Philosophy

The word “knowledge”, like the word “memory”, is avoided by the behaviourist. Nevertheless there is a phenomenon commonly called “knowledge”, which is tested behaviouristically in examinations. I want to consider this phenomenon in this chapter, with a view to deciding whether there is anything in it that the behaviourist cannot deal with adequately. It will be remembered that, in Chapter II, we were led to the view that knowledge is a characteristic of the complete process from stimulus to reaction, or even, in the cases of sight and hearing, from an external object to a reaction, the external object being connected with the stimulus by a chain of physical causation in the outer world. Let us, for the moment, leave on one side such cases as sight and hearing, and confine ourselves, for the sake of definiteness, to knowledge derived from touch. We can observe touch producing reactions in quite humble animals, such as worms and sea anemones. Are we to say that they have “knowledge” of what they touch? In some sense, yes. Knowledge is a matter of degree. When it is regarded in a purely behaviouristic manner, we shall have to concede that it exists, in some degree, wherever there is a characteristic reaction to a stimulus of a certain kind, and this reaction does not occur in the absence of the right kind of stimulus. In this sense, “knowledge” is indistinguishable from “sensitivity”, which we considered in connection with perception. We might say that a thermometer “knows” the temperature, and that a compass “knows” the direction of the magnetic north. This is the only sense in which, on grounds of observation, we can attribute knowledge to animals that are low in the scale. Many animals, for example, hide themselves when exposed to light, but as a rule not otherwise. In this, however, they do not differ from a radiometer. No doubt the mechanism is different, but the observed molar motion has similar characteristics. Wherever there is a reflex, an animal may be said, in a sense, to “know” the stimulus. This is, no doubt, not the usual sense of “knowledge”, but it is the germ out of which knowledge in the usual sense has grown, and without which no knowledge would be possible. Knowledge in any more advanced sense is only possible as a result of learning, in the sense considered in Chapter III. The rat that has learned the maze “knows” the way out of it; the boy who has learned certain verbal reactions “knows” the multiplication table. Between these two cases there is no important difference. In both cases, we say that the subject “knows” something because he reacts in a manner advantageous to himself, in which he could not react before he had had certain experiences. I do not think, however, that we ought to use such a notion as “advantageous” in connection with knowledge. What we can observe, for instance, with the rat in the maze, is violent activity until the food is reached, followed by eating when it is reached; also a gradual elimination of acts which do not lead to the food. Where this sort of behaviour is observed, we may say that it is directed towards the food, and that the animal “knows” the way to the food when he gets to it by the shortest possible route. But if this view is right, we cannot define any knowledge acquired by learning except with reference to circumstances toward which an animal’s activity is directed. We should say, popularly, that the animal “desires” such circumstances. “Desire”, like “knowledge”, is capable of a behaviouristic definition, and it would seem that the two are correlative. Let us, then, spend a little time on the behaviouristic treatment of “desire”. The best example of desire, from this point of view, is hunger. The stimulus to hunger is a certain well-ascertained bodily condition. When in this condition, an animal moves restlessly; if he sees or smells food, he moves in a manner which, in conditions to which he is accustomed, would bring him to the food; if he reaches it, he eats it, and if the quantity is sufficient he then becomes quiescent. This kind of behaviour may be summarised by saying that a hungry animal “desires” food. It is behaviour which is in various ways different from that of inanimate matter, because restless movements persist until a certain condition is realised. These movements may or may not be the best adapted to realising the condition in question. Every one knows about the pike that was put on one side of a glass partition, with minnows on the other side. He continually bumped his nose on the glass, and after six weeks gave up the attempt to catch them. When, after this, the partition was removed, he still refrained from pursuing them. I do not know whether the experiment was tried of leaving a possibility of getting to the minnows by a roundabout route. To have learned to take a roundabout route would perhaps have required a degree of intelligence beyond the capacity of fishes; this is a matter, however, which offers little difficulty to dogs or monkeys. What applies to hunger applies equally to other forms of “desire”. Every animal has a certain congenital apparatus of “desires”; that is to say, in certain bodily conditions he is stimulated to restless activities which tend towards the performance of some reflex, and if a given situation is often repeated the animal arrives more and more quickly at the performance of the reflex. This last, however, is only true of the higher animals; in the lower, the whole process from beginning to end is reflex, and can therefore only succeed in normal circumstances. The higher animals, and more especially men, have a larger proportion of learning and a smaller proportion of reflexes in their behaviour, and are therefore better