In other words, the man of science extends our knowledge and makes it more accurate; he does not analyze certain fundamental conceptions, which we all use, but of which we can usually give a very poor account.
On the other hand, it is the task of reflective thought, not in the first instance, to extend the limits of our knowledge of the world of matter and of minds, but rather to make us more clearly conscious of what that knowledge really is. Philosophical reflection takes up and tries to analyze complex thoughts that men use daily without caring to analyze them, indeed, without even realizing that they may be subjected to analysis.
It is to be expected that it should impress many of those who are introduced to it for the first time as rather a fantastic creation of problems that do not present themselves naturally to the healthy mind. There is no thoughtful man who does not reflect sometimes and about some things; but there are few who feel impelled to go over the whole edifice of their knowledge and examine it with a critical eye from its turrets to its foundations. In a sense, we may say that philosophical thought is not natural, for he who is examining the assumptions upon which all our ordinary thought about the world rests is no longer in the world of the plain man. He is treating things as men do not commonly treat them, and it is perhaps natural that it should appear to some that, in the solvent which he uses, the real world in which we all rejoice should seem to dissolve and disappear.
I have said that it is not the task of reflective thought, in the first instance, to extend the limits of our knowledge of the world of matter and of minds. This is true. But this does not mean that, as a result of a careful reflective analysis, some errors which may creep into the thought both of the plain man and of the scientist may not be exploded; nor does it mean that some new extensions of our knowledge may not be suggested.
In the chapters to follow I shall take up and examine some of the problems of reflective thought. And I shall consider first those problems that present themselves to those who try to subject to a careful scrutiny our knowledge of the external world. It is well to begin with this, for, even in our common experience, it seems to be revealed that the knowledge of material things is a something less vague and indefinite than the knowledge of minds.
II. PROBLEMS TOUCHING THE EXTERNAL WORLD
CHAPTER III
IS THERE AN EXTERNAL WORLD?
12. HOW THE PLAIN MAN THINKS HE KNOWS THE WORLD.—As schoolboys we enjoyed Cicero's joke at the expense of the "minute philosophers." They denied the immortality of the soul; he affirmed it; and he congratulated himself upon the fact that, if they were right, they would not survive to discover it and to triumph over him.
At the close of the seventeenth century the philosopher John Locke was guilty of a joke of somewhat the same kind. "I think," said he, "nobody can, in earnest, be so skeptical as to be uncertain of the existence of those things which he sees and feels. At least, he that can doubt so far (whatever he may have with his own thoughts) will never have any controversy with me; since he can never be sure I say anything contrary to his own opinion."
Now, in this chapter and in certain chapters to follow, I am going to take up and turn over, so that we may get a good look at them, some of the problems that have presented themselves to those who have reflected upon the world and the mind as they seem given in our experience. I shall begin by asking whether it is not possible to doubt that there is an external world at all.
The question cannot best be answered by a jest. It may, of course, be absurd to maintain that there is no external world; but surely he, too, is in an absurd position who maintains dogmatically that there is one, and is yet quite unable to find any flaw in the reasonings of the man who seems to be able to show that this belief has no solid foundation. And we must not forget that the men who have thought it worth while to raise just such questions as this, during the last twenty centuries, have been among the most brilliant intellects of the race. We must not assume too hastily that they have occupied themselves with mere trivialities.
Since, therefore, so many thoughtful men have found it worth while to ask themselves seriously whether there is an external world, or, at least, how we can know that there is an external world, it is not unreasonable to expect that, by looking for it, we may find in our common experience or in science some difficulty sufficient to suggest the doubt which at first strikes the average man as preposterous. In what can such a doubt take its rise? Let us see.
I think it is scarcely too much to say that the plain man believes that he does not directly perceive an external world, and that he, at the same time, believes that he does directly perceive one. It is quite possible to believe contradictory things, when one's thought of them is somewhat vague, and when one does not consciously bring them together.
As to the first-mentioned belief. Does not the plain man distinguish between his ideas of things and the things themselves? Does he not believe that his ideas come to him through the avenues of the senses? Is he not aware of the fact that, when a sense is disordered, the thing as he perceives it is not like the thing "as it is"? A blind man does not see things when they are there; a color-blind man sees them as others do not see them; a man suffering under certain abnormal conditions of the nervous system sees things when they are not there at all, i.e. he has hallucinations. The thing itself, as it seems, is not in the man's mind; it is the idea that is in the man's mind, and that represents the thing. Sometimes it appears to give a true account of it; sometimes it seems to give a garbled account; sometimes it is a false representative throughout—there is no reality behind it. It is, then, the idea that is immediately known, and not the thing; the thing is merely inferred to exist.
I do not mean to say that the plain man is conscious of drawing this conclusion. I only maintain that it seems a natural conclusion to draw from the facts which he recognizes, and that sometimes he seems to draw the conclusion half-consciously.
On the other hand, we must all admit that when the plain man is not thinking about the distinction between ideas and things, but is looking at some material object before him, is touching it with his fingers and turning it about to get a good look at it, it never occurs to him that he is not directly conscious of the thing itself.
He seems to himself to perceive the thing immediately; to perceive it as it is and where it is; to perceive it as a really extended thing, out there in space before his body. He does not think of himself as occupied with mere images, representations of the object. He may be willing to admit that his mind is in his head, but he cannot think that what he sees is in his head. Is not the object there? does he not see and feel it? Why doubt such evidence as this? He who tells him that the external world does not exist seems to be denying what is immediately given in his experience.
The man who looks at things in this way assumes, of course, that the external object is known directly, and is not a something merely inferred to exist from the presence of a representative image. May one embrace this belief and abandon the other one? If we elect to do this, we appear to be in difficulties at once. All the considerations which made us distinguish so carefully between our ideas of things and the things themselves crowd in upon us. Can it be that we know things independently of the avenues of the senses? Would a man with different senses know things just as we do? How can any man suffer from an hallucination, if things are not inferred from images, but are known independently?
The difficulties encountered appear sufficiently serious even if we keep to that knowledge of things which seems to be given in common experience. But even the plain man has heard of atoms and molecules; and if he accepts the extension of knowledge offered him by the man of science, he must admit that, whatever this apparently immediately perceived external thing may be, it cannot be the external thing that science assures him is out there in space beyond his body, and which must be a very different sort of thing from the thing he seems to perceive. The thing he perceives must, then, be appearance; and where can that appearance be if not in his own mind?
