(1) There can be no doubt that he refers the mind to the body in some way, although he may shake his head over the use of the word "in."
(2) As to whether the mind acts and reacts with matter, in any sense of the words a.n.a.logous to that in which they are commonly used, there is a division in the camp. Some affirm such interaction; some deny it. The matter will be discussed in the next chapter.
(3) The psychologist--the more modern one--inclines to repudiate any substance or substratum of the sort accepted in the Middle Ages and believed in by many men now. To him the mind is the whole complex of mental phenomena in their interrelations. In other words, the mind is not an unknown and indescribable something that is merely inferred; it is something revealed in consciousness and open to observation.
(4) The psychologist is certainly not inclined to regard the mind or any idea belonging to it as material or as extended. But he does recognize implicitly, if not explicitly, that ideas are composite. To him, as to the plain man, the image held in the memory or imagination _seems_ to be extended, and he can distinguish its parts. He does not do much towards clearing away the difficulty alluded to at the close of the last section. It remains for the metaphysician to do what he can with it, and to him we must turn if we wish light upon this obscure subject.
34. THE METAPHYSICIAN AND THE MIND.--I have reserved for the next chapter the first two points mentioned as belonging to the plain man"s doctrine of the mind. In what sense the mind may be said to be in the body, and how it may be conceived to be related to the body, are topics that deserve to be treated by themselves in a chapter on "Mind and Body." Here I shall consider what the metaphysician has to say about the mind as substance, and about the mind as nonextended and immaterial.
It has been said that the Lockian substance is really an "unknowable."
No one pretends to have experience of it; it is revealed to no sense; it is, indeed, a name for a mere nothing, for when we abstract from a thing, in thought, every single quality, we find that there is left to us nothing whatever.
We cannot say that the substance, in this sense of the word, is the _reality_ of which the qualities are _appearances_. In Chapter V we saw just what we may legitimately mean by realities and appearances, and it was made clear that an unknowable of any sort cannot possibly be the reality to which this or that appearance is referred. Appearances and realities are experiences which are observed to be related in certain ways. That which is not open to observation at all, that of which we have, and can have, no experience, we have no reason to call the reality of anything. We have, in truth, no reason to talk about it at all, for we know nothing whatever about it; and when we do talk about it, it is because we are laboring under a delusion.
This is equally true whether we are concerned with the substance of material things or with the substance of minds. An "unknowable" is an "unknowable" in any case, and we may simply discard it. We lose nothing by so doing, for one cannot lose what one has never had, and what, by hypothesis, one can never have. The loss of a mere word should occasion us no regret.
Now, we have seen that we do not lose the world of real material things in rejecting the "Unknowable" (Chapter V). The things are complexes of qualities, of physical phenomena; and the more we know about these, the more do we know about real things.
But we have also seen (Chapter IV) that physical phenomena are not the only phenomena of which we have experience. We are conscious of mental phenomena as well, of the phenomena of the subjective order, of sensations and ideas. Why not admit that these _const.i.tute_ the mind, as physical phenomena const.i.tute the things which belong to the external world?
He who says this says no more than that the mind is known and is knowable. It is what it is perceived to be; and the more we know of mental phenomena, the more do we know of the mind. Shall we call the mind as thus known a _substance_? That depends on the significance which we give to this word. It is better, perhaps, to avoid it, for it is fatally easy to slip into the old use of the word, and then to say, as men have said, that we do not know the mind as it is, but only as it appears to us to be--that we do not know the reality, but only its appearances.
And if we keep clearly before us the view of the mind which I am advocating, we shall find an easy way out of the difficulties that seem to confront us when we consider it as nonextended and immaterial.
Certain complexes of mental phenomena--for example, the barber"s pole above alluded to--certainly appear to be extended. Are they really extended? If I imagine a tree a hundred feet high, is it really a hundred feet high? Has it any real size at all?
Our problem melts away when we realize what we mean by this "real size." In Chapter V, I have distinguished between apparent s.p.a.ce and real s.p.a.ce. Real s.p.a.ce is, as was pointed out, the "plan" of the real physical world. To occupy any portion of real s.p.a.ce, a thing must be a real external thing; that is, the experiences const.i.tuting it must belong to the objective order, they must not be of the cla.s.s called mental. We all recognize this, in a way. We know that a real material foot rule cannot be applied to an imaginary tree. We say, How big did the tree seen in a dream _seem_; we do not say, How big was it _really_? If we did ask such a question, we should be puzzled to know where to look for an answer.
