Part 3

Sense perception is obviously possible only through processes in the sensory organs, and objects were thought of as producing impressions through the sensory organs in the brain, and the mind as then becoming aware of them in the brain. Hence, when Locke says that the mind only knows its own ideas, he tends to mean (though the facts are sometimes too much for him and he is nobly inconsistent) that the mind only knows objects inside the brain. The main objection to this doctrine, apart from the fact that it is based on a confusion, is that it makes it quite inexplicable how the notion of an outside world ever arises. For if we know, and must eternally know, only ideas inside our head, why should we ever imagine that there an outside world exists. Yet if nothing outside us were observed--if we knew of no process which went on between outside objects and the brain, the doctrine would have no basis on which to rest. There cannot be any meaning in saying something is "only an idea," if we do not know what is real in the sense of its having an existence independent of our minds.

Locke supposed that, although we knew only ideas, we could somehow refer from our ideas to an outside world. For he thought that truth was concerned with the agreement of our ideas with reality. This form of the doctrine, the commonest, is sometimes called Representationism. For it thinks of the mind as concerned with representations, or pictures, or images which it may compare with the real objects. Its futility is obvious enough. We can only compare a picture with the thing it represents, if we can know both. If we can only know ideas, we can never know that they are only ideas, and can never compare them with anything else.

This difficulty was seen by Berkeley, the most consistent of subjective idealists, and led him to deny the existence of outside objects, and hold that existence or reality meant being perceived and nothing more. But if we take Berkeley's position, it becomes very difficult to say what we mean by judgments being true. If things only exist as we think of them, or perceive them, or rather if they are only our thinking of or perceiving them, the question of the truth or falsity of our statements about them cannot arise.

This idealism Kant is careful to refute, and he points out that there is no evidence for its fundamental proposition that we know our mind more directly than we know objects. We are only conscious of ourselves in knowing something not ourselves. We do not invent the notion of externality or outsideness in space from an experience in which it originally has no part. Externality is implied in our most simple experience. We begin with consciousness of outside things, and only become conscious of our own mental states or processes later. But it is important to observe that, the truth or falsity of subjective idealism has no bearing whatsoever on the question with which Kant was concerned. If I ask how I can lay down rules about what I have not yet experienced, I am not in the least helped by being told that I only experience what is in my mind. For the question will equally arise, How do I know what is going to be in my mind? The question idealism ordinarily discusses, as to whether the objects of our awareness are in our mind or outside, are in their nature mental and dependent on the mind or not, is entirely and absolutely irrelevant to Kant's purposes.

But it is a fact, and one that has got to be explained that in judgment we go beyond what is present to our minds, and that, in so anticipating what we shall experience, we assume that certain principles hold of all that has been or may be present. With that difficulty idealism, as ordinarily understood, has nothing to do. Representationism tried to give some account of this going beyond what is present to our minds by suggesting that truth is a reference from ideas to reality; but, as we saw, if we know only ideas, such a reference is impossible. The doctrines opposed to representationism, that only ideas exist, or that we directly know real objects, allow the existence of nothing contrasted with what we are apprehending to which a reference in judgment can be made. No one who is satisfied with any of these positions can have seen Kant's problem.

If Kant then, is not a subjective idealist what does he mean by saying, as he constantly does, that we only know phenomena, and why should that limitation of knowledge help him in any of his difficulties? He means, in the first place, that all knowledge depends upon perception. The first paragraph of the first part of the Critique of Pure Reason makes that clear. "Whatever the process and the means may be by which knowledge reaches its objects, there is one that reaches them directly and forms the ultimate material of all thought, viz. perception. This is possible only when the object is given, and the object can be given only (to human beings, at least) through a certain affection of the mind."