The man who has made no study of philosophy at all does not usually think these things out; but surely there are interrogation marks written up all over his experience, and he misses them only because he does not see clearly. By judiciously asking questions one may often lead him either to affirm or to deny that he has an immediate knowledge of the external world, pretty much as one pleases. If he affirms it, his position does not seem to be a wholly satisfactory one, as we have seen; and if he denies it, he makes the existence of the external world wholly a matter of inference from the presence of ideas in the mind, and he must stand ready to justify this inference.
To many men it has seemed that the inference is not an easy one to justify. One may say: We could have no ideas of things, no sensations, if real things did not exist and make an impression upon our senses. But to this it may be answered: How is that statement to be proved? Is it to be proved by observing that, when things are present and affect the senses, there come into being ideas which represent the things? Evidently such a proof as this is out of the question, for, if it is true that we know external things only by inference and never immediately, then we can never prove by observation that ideas and things are thus connected. And if it is not to be proved by observation, how shall it be proved? Shall we just assume it dogmatically and pass on to something else? Surely there is enough in the experience of the plain man to justify him in raising the question whether he can certainly know that there is an external world.
13. THE PSYCHOLOGIST AND THE EXTERNAL WORLD.—We have seen just above that the doubt regarding the existence of the world seems to have its root in the familiar distinction between ideas and things, appearances and the realities which they are supposed to represent. The psychologist has much to say about ideas; and if sharpening and making clear this distinction has anything to do with stirring up doubts, it is natural to suppose that they should become more insistent when one has exchanged the ignorance of everyday life for the knowledge of the psychologist.
Now, when the psychologist asks how a given mind comes to have a knowledge of any external thing, he finds his answer in the messages which have been brought to the mind by means of the bodily senses. He describes the sense-organs and the nervous connections between these and the brain, and tells us that when certain nervous impulses have traveled, let us say, from the eye or the ear to the brain, one has sensations of sight or sound.
He describes for us in detail how, out of such sensations and the memories of such sensations, we frame mental images of external things. Between the mental image and the thing that it represents he distinguishes sharply, and he informs us that the mind knows no more about the external thing than is contained in such images. That a thing is present can be known only by the fact that a message from the thing is sent along the nerves, and what the thing is must be determined from the character of the message. Given the image in the absence of the thing,—that is to say, an hallucination,—the mind will naturally suppose that the thing is present. This false supposition cannot be corrected by a direct inspection of the thing, for such a direct inspection of things is out of the question. The only way in which the mind concerned can discover that the thing is absent is by referring to its other experiences. This image is compared with other images and is discovered to be in some way abnormal. We decide that it is a false representative and has no corresponding reality behind it.
This doctrine taken as it stands seems to cut the mind off from the external world very completely; and the most curious thing about it is that it seems to be built up on the assumption that it is not really true. How can one know certainly that there is a world of material things, including human bodies with their sense-organs and nerves, if no mind has ever been able to inspect directly anything of the sort? How can we tell that a sensation arises when a nervous impulse has been carried along a sensory nerve and has reached the brain, if every mind is shut up to the charmed circle of its own ideas? The anatomist and the physiologist give us very detailed accounts of the sense-organs and of the brain; the physiologist even undertakes to measure the speed with which the impulse passes along a nerve; the psychologist accepts and uses the results of their labors. But can all this be done in the absence of any first-hand knowledge of the things of which one is talking? Remember that, if the psychologist is right, any external object, eye, ear, nerve, or brain, which we can perceive directly, is a mental complex, a something in the mind and not external at all. How shall we prove that there are objects, ears, eyes, nerves, and brains,—in short, all the requisite mechanism for the calling into existence of sensations,—in an outer world which is not immediately perceived but is only inferred to exist?
I do not wish to be regarded as impugning the right of the psychologist to make the assumptions which he does, and to work as he does. He has a right to assume, with the plain man, that there is an external world and that we know it. But a very little reflection must make it manifest that he seems, at least, to be guilty of an inconsistency, and that he who wishes to think clearly should strive to see just where the trouble lies.
So much, at least, is evident: the man who is inclined to doubt whether there is, after all, any real external world, appears to find in the psychologist's distinction between ideas and things something like an excuse for his doubt. To get to the bottom of the matter and to dissipate his doubt one has to go rather deeply into metaphysics. I merely wish to show just here that the doubt is not a gratuitous one, but is really suggested to the thoughtful mind by a reflection upon our experience of things. And, as we are all apt to think that the man of science is less given to busying himself with useless subtleties than is the philosopher, I shall, before closing this chapter, present some paragraphs upon the subject from the pen of a professor of mathematics and mechanics.
14. THE "TELEPHONE EXCHANGE."—"We are accustomed to talk," writes Professor Karl Pearson,[1] "of the 'external world,' of the 'reality' outside us. We speak of individual objects having an existence independent of our own. The store of past sense-impressions, our thoughts and memories, although most probably they have beside their psychical element a close correspondence with some physical change or impress in the brain, are yet spoken of as inside ourselves. On the other hand, although if a sensory nerve be divided anywhere short of the brain, we lose the corresponding class of sense impression, we yet speak of many sense-impressions, such as form and texture, as existing outside ourselves. How close then can we actually get to this supposed world outside ourselves? Just as near but no nearer than the brain terminals of the sensory nerves. We are like the clerk in the central telephone exchange who cannot get nearer to his customers than his end of the telephone wires. We are indeed worse off than the clerk, for to carry out the analogy properly we must suppose him never to have been outside the telephone exchange, never to have seen a customer or any one like a customer—in short, never, except through the telephone wire, to have come in contact with the outside universe. Of that 'real' universe outside himself he would be able to form no direct impression; the real universe for him would be the aggregate of his constructs from the messages which were caused by the telephone wires in his office. About those messages and the ideas raised in his mind by them he might reason and draw his inferences; and his conclusions would be correct—for what? For the world of telephonic messages, for the type of messages that go through the telephone. Something definite and valuable he might know with regard to the spheres of action and of thought of his telephonic subscribers, but outside those spheres he could have no experience. Pent up in his office he could never have seen or touched even a telephonic subscriber in himself. Very much in the position of such a telephone clerk is the conscious ego of each one of us seated at the brain terminals of the sensory nerves. Not a step nearer than those terminals can the ego get to the 'outer world,' and what in and for themselves are the subscribers to its nerve exchange it has no means of ascertaining. Messages in the form of sense-impressions come flowing in from that 'outside world,' and these we analyze, classify, store up, and reason about. But of the nature of 'things-in-themselves,' of what may exist at the other end of our system of telephone wires, we know nothing at all.
