they only become possible when the science has actually reached completeness; they come at the end, not at the beginning of the investigation. Only too often have crude psychological definitions been considered trustworthy starting points for the investigations of brain physiology."

If, however, our knowledge of the physiological causes were so profound that we could deduce from them their psychical effects without paying any attention to the mental processes as we now do in psychology, then indeed the physiologist could afford to ignore psychology. But there would still remain another way of studying the mind, a more direct way, in which we should come face to face with the states deduced by the scientist, and this too would be interesting if only as an experimental verification of the