There must be a pure or _a priori_ manifold; this is to be found in individual s.p.a.ces and individual times. There must be an act of pure synthesis of this manifold; this is effected by the pure imagination.
Finally, this pure synthesis must be brought under a conception. This is effected by the pure understanding by means of its pure or a priori conceptions, i. e. the categories. This, then, is the process by which _a priori_ knowledge is originated. The activity of thought or understanding, however, which unites two conceptions in a judgement by a.n.a.lysis of them--this being the act studied by Formal Logic--is the same as that which gives unity to the synthesis of the pure manifold of perception--this being the act studied by Transcendental Logic.
Consequently, "the same understanding, and indeed by the same activities whereby in dealing with conceptions it unifies them in a judgement by an act of a.n.a.lysis, introduces by means of the synthetical unity which it produces in the pure manifold of perception a content into its own conceptions, in consequence of which these conceptions are called pure conceptions of the understanding,"[4] and we are ent.i.tled to say _a priori_ that these conceptions apply to objects because they are involved in the process by which we acquire _a priori_ knowledge of objects."
[4] An interpretation of B. 105 init., M. 63 fin.
A discussion of the various difficulties raised by the general drift of this pa.s.sage, as well as by its details,[5] is unnecessary, and would antic.i.p.ate discussion of the _Transcendental Deduction_. But it is necessary to draw attention to three points.
[5] E. g. Kant"s arbitrary a.s.sertion that the operation of counting presupposes the conception of that number which forms the scale of notation adopted as the source of the unity of the synthesis. This is of course refuted among other ways by the fact that a number of units less than the scale of notation can be counted.
In the first place, as has been said, Kant here introduces--and introduces without warning--a totally new account of knowledge. It has its origin in his theory of perception, according to which knowledge begins with the production of sensations in us by things in themselves. Since the spatial world which we come to know consists in a multiplicity of related elements, it is clear that the isolated data of sensation have somehow to be combined and unified, if we are to have this world before us or, in other words, to know it. Moreover, since these empirical data are subject to s.p.a.ce and time as the forms of perception, individual s.p.a.ces and individual times, to which the empirical data will be related, have also to be combined and unified.
On this view, the process of knowledge consists in combining certain data into an individual whole and in unifying them through a principle of combination.[6] If the data are empirical, the resulting knowledge will be empirical; if the data are _a priori_, i. e. individual s.p.a.ces and individual times, the resulting knowledge will be _a priori_.[7]
This account of knowledge is new, because, although it treats knowledge as a process or act of unifying a manifold, it describes a different act of unification. As Kant first described the faculty of judgement,[8] it unifies a group of particulars through relation to the corresponding universal. As Formal Logic, according to Kant, treats the faculty of judgement, it unifies two conceptions or two prior judgements into a judgement. As Kant now describes the faculty of judgement or thought, it unifies an empirical or an _a priori_ manifold of perception combined into an individual whole, through a conception which const.i.tutes a principle of unity. The difference between this last account and the others is also shown by the fact that while the first two kinds of unification are held to be due to mere a.n.a.lysis of the material given to thought, the third kind of unification is held to be superinduced by thought, and to be in no way capable of being extracted from the material by a.n.a.lysis. Further, this new account of knowledge does not replace the others, but is placed side by side with them. For, according to Kant, there exist _both_ the activity of thought which relates two conceptions in a judgement,[9] _and_ the activity by which it introduces a unity of its own into a manifold of perception. Nevertheless, this new account of knowledge, or rather this account of a new kind of knowledge, must be the important one; for it is only the process now described for the first time which produces synthetic as opposed to a.n.a.lytic knowledge.
[6] Cf. A. 97, Mah. 193, "Knowledge is a totality of compared and connected representations."
[7] No doubt Kant would allow that at least some categories, e. g. the conception of cause and effect, are principles of synthesis of a manifold which at any rate contains an empirical element, but it _includes_ just one of the difficulties of the pa.s.sage that it implies that _a priori_ knowledge either is, or involves, a synthesis of pure or _a priori_ elements.