Now, although we perceive an objective reality, sense perception obviously gives a very imperfect knowledge of objects. We see only some sides and aspects of things, and not others. What we see depends on changes in our position. Further, we know that what we see is only a small part of the nature of anything. We think of reality as an interconnected system, but we only perceive a very small part of it, and what we perceive depends upon the particular time and the particular part of space in which we live. In our experience we are never really content simply with what we perceive; we perceive much too little for that. We are always inferring from what we see to something beyond it. What is that something beyond, which, as we have seen, is implied in all judgment? We might hold that it was the things as they really are as distinguished from things as they appear, or phenomena, and that, when we turned from perception to thought, we turned from illusion to reality. Kant denied this. He held that, if you examine a scientific judgment about anything you perceive, such as that yellow thing is gold, you will find that, if you know what the judgment means, you will be able to say: Then, under such-and-such conditions--if you weigh it, for example--you will have such-and-such a perception. The appeal is not from what you perceive to what you think, but from what you perceive now to what you will perceive under such-and-such conditions. Such a reference indeed, implies thought and what is ordinarily called a concept; but our knowledge of concepts used in science always means that, if we know what is meant e.g. by calling anything gold, we know how it will behave under such-and-such conditions. The concept, in Kant's words, is a function of unity in our representations. The task of thought, then, is not to turn the mind away from what we perceive, but to help us to transcend some of the limitations of our perceptions, or, to speak more accurately, to set somewhat further back the limits of our perception; for thought never entirely transcends these limits. Our knowledge is always conditioned by the fact that we are finite minds living in a particular place and at a particular time; but thought can extend the range of our perception in space and in time.

The limitations of our perception have, for Kant, a double aspect, which determines his division of the first part of the Critique into two parts--the AEsthetic and the Analytic. In the first place, our direct knowledge of space at any one time is always knowledge only of a part of space; our direct knowledge of time, whether in present consciousness or in memory of our own experience, is knowledge of only a part of time; and the things in the space we directly perceive, or in the time we experience, are what they are by their relation to space outside the space we see, and time beyond the time we experience, and that limited space and time we treat, therefore, as parts of one all-embracing space and one all-embracing time, and in the conception of an indefinitely extended space and time we can think of the space in which all things exist, and the time in which all things occur, of which we only see and experience a small part. The science of astronomy obviously talks of space and time far beyond anything we could ever perceive, but we go beyond such direct perception in such simple expressions as "forty miles from here" or "three days hence." And, when Kant says that space and time are only phenomenal, he does not mean that they are mental, but that we only know them through perception, and that we get at absolute space and time not by going from what we perceive to what we think, but by thinking of what we perceive indefinitely extended. All definite statements about space must come back in the end to "so far from here," all about time to "so long from now," and the fact that all our knowledge of space and time is got by adding to or extending in thought the space and time we directly perceive does, according to Kant, solve some obstinate puzzles about the nature of space and time.

In the second place, if we consider our knowledge of objects, we realise that, as we said, at any one moment we only perceive them in part or from one position. What we directly perceive of them is fragmentary and discontinuous, one aspect seen now, and another aspect seen at another time. But we do not think of the things as existing in that discontinuous way; we think of them as having a nature of their own. That does not contradict, but is something very much more than, what we perceive, and our knowledge of any object is got by piecing together the aspects we directly perceive; but that piecing together, or synthesis, is not haphazard. It is governed by rules--rules partly derived from the nature of the particular thing we are concerned with, and partly more general rules, which come from the relation of this work of piecing together to the framework of space and time by help of which it is done.

Kant's conception of knowledge, then, is something like this. Each of us is in direct contact with reality, but we perceive directly only a small part of it, and, as our consciousness moves on in time, and as we change our position in space, we are directly conscious of different small portions of reality. A part of the whole is illumined by direct perception, but the whole stretches beyond that indefinitely in space and time. In the part we directly perceive there is a temporal order and a spatial order. Things are given to us arranged in space and ordered in time, and these arrangements or orders in the space and time that is directly given to us in perception have certain rules, and we think of these principles of arrangement as extending indefinitely beyond the space and time given to us in perception. When we make judgments about reality beyond our perception, we think of things as so arranged in the space and time beyond our perception as we should see them arranged were the range of our perception sufficiently wide. Further, it is most important to remember that we do not remain in one place and at one time and make guesses of what may happen in the darkness beyond. Though our perception at any one moment is limited, we can connect what we see at one time with what we see at another. We can, by means of language and writing, use the perception of others to fill out our experience, until gradually our scientific judgments, our knowledge of what we should perceive under all sorts of possible experience, seems to bulk much more largely than could our individual perceptions. But we are still, Kant would say, getting at our knowledge of what is beyond by piecing together what we and other people have perceived, and the whole is always much more than that.