"But the reader, perhaps, remarks, 'I not only see an object, but I can touch it. I can trace the nerve from the tip of my finger to the brain. I am not like the telephone clerk, I can follow my network of wires to their terminals and find what is at the other end of them.' Can you, reader? Think for a moment whether your ego has for one moment got away from his brain exchange. The sense-impression that you call touch was just as much as sight felt only at the brain end of a sensory nerve. What has told you also of the nerve from the tip of your finger to your brain? Why, sense-impressions also, messages conveyed along optic or tactile sensory nerves. In truth, all you have been doing is to employ one subscriber to your telephone exchange to tell you about the wire that goes to a second, but you are just as far as ever from tracing out for yourself the telephone wires to the individual subscriber and ascertaining what his nature is in and for himself. The immediate sense-impression is just as far removed from what you term the 'outside world' as the store of impresses. If our telephone clerk had recorded by aid of a phonograph certain of the messages from the outside world on past occasions, then if any telephonic message on its receipt set several phonographs repeating past messages, we have an image analogous to what goes on in the brain. Both telephone and phonograph are equally removed from what the clerk might call the 'real outside world,' but they enable him through their sounds to construct a universe; he projects those sounds, which are really inside his office, outside his office, and speaks of them as the external universe. This outside world is constructed by him from the contents of the inside sounds, which differ as widely from things-in-themselves as language, the symbol, must always differ from the thing it symbolizes. For our telephone clerk sounds would be the real world, and yet we can see how conditioned and limited it would be by the range of his particular telephone subscribers and by the contents of their messages.
"So it is with our brain; the sounds from telephone and phonograph correspond to immediate and stored sense-impressions. These sense-impressions we project as it were outwards and term the real world outside ourselves. But the things-in-themselves which the sense-impressions symbolize, the 'reality,' as the metaphysicians wish to call it, at the other end of the nerve, remains unknown and is unknowable. Reality of the external world lies for science and for us in combinations of form and color and touch—sense-impressions as widely divergent from the thing 'at the other end of the nerve' as the sound of the telephone from the subscriber at the other end of the wire. We are cribbed and confined in this world of sense-impressions like the exchange clerk in his world of sounds, and not a step beyond can we get. As his world is conditioned and limited by his particular network of wires, so ours is conditioned by our nervous system, by our organs of sense. Their peculiarities determine what is the nature of the outside world which we construct. It is the similarity in the organs of sense and in the perceptive faculty of all normal human beings which makes the outside world the same, or practically the same, for them all. To return to the old analogy, it is as if two telephone exchanges had very nearly identical groups of subscribers. In this case a wire between the two exchanges would soon convince the imprisoned clerks that they had something in common and peculiar to themselves. That conviction corresponds in our comparison to the recognition of other consciousness."
I suggest that this extract be read over carefully, not once but several times, and that the reader try to make quite clear to himself the position of the clerk in the telephone exchange, i.e. the position of the mind in the body, as depicted by Professor Pearson, before recourse is had to the criticisms of any one else. One cannot find anywhere better material for critical philosophical reflection.
As has been seen, our author accepts without question, the psychological doctrine that the mind is shut up within the circle of the messages that are conducted to it along the sensory nerves, and that it cannot directly perceive anything truly external. He carries his doctrine out to the bitter end in the conclusion that, since we have never had experience of anything beyond sense-impressions, and have no ground for an inference to anything beyond, we must recognize that the only external world of which we know anything is an external world built up out of sense-impressions. It is, thus, in the mind, and is not external at all; it is only "projected outwards," thought of as though it were beyond us. Shall we leave the inconsistent position of the plain man and of the psychologist and take our refuge in this world of projected mental constructs?
Before the reader makes up his mind to do this, I beg him to consider the following:—
(1) If the only external world of which we have a right to speak at all is a construct in the mind or ego, we may certainly affirm that the world is in the ego, but does it sound sensible to say that the ego is somewhere in the world?
(2) If all external things are really inside the mind, and are only "projected" outwards, of course our own bodies, sense-organs, nerves, and brains, are really inside and are merely projected outwards. Now, do the sense-impressions of which everything is to be constructed "come flowing in" along these nerves that are really inside?
(3) Can we say, when a nerve lies entirely within the mind or ego, that this same mind or ego is nearer to one end of the nerve than it is to the other? How shall we picture to ourselves "the conscious ego of each one of us seated at the brain terminals of the sensory nerves"? How can the ego place the whole of itself at the end of a nerve which it has constructed within itself? And why is it more difficult for it to get to one end of a nerve like this than it is to get to the other?
(4) Why should the thing "at the other end of the nerve" remain unknown and unknowable? Since the nerve is entirely in the mind, is purely a mental construct, can anything whatever be at the end of it without being in the mind? And if the thing in question is not in the mind, how are we going to prove that it is any nearer to one end of a nerve which is inside the mind than it is to the other? If it may really be said to be at the end of the nerve, why may we not know it quite as well as we do the end of the nerve, or any other mental construct?
It must be clear to the careful reader of Professor Pearson's paragraphs, that he does not confine himself strictly to the world of mere "projections," to an outer world which is really inner. If he did this, the distinction between inner and outer would disappear. Let us consider for a moment the imprisoned clerk. He is in a telephone exchange, about him are wires and subscribers. He gets only sounds and must build up his whole universe of things out of sounds. Now we are supposing him to be in a telephone exchange, to be receiving messages, to be building up a world out of these messages. Do we for a moment think of him as building up, out of the messages which came along the wires, those identical wires which carried the messages and the subscribers which sent them? Never! we distinguish between the exchange, with its wires and subscribers, and the messages received and worked up into a world. In picturing to ourselves the telephone exchange, we are doing what the plain man and the psychologist do when they distinguish between mind and body,—they never suppose that the messages which come through the senses are identical with the senses through which they come.
But suppose we maintain that there is no such thing as a telephone exchange, with its wires and subscribers, which is not to be found within some clerk. Suppose the real external world is something inner and only "projected" without, mistakenly supposed by the unthinking to be without. Suppose it is nonsense to speak of a wire which is not in the mind of a clerk. May we under such circumstances describe any clerk as in a telephone exchange? as receiving messages? as no nearer to his subscribers than his end of the wire? May we say that sense-impressions come flowing in to him? The whole figure of the telephone exchange becomes an absurdity when we have once placed the exchange within the clerk. Nor can we think of two clerks as connected by a wire, when it is affirmed that every wire must "really" be in some clerk.
The truth is, that, in the extracts which I have given above and in many other passages in the same volume, the real external world, the world which does not exist in the mind but without it, is much discredited, and is yet not actually discarded. The ego is placed at the brain terminals of the sensory nerves, and it receives messages which flow in; i.e. the clerk is actually placed in an exchange. That the existence of the exchange is afterward denied in so many words does not mean that it has not played and does not continue to play an important part in the thought of the author.