[8] B. 92-4, M. 56-8.
[9] Kant, of course, thinks of this activity of thought, as identical with that which brings particulars under a conception.
In the second place, the pa.s.sage incidentally explains why, according to Kant, the forms of judgement distinguished by Formal Logic do not involve the categories.[10] For its doctrine is that while thought, if exercised under the conditions under which it is studied by Formal Logic, can only a.n.a.lyse the manifold given to it, and so has, as it were, to borrow from the manifold the unity through which it relates the manifold,[11] yet if an _a priori_ manifold be given to it, it can by means of a conception introduce into the manifold a unity of its own which could not be discovered by a.n.a.lysis of the manifold. Thus thought as studied by Formal Logic merely a.n.a.lyses and consequently does not and cannot make use of conceptions of its own; it can use conceptions of its own only when an _a priori_ manifold is given to it to deal with.
[10] Cf. pp. 155-6.
[11] In bringing perceptions under a conception, thought, according to Kant, finds the conception _in_ the perceptions by a.n.a.lysis of them, and in relating two conceptions in judgement, it determines the particular form of judgement by a.n.a.lysis of the conceptions.
In the third place, there is great difficulty in following the part in knowledge a.s.signed to the understanding. The synthesis of the manifold of perception is a.s.signed to the imagination, a faculty which, like the new kind of knowledge, is introduced without notice. The business of the understanding is to "bring this synthesis to conceptions" and thereby to "give unity to the synthesis". Now the question arises whether "the activity of giving unity to the synthesis" really means what it says, i. e. an activity which _unifies_ or _introduces a unity into_ the synthesis, or whether it only means an activity which _recognizes_ a unity already given to the synthesis by the imagination. Prima facie Kant is maintaining that the understanding really unifies, or introduces the principle of unity. For the twice-repeated phrase "give unity to the synthesis" seems unmistakable in meaning, and the important role in knowledge is plainly meant to be a.s.signed to the understanding. Kant"s language, however, is not decisive; for he speaks of the synthesis of the manifold as that which "first produces a knowledge which indeed at first may be crude and confused and therefore needs _a.n.a.lysis_[12]", and he says of the conceptions which give unity to the synthesis that "they consist solely in the _representation_[13] of this necessary synthetical unity".[14] Again, "to bring the synthesis to a conception" may well be understood to mean "to recognize the synthesis as an instance of the conception"; and, since Kant is speaking of knowledge, "to give unity to the synthesis" may only mean "to give unity to the synthesis _for us_", i. e. "to make us aware of its unity". Moreover, consideration of what thought can possibly achieve with respect to a synthesis presented to it by the imagination renders it necessary to hold that the understanding only recognizes the unity of the synthesis. For if a synthesis has been effected, it must have been effected in accordance with a principle of construction or synthesis, and therefore it would seem that the only work left for the understanding is to discover the principle latent in the procedure of the imagination. At any rate, if the synthesis does not involve a principle of synthesis, it is impossible to see how thought can subsequently introduce a principle. The imagination, then, must be considered to have already introduced the principle of unity into the manifold by combining it in accordance with a conception or principle of combination, and the work of the understanding must be considered to consist in recognizing that the manifold has been thereby combined and unified through the conception. We are therefore obliged to accept one of two alternatives. _Either_ the understanding merely renders the mind conscious of the procedure of a faculty different from itself, viz. the imagination, in which case the important role in knowledge, viz. the effecting of the synthesis according to a principle, is played by a faculty different from the understanding; _or_ the imagination is the understanding working unreflectively, and the subsequent process of bringing the synthesis to a conception is merely a process by which the understanding becomes conscious of its own procedure. Moreover, it is the latter alternative which we must accept as more in accordance with the general tenor of Kant"s thought. For the synthesis of the imagination is essentially the outcome of activity or spontaneity, and, as such, it belongs to the understanding rather than to the sensibility; in fact we find Kant in one place actually saying that "it is one and the same spontaneity which at one time under the name of imagination, at another time under that of understanding, introduces connexion into the manifold of perception".[15] Further, it should be noted that since the imagination must be the understanding working unreflectively, and since it must be that which introduces unity into the manifold, there is some justification for his use of language which implies that the understanding is the source of the unity, though it will not be so in the sense in which the pa.s.sage under discussion might at first sight lead us to suppose.
