Philosophy

We have considered perception already from the behaviourist standpoint, and also from that of physics. In the present chapter we are to consider it from the standpoint of self-observation, with a view to discovering as much as we can about the intrinsic character of the event in us when we perceive. I shall begin with certain traditional doctrines as to mental events, and shall thence pass to the doctrines that I wish to advocate.

The words “mind” and “matter” are used glibly, both by ordinary people and by philosophers, without any adequate attempt at definition. Philosophers are much to blame for this. My own feeling is that there is not a sharp line, but a difference of degree; an oyster is less mental than a man, but not wholly un-mental. And I think “mental” is a character, like “harmonious” or “discordant”, that cannot belong to a single entity in its own right, but only to a system of entities. But before defending this view, I wish to spend some time on the theories that have been current in the past.

Traditionally, there are two ways of becoming aware that something exists, one by the senses, the other by what is called “introspection”, or what Kant called the “inner sense”. By means of introspection, it is maintained, we become aware of occurrences quite different in kind from those perceived through the outer senses. Occurrences known through introspection are traditionally called “mental”, and so are any other occurrences which intrinsically resemble them.

Mental occurrences are traditionally of three main types, called knowing, willing, and feeling. “Feeling”, in this connection, means pleasure and unpleasure—we do not say “pleasure and pain”, because “pain” is an ambiguous word: it may stand for painful sensation, as when you say “I have a pain in my tooth”, or it may stand for the unpleasant character of the sensation. Roughly pleasure is a quality which makes you want an experience to continue, and unpleasure is the opposite quality which makes you want an experience to stop. However, I am not concerned to enlarge upon feeling at present.

As for the other two kinds of mental occurrence, “knowing” and “willing” are recognised as too narrow to describe what is meant. Philosophers wish to include not only knowledge but also error, and not only the sort of knowledge that is expressed in beliefs but also the sort that occurs in perception. The word “cognition” or “cognitive state” is used to cover everything that could possibly be described as either knowledge or error; perception is prima facie included, but pure sensation is more debatable.

“Willing”, again, is too narrow a term. A term is required which will include desire and aversion, and generally those states of mind which lead up to action. These are all included under the head of “conation”, a technical term invented for this special purpose.

Cognition and conation both have, in the orthodox theory, the property of being directed to an object. What you perceive or believe, what you desire or will, is something different from your state of mind. To take instances: you remember a past event, but your remembering occurs now; therefore your remembering is a different occurrence from what you remember. You will to move your arm, but the movement is a physical occurrence, and therefore obviously different from your volition. Many psychologists have taken this relation to an object as the essential characteristic of mind—notably the two Austrians Brentano and Meinong. Sometimes feeling also is regarded as having an object: it is held that we are pleased or displeased at something. This view, however, has never won general acceptance, whereas the view that cognition and conation are directed to objects may be regarded as orthodox.

It is undeniable that this characteristic of being directed to objects is, in some sense, a property of cognition and conation, but there is room for great difference of opinion as to the proper analysis of the property. I think we cannot hope to understand the word “mental” until we have undertaken this analysis, and I shall therefore proceed to address myself to it. I shall confine myself to cognition, which is more important for our present purposes than conation.

As regards cognition, though philosophers have disagreed widely, I think that, until recently, most would have assented to at least the following paragraph:

Cognition is of various sorts. Take, as important kinds, perception, memory, conception, and beliefs involving concepts. Perception is the ordinary awareness of sensible objects: seeing a table, hearing a piano, and so on. Memory is awareness of a past occurrence, when this awareness is direct, not inferred or derived from testimony. Conception is more difficult to characterise. One may say, as a way of pointing out what is intended, that we “conceive” whenever we understand the meaning of an abstract word, or think of that which is in fact the meaning of the word. If you see a white patch of snow, or recall it by means of images, you do not have a concept; but if you think about whiteness, you have a concept. Similarly if, after seeing a number of coins, you think about roundness as a common characteristic of all of them, you have a concept. The object of your thought, in such a case, is a universal or a Platonic idea. Every sentence must contain at least one word expressing a concept, and therefore every belief that can be expressed in words contains concepts.

Each of these kinds of cognitive attitude involves its own problems. In the present chapter we are concerned with perception. This has to be treated both introspectively and causally; it is the introspective treatment that we have now to undertake.

