Philosophy · Bertrand Russell
SELF-OBSERVATION
It will be remembered that throughout Part I, we agreed to consider only those facts about a man which can be discovered by external observation, and we postponed the question whether this excluded any genuine knowledge or not. The usual view is that we know many things which could not be known without self-observation, but the behaviourist holds that this view is mistaken. I might be inclined to agree wholly with the behaviourist but for the considerations which were forced upon us in Part II, when we were examining our knowledge of the physical world. We were then led to the conclusion that, assuming physics to be correct, the data for our knowledge of physics are infected with subjectivity, and it is impossible for two men to observe the same phenomenon except in a rough and approximate sense. This undermines the supposed objectivity of the behaviourist method, at least in principle; as a matter of degree, it may survive to some extent. Broadly speaking, if physics is true and if we accept a behaviourist definition of knowledge such as that of Chapter VIII, we ought, as a rule, to know more about things that happen near the brain than about things that happen far from it, and most of all about things that happen in the brain. This _seemed_ untrue because people thought that what happens in the brain is what the physiologist sees when he examines it; but this, according to the theory of Chapter XII, happens in the brain of the physiologist. Thus the _a priori_ objection to the view that we know best what happens in our brains is removed, and we are led back to self-observation as the most reliable way of obtaining knowledge. This is the thesis which is to be expanded and sustained in the present chapter.
As every one knows, the certainty of self-observation was the basis of Descartes’ system, with which modern philosophy began. Descartes, being anxious to build his metaphysic only upon what was absolutely certain, set to work, as a preliminary, to doubt anything that he could make himself doubt. He succeeded in doubting the whole external world, since there might be a malicious demon who took pleasure in presenting deceitful appearances to him. (For that matter, dreams would have supplied a sufficient argument.) But he could not manage to doubt his own existence. For, said he, I am really doubting; whatever else may be doubtful, the fact that I doubt is indubitable. And I could not doubt if I did not exist. He summed up the argument in his famous formula: _I think, therefore I am_. And having arrived at this certainty, he proceeded to build up the world again by successive inferences. Oddly enough, it was very like the world in which he had believed before his excursion into scepticism.
It is instructive to contrast this argument with Dr. Watson’s. Dr. Watson, like Descartes, is sceptical of many things which others accept without question; and, like Descartes, he believes that there are some things so certain that they can be safely used as the basis of a startling philosophy. But the things which Dr. Watson regards as certain are just those which Descartes regarded as doubtful, and the thing which Dr. Watson most vehemently rejects is just what Descartes regarded as absolutely unquestionable. Dr. Watson maintains that there is no such thing as thinking. No doubt he believes in his own existence, but not because he thinks he can think. The things that strike him as absolutely indubitable are rats in mazes, time-measurements, physiological facts about glands and muscles, and so on. What are we to think when two able men hold such opposite views? The natural inference would be that _everything_ is doubtful. This may be true, but there are degrees of doubtfulness, and we should like to know which of these two philosophers, if either, is right as to the region of minimum doubtfulness.
Let us begin by examining Descartes’ view. “I think, therefore I am” is what he says, but this won’t do as it stands. What, from his own point of view, he should profess to know is not “_I_ think”, but “there is thinking”. He finds doubt going on, and says: There is doubt. Doubt is a form of thought, therefore there is thought. To translate this into “_I_ think” is to assume a great deal that a previous exercise in scepticism ought to have taught Descartes to call in question. He would say that thoughts imply a thinker. But why should they? Why should not a thinker be simply a certain series of thoughts, connected with each other by causal laws? Descartes believed in “substance”, both in the mental and in the material world. He thought that there could not be motion unless something moved, nor thinking unless some one thought. No doubt most people would still hold this view; but in fact it springs from a notion--usually unconscious--that the categories of grammar are also the categories of reality. We have already seen that “matter” is merely a name for certain strings of sets of events.
It follows that what we call motion of matter really means that the centre of such a set of events at one time does not have the same spatial relations to other events as the connected centre at another time has to the connected other events. It does not mean that there is a definite entity, a piece of matter, which is now in one place and now in another. Similarly, when we say, “I think first this and then that”, we ought not to mean that there is a single entity “I” which “has” two successive thoughts. We ought to mean only that there are two successive thoughts which have causal relations of the kind that makes us call them parts of one biography, in the same sort of way in which successive notes may be parts of one tune; and that these thoughts are connected with the body which is speaking in the way (to be further investigated) in which thoughts and bodies are connected. All this is rather complicated, and cannot be admitted as part of any ultimate certainty. What Descartes really felt sure about was a certain occurrence, which he described in the words “I think”. But the words were not quite an accurate representation of the occurrence; indeed, words never can escape from certain grammatical and social requirements which make them say at once more and less than we really mean. I think we ought to admit that Descartes was justified in feeling sure that there was a certain occurrence, concerning which doubt was impossible; but he was not justified in bringing in the word “I” in describing this occurrence, and it remains to be considered whether he was justified in using the word “think”.
