Part 3

Now the scientific method is a method of getting knowledge by inference, and that of two different kinds. One kind of inference is that which is used in the physical and natural sciences, and it enables us to go from known phenomena to unknown phenomena. Because a stone is heavy in the morning, I infer that it will be heavy in the afternoon; and I infer this by assuming a certain uniformity of nature. The sort of uniformity that I assume depends upon the extent of my scientific education; the rules of inference become more and more definite as we go on. At first I might assume that all things are always alike; this would not be true, but it has to be assumed in a vague way, in order that a thing may have the same name at different times. Afterward I get the more definite belief that certain particular qualities, like weight, have nothing to do with the time of day; and subsequently I find that weight has nothing to do with the shape of the stone, but only with the quantity of it. The uniformity which we assume, then, is not that vague one that we started with, but a chastened and corrected uniformity. I might go on to suppose, for example, that the weight of the stone had nothing to do with the place where it was; and a great deal might be said for this supposition. It would, however, have to be corrected when it was found that the weight varies slightly in different latitudes. On the other hand, I should find that this variation was just the same for my stone as for a piece of iron or wood; that it had nothing to do with the kind of matter. And so I might be led to the conclusion that all matter is heavy, and that the weight of it depends only on its quantity and its position relative to the earth. You see here that I go on arriving at conclusions always of this form; that some one circumstance or quality has nothing to do with some other circumstance or quality. I begin by assuming that it is independent of everything; I end by finding that it is independent of some definite things. That is, I begin by assuming a vague uniformity. I always use this assumption to infer from some one fact a great number of other facts; but as my education proceeds, I get to know what sort of things may be inferred and what may not. An observer of scientific mind takes note of just those things from which inferences may be drawn, and passes by the rest. If an astronomer, observing the sun, were to record the fact that at the moment when a sun-spot began to shrink there was a rap at his front door, we should know that he was not up to his work. But if he records that sun-spots are thickest every eleven years, and that this is also the period of extra cloudiness in Jupiter, the observation may or may not be confirmed, and it may or may not lead to inferences of importance; but still it is the kind of thing from which inferences may be drawn. There is always a certain instinct among instructed people which tells them in this way what kinds of inferences may be drawn; and this is the unconscious effect of the definite uniformity which they have been led to assume in nature. It may subsequently be organized into a law or general truth, and no doubt becomes a surer guide by that process. Then it goes to form the more precise instinct of the next generation.

What we have said about this first kind of inference, which goes from phenomena to phenomena, is shortly this. It proceeds upon an assumption of uniformity in nature; and this assumption is not fixed and made once for all, but is a changing and growing thing, becoming more definite as we go on.

If I were told to pick out some one character which especially colors this guiding conception of uniformity in our present stage of science, I should certainly reply, Atomism. The form of this with which we are most familiar is the molecular theory of bodies; which represents all bodies as made up of small elements of uniform character, each practically having relations only with the adjacent ones, and these relations the same all through--namely, some simple mechanical action upon each other's motions. But this is only a particular case. A palace, a cottage, the tunnel of the underground railway, and a factory chimney, are all built of bricks; the bricks are alike in all these cases, each brick is practically related only to the adjacent ones, and the relation is throughout the same, namely, two flat sides are stuck together with mortar. There is an atomism in the sciences of number, of quantity, of space; the theorems of geometry are groupings of individual points, each related only to the adjacent ones by certain definite laws. But what concerns us chiefly at present is the atomism of human physiology. Just as every solid is built up of molecules, so the nervous system is built up of nerve-threads and nerve-corpuscles. We owe to Mr. Lewes our very best thanks for the stress which he has laid on the doctrine that nerve-fiber is uniform in structure and function, and for the word neurility, which expresses its common properties. And similar gratitude is due to Dr. Hughlings Jackson for his long defense of the proposition that the element of nervous structure and function is a sensori-motor process. In structure, this is two fibers or bundles of fibers going to the same gray corpuscle; in function it is a message traveling up one fiber or bundle to the corpuscle, and then down the other fiber or bundle. Out of this, as a brick, the house of our life is built. All these simple elementary processes are alike, and each is practically related only to the adjacent ones; the relation being in all cases of the same kind, viz., the passage from a simple to a complex message, or vice versâ.