[12] The italics are mine.
[13] The italics are mine.
[14] Cf. the description of the imagination as "blind".
[15] B. 162 note, M. 99 note. Cf. B. 152, M. 93. Similarly at one point in the pa.s.sage under discussion (B. 102 fin., M. 62 med.) the synthesis is expressly attributed to the spontaneity of thought.
We can now turn to the argument of the _Transcendental Deduction_ itself. Kant introduces it in effect by raising the question, "How is it that, beginning with the isolated data of sense, we come to acquire knowledge?" His aim is to show (1) that knowledge requires the performance of certain operations by the mind upon the manifold of sense; (2) that this process is a condition not merely of knowledge, but also of self-consciousness; and (3) that, since the manifold is capable of entering into knowledge, and since we are capable of being self-conscious, the categories, whose validity is implied by this process, are valid.
Kant begins by pointing out[16] that all knowledge, _a priori_ as well as empirical, requires the manifold, produced successively in the mind, to be subjected to three operations.
[16] A. 95-104, Mah. 194-8.
1. Since the elements of the manifold are as given mere isolated units, and since knowledge is the apprehension of a unity of connected elements, the mind must first run through the multiplicity of sense and then grasp it together into a whole, i. e. into an image.[17]
This act is an act of synthesis; it is called "the synthesis of apprehension" and is ascribed to the imagination. It must be carried out as much in respect of the pure or _a priori_ elements of s.p.a.ce and time as in respect of the manifold of sensation, for individual s.p.a.ces and times contain a multiplicity which, to be apprehended, must be combined.[18] The necessity of this act of synthesis is emphasized in the second edition. "We cannot represent anything as combined in the object without having previously combined it ourselves. Of all representations, _combination_ is the only one which cannot be given through objects,[19] but can be originated only by the subject itself because it is an act of its own activity."[20]
[17] Cf. A. 120, Mah. 211.
[18] "Combine" is used as the verb corresponding to "synthesis".
[19] I. e. given to us through the operation of things in themselves upon our sensibility.
[20] B. 130, M. 80.
2. Since the data of perception are momentary, and pa.s.s away with perception, the act of grasping them together requires that the mind shall reproduce the past data in order to combine them with the present datum. "It is plain that if I draw a line in thought, or wish to think of the time from one midday to another, or even to represent to myself a certain number, I must first necessarily grasp in thought these manifold representations one after another. But if I were continually to lose from my thoughts the preceding representations (the first parts of the line, the preceding parts of time or the units successively represented), and were not to reproduce them, while I proceeded to the succeeding parts, there could never arise a complete representation, nor any of the thoughts just named, not even the first and purest fundamental representations of s.p.a.ce and time."[21] This act of reproduction is called "the synthesis of reproduction in the imagination".[22]
[21] A. 102, Mah. 197.
[22] The term "synthesis" is undeserved, and is due to a desire to find a verbal parallel to the "synthesis of apprehension in perception". For the inappropriateness of "reproduction" and of "imagination" see pp. 239-41.
Further, the necessity of reproduction brings to light a characteristic of the synthesis of apprehension. "It is indeed only an empirical law, according to which representations which have often followed or accompanied one another in the end become a.s.sociated, and so form a connexion, according to which, even in the absence of the object, one of these representations produces a transition of the mind to another by a fixed rule. But this law of reproduction presupposes that phenomena themselves are actually subject to such a rule, and that in the manifold of their representations there is a concomitance or sequence, according to a fixed rule; for, without this, our empirical imagination would never find anything to do suited to its capacity, and would consequently remain hidden within the depths of the mind as a dead faculty, unknown to ourselves. If cinnabar were now red, now black, now light, now heavy, if a man were changed now into this, now into that animal shape, if our fields were covered on the longest day, now with fruit, now with ice and snow, then my empirical faculty of imagination could not even get an opportunity of thinking of the heavy cinnabar when there occurred the representation of red colour; or if a certain name were given now to one thing, now to another, or if the same thing were called now by one and now by another name, without the control of some rule, to which the phenomena themselves are already subject, no empirical synthesis of reproduction could take place."
