A Commentary to Kant's 'Critique of Pure Reason'

by Norman Kemp Smith

“Schopenhauer points out that what we call chance is just a sequence of events which do not stand in causal connexion. ‘I come out of the house and a tile falls from the roof which strikes me; in such a case there is no causal connexion between the falling of the tile and my coming out of the house, yet the succession of these two events is objectively determined in my apprehension of them.’ How have we to criticise this case from the transcendental point of view? We know that successions become necessary, i.e. objective, for our consciousness, when we regard them as changes of a substance which are determined by a cause. But it is shown here that there are successions in which the single members are changes of different substances. If substance S changes its state A into B on account of the cause X, and substance S´ changes its state A´ into B´ on account of the cause X´, and if I call the first change V and the second V´, the question arises how the objectivity of the succession V V´ is related to the law of causality. Sequences such as V V´ are very frequent, and our consciousness of the objectivity is certain. Do we owe this consciousness to the same rule as holds good in other cases? Certainly. The distinction is not qualitative, but rests only on the greater complication of the change in question. The sequence V V´ can become objective only if I think it as a necessary connexion. It must be so determined that V can only follow V´ in ‘consciousness in general’; there must be a U, the introduction of which is the cause that V´ follows V. To be convinced of this, I do not need actually to know U. I know that on every occasion U causes the succession V V´. Of course, this presupposes that all data of the states considered, A and A´, remain identical. But whether these data are very simple or endlessly complex, whether they are likely to combine to the given result frequently or seldom, is indifferent for the objectifying of the event; it is not the perception of U, but the presupposition of it, which makes the change necessary and so objective for us.”[1217]

To turn now to the other difficulty which Kant himself raises in A 202-3 = B 247-8, viz. that cause and effect would frequently seem to be coexistent, and the “sole empirical criterion” to be therefore absent. It may from this point of view be maintained that the great majority of causes occur simultaneously with their effects, and that such time sequence as occurs is due solely to the fact that the cause cannot execute itself in one single instant. Kant has little difficulty in disposing of this objection. Causality concerns only the order, not the lapse, of time; and the sequence relation must remain even though there is no interval between the two events. If a leaden ball lies upon a cushion it makes a depression in it. The ball and the depression are coexistent. None the less, when viewed in their dynamical relation, the latter must be regarded as sequent upon the former. If the leaden ball is placed upon a smooth cushion a hollow is at once made, but if a hollow exists in a cushion a ball need not appear. In other words, the criteria for the determination of specific causal relations are neither the presence nor the absence of sequence, but are empirical considerations verifiable only upon special investigation.[1218] The observer is called upon to disentangle the complicated web of given appearances under the guidance of the quite general and formal principle that every event is due to some antecedent cause. He must do so as best he can through the application of his acquired insight, and, when necessary, by means of the requisite experimental variation of conditions.

In the two following paragraphs (A 204-5 = B 249-51) Kant raises points which he later discussed more fully in the Metaphysical First Principles of Natural Science.[1219] As adequate explanation of the argument would be a very lengthy matter, and not of any very real importance for the understanding of the general Critical position, we may omit all treatment of it. In the sections of the Metaphysical First Principles just cited, the reader will find the necessary comment and explanation. Such bearing as these two paragraphs have upon Kant’s view of the nature of the causal relation has been noted above.[1220]

In the section on Anticipations of Perception[1221] Kant has stated that the principle of the continuity of change involves empirical factors, and therefore falls outside the limits of transcendental philosophy. To this more correct attitude Kant, unfortunately, did not hold. In A 207-11 = B 252-6 he professes to establish the principle in a priori transcendental fashion as a necessary consequence of the nature of time. This proof is indeed thrice repeated with unessential variations, thereby clearly showing that these paragraphs also are of composite origin. The argument in all three cases consists in inferring from the continuity of time the continuity of all changes in time. As the parts of time are themselves times, of which no one is the smallest, so in all generation in time, the cause must in its action pass through all the degrees of quantity from zero to that of the final effect.

“Every change has a cause which evinces its causality in the whole time in which the change takes place. This cause, therefore, does not engender the change suddenly (at once or in one moment), but in a time, so that, as the time increases from its initial moment a to its completion in b, the quantity of the reality (b-a) is in like manner generated through all lesser degrees which are contained between the first and the last.”[1222]

This argument is inconclusive. As Kant himself recognises in regard to space,[1223] we may not without special proof assume that what is true of time must be true of the contents of time. If time, change, and causation can be equated, what is true of one will be true of all three. But the assumption upon which the argument thus rests has not itself been substantiated.

In the third proof[1224] the argument is stated in extreme subjectivist terms which involve the further assumption that what is true of apprehension is ipso facto true of everything apprehended. The possibility of establishing the law of dynamical continuity follows, Kant declares, as a consequence of its being a law of our subjective apprehension.

“We anticipate only our own apprehension, the formal condition of which, inasmuch as it inheres in the mind prior to all given appearances, must certainly be capable of being known a priori.”[1225]

Kant’s attitude towards the physical principle of continuity underwent considerable change. In his New Doctrine of Motion and Rest (1758)[1226] he maintains that it cannot be proved, and that physicists may rightly refuse to recognise it even as an hypothesis. It is in the Essay on Negative Quantity (1763)[1227] that Kant first adopts the attitude of the Critique, and rejects the “speculative” objections raised against the mathematical conception of the infinitely small. In the Metaphysical First Principles of Natural Science[1228] the principle of continuity is defended and developed, but only in its application to material existence, not in its relation to the causal process.

C. Third Analogy.—All substances, in so far as they are coexistent, stand in thoroughgoing communion,[1229] i.e. in reciprocity with one another. Or, as in the second edition: All substances, so far as they can be perceived to coexist in space, are in thoroughgoing reciprocity.