Kant's Theory of Knowledge Part 6

We may now turn to the way in which we draw the distinction with respect to the secondary qualities of physical things. It must, it seems, be admitted that in our ordinary consciousness we treat these qualities as real qualities of bodies. We say that a bell is noisy; that sugar is sweet; that roses smell; that a mustard plaster is hot; that the sky is blue. It must also be admitted that in our ordinary consciousness we draw a distinction between appearance and reality _within_ these qualities, just as we do _within_ the primary qualities. Just as we speak of the right or real shape of a body, so we speak of its right or real colour, taste, &c., and distinguish these from its apparent colours, taste, &c., to some individual. We thereby imply that these qualities are real qualities of bodies, and that the only difficulty is to determine the particular character of the quality in a given case. Yet, as the history of philosophy shows, it takes but little reflection to throw doubt on the reality of these qualities. The doubt arises not merely from the apparent impossibility of finding a principle by which to determine the right or real quality in a given case, but also and mainly from misgivings as to the possible reality of heat, smell, taste, noise, and colour apart from a percipient. It must also be admitted that this misgiving is well founded; in other words, that these supposed real qualities do presuppose a percipient, and therefore cannot be qualities of things, since the qualities of a thing must exist independently of the perception of the thing.[20] This will readily be allowed in the case of all the secondary qualities except colour. No one, it may reasonably be said, who is familiar with and really faces the issue, will maintain that sounds, smells, tastes, and sensations of touch exist apart from a sensitive subject. So much is this the case, that when once the issue is raised, it is difficult and, in the end, impossible to use the word 'appear' in connexion with these qualities.

Thus it is difficult and, in the end, impossible to say that a bell _appears_ noisy, or that sugar _appears_ sweet. We say, rather, that the bell and the sugar produce certain sensations[21] in us.

[20] Cf. pp. 72-3, and 91.

[21] _Not_ 'appearances'.

The case of colour, however, is more difficult. From the closeness of its relation to the shape of bodies, it seems to be a real quality of bodies, and not something relative to a sensitive subject like the other secondary qualities. In fact, so intimate seems the relation of colour to the shape of bodies, that it would seem--as has, of course, often been argued--that if colour be relative to a sensitive subject, the primary qualities of bodies must also be relative to a sensitive subject, on the ground that shape is inseparable from colour.[22] Yet whether this be so or not, it must, in the end, be allowed that colour does presuppose a sensitive subject in virtue of its own nature, and quite apart from the difficulty--which is in itself insuperable--of determining the right colour of individual bodies. It must, therefore, be conceded that colour is not a quality of bodies. But if this be true, the use of the term 'look' or 'appear' in connexion with colour involves a difficulty which does not arise when it is used in connexion with the primary qualities. Bodies undoubtedly look or appear coloured. Now, as has already been suggested,[23] the term 'look' seems to presuppose some ident.i.ty between what a thing is and what it looks, and at least the possibility of cases in which they are what they look--a possibility which, as we have seen, is realized in the case of the primary qualities. Yet, if colour is not a quality of bodies, then, with respect to colour, things look what they never are, or, in other words, are wholly different from what they look;[24] and since it seems impossible to hold that colour is really a property of bodies, this conclusion must, in spite of its difficulty, be admitted to be true.

[22] Cf. p. 91 note.

[23] Cf. p. 82.

[24] It is a.s.sumed that there is not even plausibility in the supposition of continuity or ident.i.ty between colour proper and its physical conditions in the way of light vibrations.

There remain, however, to be noticed two respects in which a.s.sertions concerning what things look in respect of colour agree with corresponding a.s.sertions in respect of the primary qualities. They imply that what we perceive is a reality, in the sense already explained.[25] Thus the a.s.sertion that the gra.s.s looks green implies that it is a reality which looks green, or, in other words, that the object of perception is a reality, and not an 'appearance'. Again, such a.s.sertions imply that the reality about which the a.s.sertion is made is spatial. The term 'gra.s.s' implies extension, and only what is extended can be said to look coloured. If it be urged that what looks coloured need only _look_ extended, it may be replied that the two considerations which lead us to think that things only _look_ coloured presuppose that they _are_ spatial. For the two questions, the consideration of which leads to this conclusion, are, 'What is the right or real colour of an individual thing?' and 'Has it really any colour at all, or does it only look coloured?' and neither question is significant unless the thing to which it refers is understood to be spatial.