The result of atomism in any form, dealing with any subject, is that the principle of uniformity is hunted down into the elements of things; it is resolved into the uniformity of these elements or atoms, and of the relations of those which are next to each other. By an element or an atom we do not here mean something absolutely simple or indivisible, for a molecule, a brick, and a nerve-process are all very complex things. We only mean that, for the purpose in hand, the properties of the still more complex thing which is made of them have nothing to do with the complexities or the differences of these elements. The solid made of molecules, the house made of bricks, the nervous system made of sensori-motor processes, are nothing more than collections of these practically uniform elements, having certain relations of nextness, and behavior uniformly depending on that nextness.

The inference of phenomena from phenomena, then, is based upon an assumption of uniformity, which in the present stage of science may be called an atomic uniformity.

The other mode of inference which belongs to the scientific method is that which is used in what are called the mental and moral sciences; and it enables us to go from phenomena to the facts which underlie phenomena, and which are themselves not phenomena at all. If I pinch your arm, and you draw it away and make a face, I infer that you have felt pain. I infer this by assuming that you have a consciousness similar to my own, and related to your perception of your body as my consciousness is related to my perception of my body. Now is this the same assumption as before, a mere assumption of the uniformity of nature? It certainly seems like it at first; but if we think about it we shall find that there is a very profound difference between them. In physical inference I go from phenomena to phenomena; that is, from the knowledge of certain appearances or representations actually present to my mind I infer certain other appearances that might be present to my mind. From the weight of a stone in the morning--that is, from my feeling of its weight, or my perception of the process of weighing it, I infer that the stone will be heavy in the afternoon--that is, I infer the possibility of similar feelings and perceptions in me at another time. The whole process relates to me and my perceptions, to things contained in my mind. But when I infer that you are conscious from what you say or do, I pass from that which is my feeling or perception, which is in my mind and part of me, to that which is not my feeling at all, which is outside me altogether, namely, your feelings and perceptions. Now there is no possible physical inference, no inference of phenomena from phenomena, that will help me over that gulf. I am obliged to admit that this second kind of inference depends upon another assumption, not included in the assumption of the uniformity of phenomena.

How does a dream differ from waking life? In a fairly coherent dream everything seems quite real, and it is rare, I think, with most people to know in a dream that they are dreaming. Now, if a dream is sufficiently vivid and coherent, all physical inferences are just as valid in it as they are in waking life. In a hazy or imperfect dream, it is true, things melt into one another unexpectedly and unaccountably; we fly, remove mountains, and stop runaway horses with a finger. But there is nothing in the mere nature of a dream to hinder it from being an exact copy of waking experience. If I find a stone heavy in one part of my dream, and infer that it is heavy at some subsequent part, the inference will be verified if the dream is coherent enough; I shall go to the stone, lift it up, and find it as heavy as before. And the same thing is true of all inferences of phenomena from phenomena. For physical purposes a dream is just as good as real life; the only difference is in vividness and coherence.

What, then, hinders us from saying that life is all a dream? If the phenomena we dream of are just as good and real phenomena as those we see and feel when we are awake, what right have we to say that the material universe has any more existence apart from our minds than the things we see and feel in our dreams? The answer which Berkeley gave to that question was, No right at all. The physical universe which I see and feel, and infer, is just my dream and nothing else; that which you see is your dream; only it so happens that all our dreams agree in many respects. This doctrine of Berkeley's has now been so far confirmed by the physiology of the senses, that it is no longer a metaphysical speculation, but a scientifically established fact.

