ANTICIPATIONS OF PERCEPTION

In all appearances, the real that is an object of sensation has intensive magnitude, that is, a degree.

Proof

Perception is empirical consciousness, that is, a conscious- ness in which sensation is to be found. Appearances, as objects of perception, are not pure, merely formal, intuitions, like space and time. For in and by themselves these latter cannot be per- ceived. Appearances contain in addition to intuition the matter for some object in general (whereby something existing in space or time is represented); they contain, that is to say, the real of sensation as merely subjective representation, which gives us only the consciousness that the subject is affected, and which we relate to an object in general. Now from empirical consciousness to pure consciousness a graduated transition is possible, the real in the former completely vanishing and a merely formal a priori consciousness of the manifold in space and time remaining.

The Anticipations of Perception

The principle which anticipates all perceptions, as such, is as follows: In all appearances sensation, and the real which corresponds to it in the object (realitas phaenomenon), has an intensive magnitude, that is, a degree.

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Consequently there is also possible a
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synthesis in the process of generating the magnitude of a sen- sation from its beginning in pure intuition = 0, up to any required magnitude. Since, however, sensation is not in itself an objective representation, and since neither the intuition of space nor that of time is to be met with in it, its mag- nitude is not extensive but intensive. This magnitude is generated in the act of apprehension whereby the empirical consciousness of it can in a certain time increase from nothing = 0 to the given measure. Corresponding to this intensity of sensation, an intensive magnitude, that is, a degree of influence on the sense [i.e. on the special sense involved], must be ascribed to all objects of perception, in so far as the perception contains sensation.