[25] I. e. in the sense of something which exists independently of perception.

We may now return to the main issue. Is it possible to maintain either (1) the position that only appearances are spatial and possess all the qualities which imply s.p.a.ce, or (2) the position that things only appear spatial and only appear or look as if they possessed the qualities which imply s.p.a.ce? It may be urged that these questions have already been implicitly answered in the negative. For the division of the qualities of things into primary and secondary is exhaustive, and, as has been shown, the distinction between 'appearance' and 'reality', when drawn with respect to the primary qualities and to colour--the only secondary quality with respect to which the term 'appears' can properly be used[26]--presupposes the reality of s.p.a.ce. Consequently, since we do draw the distinction, we must accept the reality of that which is the condition of drawing it at all. But even though this be conceded--and the concession is inevitable--the problem cannot be regarded as solved until we have discovered what it is in the nature of s.p.a.ce which makes both positions untenable. Moreover, the admission that in the case of colour there is no ident.i.ty between what things look and what they are removes at a stroke much of the difficulty of one position, viz. that we only know what things look or appear, and not what they are. For the admission makes it impossible to maintain as a general principle that there must be some ident.i.ty between what they look and what they are. Consequently, it seems _possible_ that things should be wholly different from what they appear, and, if so, the issue cannot be decided on general grounds. What is in substance the same point may be expressed differently by saying that just as things only _look_ coloured, so things may only _look_ spatial. We are thus again[27] led to see that the issue really turns on the nature of s.p.a.ce and of spatial characteristics in particular.

[26] Cf. pp. 86-7.

[27] Cf. p. 79.

In discussing the distinction between the real and the apparent shape of bodies, it was argued that while the nature of s.p.a.ce makes it necessary to distinguish in general between what a body looks and what it is, yet the use of the term _look_ receives justification from the existence of limiting cases in which what a thing looks and what it is are identical. The instances considered, however, related to qualities involving only two dimensions, e. g. convergence and bentness, and it will be found that the existence of these limiting cases is due solely to this restriction. If the a.s.sertion under consideration involves a term implying three dimensions, e. g. 'cubical' or 'cylindrical', there are no such limiting cases. Since our visual perception is necessarily subject to conditions of perspective, it follows that although we can and do see a cube, we can never see it as it _is_.

It _is_, so to say, in the way in which a child draws the side of a house, i. e. with the effect of perspective eliminated; but it never can be seen in this way. No doubt, our unreflective knowledge of the nature of perspective enables us to allow for the effect of perspective, and to ascertain the real shape of a solid object from what it looks when seen from different points. In fact, the habit of allowing for the effect of perspective is so thoroughly ingrained in human beings that the child is not aware that he is making this allowance, but thinks that he draws the side of the house as he sees it. Nevertheless, it is true that we never see a cube as it is, and if we say that a thing looks cubical, we ought only to mean that it looks precisely what a thing looks which is a cube.

It is obvious, however, that two dimensions are only an abstraction from three, and that the spatial relations of bodies, considered fully, involve three dimensions; in other words, spatial characteristics are, properly speaking, three-dimensional. It follows that terms which fully state spatial characteristics can never express what things look, but only what they are. A body may be cylindrical, and we may see a cylindrical body; but such a body can never, strictly speaking, _look_ cylindrical. The opposition, however, between what a thing _is_ and what it _looks_ implies that what it _is_ is independent of a percipient, for it is precisely correlation to a percipient which is implied by 'looking' or 'appearing'. In fact, it is the view that what a thing really is it is, independently of a percipient, that forms the real starting-point of Kant's thought.