able to adapt themselves to new circumstances. The helplessness of infants is a necessary condition for the adaptability of adults; infants have fewer useful reflexes than the young of animals, but have far more power of forming useful habits, which can be adapted to circumstances and are not fatally fixed from birth. This fact is intimately connected with the superiority of the human intelligence above that of the brutes. Desire is extremely subject to “conditioning”. If A is a primitive desire and B has on many occasions been a means to A, B comes to be desired in the same sense in which A was previously desired. It may even happen, as in misers, that the desire for B completely displaces the desire for A, so that B, when attained, is no longer used as a means to A. This, however, is more or less exceptional. In general, the desire for A persists, although the desire for B has a more or less independent life. The “conditioning” of primitive desires in human beings is the source of much that distinguishes our life from that of animals. Most animals only seek food when they are hungry; they may, then, die of starvation before they find it. Men, on the contrary, must have early acquired pleasure in hunting as an art, and must have set out on hunting expeditions before they were actually hungry. A further stage in the conditioning of hunger came with domestic animals; a still further stage with agriculture. Nowadays, when a man sets to work to earn his living, his activity is still connected, though not very directly, with hunger and the other primitive desires that can be gratified by means of money. These primitive desires are still, so to speak, the power station, though their energy is widely distributed to all sorts of undertakings that seem, at first sight, to have no connection with them. Consider “freedom” and the political activities it inspires; this is derivable, by “conditioning”, from the emotion of rage which Dr. Watson observed in infants whose limbs are not “free”. Again we speak of the “fall” of empires and of “fallen” women; this is connected with the fear which infants display when left without support. After this excursion into the realm of desire, we can now return to “knowledge”, which, as we saw, is a term correlative to “desire”, and applicable to another feature of the same kind of activity. We may say, broadly, that a response to a stimulus of the kind involving desire in the above sense shows “knowledge” if it leads by the quickest or easiest route to the state of affairs which, in the above sense, is behaviouristically the object of desire. Knowledge is thus a matter of degree: the rat, during its progressive improvements in the maze, is gradually acquiring more and more knowledge. Its “intelligence quotient”, so far as that particular task is concerned, will be the ratio of the time it took on the first trial to the time it takes now to get out of the maze. Another point, if our definition of knowledge is accepted, is, that there is no such thing as purely contemplative knowledge: knowledge exists only in relation to the satisfaction of desire, or, as we say, in the capacity to choose the right means to achieve our ends. But can such a definition as the above really stand? Does it represent at all the sort of thing that would commonly be called knowledge? I think it does in the main, but there is need of some discussion to make this clear. In some cases, the definition is obviously applicable. These are the cases that are analogous to the rat in the maze, the consideration of which led us to our definition. Do you “know” the way from Trafalgar Square to St. Pancras? Yes, if you can walk it without taking any wrong turnings. In practice, you can give verbal proof of such knowledge, without actually having to walk the distance; but that depends upon the correlation of names with streets, and is part of the process of substituting words for things. There may, it is true, come doubtful cases. I was once on a bus in Whitehall, and my neighbour asked “What street is this?” I answered him, not without surprise at his ignorance. He then said, “What building is that?” and I replied “The Foreign Office”. To this he retorted, “but I thought the Foreign Office was in Downing Street”. This time, it was his knowledge that surprised me. Should we say that he knew where the Foreign Office is? The answer is yes or no according to his purpose. From the point of view of sending a letter to it, he knew; from the point of view of walking to it, he did not know. He had, in fact, been a British Consul in South America, and was in London for the first time. But now let us come to cases less obviously within the scope of our definition. The reader “knows” that Columbus crossed the ocean in 1492. What do we mean by saying that he “knows” this? We mean, no doubt, primarily that writing down this statement is the way to pass examinations, which is just as useful to us as getting out of the maze is to the rat. But we do not mean only this. There is historical evidence of the fact, at least I suppose there is. The historical evidence consists of printed books and manuscripts. Certain rules have been developed by historians as to the conditions in which statements in books or manuscripts may be accepted as true, and the evidence in our case is (I presume) in accordance with these rules. Historical facts often have importance in the present; for example, wills, or laws not yet repealed. The rules for weighing historical evidence are such as will, in general bring out self-consistent results. Two results are self-consistent when, in relation to a desire to which both are relevant, they enjoin the same action, or actions which can form part of the