In using a general word such as “think”, we are obviously going beyond the datum, from a logical point of view. We are subsuming a particular occurrence under a heading, and the heading is derived from past experience. Now all words are applicable to many occurrences; therefore all words go beyond any possible datum. In this sense, it is impossible ever to convey in words the particularity of a concrete experience; all words are more or less abstract. Such, at least, is a plausible line of argument, but I am by no means sure that it is valid. For example, the sight of a particular dog may make the general word “dog” come into your mind; you then know that it is a dog, but you may not notice what sort of dog it is. In this sense, the knowledge with which we start is abstract and general; that is to say, it consists of a learned reaction to a stimulus of a certain sort. The reactions, at any rate in so far as they are verbal, are more uniform than the stimuli. A witness might be asked “Did you see a dog?” “Yes.” “What sort of dog?” “Oh, just an ordinary dog; I don’t remember more about it.” That is to say, the witness’s reaction consisted of the generalised word “dog” and no more. One is almost reminded of quantum phenomena in the atom. When light falls on a hydrogen atom, it may make the electron jump from the first orbit to the second, or to the third, etc. Each of these is a generalised reaction to a stimulus which has no corresponding generality. So dogs and cats have each their individual peculiarities, but the ordinary inobservant person responds with the generalised reaction “dog” or “cat”, and the particularity of the stimulus leads to no corresponding particularity in the knowledge-reaction.
To return to Descartes and his thinking: it is possible, according to what we have just said, that Descartes knew he was thinking with more certainty than he knew what he was thinking about. This possibility requires that we should ask what he meant by “thinking”. And since, for him, thinking was the primitive certainty, we must not introduce any external stimulus, since he considered it possible to doubt whether anything external existed. Descartes used the word “thinking” somewhat more widely than we should generally do nowadays. He included all perception, emotion, and volition, not only what are called “intellectual” processes. We may perhaps with advantage concentrate upon perception. Descartes would say that, when he “sees the moon”, he is more certain of his visual percept than he is of the outside object. As we have seen, this attitude is rational from the standpoint of physics and physiology, because a given occurrence in the brain is capable of having a variety of causes, and where the cause is unusual common sense will be misled. It would be theoretically possible to stimulate the optic nerve artificially in just the way in which light coming from the moon stimulates it; in this case, we should have the same experience as when we “see the moon”, but should be deceived as to its external source. Descartes was influenced by an argument of this sort, when he brought up the possibility of a deceitful demon. Therefore what he felt certain about was not what he had initially felt certain about, but what remained certain after an argument as to the causes of perception. This brings us to a distinction which is important, but difficult to apply; the distinction between what we in fact do not doubt, and what we should not doubt if we were completely rational. We do not in fact question the existence of the sun and moon, though perhaps we might teach ourselves to do so by a long course of Cartesian doubt. Even then, according to Descartes, we could not doubt that we have the experiences which we have hitherto called “seeing the sun” and “seeing the moon”, although we shall need different words if we are to describe these experiences correctly.
The question arises: Why should we not doubt everything? Why should we remain convinced that we have these experiences? Might not a deceitful demon perpetually supply us with false memories? When we say “a moment ago I had the experience which I have hitherto called seeing the sun”, perhaps we are deceived. In dreams we often remember things that never happened. At best, therefore, we can be sure of our present momentary experience, not of anything that happened even half a minute ago. And before we can so fix our momentary experience as to make it the basis of a philosophy, it will be past, and therefore uncertain. When Descartes said “I think”, he may have had certainty; but by the time he said “therefore I am”, he was relying upon memory, and may have been deceived. This line of argument leads to complete scepticism about everything. If we are to avoid such a result, we must have some new principle. In actual fact, we start by feeling certainty about all sorts of things, and we surrender this feeling only where some definite argument has convinced us that it is liable to lead to error. When we find any class of primitive certainties which never leads to error, we retain our convictions in regard to this class. That is to say, wherever we feel initial certainty, we require an argument to make us doubt, not an argument to make us believe. We may therefore take, as the basis of our beliefs, any class of primitive certainties which cannot be shown to lead us into error. This is really what Descartes does, although he is not clear about it himself.