It is interesting to see how a man of science, whose reflections compel him to deny the existence of the external world that we all seem to perceive and that we somehow recognize as distinct from anything in our minds, is nevertheless compelled to admit the existence of this world at every turn.
But if we do admit it, what shall we make of it? Shall we deny the truth of what the psychologist has to tell us about a knowledge of things only through the sensations to which they give rise? We cannot, surely, do that. Shall we affirm that we know the external world directly, and at the same time that we do not know it directly, but only indirectly, and through the images which arise in our minds? That seems inconsistent. Certainly there is material for reflection here.
Nevertheless the more we reflect on that material, the more evident does it become that the plain man cannot be wrong in believing in the external world which seems revealed in his experiences. We find that all attempts to discredit it rest upon the implicit assumption of its existence, and fall to the ground when that existence is honestly denied. So our problem changes its form. We no longer ask: Is there an external world? but rather: What is the external world, and how does it differ from the world of mere ideas?
[1] "The Grammar of Science," 2d Ed., London, 1900, pp. 60-63.
CHAPTER IV
SENSATIONS AND "THINGS"
15. SENSE AND IMAGINATION.—Every one distinguishes between things perceived and things only imagined. With open eyes I see the desk before me; with eyes closed, I can imagine it. I lay my hand on it and feel it; I can, without laying my hand on it, imagine that I feel it. I raise my eyes, and see the pictures on the wall opposite me; I can sit here and call before my mind the image of the door by which the house is entered.
What is the difference between sense and imagination? It must be a difference of which we are all somehow conscious, for we unhesitatingly distinguish between the things we perceive and the things we merely imagine.
It is well to remember at the outset that the two classes of experiences are not wholly different. The blue color that I imagine seems blue. It does not lose this quality because it is only imaginary. The horse that I imagine seems to have four legs, like a horse perceived. As I call it before my mind, it seems as large as the real horse. Neither the color, nor the size, nor the distribution of parts, nor any other attribute of the sort appears to be different in the imaginary object from what it is in the object as given in sensation.
The two experiences are, nevertheless, not the same; and every one knows that they are not the same. One difference that roughly marks out the two classes of experiences from one another is that, as a rule, our sense-experiences are more vivid than are the images that exist in the imagination.
I say, as a rule, for we cannot always remark this difference. Sensations may be very clear and unmistakable, but they may also be very faint and indefinite. When a man lays his hand firmly on my shoulder, I may be in little doubt whether I feel a sensation or do not; but when he touches my back very lightly, I may easily be in doubt, and may ask myself in perplexity whether I have really been touched or whether I have merely imagined it. As a vessel recedes and becomes a mere speck upon the horizon, I may well wonder, before I feel sure that it is really quite out of sight, whether I still see the dim little point, or whether I merely imagine that I see it.
On the other hand, things merely imagined may sometimes be very vivid and insistent. To some persons, what exists in the imagination is dim and indefinite in the extreme. Others imagine things vividly, and can describe what is present only to the imagination almost as though it were something seen. Finally, we know that an image may become so vivid and insistent as to be mistaken for an external thing. That is to say, there are such things as hallucinations.
The criterion of vividness will not, therefore, always serve to distinguish between what is given in the sense and what is only imagined. And, indeed, it becomes evident, upon reflection, that we do not actually make it our ultimate test. We may be quite willing to admit that faint sensations may come to be confused with what is imagined, with "ideas," but we always regard such a confusion as somebody's error. We are not ready to admit that things perceived faintly are things imagined, or that vivid "ideas" are things perceived by sense.
Let us come back to the illustrations with which we started. How do I know that I perceive the desk before me; and how do I know that, sitting here, I imagine, and do not see, the front door of the house?
My criterion is this: when I have the experience I call "seeing my desk," the bit of experience which presents itself as my desk is in a certain setting. That is to say, the desk seen must be in a certain relation to my body, and this body, as I know it, also consists of experiences. Thus, if I am to know that I see the desk, I must realize that my eyes are open, that the object is in front of me and not behind me, etc.
The desk as seen varies with the relation to the body in certain ways that we regard as natural and explicable. When I am near it, the visual experience is not just what it is when I recede from it. But how can I know that I am near the desk or far from it? What do these expressions mean? Their full meaning will become clearer in the next chapter, but here I may say that nearness and remoteness must be measured for me in experiences of some sort, or I would never know anything as near to or far from my body.
Thus, all our sensory experiences are experiences that fall into a certain system or order. It is a system which we all recognize implicitly, for we all reject as merely imaginary those experiences which lack this setting. If my eyes are shut—I am speaking now of the eyes as experienced, as felt or perceived, as given in sensation—I never say; "I see my desk," no matter how vivid the image of the object. Those who believe in "second sight" sometimes talk of seeing things not in this setting, but the very name they give to the supposed experience indicates that there is something abnormal about it. No one thinks it remarkable that I see the desk before which I perceive myself to be sitting with open eyes. Every one would think it strange if I could see and describe the table in the next room, now shut away from me. When a man thinks he hears his name pronounced, and, turning his head, seeks in vain for the speaker, he sets his experience down as a hallucination. He says, I did not really hear that; I merely imagined it.
May one not, with open eyes, have a hallucination of vision, just as one may seem to hear one's name pronounced when no one is by? Certainly. But in each case the experience may be proved to be a hallucination, nevertheless. It may be recognized that the sensory setting is incomplete, though it may not, at first, seem so. Thus the unreal object which seems to be seen may be found to be a thing that cannot be touched. Or, when one has attained to a relatively complete knowledge of the system of experiences recognized as sensory, one may make use of roundabout methods of ascertaining that the experience in question does not really have the right setting. Thus, the ghost which is seen by the terrified peasant at midnight, but which cannot be photographed, we may unhesitatingly set down as something imagined and not really seen.
All our sensations are, therefore, experiences which take their place in a certain setting. This is our ultimate criterion. We need not take the word of the philosopher for it. We need only reflect, and ask ourselves how we know that, in a given case, we are seeing or hearing or touching something, and are not merely imagining it. In every case, we shall find that we come back to the same test. In common life, we apply the test instinctively, and with little realization of what we are doing.
And if we turn to the psychologist, whose business it is to be more exact and scientific, we find that he gives us only a refinement of this same criterion. It is important to him to distinguish between what is given in sensation and what is furnished by memory or imagination, and he tells us that sensation is the result of a message conducted along a sensory nerve to the brain.
Here we see emphasized the relation to the body which has been mentioned above. If we ask the psychologist how he knows that the body he is talking about is a real body, and not merely an imagined one, he has to fall back upon the test which is common to us all. A real hand is one which we see with the eyes open, and which we touch with the other hand. If our experiences of our own body had not the setting which marks all sensory experiences, we could never say: I perceive that my body is near the desk. When we call our body real, as contrasted with things imaginary, we recognize that this group of experiences belongs to the class described; it is given in sensation, and is not merely thought of.
