An Introduction to Philosophy

by George Stuart Fullerton

But this conclusion is not judged sufficiently accurate by the man of science. The investigations of the physiologist and the psychologist have revealed that the brain holds a peculiar place in the economy of the body. If the nerve which connects the sense organ with the brain be severed, the sensation does not arise. Injuries to the brain affect the mental life as injuries to other parts of the body do not. Hence, it is concluded that, to get the real time of the emergence of a sensation, we must not inquire merely when an impression was made upon the organ of sense, but must determine when the message sent along the nerve has reached some part of the brain. The resulting brain change is regarded as the true concomitant of the sensation. If there is a brain change of a certain kind, there is the corresponding sensation. It need hardly be said that no one knows as yet much about the brain motions which are supposed to be concomitants of sensations, although a good deal is said about them.

It is very important to remark that in all this no new meaning has been given to the word "concomitance." The plain man remarks that sensations and their changes must be referred to the body. With the body disposed in a certain way, he has sensations of a certain kind; with changes in the body, the sensations change. He does not perceive the sensations to be in the body. As I recede from a house I have a whole series of visual experiences differing from each other and ending in a faint speck which bears little resemblance to the experience with which I started. I have had, as we say, a series of sensations, or groups of such. Did any single group, did the experience which I had at any single moment, seem to me to be in my body? Surely not. Its relation to my body is other than that.

And when the man of science, instead of referring sensations vaguely to the body, refers them to the brain, the reference is of precisely the same nature. From our common experience of the relation of the physical and the mental he starts out. He has no other ground on which to stand. He can only mark the reference with greater exactitude.

I have been speaking of the relation of sensations to the brain. It is scarcely necessary for me to show that all other mental phenomena must be referred to the brain as well, and that the reference must be of the same nature. The considerations which lead us to refer ideas to the brain are set forth in our physiologies and psychologies. The effects of cerebral disease, injuries to the brain, etc., are too well known to need mention; and it is palpably as absurd to put ideas in the brain as it is to put sensations there.

Now, the parallelist, if he be a wise man, will not attempt to explain the reference of mental phenomena to the brain—to explain the relation between mind and matter. The relation appears to be unique. Certainly it is not identical with the relation between two material things. We explain things, in the common acceptation of the word, when we show that a case under consideration is an exemplification of some general law—when we show, in other words, that it does not stand alone. But this does stand alone, and is admitted to stand alone. We admit as much when we say that the mind is immaterial, and yet hold that it is related to the body. We cannot, then, ask for an explanation of the relation.

But this does not mean that the reference of mental phenomena to the body is a meaningless expression. We can point to those experiences of concomitance that we all have, distinguish them carefully from relations of another kind, and say: This is what the word means, whether it be used by the plain man or by the man of science.

I have said above: "If there is a brain change of a certain kind, there is the corresponding sensation." Perhaps the reader will feel inclined to say here: If you can say as much as this, why can you not go a little farther and call the brain change the cause of the sensation?

But he who speaks thus, forgets what has been said above about the uniqueness of the relation. In the objective order of our experiences, in the external world, we can distinguish between antecedents and consequents, between causes and their effects. The causes and their effects belong to the one order, they stand in the same series. The relation of the physical to the mental is, as we have seen, a different relation. Hence, the parallelist seems justified in objecting to the assimilation of the two. He prefers the word "concomitance," just because it marks the difference. He does not mean to indicate that the relation is any the less uniform or dependable when he denies that it is causal.

38. IN WHAT SENSE MENTAL PHENOMENA HAVE A TIME AND PLACE.—We have seen in Chapters VI and VII what space and time—real space and time—are. They are the plan of the real external world and its changes; they are aspects of the objective order of experience.

To this order no mental phenomenon can belong. It cannot, as we have seen (section 35), occupy any portion of space or even have a location in space. It is equally true that no series of mental changes can occupy any portion of time, real time, or even fill a single moment in the stream of time. There are many persons to whom this latter statement will seem difficult of acceptance; but the relation of mental phenomena to space and to time is of the same sort, and we can consider the two together.