Moreover, when we have found an error in something of which we were previously certain, we do not as a rule abandon entirely the belief which misled us, but we seek, if we can, to modify it so that it shall no longer be demonstrably false. This is what has happened with perception. When we think we see an external object, we may be deceived by a variety of causes. There may be a mirage or a reflection; in this case, the source of the error is in the external world, and a photographic plate would be equally deceived. There may be a stimulus to the eye of the sort that makes us “see stars”, or we may see little black dots owing to a disordered liver, in which case, the source of the error is in the body but not in the brain. We may have dreams in which we seem to see all sorts of things; in this case, the source of the error is in the brain. Having gradually discovered these possibilities of error, people have become somewhat wary as to the objective significance of their perceptions; but they have remained convinced that they really have the perceptions they thought they had, although the common-sense interpretation of them is sometimes at fault. Thus, while retaining the conviction that they are sure of something, they have gradually changed their view as to what it is that they are sure of. Nothing is known that tends to show error in the view that we really have the percepts we think we have, so long as we are prudent in interpreting them as signs of something external. That is the valid basis for Descartes’ view that “thought” is more certain than external objects. When “thought” is taken to mean the experiences which we usually regard as percepts of objects, there are sound reasons for accepting Descartes’ opinion to this extent.
Let us now take up Dr. Watson’s view. We shall find, if I am not mistaken, that his position also is to a very large extent valid. That being so, we shall seek to find an intermediate opinion, accepting what seems valid and rejecting what seems doubtful in the contentions of both protagonists. Dr. Watson’s view as to what is most certain is one which is in entire accordance with common sense. All psychological matters the plain man regards as more or less open to question, but he has no doubts about his office, his morning train, the tax-collector, the weather, and the other blessings of this life. It may amuse him, in an idle hour, to listen to some one playing with the idea that life is a dream, or suggesting that the thoughts of the people in the train are more real than the train. But unless he is a philosophical lecturer, he does not countenance such notions in business hours. Who can imagine a clerk in an office conceiving metaphysical doubts as to the existence of his boss? Or would any railroad president regard with favour the theory that his railroad is only an idea in the minds of the shareholders? Such a view, he would say, though it is often sound as regards gold-mines, is simply silly when it comes to a railroad: anybody can see it, and can get himself run over if he wanders on the tracks under the impression that they do not exist. Belief in the unreality of matter is likely to lead to an untimely death, and that, perhaps, is the reason why this belief is so rare, since those who entertained it died out. We cannot dismiss the common-sense outlook as simply silly, since it succeeds in daily life; if we are going to reject it in part, we must be sure that we do so in favor of something equally tough as a means of coping with practical problems.
Descartes says: I think, therefore I am. Watson says: There are rats in mazes, therefore I don’t think. At least, a parodist might thus sum up his philosophy. What Watson really says is more like this: (1) The most certain facts are those which are public, and can be confirmed by the testimony of a number of observers. Such facts form the basis of the physical sciences: physics, chemistry, biology, anatomy, physiology, to mention only those that are relevant to the matter in question. (2) The physical sciences are capable of affording an explanation of all the publicly observable facts about human behaviour. (3) There is no reason to suppose that there are any facts about human beings that can be known only in some other way. (4) In particular, “introspection”, as a means of discovering by self-observation things that are in principle undiscoverable by observation of others, is a pernicious superstition, which must be swept away before any really sound knowledge of man becomes possible. (5) And, as a corollary, there is no reason to believe in the existence of “thought” as opposed to speech and other bodily behaviour. I have numbered the above propositions, as it is important to keep them separate. On the whole, (1), (2), and (3) seem to me to be true, but (4) and (5) seem to me to be false. Behaviourists, I think, incline to the view that (4) and (5) follow from (1), (2), and (3); but this view I attribute to what I should regard as errors concerning the basis of physics. That is why it was necessary to discuss physics before coming to a decision on this question of self-observation. But let us examine each of the above propositions in turn.