What, then, is meant by the contention that we can know things in themselves which Kant is earnest to refute? It might mean that we do in perception attain to a complete knowledge, but that would be obviously untrue. As Kant understood the claim, it meant rather something like this: In thought we are obviously not limited by our perception. We are always assuming certain principles, such as the laws of space or the principle of causation, to hold of all reality, both what we do and what we do not directly perceive. May we not say, then, that these principles hold of all reality, and argue from that fact to what the nature of the whole must be? If everything that we know is caused, e.g., may we not apply the principle of causation to all reality and say that it must have a cause?

When we come to consider the Dialectic, the second main division of the first Critique, we shall notice Kant's detailed analysis of these arguments, and how he points out that you can in this way get contradictory results. In the meantime it must be observed that in these arguments we start from principles applied to what we perceive and expressing connections between the different things we perceive, and then apply them beyond everything we do or could perceive. That means that we imagine that we can take these principles out of relation not only to this or that detail of perception, but out of relation to any perception at all, and thus apprehend reality by thought independently of perception.

Kant's answer is that thought cannot directly apprehend the nature of the whole, and these universal principles, such as the principle of causation, are only principles by which we connect one perception with another to amend the discontinuous and fragmentary nature of our perception; they are rules for the synthesis of what we perceive. By so synthesising our perceptions we come to a less imperfect knowledge of the whole, but apart from perceptions the principles have no meaning at all.

Kant's idealism, i.e. his insistence that we know only phenomena, not things in themselves, is relevant to his problem, because it implies the denial of the view that thought has objects apprehended independently of perception, and because it insists that we can only know directly what we perceive, or things as they appear to us, that in our process from perception to knowledge we start with what is present to our perception and end with what is or with what might be present to our perception, and that this process is possible by reason of our continued consciousness in time. The process, Kant holds, is governed by certain principles. These depend upon the part played by space and time in all our perception, and the manner in which we employ space and time in piecing together our discontinuous perceptions.

Now, obviously it is quite possible to hold this position without having thought out what is implied in being present to the mind in perception. This is what Kant did. He describes perception in different and inconsistent ways. The reason for this inconsistency is that Kant is not concerned with the nature of perception, but with the relation of what is immediately perceived to what is not but may be immediately perceived, and he therefore never worked out any consistent account of perception. He sometimes talks of perception reaching objects directly, and refutes the view that we perceive only what is in our mind. (This, indeed, is implied in his distinction of space and time as forms of external and internal sense respectively.) But usually he takes the ordinary idealist view that we do not perceive things, but affections produced in us by things. Owing to this inconsistency Kant constantly seems to be stating very much more than he has any right to. This is especially true in all that he says about knowledge being confined to phenomena and not extending to things in themselves. When he talks of our knowing only phenomena, he sometimes seems to mean that we know objects, things in themselves, only in part, in so far as they appear to us. That would make the distinction between the phenomenon and the thing in itself a distinction between the same thing imperfectly and perfectly understood. He sometimes, and this is his more usual view, seems to mean that we are aware of appearances, entities separate and distinguishable from the objects which produce them in our minds. But if we work out in any of Kant's arguments the point of his appeal to the fact that knowledge is only of phenomena, we shall find that in every case the difference between a subjective idealist and a realist view of perception, of what "being present to the mind" means, is irrelevant, and that his argument holds on either theory.

We must now turn to Kant's account of space and time which is given in the AEsthetic, the first part of the Critique. He begins by showing the impossibility of the two views of the nature of space and time which then held the field, the views of Newton and Leibniz. Newton had thought of space and time as realities, things in themselves existing along with other things. But obviously we cannot think of space as a separate thing existing by itself; for space without things would have no determination or possibility of determination, and would be to us just nothing, whereas, as it is, it is something to us. The same holds of time. The Newtonian doctrine, Kant says, "forces us to assume two eternal, infinite, and self-subsisting non-realities, which are there, without any reality in them, only that they may comprehend all reality." Just because things are in space and time, space and time are not themselves things. But if this makes us say that space and time are only relations between or qualities of things, we find ourselves in difficulties as obvious. We do not come to apprehend space and time by comparing things and seeing that they have a common quality of being "spatial" or "temporal," as we come to apprehend redness, e.g., by seeing red things. The perception of space and time is implied in each and every perception of things. We cannot, therefore, derive them from our study of things; we must begin with them. Further, Kant notices, as against Leibniz, that space and time are not ordinary concepts because they have no instances. Different men are instances of man, but different spaces or times are only parts or determinations of the one space and the one time. As against the view, then, that would make space and time only relations, derived from our comparison of things which are not temporal or spatial, Kant insists that space and time are a priori. We cannot see things without seeing them outside one another--i.e. in space--or experience succession or change without experiencing it in time. Space and time, then, have a certain independence of things in space and time. The qualitative differences of things in space or events in time do not affect the nature of space and time, and we can and do study and discuss spatial and temporal relations quite independently of such differences.