And this for a very good reason. He who asks: How big was that imaginary tree really? asks, in effect: How much real s.p.a.ce did the unreal tree fill? The question is a foolish one. It a.s.sumes that phenomena not in the objective order are in the objective order. As well ask how a color smells or how a sound looks. When we are dealing with the material we are not dealing with the mental, and we must never forget this.
The tree imagined or seen in a dream seems extended. Its extension is _apparent_ extension, and this apparent extension has no place in the external world whatever. But we must not confound this apparent extension with a real mathematical point, and call the tree nonextended in this sense. If we do this we are still in the old error--we have not gotten away from real s.p.a.ce, but have subst.i.tuted position in that s.p.a.ce for extension in that s.p.a.ce. Nothing mental can have even a position in real s.p.a.ce. To do that it would have to be a real thing in the sense indicated.
Let us, then, agree with the plain man in affirming that the mind is nonextended, but let us avoid misconception. The mind is const.i.tuted of experiences of the subjective order. None of these are in s.p.a.ce--real s.p.a.ce. But some of them have apparent extension, and we must not overlook all that this implies.
Now for the mind as immaterial. We need not delay long over this point. If we mean by the mind the phenomena of the subjective order, and by what is material the phenomena of the objective order, surely we may and must say that the mind is immaterial. The two cla.s.ses of phenomena separate themselves out at once.
[1] "The Pa.s.sions," Articles 34 and 42.
CHAPTER IX
MIND AND BODY
35. IS THE MIND IN THE BODY?--There was a time, as we have seen in the last chapter (section 30), when it did not seem at all out of the way to think of the mind as in the body, and very literally in the body.
He who believes the mind to be a breath, or a something composed of material atoms, can conceive it as being in the body as unequivocally as chairs can be in a room. Breath can be inhaled and exhaled; atoms can be in the head, or in the chest, or the heart, or anywhere else in the animal economy. There is nothing dubious about this sense of the preposition "in."
But we have also seen (section 31) that, as soon as men began to realize that the mind is not material, the question of its presence in the body became a serious problem. If I say that a chair is in a room, I say what is comprehensible to every one. It is a.s.sumed that it is in a particular place in the room and is not in some other place. If, however, I say that the chair is, as a whole, in every part of the room at once, I seem to talk nonsense. This is what Plotinus and those who came after him said about the mind. Are their statements any the less nonsensical because they are talking about minds? When one speaks about things mental, one must not take leave of good sense and utter unmeaning phrases.
If minds are enough like material things to be in anything, they must be in things in some intelligible sense of the word. It will not do to say: I use the word "in," but I do not really mean _in_. If the meaning has disappeared, why continue to use the word? It can only lead to mystification.
Descartes seemed to come back to something like an intelligible meaning when he put the mind in the pineal gland in the brain. Yet, as we have seen, he clung to the old conception. He could not go back to the frank materialization of mind.
And the plain man to-day labors under the same difficulty. He puts the mind in the body, in the brain, but he does not put it there frankly and unequivocally. It is in the brain and yet not exactly in the brain. Let us see if this is not the case.
If we ask him: Does the man who wags his head move his mind about? does he who mounts a step raise his mind some inches? does he who sits down on a chair lower his mind? I think we shall find that he hesitates in his answers. And if we go on to say: Could a line be so drawn as to pa.s.s through your image of me and my image of you, and to measure their distance from one another? I think he will say, No. He does not regard minds and their ideas as existing in s.p.a.ce in this fashion.
Furthermore, it would not strike the plain man as absurd if we said to him: Were our senses far more acute than they are, it is conceivable that we should be able to perceive every atom in a given human body, and all its motions. But would he be willing to admit that an increase in the sharpness of sense would reveal to us directly the mind connected with such a body? It is not, then, in the body as the atoms are. It cannot be seen or touched under any conceivable circ.u.mstances.
What can it mean, hence, to say that it is _there_? Evidently, the word is used in a peculiar sense, and the plain man cannot help us to a clear understanding of it.
His position becomes intelligible to us when we realize that he has inherited the doctrine that the mind is immaterial, and that he struggles, at the same time, with the tendency so natural to man to conceive it after the a.n.a.logy of things material. He thinks of it as in the body, and, nevertheless, tries to dematerialize this "in." His thought is sufficiently vague, and is inconsistent, as might be expected.
If we will bear in mind what was said in the closing section of the last chapter, we can help him over his difficulty. That mind and body are related there can be no doubt. But should we use the word "in" to express this relation?
The body is a certain group of phenomena in the objective order; that is, it is a part of the external world. The mind consists of experiences in the subjective order. We have seen that no mental phenomenon can occupy s.p.a.ce--real s.p.a.ce, the s.p.a.ce of the external world--and that it cannot even have a position in s.p.a.ce (section 34).