(1) It is true that the facts upon which the physical sciences are based are all of them public, in the sense that many men can observe them. If a phenomenon is photographed, any number of people can inspect the photograph. If a measurement is made, not only may several people be present, but others can repeat the experiment. If the result does not confirm the first observer, the supposed fact is rejected. The publicity of physical facts is always regarded as one of the greatest assets of physics. On a common-sense basis, therefore, the first of the propositions in which we have summed up the behaviourist philosophy must be admitted. There are, however, some very important provisos which must be mentioned. In the first place, a scientific observer is not expected to note his integral reaction to a situation, but only that part of it which experience leads him to regard as “objective”, _i.e._ the same as the reaction of any other competent observer. This process of learning to note only “objective” features in our reaction is, as we have seen, begun in infancy; training in science only carries it further. A “good” observer does not mention what is peculiar to himself in his reaction. He does not say: “A boring speck of light danced about, causing me eye-fatigue and irritation; finally it settled at such-and-such a point.” He says simply: “The reading was such-and-such”. All this objectivity is a result of training and experience. One may say, in fact, that very few men have the “right” reaction to a scientific situation. Therefore an immense amount of theory is mixed up with what passes in science as pure observation. The nature and justification of this theory is a matter requiring investigation.
In the second place, we must not misinterpret the nature of the publicity in the case of physical phenomena. The publicity consists in the fact that a number of people make closely similar reactions at a given moment. Suppose, for example, that twelve men are told to watch a screen for the appearance of a bright light, and to say “now” when it appears. Suppose the experimenter hears them all just when he himself sees the light; then he has good reason to believe that they have each had a stimulus similar to his. But physics compels us to hold that they have had twelve separate stimuli, so that when we say they have all seen the same light we can only legitimately mean that their twelve stimuli had a common causal origin. In attributing our perceptions to a normal causal origin outside ourselves, we run a certain risk of error, since the origin may be unusual: there may be reflection or refraction on the way to the eye, there may be an unusual condition of the eye or optic nerve or brain. All these considerations give a certain very small probability that, on a given occasion, there is not such an outside cause as we suppose. If, however, a number of people concur with us, _i.e._ simultaneously have reactions which they attribute to an outside cause that can be identified with the one we had inferred, then the probability of error is enormously diminished. This is exactly the usual case of concurrent testimony. If twelve men, each of whom lies every other time that he speaks, independently testify that some event has occurred, the odds in favour of their all speaking the truth are 4095 to 1. The same sort of argument shows that our public senses, when confirmed by others, are probably speaking the truth, except where there are sources of collective illusion such as mirage or suggestion.
In this respect, however, there is no _essential_ difference between matters of external observation and matters of self-observation. Suppose, for example, that, for the first time in your life, you smell assafœtida. You say to yourself “that is a most unpleasant smell”. Now unpleasantness is a matter of self-observation. It may be _correlated_ with physiological conditions which can be observed in others, but it is certainly not identical with these, since people knew that things were pleasant and unpleasant before they knew about the physiological conditions accompanying pleasure and its opposite. Therefore when you say “that smell is unpleasant” you are noticing something that does not come into the world of physics as ordinarily understood. You are, however, a reader of psycho-analysis, and you have learned that sometimes hate is concealed love and love is concealed hate. You say to yourself, therefore: “Perhaps I really like the smell of assafœtida, but am ashamed of liking it”. You therefore make your friends smell it, with the result that you soon have no friends. You then try children, and finally chimpanzees. Friends and children give verbal expression to their disgust: chimpanzees are expressive, though not verbal. All these facts lead you to state: “The smell of assafœtida is unpleasant”. Although self-observation is involved, the result has the same kind of certainty, and the same kind of objective verification, as if it were one of the facts that form the empirical basis of physics.
(2) The second proposition, to the effect that the physical sciences are capable of affording an explanation of all the publicly observable facts about human behaviour, is one as to which it is possible to argue endlessly. The plain fact is that we do not yet know whether it is true or false. There is much to be said in its favour on general scientific grounds, particularly if it is put forward, not as a dogma, but as a methodological precept, a recommendation to scientific investigators as to the direction in which they are to seek for solution of their problems. But so long as much of human behaviour remains unexplained in terms of physical laws, we cannot assert dogmatically that there is no residue which is theoretically inexplicable by this method. We may say that the trend of science, so far, seems to render such a view improbable, but to say even so much is perhaps rash, though, for my part, I should regard it as still more rash to say that there certainly is such a residue. I propose, therefore, as a matter of argument, to admit the behaviourist position on this point, since my objections to behaviourism as an ultimate philosophy come from quite a different kind of considerations.
Ideas discussed in this chapter
Text from Project Gutenberg, public domain in the United States.