But there is a difference between dreams and waking life, which is of far too great importance for any of us to be in danger of neglecting it. When I see a man in my dream, there is just as good a body as if I were awake; muscles, nerves, circulation, capability of adapting means to ends. If only the dream is coherent enough, no physical test can establish that it is a dream. In both cases I see and feel the same thing. In both cases I assume the existence of more than I can see and feel, namely, the consciousness of this other man. But now here is a great difference, and the only difference--in a dream this assumption is wrong; in waking life it is right. The man I see in my dream is a mere machine, a bundle of phenomena with no underlying reality; there is no consciousness involved except my consciousness, no feeling in the case except my feelings. The man I see in waking life is more than a bundle of phenomena; his body and its actions are phenomena, but these phenomena are merely the symbols and representatives in my mind of a reality which is outside my mind, namely, the consciousness of the man himself which is represented by the working of his brain, and the simpler quasi-mental facts, not woven into his consciousness, which are represented by the working of the rest of his body. What makes life not to be a dream is the existence of those facts which we arrive at by our second process of inference; the consciousness of men and the higher animals, the sub-consciousness of lower organisms and the quasi-mental facts which go along with the motions of inanimate matter. In a book which is very largely and deservedly known by heart, 'Through the Looking-glass,' there is a very instructive discussion upon this point. Alice has been taken to see the Red King as he lies snoring; and Tweedledee asks, 'Do you know what he is dreaming about?' 'Nobody can guess that,' replies Alice. 'Why, about you,' he says triumphantly. 'And if he stopped dreaming about you, where do you suppose you'd be?' 'Where I am now of course,' said Alice. 'Not you,' said Tweedledee, 'you'd be nowhere. You are only a sort of thing in his dream.' 'If that there King was to wake,' added Tweedledum, 'you'd go out, bang! just like a candle.' Alice was quite right in regarding these remarks as unphilosophical. The fact that she could see, think, and feel was proof positive that she was not a sort of thing in anybody's dream. This is the meaning of that saying, Cogito ergo sum, of Descartes. By him, and by Spinoza after him, the verb cogito and the substantive cogitatio were used to denote consciousness in general, any kind of feeling, even what we now call sub-consciousness. The saying means that feeling exists in and for itself, not as a quality or modification or state or manifestation of anything else.

We are obliged in every hour of our lives to act upon beliefs which have been arrived at by inferences of these two kinds; inferences based on the assumption of uniformity in nature, and inferences which add to this the assumption of feelings which are not our own. By organizing the 'common sense' which embodies the first class of inferences, we build up the physical sciences; that is to say, all those sciences which deal with the physical, material, or phenomenal universe, whether animate or inanimate. And so by organizing the common sense which embodies the second class of inferences, we build up various sciences of mind. The description and classification of feelings, the facts of their association with each other, and of their simultaneity with phenomena of nerve-action,--all this belongs to psychology, which may be historical and comparative. The doctrine of certain special classes of feelings is organized into the special sciences of those feelings; thus the facts about the feelings which we are now considering, about the feelings of moral approbation and reprobation, are organized into the science of ethics and the facts about the feeling of beauty or ugliness are organized into the science of æsthetics, or, as it is sometimes called, the philosophy of art. For all of these the uniformity of nature has to be assumed as a basis of inference; but over and above that it is necessary to assume that other men are conscious in the same way that I am. Now in these sciences of mind, just as in the physical sciences, the uniformity which is assumed in the inferred mental facts is a growing thing which becomes more definite as we go on, and each successive generation of observers knows better what to observe and what sort of inferences may be drawn from observed things. But, moreover, it is as true of the mental sciences as of the physical ones that the uniformity is in the present stage of science an atomic uniformity. We have learned to regard our consciousness as made up of elements practically alike, having relations of succession in time and of contiguity at each instant, which relations are in all cases practically the same. The element of consciousness is the transference of an impression into the beginning of action. Our mental life is a structure made out of such elements, just as the working of our nervous system is made out of sensori-motor processes. And accordingly the interaction of the two branches of science leads us to regard the mental facts as the realities or things-in-themselves, of which the material phenomena are mere pictures or symbols. The final result seems to be that atomism is carried beyond phenomena into the realities which phenomena represent; and that the observed uniformities of nature, in so far as they can be expressed in the language of atomism, are actual uniformities of things in themselves.

So much for the two things which I have promised to bring together; the facts of our moral feelings, and the scientific method. It may appear that the latter has been expounded at more length than was necessary for the treatment of this particular subject; but the justification for this length is to be found in certain common objections to the claims of science to be the sole judge of mental and moral questions. Some of the chief of these objections I will now mention.