It follows, then, that the spatial characteristics of things, and therefore s.p.a.ce itself, must belong to what they are in themselves apart from a percipient, and not to what they look.[28] Consequently, it is so far from being true that we only know what things look and not what they are, that in the case of spatial relations we actually know what things are, even though they never look what they are.

[28] This consideration disposes of the view that, if colour is relative to perception, the primary qualities, as being inseparable from colour, must also be relative to perception; for it implies that the primary qualities cannot from their very nature be relative to perception. Moreover, if the possibility of the separation of the primary qualities from colour is still doubted, it is only necessary to appeal to the blind man's ability to apprehend the primary qualities, though he may not even know what the word 'colour' means. Of course, it must be admitted that some sensuous elements are involved in the apprehension of the primary qualities, but the case of the blind man shows that these may relate to sight instead of to touch. Moreover, it, of course, does not follow from the fact that sensuous elements are inseparable from our perception of bodies that they belong to, and are therefore inseparable from, the bodies perceived.

This conclusion, however, seems to present a double difficulty. It is admitted that we perceive things as they look, and not as they are.

How, then, is it possible for the belief that things _are_ spatial to arise? For how can we advance from knowledge of what they look to knowledge of what they are but do not look? Again, given that the belief has arisen, may it not after all be illusion? No vindication seems possible. For how can it be possible to base the knowledge of what things are, independently of perception, upon the knowledge of what they look? Nevertheless, the answer is simple. In the case of the perception of what is spatial there is no transition _in principle_ from knowledge of what things look to knowledge of what things are, though there is continually such a transition _in respect of details_.

It is, of course, often necessary, and often difficult, to determine the precise position, shape, &c., of a thing, and if we are to come to a decision, we must appeal to what the thing looks or appears under various conditions. But, from the very beginning, our consciousness of what a thing appears in respect of spatial characteristics implies the consciousness of it as spatial and therefore also as, in particular, three-dimensional. If we suppose the latter consciousness absent, any a.s.sertion as to what a thing appears in respect of spatial characteristics loses significance. Thus, although there is a process by which we come to learn that railway lines are really parallel, there is no process by which we come to learn that they are really spatial. Similarly, although there is a process by which we become aware that a body is a cube, there is no process by which we become aware that it has a solid shape of some kind; the process is only concerned with the determination of the precise shape of the body.

The second difficulty is, therefore, also removed. For if a.s.sertions concerning the apparent shape, &c. of things presuppose the consciousness that the things _are_ spatial, to say that this consciousness may be illusory is to say that all statements concerning what things _appear_, in respect of spatial relations, are equally illusory. But, since it is wholly impossible to deny that we can and do state what things appear in this respect, the difficulty must fall to the ground.

There remains to be answered the question whether Kant's position is tenable in its other form, viz. that while we cannot say that reality is spatial, we can and must say that the appearances which it produces are spatial. This question, in view of the foregoing, can be answered as soon as it is stated. We must allow that reality is spatial, since, as has been pointed out, a.s.sertions concerning the apparent shape of things presuppose that they are spatial. We must equally allow that an appearance cannot be spatial. For on the one hand, as has just been shown, s.p.a.ce and spatial relations can only qualify something the existence of which is not relative to perception, since it is impossible to perceive what is spatial as it is; and on the other hand an appearance, as being _ex hypothesi_ an appearance to some one, i. e. to a percipient, must be relative to perception.

We may say, then, generally, that a.n.a.lysis of the distinction between appearance and reality, as it is actually drawn in our ordinary consciousness, shows the falsity of both forms of the philosophical agnosticism which appeals to the distinction. We know things; not appearances. We know what things are; and not merely what they appear but are not. We may also say that Kant cannot possibly be successful in meeting, at least in respect of s.p.a.ce, what he calls 'the easily foreseen but worthless objection that the ideality of s.p.a.ce and of time would turn the whole sensible world into pure illusion'.[29] For s.p.a.ce, according to him, is not a property of things in themselves; it cannot, as has been shown, be a property of appearances; to say that it is a property of things as they appear to us is self-contradictory; and there is nothing else of which it can be said to be a property.