It will be observed that, in distinguishing between sensations and things imaginary, we never go beyond the circle of our experiences. We do not reach out to a something beyond or behind experiences, and say: When such a reality is present, we may affirm that we have a sensation, and when it is not, we may call the experience imaginary. If there were such a reality as this, it would do us little good, for since it is not supposed to be perceived directly, we should have to depend upon the sensations to prove the presence of the reality, and could not turn to the reality and ask it whether we were or were not experiencing a sensation. The distinction between sensations and what is imaginary is an observed distinction. It can be proved that some experiences are sensory and that some are not. This means that, in drawing the distinction, we remain within the circle of our experiences.
There has been much unnecessary mystification touching this supposed reality behind experiences. In the next chapter we shall see in what senses the word "reality" may properly be used, and in what sense it may not. There is a danger in using it loosely and vaguely.
16. MAY WE CALL "THINGS" GROUPS OF SENSATIONS?—Now, the external world seems to the plain man to be directly given in his sense experiences. He is willing to admit that the table in the next room, of which he is merely thinking, is known at one remove, so to speak. But this desk here before him: is it not known directly? Not the mental image, the mere representative, but the desk itself, a something that is physical and not mental?
And the psychologist, whatever his theory of the relation between the mind and the world, seems to support him, at least, in so far as to maintain that in sensation the external world is known as directly as it is possible for the external world to be known, and that one can get no more of it than is presented in sensation. If a sense is lacking, an aspect of the world as given is also lacking; if a sense is defective, as in the color-blind, the defect is reflected in the world upon which one gazes.
Such considerations, especially when taken together with what has been said at the close of the last section about the futility of looking for a reality behind our sensations, may easily suggest rather a startling possibility. May it not be, if we really are shut up to the circle of our experiences, that the physical things, which we have been accustomed to look upon as non-mental, are nothing more than complexes of sensations? Granted that there seems to be presented in our experience a material world as well as a mind, may it not be that this material world is a mental thing of a certain kind—a mental thing contrasted with other mental things, such as imaginary things?
This question has always been answered in the affirmative by the idealists, who claim that all existence must be regarded as psychical existence. Their doctrine we shall consider later (sections 49 and 53). It will be noticed that we seem to be back again with Professor Pearson in the last chapter.
To this question I make the following answer: In the first place, I remark that even the plain man distinguishes somehow between his sensations and external things. He thinks that he has reason to believe that things do not cease to exist when he no longer has sensations. Moreover, he believes that things do not always appear to his senses as they really are. If we tell him that his sensations are the things, it shocks his common sense. He answers: Do you mean to tell me that complexes of sensation can be on a shelf or in a drawer? can be cut with a knife or broken with the hands? He feels that there must be some real distinction between sensations and the things without him.
Now, the notions of the plain man on such matters as these are not very clear, and what he says about sensations and things is not always edifying. But it is clear that he feels strongly that the man who would identify them is obliterating a distinction to which his experience testifies unequivocally. We must not hastily disregard his protest. He is sometimes right in his feeling that things are not identical, even when he cannot prove it.
In the second place, I remark that, in this instance, the plain man is in the right, and can be shown to be in the right. "Things" are not groups of sensations. The distinction between them will be explained in the next section.
17. THE DISTINCTION BETWEEN SENSATIONS AND "THINGS"—Suppose that I stand in my study and look at the fire in the grate. I am experiencing sensations, and am not busied merely with an imaginary fire. But may my whole experience of the fire be summed up as an experience of sensations and their changes? Let us see.
If I shut my eyes, the fire disappears. Does any one suppose that the fire has been annihilated? No. We say, I no longer see it, but nothing has happened to the fire.
Again, I may keep my eyes open, and simply turn my head. The fire disappears once more. Does any one suppose that my turning my head has done anything to the fire? We say unhesitatingly, my sensations have changed, but the fire has remained as it was.
Still, again, I may withdraw from the fire. Its heat seems to be diminished. Has the fire really grown less hot? And if I could withdraw to a sufficient distance, I know that the fire would appear to me smaller and less bright. Could I get far enough away to make it seem the faintest speck in the field of vision, would I be tempted to claim that the fire shrunk and grew faint merely because I walked away from it? Surely not.
Now, suppose that I stand on the same spot and look at the fire without turning my head. The stick at which I am gazing catches the flame, blazes up, turns red, and finally falls together, a little mass of gray ashes. Shall I describe this by saying that my sensations have changed, or may I say that the fire itself has changed? The plain man and the philosopher alike use the latter expression in such a case as this.
Let us take another illustration. I walk towards the distant house on the plain before me. What I see as my goal seems to grow larger and brighter. It does not occur to me to maintain that the house changes as I advance. But, at a given instant, changes of a different sort make their appearance. Smoke arises, and flames burst from the roof. Now I have no hesitation in saying that changes are taking place in the house. It would seem foolish to describe the occurrence as a mere change in my sensations. Before it was my sensations that changed; now it is the house itself.
We are drawing this distinction between changes in our sensations and changes in things at every hour in the day. I cannot move without making things appear and disappear. If I wag my head, the furniture seems to dance, and I regard it as a mere seeming. I count on the clock's going when I no longer look upon its face. It would be absurd to hold that the distinction is a mere blunder, and has no foundation in our experience. The rôle it plays is too important for that. If we obliterate it, the real world of material things which seems to be revealed in our experience melts into a chaos of fantastic experiences whose appearances and disappearances seem to be subject to no law.
And it is worthy of remark that it is not merely in common life that the distinction is drawn. Every man of science must give heed to it. The psychologist does, it is true, pay much attention to sensations; but even he distinguishes between the sensations which he is studying and the material things to which he relates them, such as brains and sense-organs. And those who cultivate the physical sciences strive, when they give an account of things and their behavior, to lay before us a history of changes analogous to the burning of the stick and of the house, excluding mere changes in sensations.
There is no physicist or botanist or zoölogist who has not our common experience that things as perceived by us—our experiences of things—appear or disappear or change their character when we open or shut our eyes or move about. But nothing of all this appears in their books. What they are concerned with is things and their changes, and they do not consider such matters as these as falling within their province. If a botanist could not distinguish between the changes which take place in a plant, and the changes which take place in his sensations as he is occupied in studying the plant, but should tell us that the plant grows smaller as one recedes from it, we should set him down as weak-minded.