It is sometimes said that science can only deal with what is, but that art and morals deal with what ought to be. The saying is perfectly true, but it is quite consistent with what is equally true, that the facts of art and morals are fit subject-matter of science. I may describe all that I have in my house, and I may state everything that I want in my house; these are two very different things, but they are equally statements of facts. One is a statement about phenomena, about the objects which are actually in my possession; the other is a statement about my feelings, about my wants and desires. There are facts, to be got at by common sense, about the kind of thing that a man of a certain character and occupation will like to have in his house, and these facts may be organized into general statements on the assumption of uniformity in nature. Now the organized results of common sense dealing with facts are just science and nothing else. And in the same way I may say what men do at the present day, how we live now, or I may say what we ought to do, namely, what course of conduct, if adopted, we should morally approve; and no doubt these would be two very different things. But each of them would be a statement of facts. One would belong to the sociology of our time; in so far as men's deeds could not be adequately described to us without some account of their feelings and intentions, it would involve facts belonging to psychology as well as facts belonging to the physical sciences. But the other would be an account of a particular class of our feelings, namely, those which we feel toward an action when it is regarded as right or wrong. These facts may be organized by common sense on the assumption of uniformity in nature just as well as any other facts. And we shall see farther on that not only in this sense, but in a deeper and more abstract sense, 'what ought to be done' is a question for scientific inquiry.

The same objection is sometimes put into another form. It is said that laws of chemistry, for example, are general statements about what happens when bodies are treated in a certain way, and that such laws are fit matter for science; but that moral laws are different, because they tell us to do certain things, and we may or may not obey them. The mood of the one is indicative, of the other imperative. Now it is quite true that the word law in the expression 'law of nature,' and in the expressions 'law of morals,' 'law of the land,' has two totally different meanings, which no educated person will confound; and I am not aware that any one has rested the claim of science to judge moral questions on what is no better than a stale and unprofitable pun. But two different things may be equally matters of scientific investigation, even when their names are alike in sound. A telegraph post is not the same thing as a post in the War Office, and yet the same intelligence may be used to investigate the conditions of the one and the other. That such and such things are right or wrong, that such and such laws are laws of morals or laws of the land, these are facts, just as the laws of chemistry are facts; and all facts belong to science, and are her portion forever.

Again, it is sometimes said that moral questions have been authoritatively settled by other methods; that we ought to accept this decision, and not to question it by any method of scientific inquiry; and that reason should give way to revelation on such matters. I hope before I have done to show just cause why we should pronounce on such teaching as this no light sentence of moral condemnation: first, because it is our duty to form those beliefs which are to guide our actions by the two scientific modes of inference, and by these alone; and, secondly, because the proposed mode of settling ethical questions by authority is contrary to the very nature of right and wrong.

Leaving this, then, for the present, I pass on to the most formidable objection that has been made to a scientific treatment of ethics. The objection is that the scientific method is not applicable to human action, because the rule of uniformity does not hold good. Whenever a man exercises his will, and makes a voluntary choice of one out of various possible courses, an event occurs whose relation to contiguous events cannot be included in a general statement applicable to all similar cases. There is something wholly capricious and disorderly, belonging to that moment only; and we have no right to conclude that if the circumstances were exactly repeated, and the man himself absolutely unaltered, he would choose the same course.

It is clear that if the doctrine here stated is true, the ground is really cut from under our feet, and we cannot deal with human action by the scientific method. I shall endeavor to show, moreover, that in this case, although we might still have a feeling of moral approbation or reprobation toward actions, yet we could not reasonably praise or blame men for their deeds, nor regard them as morally responsible. So that, if my contention is just, to deprive us of the scientific method is practically to deprive us of morals altogether. On both grounds, therefore, it is of the greatest importance that we should define our position in regard to this controversy; if, indeed, that can be called a controversy in which the practical belief of all mankind and the consent of nearly all serious writers are on one side.

Let us in the first place consider a little more closely the connection between conscience and responsibility. Words in common use, such as these two, have their meanings practically fixed before difficult controversies arise; but after the controversy has arisen each party gives that slight tinge to the meaning which best suits its own view of the question. Thus it appears to each that the common language obviously supports their own view, that this is the natural and primary view of the matter, and that the opponents are using words in a new meaning and wrestling them from their proper sense. Now this is just my position. I have endeavored so far to use all words in their common every-day sense, only making this as precise as I can; and, with two exceptions, of which due warning will be given, I shall do my best to continue this practice in future. I seem to myself to be talking the most obvious platitudes; but it must be remembered that those who take the opposite view will think I am perverting the English language.