[29] _Prol_., -- 13, Remark iii. (Cf. p. 100 note.) Cf. the confused note B. 70, M. 42. (See Dr. Vaihinger's Commentary on the _Critique_, ii, 488 ff.)

In conclusion, it may be pointed out that the impossibility that s.p.a.ce[30] and spatial characteristics should qualify appearances renders untenable Kant's attempt to draw a distinction between reality and appearance _within_ 'phenomena' or 'appearances'. The pa.s.sage in which he tries to do so runs as follows:

[30] The case of time can be ignored, since, as will be seen later (pp. 112-14), the contention that s.p.a.ce is 'ideal'

really involves the admission that time is real.

"We generally indeed distinguish in appearances that which essentially belongs to the perception of them, and is valid for every human sense in general, from that which belongs to the same perception accidentally, as valid not for the sensibility in general, but for a particular state or organization of this or that sense. Accordingly, we are accustomed to say that the former is knowledge which represents the object itself, whilst the latter represents only the appearance of the same. This distinction, however, is only empirical. If we stop here (as is usual) and do not again regard that empirical perception as itself a mere phenomenon (as we ought to do), in which nothing which concerns a thing in itself is to be found, our transcendental distinction is lost; and in that case we are after all believing that we know things in themselves, although in the world of sense, investigate its objects as profoundly as we may, we have to do with nothing but appearances. Thus we call the rainbow a mere appearance during a sunny shower, but the rain the thing in itself; and this is right, if we understand the latter conception only physically as that which in universal experience and under all different positions with regard to the senses is in perception so and so determined and not otherwise. But if we consider this empirical element[31] in general, and inquire, without considering its agreement with every human sense, whether it represents an object in itself (not the raindrops, for their being phenomena by itself makes them empirical objects), the question of the relation of the representation to the object is transcendental; and not only are the raindrops mere appearances, but even their circular form, nay, even the s.p.a.ce in which they fall, are nothing in themselves but mere modifications or fundamental dispositions of our sensuous perception; the transcendental object, however, remains unknown to us."[32]

[31] _Dieses Empirische._

[32] B. 62-3, M. 37-8. _Erscheinung_ is here translated 'appearance'.

Kant's meaning is plain. He is anxious to justify the physical distinction made in our ordinary or non-philosophical consciousness between a thing in itself and a mere appearance,[33] but at the same time to show that it falls within appearances, in respect of the philosophical distinction between things in themselves and appearances or phenomena. The physical distinction is the first of which we become aware, and it arises through problems connected with our senses.

Owing, presumably, to the contradictions which would otherwise ensue, the mind is forced to distinguish between things and the 'appearances'

which they produce, and to recognize that they do not correspond. The discrepancy is due to the fact that our perceptions are conditioned by the special positions of our physical organs with regard to the object of perception, and we discover its real nature by making allowance for these special positions. We thereby advance in knowledge to the extent of overcoming an obstacle due to the nature of our senses. But, this obstacle overcome, philosophical reflection forces upon us another.

The thing which we distinguish in our ordinary consciousness from its appearances is, after all, only another appearance; and although the physical problem is solved concerning its accordance with our special senses, there remains the philosophical problem as to whether this appearance need correspond to what in the end is the real thing, viz.

that which exists in itself and apart from all perception. The only possible answer is that it need not. We therefore can only know appearances and not reality; in other words, we cannot have knowledge proper. At the same time, our knowledge of appearances is objective to the extent that the appearances in question are the same for every one, and for us on various occasions; for the effects due to special positions of our senses have been removed. If, therefore, we return to the physical distinction, we see that the 'things' to which it refers are only a special kind of appearance, viz. that which is the same for every one, and for us at all times. The physical distinction, then, being a distinction between one kind of appearance and another, falls within 'phenomena' or 'appearances'.