"There must then be something which makes this very reproduction of phenomena possible, by being the _a priori_ foundation of a necessary synthetical unity of them. But we soon discover it, if we reflect that phenomena are not things in themselves, but the mere play of our representations, which in the end resolve themselves into determinations of our internal sense. For if we can prove that even our purest _a priori_ perceptions afford us no knowledge, except so far as they contain such a combination of the manifold as renders possible a thoroughgoing synthesis of reproduction, then this synthesis of imagination is based, even before all experience, on _a priori_ principles, and we must a.s.sume a pure transcendental synthesis of the imagination which lies at the foundation of the very possibility of all experience (as that which necessarily presupposes the reproducibility of phenomena)."[23]
[23] A. 100-2, Mah. 195-7.
In other words, the faculty of reproduction, if it is to get to work, presupposes that the elements of the manifold are parts of a necessarily related whole; or, as Kant expresses it later, it presupposes the _affinity_ of phenomena; and this affinity in turn presupposes that the synthesis of apprehension by combining the elements of the manifold on certain principles makes them parts of a necessarily related whole.[24]
[24] Cf. A. 113, Mah. 205; A. 121-2, Mah. 211-12; and Caird, i. 362-3. For a fuller account of these presuppositions, and for a criticism of them, cf. Ch. IX, p. 219 and ff.
3. Kant introduces the third operation, which he calls "the synthesis of recognition in the conception",[25] as follows:
[25] This t.i.tle also is a misnomer due to the desire to give parallel t.i.tles to the three operations involved in knowledge. There is really only one synthesis referred to, and the t.i.tle here should be "the recognition of the synthesis in the conception".
"Without consciousness that what we are thinking is identical with what we thought a moment ago, all reproduction in the series of representations would be in vain. For what we are thinking would be a new representation at the present moment, which did not at all belong to the act by which it was bound to have been gradually produced, and the manifold of the same would never const.i.tute a whole, as lacking the unity which only consciousness can give it. If in counting I forget that the units which now hover before my mind have been gradually added by me to one another, I should not know the generation of the group through this successive addition of one to one, and consequently I should not know the number, for this conception consists solely in the consciousness of this unity of the synthesis."
"The word "conception"[26] might itself lead us to this remark. For it is this _one_ consciousness which unites the manifold gradually perceived and then also reproduced into one representation. This consciousness may often be only weak, so that we connect it with the production of the representation only in the result but not in the act itself, i. e. immediately; but nevertheless there must always be one consciousness, although it lacks striking clearness, and without it conceptions, and with them knowledge of objects, are wholly impossible."[27]
[26] _Begriff._
[27] A. 103-4, Mah. 197-8.