As mental, it is excluded from the objective order altogether. The mind is not, then, strictly speaking, _in_ the body, although it is related to it. It remains, of course, to ask ourselves how we ought to conceive the relation. This we shall do later in the present chapter.
But, it may be said, it would sound odd to deny that the mind is in the body. Does not every one use the expression? What can we subst.i.tute for it? I answer: If it is convenient to use the expression let us continue to do so. Men must talk so as to be understood. But let us not perpetuate error, and, as occasion demands it, let us make clear to ourselves and to others what we have a right to understand by this _in_ when we use it.
36. THE DOCTRINE OF THE INTERACTIONIST.--There is no man who does not know that his mind is related to his body as it is not to other material things. We open our eyes, and we see things; we stretch out our hand, and we feel them; our body receives a blow, and we feel pain; we wish to move, and the muscles are set in motion.
These things are matters of common experience. We all perceive, in other words, that there is an interaction, in some sense of the term, between mind and body.
But it is important to realize that one may be quite well aware of all such facts, and yet may have very vague notions of what one means by body and by mind, and may have no definite theory at all of the sort of relation that obtains between them. The philosopher tries to attain to a clearer conception of these things. His task, be it remembered, is to a.n.a.lyze and explain, not to deny, the experiences which are the common property of mankind.
In the present day the two theories of the relation of mind and body that divide the field between them and stand opposed to each other are _interactionism_ and _parallelism_. I have used the word "interaction"
a little above in a loose sense to indicate our common experience of the fact that we become conscious of certain changes brought about in our body, and that our purposes realize themselves in action. But every one who accepts this fact is not necessarily an interactionist.
The latter is a man who holds a certain more or less definite theory as to what is implied by the fact. Let us take a look at his doctrine.
Physical things interact. A billiard ball in motion strikes one which has been at rest; the former loses its motion, the latter begins to roll away. We explain the occurrence by a reference to the laws of mechanics; that is to say, we point out that it is merely an instance of the uniform behavior of matter in motion under such and such circ.u.mstances. We distinguish between the state of things at one instant and the state of things at the next, and we call the former _cause_ and the latter _effect_.
It should be observed that both cause and effect here belong to the one order, the objective order. They have their place in the external world. Both the b.a.l.l.s are material things; their motion, and the s.p.a.ce in which they move, are aspects of the external world.
If the b.a.l.l.s did not exist in the same s.p.a.ce, if the motion of the one could not be towards or away from the other, if contact were impossible, we would manifestly have no interaction _in the sense of the word employed above_. As it is, the interaction of physical things is something that we can describe with a good deal of definiteness.
Things interact in that they stand in certain physical relations, and undergo changes of relations according to certain laws.
Now, to one who conceives the mind in a grossly material way, the relation of mind and body can scarcely seem to be a peculiar problem, different from the problem of the relation of one physical thing to another. If my mind consists of atoms disseminated through my body, its presence in the body appears as unequivocal as the presence of a dinner in a man who has just risen from the table. Nor can the interaction of mind and matter present any unusual difficulties, for mind is matter. Atoms may be conceived to approach each other, to clash, to rearrange themselves. Interaction of mind and body is nothing else than an interaction of bodies. One is not forced to give a new meaning to the word.
When, however, one begins to think of the mind as immaterial, the case is very different. How shall we conceive an immaterial thing to be related to a material one?
Descartes placed the mind in the pineal gland, and in so far he seemed to make its relation to the gland similar to that between two material things. When he tells us that the soul brings it about that the gland bends in different directions, we incline to view the occurrence as very natural--is not the soul in the gland?
But, on the other hand, Descartes also taught that the essence of mind is _thought_ and the essence of body is _extension_. He made the two natures so different from each other that men began to ask themselves how the two things could interact at all. The mind wills, said one philosopher, but that volition does not set matter in motion; when the mind wills, G.o.d brings about the appropriate change in material things.
The mind perceives things, said another, but that is not because they affect it directly; it sees things in G.o.d. Ideas and things, said a third, const.i.tute two independent series; no idea can cause a change in things, and no thing can cause a change in ideas.
The interactionist is a man who refuses to take any such turn as these philosophers. His doctrine is much nearer to that of Descartes than it is to any of theirs. He uses the one word "interaction" to describe the relation between material things and also the relation between mind and body, nor does he dwell upon the difference between the two. He insists that mind and matter stand in the one causal nexus; that a change in the outside world may be the _cause_ of a perception coming into being in a mind, and that a volition may be the _cause_ of changes in matter.