[33] It should be noticed that the pa.s.sage is, in the main, expressed in terms of the distinction between 'things' and 'appearances', and not, as it should be, in terms of the distinction between what things are and what things appear or look.

Now the obvious objection to this line of thought is that the result of the second or metaphysical application of the distinction between reality and appearance is to destroy or annul the first or physical application of it. To oppose the rain, i. e. the raindrops as the thing in itself to the rainbow as a mere appearance is to imply that the rain is not an appearance. For though what is opposed to a _mere_ appearance may still be an appearance, it cannot be called an appearance at all if it be described as the thing in itself. If it be only another appearance, it is the same in principle as that to which it is opposed, and consequently cannot be opposed to it. Thus, if Kant means by the rain, in distinction from the rainbow, the appearance when, as we say, we see the circular raindrops, the t.i.tle of this appearance to the term thing in itself is no better than that of the rainbow; it is, in fact, if anything, worse, for the appearance is actual only under exceptional circ.u.mstances. We may never see the raindrops thus, or in Kant's language, have this 'appearance'; and therefore, in general, an appearance of this kind is not actual but only possible. The truth is that we can only distinguish something as the thing in itself from an appearance, so long as we mean by the thing in itself what Kant normally means by it, viz. something which exists independently of perception and is not an appearance at all.[34] That of which Kant is really thinking, and which he _calls_ the appearance which is the thing, in distinction from a mere appearance, is not an appearance; on the contrary, it is the raindrops themselves, which he describes as circular and as falling through s.p.a.ce, and which, as circular and falling, must exist and have these characteristics in themselves apart from a percipient. Kant's formula for an empirical thing, i. e. a thing which is an appearance, viz.

'that which in universal experience and under all different positions with regard to the senses is in perception so and so determined', is merely an attempt to achieve the impossible, viz. to combine in one the characteristics of a thing and an appearance. While the reference to _perception_ and to _position with regard to the senses_ implies that what is being defined is an appearance, the reference to _universal_ experience, to _all_ positions with regard to the senses, and to that which _is so and so determined_ implies that it is a thing. But, plainly, mention of position with regard to the senses, if introduced at all, should refer to the _differences_ in perception due to the different position of the object in particular cases. There is nothing of which it can be said that we perceive it in the same way or that it looks the same from _all_ positions. When Kant speaks of that which under _all_ different positions with regard to the senses is so and so determined, he is really referring to something in the consideration of which all reference to the senses has been discarded; it is what should be described as that which _in reality and apart from_ all positions with regard to the senses is so and so determined; and this, as such, cannot be an appearance. Again, the qualification of 'is so and so determined' by 'in perception' is merely an attempt to treat as relative to perception, and so as an appearance, what is essentially independent of perception.[35] Kant, no doubt, is thinking of a real presupposition of the process by which we distinguish between the real and the apparent qualities of bodies, i. e. between what they are and what they appear. We presuppose that that quality is really, and not only apparently, a quality of a body, which we and every one, judging from what it looks under various conditions (i. e.

'in universal experience'), must believe it to possess in itself and independently of all perception. His mistake is that in formulating this presupposition he treats as an appearance, and so as relative to perception, just that which is being distinguished from what, as an appearance, is relative to perception.

[34] Hence Kant's protest (B. 45, M. 27), against ill.u.s.trating the ideality of s.p.a.ce by the 'inadequate'

examples of colour, taste, &c., must be unavailing. For his contention is that, while the a.s.sertion that s.p.a.ce is not a property of things means that it is not a property of things in themselves, the a.s.sertion that colour, for example, is not a property of a rose only means that it is not a property of a thing in itself in an empirical sense, i. e. of an appearance of a special kind.

[35] Cf. pp. 72-3.