When you have the experience called “seeing a table”, there is a certain amount of difference between your unreflecting judgment and what careful examination reveals as to the nature of your experience. You judge that the table is rectangular, but the patch of colour in your visual field is not a rectangle; when you learn to draw, you have to draw the table as it really seems and not as it seems to seem. You have images of sensations of touch; if you were to try to touch the table and it turned out to be an optical illusion, you would get a violent shock of surprise. You have also expectations of a certain degree of permanence and weight. If you went to lift the table, you would find your muscles quite wrongly adjusted if the table were much lighter than it looked. All these elements must be included in the perception, though not in the sensation.

“Sensation”, as opposed to perception, is more or less hypothetical. It is supposed to be the core, in the perception, which is solely due to the stimulus and the sense-organ, not to past experience. When you judge that the table is rectangular, it is past experience that enables and compels you to do so; if you had been born blind and just operated upon, you could not make this judgment. Nor would you have expectations of hardness, etc. But none of this can be discovered by introspection. From an introspective point of view, the elements due to past experience are largely indistinguishable from those due to the stimulus alone. One supposes that past experience modifies the brain, and thereby modifies the mental occurrence due to the stimulus. The notion of sensation as opposed to perception belongs, therefore, to the causal study of perception, not to the introspective study.

There is, however, a distinction to be made here. You can discover by mere self-observation that visual objects are accompanied by expectations or images of touch; and similarly if you touch an object in the dark you will probably be led to form some visual image of it. Here you can arrive at a certain degree of analysis of your perception through the fact that images, as a rule, feel different from the immediate results of a sensory stimulus. On the other hand, no amount of introspection alone will reveal such things as the blind spot. The filling in of a sensation by elements belonging to the same sense is much less discoverable by introspection than the filling in by associated images belonging to other senses. Thus although by introspection alone we could discover part of the influence of experience on perception, there is another part which we cannot discover in this way.

Remaining in the introspective attitude, it is evident that the contents of our minds at any given moment are very complex. Throughout our normal waking life we are always seeing, hearing, and touching, sometimes smelling and tasting, always having various bodily sensations, always feeling pleasant or unpleasant feelings (usually both), always having desires or aversions. We are not normally aware of all these items, but we can become aware of any of them by turning our attention in the right direction. I am not at present discussing “unconscious mental states”, because they, obviously, can only be known causally, and we are now considering what can be known introspectively. There may be any number of perceptions that cannot be known by introspection; the point for us, at the moment, is that those that can be discovered by introspection at any one time are many and various.

I do not wish, just now, to discuss the nature of attention; I wish only to point out that it enables us to take the first steps in abstraction. Out of the whole multiplicity of objects of sense, it enables us to single out a small selection, which is an indispensable preliminary to abstraction. For example, attention will enable us to discriminate a coloured pattern which we are seeing, and to separate it from the other things we see and from images and other objects of sense and thoughts which may exist simultaneously. For the sake of simplicity, let us suppose that we discriminate a black and white pattern in the form of a triangle. Within this pattern we can further discriminate sides and angles and an inside and outside—of course the sides are not mathematical lines nor the angles mathematical points.

We now come to a question of very great importance, upon which our views of the relations of mind and matter largely depend. The question is this:

What difference is there between the propositions “there is a triangle” and “I see a triangle”?

Both these statements seem as certain as any statement can be—at least if rightly interpreted. As always happens in such cases, we are quite certain of something, but not quite certain what it is that we are certain of. I want to ask whether this something that we are certain of is really different in the above two statements, or whether the difference between them is only as to surroundings of which we are not certain. Most philosophers hold that there is a difference in what we are certain of; Mach, James, Dewey, the American realists, and I hold that the difference is in the uncertain context. Let us examine this question.

The suggestions of the two statements “I see a triangle” and “there is a triangle” are obviously different. The first states an event in my life, and suggests its possible effects upon me. The second aims at stating an event in the world, supposed to be equally discoverable by other people. You might say “there is a triangle” if you had seen it a moment ago but now had your eyes shut; in this case you would not say “I see a triangle”. On the other hand, one sometimes, under the influence of indigestion or fatigue, sees little black dots floating in the air; in such circumstances you would say “I see a black dot”, but not “there is a black dot”. This illustration shows that when you say “there is a black dot” you are making a stronger assertion than when you say “I see a black dot”. In the other case, when you say “there is a triangle” because you saw it a moment ago, though not now, you have three stages: First, memory assures you of the proposition “I saw a triangle”, and then you pass on to “there was a triangle”, and then, further, to “there is a triangle, because nothing can have happened to destroy it so quickly.” Here we have obviously passed far beyond the region of immediate certainty.