That the distinction is everywhere drawn, and that we must not obliterate it, is very evident. But we are in the presence of what has seemed to many men a grave difficulty. Are not things presented in our experience only as we have sensations? what is it to perceive a thing? is it not to have sensations? how, then, can we distinguish between sensations and things? We certainly do so all the time, in spite of the protest of the philosopher; but many of us do so with a haunting sense that our behavior can scarcely be justified by the reason.
Our difficulty, however, springs out of an error of our own. Grasping imperfectly the full significance of the word "sensation," we extend its use beyond what is legitimate, and we call by that name experiences which are not sensations at all. Thus the external world comes to seem to us to be not really a something contrasted with the mental, but a part of the mental world. We accord to it the attributes of the latter, and rob it of those distinguishing attributes which belong to it by right. When we have done this, we may feel impelled to say, as did Professor Pearson, that things are not really "outside" of us, as they seem to be, but are merely "projected" outside—thought of as if they were "outside." All this I must explain at length.
Let us come back to the first of the illustrations given above, the case of the fire in my study. As I stand and look at it, what shall I call the red glow which I observe? Shall I call it a quality of a thing, or shall I call it a sensation?
To this I answer: I may call it either the one or the other, according to its setting among other experiences.
We have seen (section 15) that sensations and things merely imaginary are distinguished from one another by their setting. With open eyes we see things; with our eyes closed we can imagine them: we see what is before us; we imagine what lies behind our backs. If we confine our attention to the bit of experience itself, we have no means of determining whether it is sensory or imaginary. Only its setting can decide that point. Here, we have come to another distinction of much the same sort. That red glow, that bit of experience, taken by itself and abstracted from all other experiences, cannot be called either a sensation or the quality of a thing. Only its context can give us the right to call it the one or the other.
This ought to become clear when we reflect upon the illustration of the fire. We have seen that one whole series of changes has been unhesitatingly described as a series of changes in my sensations. Why was this? Because it was observed to depend upon changes in the relations of my body, my senses (a certain group of experiences), to the bit of experience I call the fire. Another series was described as a series of changes in the fire. Why? Because, the relation to my senses remaining unchanged, changes still took place, and had to be accounted for in other ways.
It is a matter of common knowledge that they can be accounted for in other ways. This is not a discovery of the philosopher. He can only invite us to think over the matter and see what the unlearned and the learned are doing at every moment. Sometimes they are noticing that experiences change as they turn their heads or walk toward or away from objects; sometimes they abstract from this, and consider the series of changes that take place independently of this.
That bit of experience, that red glow, is not related only to my body. Such experiences are related also to each other; they stand in a vast independent system of relations, which, as we have seen, the man of science can study without troubling himself to consider sensations at all. This system is the external world—the external world as known or as knowable, the only external world that it means anything for us to talk about. As having its place in this system, a bit of experience is not a sensation, but is a quality or aspect of a thing.
Sensations, then, to be sensations, must be bits of experience considered in their relation to some organ of sense. They should never be confused with qualities of things, which are experiences in a different setting. It is as unpardonable to confound the two as it is to confound sensations with things imaginary.
We may not, therefore, say that "things" are groups of sensations. We may, if we please, describe them as complexes of qualities. And we may not say that the "things" we perceive are really "inside" of us and are merely "projected outside."
What can "inside" and "outside" mean? Only this. We recognize in our experience two distinct orders, the objective order, the system of phenomena which constitutes the material world, and the subjective order, the order of things mental, to which belong sensations and "ideas." That is "outside" which belongs to the objective order. The word has no other meaning when used in this connection. That is "inside" which belongs to the subjective order, and is contrasted with the former.
If we deny that there is an objective order, an external world, and say that everything is "inside," we lose our distinction, and even the word "inside" becomes meaningless. It indicates no contrast. When men fall into the error of talking in this way, what they do is to keep the external world and gain the distinction, and at the same time to deny the existence of the world which has furnished it. In other words, they put the clerk into a telephone exchange, and then tell us that the exchange does not really exist. He is inside—of what? He is inside of nothing. Then, can he really be inside?
We see, thus, that the plain man and the man of science are quite right in accepting the external world. The objective order is known as directly as is the subjective order. Both are orders of experiences; they are open to observation, and we have, in general, little difficulty in distinguishing between them, as the illustrations given above amply prove.
18. THE EXISTENCE OF MATERIAL THINGS.—One difficulty seems to remain and to call for a solution. We all believe that material things exist when we no longer perceive them. We believe that they existed before they came within the field of our observation.
In these positions the man of science supports us. The astronomer has no hesitation in saying that the comet, which has sailed away through space, exists, and will return. The geologist describes for us the world as it was in past ages, when no eye was opened upon it.
But has it not been stated above that the material world is an order of experiences? and can there be such a thing as an experience that is not experienced by somebody? In other words, can the world exist, except as it is perceived to exist?
This seeming difficulty has occasioned much trouble to philosophers in the past. Bishop Berkeley (1684-1753) said, "To exist is to be perceived." There are those who agree with him at the present day.
Their difficulty would have disappeared had they examined with sufficient care the meaning of the word "exist." We have no right to pass over the actual uses of such words, and to give them a meaning of our own. If one thing seems as certain as any other, it is that material things exist when we do not perceive them. On what ground may the philosopher combat the universal opinion, the dictum of common sense and of science? When we look into his reasonings, we find that he is influenced by the error discussed at length in the last section—he has confused the phenomena of the two orders of experience.
I have said that, when we concern ourselves with the objective order, we abstract or should abstract, from the relations which things bear to our senses. We account for phenomena by referring to other phenomena which we have reason to accept as their physical conditions or causes. We do not consider that a physical cause is effective only while we perceive it. When we come back to this notion of our perceiving a thing or not perceiving it, we have left the objective order and passed over to the subjective. We have left the consideration of "things" and have turned to sensations.
There is no reason why we should do this. The physical order is an independent order, as we have seen. The man of science, when he is endeavoring to discover whether some thing or quality of a thing really existed at some time in the past, is not in the least concerned to establish the fact that some one saw it. No one ever saw the primitive fire-mist from which, as we are told, the world came into being. But the scientist cares little for that. He is concerned only to prove that the phenomena he is investigating really have a place in the objective order. If he decides that they have, he is satisfied; he has proved something to exist. To belong to the objective order is to exist as a physical thing or quality.
When the plain man and the man of science maintain that a physical thing exists, they use the word in precisely the same sense. The meaning they give to it is the proper meaning of the word. It is justified by immemorial usage, and it marks a real distinction. Shall we allow the philosopher to tell us that we must not use it in this sense, but must say that only sensations and ideas exist? Surely not. This would mean that we permit him to obliterate for us the distinction between the external world and what is mental.