Though the pa.s.sage is obscure and confused, its general drift is clear. Kant, having spoken hitherto only of the operation of the imagination in apprehension and reproduction, now wishes to introduce the understanding. He naturally returns to the thought of it as that which recognizes a manifold as unified by a conception, the manifold, however, being not a group of particulars unified through the corresponding universal or conception, but the parts of an individual image, e. g. the parts of a line or the const.i.tuent units of a number, and the conception which unifies it being the principle on which these parts are combined.[28] His main point is that it is not enough for knowledge that we should combine the manifold of sense into a whole in accordance with a specific principle,[29] but we must also be in some degree conscious of our continuously identical act of combination,[30]
this consciousness being at the same time a consciousness of the special unity of the manifold. For the conception which forms the principle of the combination has necessarily two sides; while from our point of view it is the principle according to which we combine and which makes our combining activity one, from the point of view of the manifold it is the special principle[31] by which the manifold is made _one_. If I am to count a group of five units, I must not only add them, but also be conscious of my continuously identical act of addition, this consciousness consisting in the consciousness that I am successively taking units up to, and only up to, five, and being at the same time a consciousness that the units are acquiring the unity of being a group of five. It immediately follows, though Kant does not explicitly say so, that all knowledge implies self-consciousness. For the consciousness that we have been combining the manifold on a certain definite principle is the consciousness of our ident.i.ty throughout the process, and, from the side of the manifold, it is just that consciousness of the manifold as unified by being brought under a conception which const.i.tutes knowledge. Even though it is Kant"s view that the self-consciousness need only be weak and need only arise after the act of combination, when we are aware of its result, still, without it, there will be no consciousness of the manifold as unified through a conception and therefore no knowledge. Moreover, if the self-consciousness be weak, the knowledge will be weak also, so that if it be urged that knowledge in the strictest sense requires the full consciousness that the manifold is unified through a conception, it must be allowed that knowledge in this sense requires a full or clear self-consciousness.
[28] Cf. pp. 162-9.
[29] That the combination proceeds on a specific principle only emerges in this account of the third operation.
[30] Kant"s example shows that this consciousness is not the mere consciousness of the act of combination as throughout identical, but the consciousness of it as an identical act of a particular kind.
[31] When Kant says "this conception [i. e. the conception of the number counted] consists in the consciousness of this unity of the synthesis", he is momentarily and contrary to his usual practice speaking of a conception in the sense of the activity of conceiving a universal, and not in the sense of the universal conceived. Similarly in appealing to the meaning of _Begriff_ (conception) he is thinking of "conceiving" as the activity of combining a manifold through a conception.
As is to be expected, however, the pa.s.sage involves a difficulty concerning the respective functions of the imagination and the understanding. Is the understanding represented as only recognizing a principle of unity introduced into the manifold by the imagination, or as also for the first time introducing a principle of unity? At first sight the latter alternative may seem the right interpretation. For he says that unless we were conscious that what we are thinking is identical with what we thought a moment ago, "what we are thinking would _be_ a new representation which _did not at all belong_ to the act by which it was bound to have been gradually produced, and the manifold of the same _would never_ const.i.tute a whole, as lacking the unity which only _consciousness can give it_."[32] Again, in speaking of a conception--which of course implies the understanding--he says that "it is this one consciousness which _unites_ the manifold gradually perceived and then reproduced into _one_ representation".[33] But these statements are not decisive, for he uses the term "recognition" in his formula for the work of the understanding, and he ill.u.s.trates its work by pointing out that in counting we must _remember_ that we have added the units. Moreover, there is a consideration which by itself makes it necessary to accept the former interpretation. The pa.s.sage certainly represents the understanding as recognizing the identical action of the mind in combining the manifold on a principle, whether or not it also represents the understanding as the source of this activity. But if it were the understanding which combined the manifold, there would be no synthesis which the imagination could be supposed to have performed,[34] and therefore it could play no part in knowledge at all, a consequence which must be contrary to Kant"s meaning. Further if, as the general tenor of the deduction shows, the imagination is really only the understanding working unreflectively,[35] we are able to understand why Kant should for the moment cease to distinguish between the imagination and the understanding, and consequently should use language which implies that the understanding both combines the manifold on a principle and makes us conscious of our activity in so doing. Hence we may say that the real meaning of the pa.s.sage should be stated thus: "Knowledge requires one consciousness which, as imagination, combines the manifold on a definite principle const.i.tuted by a conception,[36] and, as understanding, is to some extent conscious of its identical activity in so doing, this self-consciousness being, from the side of the whole produced by the synthesis, the consciousness of the conception by which the manifold is unified."
[32] The italics are mine. He does not say "_we should not be conscious_ of what we are thinking as the same representation and as belonging [Greek: ktl]., _and we should not be conscious_ of the manifold as const.i.tuting a whole.
[33] The italics are mine.