It seems clear, therefore, that, of our two statements, the one which comes nearest to expressing the fact of which we are immediately certain is “I see a triangle”, because the other makes inferences to something public, and thus goes beyond the bare datum. This is on the assumption that we should not say “there is a black dot” when we see a black dot which we attribute to eye-trouble and therefore suppose that no one else can see. Let us therefore concentrate upon “I see a triangle”, and ask ourselves whether the whole of this, or only part, can be accepted as a primitive certainty.

A moment’s reflection shows that both “I” and “see” are words which take us beyond what the momentary event reveals. Take “I” to begin with. This is a word whose meaning evidently depends upon memory and expectation. “I” means the person who had certain remembered experiences and is expected to have certain future experiences. We might say “I see a triangle now and I saw a square a moment ago.” The word “I” has exactly the same meaning in its two occurrences in this sentence, and therefore evidently has a meaning dependent upon memory. Now it is our object to arrive at the contribution to your knowledge which is made by seeing the triangle at the moment. Therefore, since the word “I” takes you beyond this contribution, we must cut it out if we want to find a correct verbal expression for what is added to our knowledge by seeing the triangle. We will say “a triangle is being seen”. This is at any rate one step nearer to what we are seeking.

But now we must deal with the word “seen”. As ordinarily used, this is a causal word, suggesting something dependent upon the eyes. In this sense, it obviously involves a mass of previous experience; a new-born baby does not know that what it sees depends upon its eyes. However, we could eliminate this. Obviously all objects of sight have a common quality, which no objects of touch or hearing have; a visual object is different from an auditory object, and so on. Therefore instead of saying “a triangle is being seen”, we should say “there is a visual triangle”. Of course the meanings of the words “visual” and “triangle” can only be learnt by experience, but they are not logically dependent upon experience. A being could be imagined which would know the words at birth; such a being could express its datum in the words “there is a visual triangle”. In any case, the problems remaining belong to the study of concepts; we will therefore ignore them at present.

Now in English the words “there is” are ambiguous. When I used them before, saying, “there is a triangle”, I meant them in the sense of “voila” or “da ist”. Now I mean them in the sense of “il y a” or “es giebt”. One might express what is meant by saying “a visual triangle exists”, but the word “exist” has all sorts of metaphysical connotations that I wish to avoid. Perhaps it is best to say “occurs”.

We have now arrived at something which is just as true when your perception is illusory as when it is correct. If you say “a visual black dot is occurring”, you are speaking the truth, if there is one in your field of vision. We have eliminated the suggestion that others could see it, or that it could be touched, or that it is composed of matter in the sense of physics. All these suggestions are present when one says, in ordinary conversation, “there is a black dot”; they are intended to be eliminated by the addition of the word “visual” and the substitution of “is occurring” for “there is”. By these means we have arrived at what is indubitable and intrinsic in the addition to your knowledge derived from a visual datum.

We must now ask ourselves once more: Is there still a distinction, within what is immediate and intrinsic, between the occurrence of a visual datum and the cognition of it? Can we say, on the basis of immediate experience, not only “a visual black dot occurs”, but also “a visual black dot is cognised”? My feeling is that we cannot. When we say that it is cognised, we seem to me to mean that it is part of an experience, that is to say, that it can be remembered, or can modify our habits, or, generally, can have what are called “mnemic” effects. All this takes us beyond the immediate experience into the realm of its causal relations. I see no reason to think that there is any duality of subject and object in the occurrence itself, or that it can properly be described as a case of “knowledge”. It gives rise to knowledge, through memory, and through conscious or unconscious inferences to the common correlates of such data. But in itself it is not knowledge, and has no duality. The datum is a datum equally for physics and for psychology; it is a meeting point of the two. It is neither mental nor physical, just as a single name is neither in alphabetical order nor in order of precedence; but it is part of the raw material of both the mental and the physical worlds. This is the theory which is called “neutral monism”, and is the one that I believe to be true.