Underlying the mistake is the identification of perception with judgement. Our apprehension of what things _are_ is essentially a matter of thought or judgement, and not of perception. We do not _perceive_[36] but _think_ a thing as it is. It is true that we can follow Kant's language so far as to say that our judgement that the portion of the great circle joining two points on the surface of a sphere is the shortest way between them _via_ the surface belongs essentially to the thinking faculty of every intelligent being, and also that it is valid for all intelligences, in the sense that they must all hold it to be true; and we can contrast this judgement with a perception of the portion of the great circle as something which, though it cannot be said to be invalid, still differs for different beings according to the position from which they perceive it. Kant, however, treats the judgement as a _perception_; for if we apply his general a.s.sertion to this instance, we find him saying that what we judge the portion of the great circle to be essentially belongs to the _perception_ of it, and is valid for the _sensuous_ faculty of every human being, and that thereby it can be distinguished from what belongs to the same perception of a great circle accidentally, e. g.

its apparent colour, which is valid only for a particular organization of this or that sense.[37] In this way he correlates what the great circle really is, as well as what it looks, with perception, and so is able to speak of what it is for perception. But, in fact, what the great circle is, is correlated with thought, and not with perception; and if we raise Kant's transcendental problem in reference not to perception but to thought, it cannot be solved in Kant's agnostic manner. For it is a presupposition of thinking that things are in themselves what we think them to be; and from the nature of the case a presupposition of thinking not only cannot be rightly questioned, but cannot be questioned at all.

[36] Cf. pp. 72-3.

[37] In the _Prol._, -- 13, Remark iii, Kant carefully distinguishes judgement from perception, but destroys the effect of the distinction by regarding judgement as referring to what is relative to perception, viz. appearances.

NOTE ON THE FIRST ANTINOMY

Kant holds that the antinomy or contradiction which arises when we consider the character of the world as spatial and temporal, viz. that we are equally bound to hold that the world is infinite in s.p.a.ce and time, and that it is finite in s.p.a.ce and time, is due to regarding the world as a thing in itself. He holds that the contradiction disappears, as soon as it is recognized that the world is only a phenomenon, for then we find that we need only say that the world is _capable_ of being extended infinitely in respect of time and s.p.a.ce.[1] Objects in s.p.a.ce and time are only phenomena, and, as such, are actual only in perception. When we say that a past event, or that a body which we do not perceive, is real, we merely a.s.sert the possibility of a 'perception'. "All events from time immemorial prior to my existence mean nothing else than the possibility of prolonging the chain of experience from the present perception upwards to the conditions which determine this perception according to time."[2]

"That there may be inhabitants of the moon, although no one has ever seen them, must certainly be admitted, but this a.s.sertion only means that we could come upon them in the possible progress of experience."[3] The contradictions, therefore, can be avoided by subst.i.tuting for the actual infinity of s.p.a.ce and time, as relating to things in themselves, the possible infinity of a series of 'perceptions'.

[1] B. 532-3, M. 315.

[2] B. 523, M. 309.

[3] B. 521, M. 308.

This contention, if successful, is clearly important. If it could be shown that the treatment of the world as a thing in itself is the source of a contradiction, we should have what at least would seem a strong, if not conclusive, ground for holding that the world is a phenomenon, and, consequently, that the distinction between phenomena and things in themselves is valid.

Professor Cook Wilson has, however, pointed out that Kant's own doctrine does not avoid the difficulty. For, though, according to Kant, the infinity of actual representations of s.p.a.ces and times is only possible, yet the possibilities of these representations will be themselves infinite, and, as such, will give rise to contradictions similar to those involved in the infinity of s.p.a.ce and time. Moreover, as Professor Cook Wilson has also pointed out, there is no contradiction involved in the thought of the world as spatial and temporal; for, as we see when we reflect, we always presuppose that s.p.a.ce and time are infinite, and we are only tempted to think that they must be finite, because, when maintaining that the world must be a whole, we are apt to make the false a.s.sumption, without in any way questioning it, that any whole must be finite.