Page:Philosophical Review Volume 15.djvu/151

133 The fact, however, that mental states can be studied in connection with matter does not make psychology a branch of physics or biology, any more than it makes the latter a branch of the former. A perfect knowledge of the physical and physiological counterparts of mind would not give us a knowledge of the mind as such. Even if we could tell all about the brain and what takes place inside and outside of it, we should never come face to face with a thought or a feeling in this field, for a thought or a feeling is quite different from a molecular motion in the brain or anywhere else. "The most accurate knowledge of the processes in the nerve substance could not give us an idea of the corresponding psychical facts if we did not possess it otherwise." The physiologist, limiting himself to a study of the brain, would, to quote Professor Jodl, know as little of mind as a deaf and dumb man would know of music by studying the score of a musical composition. So long as there are thoughts and feelings and volitions, and so long as these can be reduced to law, there will be room for a specific science with the business of studying these phenomena in its own way. Whether the physiologist regards the mind as a principle of explanation, as he once did, and explains all animal and human movements by means of it, whether he casts it aside as useless for his purposes and seeks to reduce all such activity to brain machinery, or whether he makes consciousness a by-product of the brain to be accounted for mechanically, his chief interest lies in the domain of matter, while "the distinctive aim of the psychologist is," as Professor Stout says, "to investigate mental events themselves, not their mechanical accompaniments or antecedents." Call mind what you please, call it an effect or another aspect of matter, call it a distinct principle or entity alongside of matter, or a manifestation of something behind them both, call it the sole reality and matter its appearance, it is a unique fact and deserves to be investigated as such. You can ignore it if you choose; you can decide to pay attention only to its material accompaniments and antecedents, but you cannot do this and be a psychologist. But, says an objector, the physiological processes are, after