All knowledge by means of which I am enabled to know and determine a priori what belongs to empirical knowledge may be entitled an anticipation; and this is undoubtedly the sense in which Epicurus employed the term prolepsis. But as there is an element in the appearances (namely, sensation, the matter of perception) which can never be known a priori, and which therefore constitutes the distinctive difference between empirical and a priori knowledge, it follows that sensation is just that element which cannot be anticipated. On the other hand, we might very well entitle the pure determinations in space and time, in respect of shape as well as of magnitude, anticipations of appearances, since they represent a priori that which may always be given a posteriori in experience. If, however, there is in every sensation, as sensation in general (that is, without a particular sensation having to be given), something that can be known a priori, this will, in a quite especial sense, deserve to be named anticipation. For it does indeed seem surprising that we should forestall experience, precisely in that which concerns what is only to be obtained through it, namely, its matter. Yet, none the less, such is actually the case. Apprehension by means merely of sensation occupies only an instant, if, that is, I do not take into account the succes- sion of different sensations. As sensation is that element in
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the [field of] appearance the apprehension of which does not involve a successive synthesis proceeding from parts to the whole representation, it has no extensive magnitude. The absence of sensation at that instant would involve the re- presentation of the instant as empty, therefore as = 0. Now what corresponds in empirical intuition to sensation is reality (realitas phaenomenon); what corresponds to its absence is negation = 0. Every sensation, however, is capable of diminu- tion, so that it can decrease and gradually vanish. Between reality in the [field of] appearance and negation there is there- fore a continuity of many possible intermediate sensations, the difference between any two of which is always smaller than the difference between the given sensation and zero or com- plete negation. In other words, the real in the [field of] ap- pearance has always a magnitude. But since its apprehension by means of mere sensation takes place in an instant and not through successive synthesis of different sensations, and there- fore does not proceed from the parts to the whole, the mag- nitude is to be met with only in the apprehension. The real has therefore magnitude, but not extensive magnitude. A magnitude which is apprehended only as unity, and in which multiplicity can be represented only through ap- proximation to negation = 0, I entitle an intensive magnitude. Every reality in the [field of] appearance has therefore inten- sive magnitude or degree. If this reality is viewed as cause, either of sensation or of some other reality in the [field of] appearance, such as change, the degree of the reality as cause is then entitled a moment, the moment of gravity. It is so named for the reason that degree signifies only that magnitude the apprehension of which is not successive, but instan- taneous. This, however, I touch on only in passing; for with causality I am not at present dealing. Every sensation, therefore, and likewise every reality in the [field of] appearance, however small it may be, has a degree, that is, an intensive magnitude which can always be diminished. Between reality and negation there is a con- tinuity of possible realities and of possible smaller perceptions.
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Every colour, as for instance red, has a degree which, how- ever small it may be, is never the smallest; and so with heat, the moment of gravity, etc. The property of magnitudes by which no part of them is the smallest possible, that is, by which no part is simple, is called their continuity. Space and time are quanta continua, because no part of them can be given save as enclosed between limits (points or instants), and therefore only in such fashion that this part is itself again a space or a time. Space therefore consists solely of spaces, time solely of times. Points and instants are only limits, that is, mere positions which limit space and time. But positions always presuppose the intuitions which they limit or are intended to limit; and out of mere positions, viewed as constituents capable of being given prior to space or time, neither space nor time can be constructed. Such mag- nitudes may also be called flowing, since the synthesis of productive imagination involved in their production is a pro- gression in time, and the continuity of time is ordinarily designated by the term flowing or flowing away. All appearances, then, are continuous magnitudes, alike in their intuition, as extensive, and in their mere perception (sensation, and with it reality) as intensive. If the synthesis of the manifold of appearance is interrupted, we have an aggre- gate of different appearances, and not appearance as a genuine quantum. Such an aggregate is not generated by continuing without break productive synthesis of a certain kind, but through repetition of an ever-ceasing synthesis. If I called thirteen thalers a quantum of money, I should be correct, pro- vided my intention is to state the value of a mark of fine silver. For this is a continuous magnitude in which no part is the smallest, and in which every part can constitute a piece of coin that always contains material for still smaller pieces. But if I understand by the phrase thirteen round thalers, so many coins, quite apart from the question of what their silver standard may be, I then use the phrase, quantum of thalers, inappropriately. It ought to be entitled an aggregate, that is, a number of pieces of money. But as unity must be presup- posed in all number, appearance as unity is a quantum, and as a quantum is always a continum.
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Since all appearances, alike in their extensive and in their intensive aspect, are thus continuous magnitudes, it might seem to be an easy matter to prove with mathematical con- clusiveness the proposition that all alteration (transition of a thing from one state to another), is continuous. But the caus- ality of an alteration in general, presupposing, as it does, em- pirical principles, lies altogether outside the limits of a tran- scendental philosophy. For upon the question as to whether a cause capable of altering the state of a thing, that is, of determining it to the opposite of a certain given state, may be possible, the a priori understanding casts no light; and this not merely because it has no insight into its possibility (such insight is lacking to us in many other cases of a priori knowledge), but because alterableness is to be met with only in certain determinations of appearances, and because, whereas [in fact] the cause of these determinations lies in the unalterable, experience alone can teach what they are. Since in our present enquiry we have no data of which we can make use