An Introduction to Philosophy, George Stuart Fullerton [books to read in your 20s .TXT] 📗

difficult to ascertain the exact point or surface at which the mind and body come together and influence each other, in particular, how far into the body (Descartes without proof thought it to be in the pineal gland), but it is certain, that when they do meet mind knows body as having its essential properties of extension and resisting energy."

How can an immaterial thing be located at some point or surface within the body? How can a material thing and an immaterial thing "come together" at a point or surface? And if they cannot come together, what have we in mind when we say they interact?

The parallelist, for it is he who opposes interactionism, insists that we must not forget that mental phenomena do not belong to the same order as physical phenomena. He points out that, when we make the word "interaction" cover the relations of mental phenomena to physical phenomena as well as the relations of the latter to each other, we are assimilating heedlessly facts of two different kinds and are obliterating an important distinction. He makes the same objection to calling the relations between mental phenomena and physical phenomena causal. If the relation of a volition to the movement of the arm is not the same as that of a physical cause to its physical effect, why, he argues, do you disguise the difference by calling them by the same name?

37. THE DOCTRINE OF THE PARALLELIST.—Thus, the parallelist is a man who is so impressed by the gulf between physical facts and mental facts that he refuses to regard them as parts of the one order of causes and effects. You cannot, he claims, make a single chain out of links so diverse.

Some part of a human body receives a blow; a message is carried along a sensory nerve and reaches the brain; from the brain a message is sent out along a motor nerve to a group of muscles; the muscles contract, and a limb is set in motion. The immediate effects of the blow, the ingoing message, the changes in the brain, the outgoing message, the contraction of the muscles—all these are physical facts. One and all may be described as motions in matter.

But the man who received the blow becomes conscious that he was struck, and both interactionist and parallelist regard him as becoming conscious of it when the incoming message reaches some part of the brain. What shall be done with this consciousness? The interactionist insists that it must be regarded as a link in the physical chain of causes and effects—he breaks the chain to insert it. The parallelist maintains that it is inconceivable that such an insertion should be made. He regards the physical series as complete in itself, and he places the consciousness, as it were, on a parallel line.

It must not be supposed that he takes this figure literally. It is his effort to avoid materializing the mind that forces him to hold the position which he does. To put the mind in the brain is to make of it a material thing; to make it parallel to the brain, in the literal sense of the word, would be just as bad. All that we may understand him to mean is that mental phenomena and physical, although they are related, cannot be built into the one series of causes and effects. He is apt to speak of them as concomitant.

We must not forget that neither parallelist nor interactionist ever dreams of repudiating our common experiences of the relations of mental phenomena and physical. Neither one will, if he is a man of sense, abandon the usual ways of describing such experiences. Whatever his theory, he will still say: I am suffering because I struck my hand against that table; I sat down because I chose to do so. His doctrine is not supposed to deny the truth contained in such statements; it is supposed only to give a fuller understanding of it. Hence, we cannot condemn either doctrine simply by an uncritical appeal to such statements and to the experiences they represent. We must look much deeper.

Now, what can the parallelist mean by referring sensations and ideas to the brain and yet denying that they are in the brain? What is this reference?

Let us come back to the experiences of the physical and the mental as they present themselves to the plain man. They have been discussed at length in Chapter IV. It was there pointed out that every one distinguishes without difficulty between sensations and things, and that every one recognizes explicitly or implicitly that a sensation is an experience referred in a certain way to the body.

When the eyes are open, we see; when the ears are open, we hear; when the hand is laid on things, we feel. How do we know that we are experiencing sensations? The setting tells us that. The experience in question is given together with an experience of the body. This is concomitance of the mental and the physical as it appears in the experience of us all; and from such experiences as these the philosopher who speaks of the concomitance of physical and mental phenomena must draw the whole meaning of the word.

Let us here sharpen a little the distinction between sensations and things. Standing at some distance from the tree, I see an apple fall to the ground. Were I only half as far away, my experience would not be exactly the same—I should have somewhat different sensations. As we have seen (section 17), the apparent sizes of things vary as we move, and this means that the quantity of sensation, when I observe the apple from a nearer point, is greater. The man of science tells me that the image which the object looked at projects upon the retina of the eye grows larger as we approach objects. The thing, then, may remain unchanged; our sensations will vary according to the impression which is made upon our body.

Again. When I have learned something of physics, I am ready to admit that, although light travels with almost inconceivable rapidity, still, its journey through space does take time. Hence the impression made upon my eye by the falling apple is not simultaneous with the fall itself; and if I stand far away it is made a little later than when I am near. In the case in point the difference is so slight as to pass unnoticed, but there are cases in which it seems apparent even to the unlearned that sensations arise later than the occurrences of which we take them to be the report.

Thus, I stand on a hill and watch a laborer striking with his sledge upon the distant railway. I hear the sound of the blow while I see his tool raised above his head. I account for this by saying that it has taken some time for the sound-waves to reach my ear, and I regard my sensation as arising only when this has been accomplished.

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