But is it right to use the word "experience" to indicate the phenomena which have a place in the objective order? Can an experience be anything but mental?
There can be no doubt that the suggestions of the word are unfortunate—it has what we may call a subjective flavor. It suggests that, after all, the things we perceive are sensations or percepts, and must, to exist at all, exist in a mind. As we have seen, this is an error, and an error which we all avoid in actual practice. We do not take sensations for things, and we recognize clearly enough that it is one thing for a material object to exist and another for it to be perceived.
Why, then, use the word "experience"? Simply because we have no better word. We must use it, and not be misled by the associations which cling to it. The word has this great advantage: it brings out clearly the fact that all our knowledge of the external world rests ultimately upon those phenomena which, when we consider them in relation to our senses, we recognize as sensations. We cannot start out from mere imaginings to discover what the world was like in the ages past.
It is this truth that is recognized by the plain man, when he maintains that, in the last resort, we can know things only in so far as we see, touch, hear, taste, and smell them; and by the psychologist, when he tells us that, in sensation, the external world is revealed as directly as it is possible that it could be revealed. But it is a travesty on this truth to say that we do not know things, but know only our sensations of sight, touch, taste, hearing, and the like.[1]
[1] See the note on this chapter at the close of the volume.
CHAPTER V
APPEARANCES AND REALITIES
19. THINGS AND THEIR APPEARANCES.—We have seen in the last chapter that there is an external world and that it is given in our experience. There is an objective order, and we are all capable of distinguishing between it and the subjective. He who says that we perceive only sensations and ideas flies in the face of the common experience of mankind.
But we are not yet through with the subject. We all make a distinction between things as they appear and things as they really are.
If we ask the plain man, What is the real external world? the first answer that seems to present itself to his mind is this: Whatever we can see, hear, touch, taste, or smell may be regarded as belonging to the real world. What we merely imagine does not belong to it.
That this answer is not a very satisfactory one occurred to men's minds very early in the history of reflective thought. The ancient skeptic said to himself: The colors of objects vary according to the light, and according to the position and distance of the objects; can we say that any object has a real color of its own? A staff stuck into water looks bent, but feels straight to the touch; why believe the testimony of one sense rather than that of another?
Such questionings led to far-reaching consequences. They resulted in a forlorn distrust of the testimony of the senses, and to a doubt as to our ability to know anything as it really is.
Now, the distinction between appearances and realities exists for us as well as for the ancient skeptic, and without being tempted to make such extravagant statements as that there is no such thing as truth, and that every appearance is as real as any other, we may admit that it is not very easy to see the full significance of the distinction, although we are referring to it constantly.
For example, we look from our window and see, as we say, a tree at a distance. What we are conscious of is a small bluish patch of color. Now, a small bluish patch of color is not, strictly speaking, a tree; but for us it represents the tree. Suppose that we walk toward the tree. Do we continue to see what we saw before? Of course, we say that we continue to see the same tree; but it is plain that what we immediately perceive, what is given in consciousness, does not remain the same as we move. Our blue patch of color grows larger and larger; it ceases to be blue and faint; at the last it has been replaced by an expanse of vivid green, and we see the tree just before us.
During our whole walk we have been seeing the tree. This appears to mean that we have been having a whole series of visual experiences, no two of which were just alike, and each of which was taken as a representative of the tree. Which of these representatives is most like the tree? Is the tree really a faint blue, or is it really a vivid green? Or is it of some intermediate color?
Probably most persons will be inclined to maintain that the tree only seems blue at a distance, but that it really is green, as it appears when one is close to it. In a sense, the statement is just; yet some of those who make it would be puzzled to tell by what right they pick out of the whole series of experiences, each of which represents the tree as seen from some particular position, one individual experience, which they claim not only represents the tree as seen from a given point but also represents it as it is. Does this particular experience bear some peculiar earmark which tells us that it is like the real tree while the others are unlike it?
20. REAL THINGS.—And what is this real tree that we are supposed to see as it is when we are close to it?
About two hundred years ago the philosopher Berkeley pointed out that the distinction commonly made between things as they look, the apparent, and things as they are, the real, is at bottom the distinction between things as presented to the sense of sight and things as presented to the sense of touch. The acute analysis which he made has held its own ever since.
We have seen that, in walking towards the tree, we have a long series of visual experiences, each of which differs more or less from all of the others. Nevertheless, from the beginning of our progress to the end, we say that we are looking at the same tree. The images change color and grow larger. We do not say that the tree changes color and grows larger. Why do we speak as we do? It is because, all along the line, we mean by the real tree, not what is given to the sense of sight, but something for which this stands as a sign. This something must be given in our experience somewhere, we must be able to perceive it under some circumstances or other, or it would never occur to us to recognize the visual experiences as signs, and we should never say that in being conscious of them in succession we are looking at the same tree. They are certainly not the same with each other; how can we know that they all stand for the same thing, unless we have had experience of a connection of the whole series with one thing?
This thing for which so many different visual experiences may serve as signs is the thing revealed in experiences of touch. When we ask: In what direction is the tree? How far away is the tree? How big is the tree? we are always referring to the tree revealed in touch. It is nonsense to say that what we see is far away, if by what we see we mean the visual experience itself. As soon as we move we lose that visual experience and get another, and to recover the one we lost we must go back where we were before. When we say we see a tree at a distance, we must mean, then, that we know from certain visual experiences which we have that by moving a certain distance we will be able to touch a tree. And what does it mean to move a certain distance? In the last analysis it means to us to have a certain quantity of movement sensations.
Thus the real world of things, for which experiences of sight serve as signs, is a world revealed in experiences of touch and movement, and when we speak of real positions, distances, and magnitudes, we are always referring to this world. But this is a world revealed in our experience, and it does not seem a hopeless task to discover what may properly be called real and what should be described as merely apparent, when both the real and the apparent are open to our inspection.
Can we not find in this analysis a satisfactory explanation of the plain man's claim that under certain circumstances he sees the tree as it is and under others he does not? What he is really asserting is that one visual experience gives him better information regarding the real thing, the touch thing, than does another.
But what shall we say of his claim that the tree is really green, and only looks blue under certain circumstances? Is it not just as true that the tree only looks green under certain circumstances? Is color any part of the touch thing? Is it ever more than a sign of the touch thing? How can one color be more real than another?
Now, we may hold to Berkeley's analysis and maintain that, in general, the real world, as contrasted with the apparent, means to us the world that is revealed in experiences of touch and movement; and yet we may admit that the word "real" is sometimes used in rather different senses.