save only the pure fundamental concepts of all possible experience, in which there must be absolutely nothing that is empirical, we cannot, without destroying the unity of our system, anticipate general natural science, which is based on certain primary experiences. At the same time, there is no lack of proofs of the great value of our principle in enabling us to anticipate perceptions, and even to some extent to make good their absence, by placing a check upon all false inferences which might be drawn from their absence. If all reality in perception has a degree, between which and negation there exists an infinite gradation of ever smaller degrees, and if every sense must likewise possess some par- ticular degree of receptivity of sensations, no perception, and consequently no experience, is possible that could prove, either immediately or mediately (no matter how far-ranging the reasoning may be), a complete absence of all reality in the [field of] appearance. In other words, the proof of an empty space or of an empty time can never be derived from experi- ence. For, in the first place, the complete absence of reality
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from a sensible intuition can never be itself perceived; and, secondly, there is no appearance whatsoever and no difference in the degree of reality of any appearance from which it can be inferred. It is not even legitimate to postulate it in order to explain any difference. For even if the whole intuition of a certain determinate space or time is real through and through, that is, though no part of it is empty, none the less, since every reality has its degree, which can diminish to nothing (the void) through infinite gradations without in any way altering the extensive magnitude of the appearance, there must be infinite different degrees in which space and time may be filled. Intensive magnitude can in different appearances be smaller or greater, although the extensive magnitude of the intuition remains one and the same.
Let us give an example. Almost all natural philosophers, observing -- partly by means of the moment of gravity or weight, partly by means of the moment of opposition to other matter in motion -- a great difference in the quantity of various kinds of matter in bodies that have the same volume, unani- mously conclude that this volume, which constitutes the ex- tensive magnitude of the appearance, must in all material bodies be empty in varying degrees. Who would ever have dreamt of believing that these students of nature, most of whom are occupied with problems in mathematics and mechanics, would base such an inference solely on a meta- physical presupposition -- the sort of assumption they so stoutly profess to avoid? They assume that the real in space (I may not here name it impenetrability or weight, since these are empirical concepts) is everywhere uniform and varies only in extensive magnitude, that is, in amount. Now to this pre- supposition, for which they could find no support in experi- ence, and which is therefore purely metaphysical, I oppose a transcendental proof, which does not indeed explain the difference in the filling of spaces, but completely destroys the supposed necessity of the above presupposition, that the difference is only to be explained on the assumption of empty space. My proof has the merit at least of freeing the under- standing, so that it is at liberty to think this difference in some other manner, should it be found that some other hypothesis is required for the explanation of the natural
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appearances. For we then recognise that although two equal spaces can be completely filled with different kinds of matter, so that there is no point in either where matter is not present, nevertheless every reality has, while keeping its quality un- changed, some specific degree (of resistance or weight) which can, without diminution of its extensive magnitude or amount, become smaller and smaller in infinitum, before it passes into the void and [so] vanishes [out of existence]. Thus a radiation which fills a space, as for instance heat, and similarly every other reality in the [field of] appearance, can diminish in its degree in infinitum, without leaving the smallest part of this space in the least empty. It may fill the space just as completely with these smaller degrees as another appearance does with greater degrees. I do not at all intend to assert that this is what actually occurs when material bodies differ in specific gravity, but only to establish from a principle of pure understanding that the nature of our per- ceptions allows of such a mode of explanation, that we are not justified in assuming the real in appearances to be uniform in degree, differing only in aggregation and extensive magni- tude, and that we are especially in error when we claim that such interpretation can be based on an a priori principle of the understanding.
This anticipation of perception must always, however appear somewhat strange to anyone trained in transcend- ental reflection, and to any student of nature who by such teaching has been trained to circumspection. The assertion that the understanding anticipates such a synthetic principle, ascribing a degree to all that is real in the appearances, and so asserting the possibility of an internal distinction in sensa- tion itself (abstraction being made of its empirical quality), awakens doubts and difficulties. It is therefore a question not unworthy of solution, how the understanding can thus in a priori fashion pronounce synthetically upon appearances, and can indeed anticipate in that which in itself is merely empirical and concerns only sensation. The quality of sensation, as for instance in colours, taste, etc. , is always merely empirical, and cannot be represented
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a priori. But the real, which corresponds to sensations in general, as opposed to negation = 0, represents only that something the very concept of which includes being, and signifies nothing but the synthesis in an empirical conscious- ness in general. Empirical consciousness can in inner sense be raised from 0 to any higher degree, so that a certain ex- tensive magnitude of intuition, as for instance of illuminated surface, may excite as great a sensation as the combined aggregate of many such surfaces has illuminated. [Since the extensive magnitude of the appearance thus varies independ- ently], we can completely abstract from it, and still represent in the mere sensation in any one of its moments a synthesis that advances uniformly from 0 to the given empirical con- sciousness. Consequently, though all sensations as such are given only a posteriori, their property of possessing a degree can be known a priori. It is remarkable that of magnitudes in general we can know a priori only a single quality, namely, that of continuity, and that in all quality (the real in appear- ances) we can know a priori nothing save [in regard to] their intensive quantity, namely that they have degree. Everything else has to be left to experience.
Taken from http://www.hkbu.edu.hk/~ppp/cpr/anpri.html