Space and time, then, can be abstracted from things in space and time. Yet, on the other hand, we cannot think that space and time exist independently of things. They do not exist in abstraction; for, though the specific differences of things in space and time are irrelevant to the nature of space and time, if there were no things, or if there were no differences, there could be no space and time as we know them. "The empirical perception," says Kant, "is not compounded of phenomena and space, of the sensation and the empty perception." Space and time, therefore, Kant says, are not things in themselves.

What, then, are they? Kant's answer is that they are forms of our perception. Space is the form of external perception, and time is the form of internal perception, and Kant holds that by this answer we can understand both how our knowledge of space and time may be a priori, how spatial and temporal distinctions may be abstracted from the differences of things, and how we may avoid the difficulties consequent on regarding time and space as independent things.

What, then, does Kant mean by form? He seems to mean two things, which he does not clearly distinguish. The first meaning is best described in his own words: "In the phenomenon I call what corresponds to the sensation the matter of the phenomenon, and that which causes that the manifold of the phenomenon is perceived as arranged in specific relations I call the form of the phenomenon." We are here face to face with the ultimate difference of form and matter, or order and that which is ordered. When Kant calls time and space the form of our perception he is simply calling attention to the fact that in all that we perceive we find this distinction. It is something found, given, not made by us. By the word "form" Kant does not mean anything specially subjective as contrasted with matter or content, for he carefully distinguishes between space and time, and such qualities as colour, which get their nature in part, he thinks, from the specific nature of the sense organ. Compared with such qualities space and time are objective. The phrase "forms of our perception," then, does not really explain anything about space and time; it only emphasises the fact that the distinction between space and time and objects in them is found in what we perceive, and that there is no meaning in discussing either side of the distinction as though it were quite independent of what we perceive.

But form has also another meaning which justifies Kant in calling space and time only forms of our perception, and hence subjective. For, while these forms are found in what we perceive, the distinctive part which they play in our knowledge is due to the fact that we use space and time as a framework by which to connect our scattered experiences. We come to think of the space and time we perceive as parts of an absolute space and an absolute time. We perceive parts of space and time, but absolute space and absolute time we do not perceive. They are the form we perceive imagined indefinitely extended. We order the particular parts of space and time which we do perceive in reference to absolute space and time. Yet absolute space and time are only known through the finite parts of space and time which we actually experience. Hence absolute space and time are not perceived realities or perceived orders, but ways in which we organise and arrange what we perceive. Now, the qualities of space and time which are hard to think of as the qualities of a thing that exists, i.e. their infinite divisibility and infinite extension, are qualities of absolute space and time. When we say that space is infinitely divisible, we do not mean that any existing thing is made up of an infinite number of parts. The divisibility of space and the divisibility of matter are quite different. An inch as a spatial determination is infinitely divisible, but the divisibility of the actual stuff which any inch may measure is a matter of empirical investigation, and ought to admit of a definite answer. That means that, while we use determinations of space which we consider infinitely divisible and infinitely extensible to measure things in space, we do not consider that these determinations, fractions, or multiples of inches or centimetres, have anything to do with the constitution of the thing they measure. It was not put together in fractions of inches. Thus we must distinguish between space as the form of what we perceive, the next-each-otherness of things, and the use we make of that form to construct by means of measurement order in all different perception. The first is obviously the form only of what we perceive, and gives rise to no transcendental questions. But the second, infinite space, though it seems to transcend our perception, has still only meaning in reference to perception, is only a way of ordering our perceptions. The same holds good of time.

We can see now what Kant means by saying that time and space are empirically real and transcendentally ideal. Kant does not maintain that space and time are illusions. They are a constant element of what is given us in perception. It is only when we try and go beyond our perceptions, and take space and time as things existing independently of what we perceive, thus trying to transcend the limits of possible perception, that we fall into illusion. Space and time have meaning only as elements in what we perceive, or in connecting what we perceive now with what we may perceive.