It does not seem absurd for a woman to Say: This piece of silk really is yellow; it only looks white under this light. We all admit that a white house may look pink under the rays of the setting sun, and we never call it a pink house. We have seen that it is not unnatural to say: That tree is really green; it is only its distance that makes it look blue.
When one reflects upon these uses of the word "real," one recognizes the fact that, among all the experiences in which things are revealed to us, certain experiences impress us as being more prominent or important or serviceable than certain others, and they come to be called real. Things are not commonly seen by artificial light; the sun is not always setting; the tree looks green when it is seen most satisfactorily. In each case, the real color of the thing is the color that it has under circumstances that strike us as normal or as important. We cannot say that we always regard as most real that aspect under which we most commonly perceive things, for if a more unusual experience is more serviceable and really gives us more information about the thing, we give the preference to that. Thus we look with the naked eye at a moving speck on the table before us, and we are unable to distinguish its parts. We place a microscope over the speck and perceive an insect with all its members. The second experience is the more unusual one, but would not every one say: Now we perceive the thing as it is?
21. ULTIMATE REAL THINGS.—Let us turn away from the senses of the word "real," which recognize one color or taste or odor as more real than another, and come back to the real world of things presented in sensations of touch. All other classes of sensations may be regarded as related to this as the series of visual experiences above mentioned was related to the one tree which was spoken of as revealed in them all, the touch tree of which they gave information.
Can we say that this world is always to be regarded as reality and never as appearance? We have already seen (section 8) that science does not regard as anything more than appearance the real things which seem to be directly presented in our experience.
This pen that I hold in my hand seems, as I pass my fingers over it, to be continuously extended. It does not appear to present an alternation of filled spaces and empty spaces. I am told that it is composed of molecules in rapid motion and at considerable distances from one another. I am further told that each molecule is composed of atoms, and is, in its turn, not a continuous thing, but, so to speak, a group of little things.
If I accept this doctrine, as it seems I must, am I not forced to conclude that the reality which is given in my experience, the reality with which I have contrasted appearances and to which I have referred them, is, after all, itself only an appearance? The touch things which I have hitherto regarded as the real things that make up the external world, the touch things for which all my visual experiences have served as signs, are, then, not themselves real external things, but only the appearances under which real external things, themselves imperceptible, manifest themselves to me.
It seems, then, that I do not directly perceive any real thing, or, at least, anything that can be regarded as more than an appearance. What, then, is the external world? What are things really like? Can we give any true account of them, or are we forced to say with the skeptics that we only know how things seem to us, and must abandon the attempt to tell what they are really like?
Now, before one sets out to answer a question it is well to find out whether it is a sensible question to ask and a sensible question to try to answer. He who asks: Where is the middle of an infinite line? When did all time begin? Where is space as a whole? does not deserve a serious answer to his questions. And it is well to remember that he who asks: What is the external world like? must keep his question a significant one, if he is to retain his right to look for an answer at all. He has manifestly no right to ask us: How does the external world look when no one is looking? How do things feel when no one feels them? How shall I think of things, not as I think of them, but as they are?
If we are to give an account of the external world at all, it must evidently be an account of the external world; i.e. it must be given in terms of our experience of things. The only legitimate problem is to give a true account instead of a false one, to distinguish between what only appears and is not real and what both appears and is real.
Bearing this in mind, let us come back to the plain man's experience of the world. He certainly seems to himself to perceive a real world of things, and he constantly distinguishes, in a way very serviceable to himself, between the merely apparent and the real. There is, of course, a sense in which every experience is real; it is, at least, an experience; but when he contrasts real and apparent he means something more than this. Experiences are not relegated to this class or to that merely at random, but the final decision is the outcome of a long experience of the differences which characterize different individual experiences and is an expression of the relations which are observed to hold between them. Certain experiences are accepted as signs, and certain others come to take the more dignified position of thing signified; the mind rests in them and regards them as the real.
We have seen above that the world of real things in which the plain man finds himself is a world of objects revealed in experiences of touch. When he asks regarding anything: How far away is it? How big is it? In what direction is it? it is always the touch thing that interests him. What is given to the other senses is only a sign of this.
We have also seen (section 8) that the world of atoms and molecules of which the man of science tells us is nothing more than a further development of the world of the plain man. The real things with which science concerns itself are, after all, only minute touch things, conceived just as are the things with which the plain man is familiar. They exist in space and move about in space, as the things about us are perceived to exist in space and move about in space. They have size and position, and are separated by distances. We do not perceive them, it is true; but we conceive them after the analogy of the things that we do perceive, and it is not inconceivable that, if our senses were vastly more acute, we might perceive them directly.
Now, when we conclude that the things directly perceptible to the sense of touch are to be regarded as appearances, as signs of the presence of these minuter things, do we draw such a conclusion arbitrarily? By no means. The distinction between appearance and reality is drawn here just as it is drawn in the world of our common everyday experiences. The great majority of the touch things about us we are not actually touching at any given moment. We only see the things, i.e. we have certain signs of their presence. None the less we believe that the things exist all the time. And in the same way the man of science does not doubt the existence of the real things of which he speaks; he perceives their signs. That certain experiences are to be taken as signs of such realities he has established by innumerable observations and careful deductions from those observations. To see the full force of his reasonings one must read some work setting forth the history of the atomic theory.
If, then, we ask the question: What is the real external world? it is clear that we cannot answer it satisfactorily without taking into consideration the somewhat shifting senses of the word "real." What is the real external world to the plain man? It is the world of touch things, of objects upon which he can lay his hands. What is the real external world to the man of science? It is the world of atoms and molecules, of minuter touch things that he cannot actually touch, but which he conceives as though he could touch them.
It should be observed that the man of science has no right to deny the real world which is revealed in the experience of the plain man. In all his dealings with the things which interest him in common life, he refers to this world just as the plain man does. He sees a tree and walks towards it, and distinguishes between its real and its apparent color, its real and its apparent size. He talks about seeing things as they are, or not seeing things as they are. These distinctions in his experience of things remain even after he has come to believe in atoms and molecules.
Thus, the touch object, the tree as he feels it under his hand, may come to be regarded as the sign of the presence of those entities that science seems, at present, to regard as ultimate. Does this prevent it from being the object which has stood as the interpreter of all those diverse visual sensations that we have called different views of the tree? They are still the appearances, and it, relatively to them, is the reality. Now we find that it, in its turn, can be used as a sign of something else, can be regarded as an appearance of a reality more ultimate. It is clear, then, that the same thing may be regarded both as appearance and as reality—appearance as contrasted with one thing, and reality as contrasted with another.
But suppose one says: I do not want to know what the real external world is to this man or to that man; I want to know what the real external world is. What shall we say to such a demand?