*CHAPTER IV*

*THE CATEGORIES AND THE PRINCIPLES OF PURE UNDERSTANDING*

Kant makes the distinction between perception and understanding depend upon the distinction between the receptivity and the spontaneity of the mind. In the AEsthetic he has been concerned with time and space as elements in what seems to be given to the mind. Before we begin to ask the questions of science, before we analyse, describe, or classify, before we have to think, we perceive. Time and space are not got at by thinking or generalisation. For before we can say anything about any part of our experience, it is given us in a certain spatial and temporal order. If we open our eyes at any moment, we are, without any conscious effort of thought on our part, confronted with an elaborate content. It seems simple to distinguish this receptive attitude of the mind in perception from its activity in thinking.

The distinction is not really so simple as it appears. For we all know that what we perceive depends, at least to some extent, on the mind's activity. We are familiar with the reflection that men see what they want to see or what they are looking for. This is clearly shown in the case of hearing by the difference in what we hear when we are listening to a language we understand and when we are listening to an unfamiliar language, or in the common experience when, after failing to hear what someone has said, we think what it must have been, and then seem to recall the sound, not as we heard it, but as we should have heard it if we had heard it rightly. Anyone who reflects on the process of fast reading will realise that we do not perceive or notice all the letters on a page; we fill in from our imagination, as we discover when we read words that are not on the page. It is a very hard thing, giving up all interpretation and inference, to describe faithfully just what is there to see.

Passive perception, then, does not exist, and our thought affects our perception. Yet, at the same time, the distinction between thought and perception, although not simple, is real. For although our previous thought affects our perception and we see things already classified, see books, and tables, and chairs, not merely coloured surfaces, yet we can distinguish between simple immediate perception and the process of thought which begins when we ask, What is that? i.e. when we begin to make judgments.

The characteristic of thought, according to Kant, is synthesis, or putting together, and all synthesis is the work of the mind. When we begin to describe and classify the contents of our perception, we pick out separate qualities from the continuous whole we perceive, and group them together. This grouping is, of course, determined by the likenesses and differences which we perceive everywhere, but we do not, in judging, confine ourselves to noticing likeness and difference. For any content of our perception has some point of resemblance, and some of difference with any other. We are concerned with likenesses that go with or are the signs of other likenesses. On the basis of perceived likeness we erect the notion of things and qualities of a certain kind. In doing this we go beyond what we see, and unite and arrange the contents of our perception through concepts. That is what we are doing when we say that is a so-and-so. For example, if I say that rock is like a dog, I am simply expressing a likeness I perceive. I do not imply that the rock is therefore alive or will bark; I am not going beyond how the rock looks; but if I say that object is a dog, I assert that all that is implied in being a dog will hold of that object, i.e. that it will have a certain appearance and behaviour, which is known. I can anticipate, therefore, how it will behave, look, and sound under certain circumstances. All these phenomena, the appearance, the barking, and running, though I may perceive them at different times and places, are grouped together in the judgment, "That is a dog." This is what Kant means by saying, "Concepts depend on functions. By function I mean the unity of the act of arranging different representations under one common representation." Concepts, therefore, always refer to perception, and it is by means of concepts that we are enabled to introduce such order into what we perceive, that we can anticipate from what we perceive what we shall perceive. "Perceptions without concepts are blind." Without concepts what we perceive would not lead us in any way beyond what is immediately given. "Thoughts without contents are empty." Concepts are nothing, and have no meaning apart from the contents of perception which they unify.

Most of these concepts are what is called empirical. We get at them by observing likenesses and differences in what we perceive, and observing which are significant and important, and which are what we call accidental. Science, in its discovery of laws, is only carrying further this process which is implied in all simple judgments. By observing likenesses and differences, their uniformities and variations, and discovering those which are a key to the rest, we improve our concepts, and thereby have more knowledge of what we call natural laws, and can more and more anticipate experience. With these empirical concepts and their development Kant is not concerned. But there are certain concepts of which Hume had observed that they are not obtained in the ordinary way from an examination of the contents of experience. The two with which he chiefly concerned himself were substance and cause. These concepts seems to play an especially important part in the ordering and arranging of the concepts of experience. For the work of science, in moving from a simple observation of likenesses and differences to a knowledge of empirical laws, depends upon certain assumptions or principles, like the principle of causation or the principle of the conservation of energy. These principles imply concepts not derived, like the others, from generalisation from experience; they are the synthetic a priori judgments which, as we have seen, constituted a special problem for Kant.