are to be found in the table of the Categories of Freedom! in the “Critique of Practical Reason;” also in the first book of the “Critique of Judgment,” which goes through the judgment of taste according to the four titles of the categories; and, finally, in the “Metaphysical First Principles of Natural Science,” which are entirely adapted to the table of the categories, whereby the false that is mingled here and there with what is true and excellent in this important work is for the most part introduced. See, for example, at the end of the first chapter how the unity, the multiplicity, and the totality of the directions of lines are supposed to correspond to the categories, which are so named according to the quantity of judgments.
The principle of the Permanence of Substance is deduced from the category of subsistence and inherence. This, however, we know only from the form of the categorical judgment, i. e., from the connection of two concepts as subject and predicate. With what violence then is that great metaphysical principle made dependent upon this simple, purely logical form! Yet this is only done pro forma, and for the sake of symmetry. The proof of this principle, which is given here, sets entirely aside its supposed origin in the understanding and in the category, and is based upon the pure intuition or perception of time. But this proof also is quite incorrect. It is false that in mere time there is simultaneity and duration; these ideas only arise from the union of space with time, as I have already shown in the essay on the principle of sufficient reason, § 18, and worked out more fully in § 4 of the present work. I must assume a knowledge of both these expositions for the understanding of what follows. It is false that time remains the same through all change; on the contrary, it is just time itself that is fleeting; a permanent time is a contradiction. Kant's proof is untenable, strenuously as he has supported it with sophisms; indeed, he falls into the most palpable contradictions. Thus, after he has falsely set up co-existence as a mode of time (p. 177; V. 219), he says, quite rightly (p. 183; V. 226), “Co-existence is not a mode of time, for in time there are absolutely no parts together, but all in succession.” In truth, space is quite as much implicated in co-existence as time. For if two things are co-existent and yet not one, they are different in respect of space; if two states of one thing are co-existent (e. g., the glow and the heat of iron), then they are two contemporaneous effects of one thing, therefore presuppose matter, and matter presupposes space. Strictly speaking, co-existence is a negative determination, which merely signifies that two things or states are not different in respect of time; thus their difference is to be sought for elsewhere. But in any case, our knowledge of the permanence of substance, i. e., of matter, must be based upon insight a priori; for it is raised above all doubt, and therefore cannot be drawn from experience. I deduce it from the fact that the principle of all becoming and passing away, the law of causality, of which we are conscious a priori, is essentially concerned only with the changes, i. e., the successive states of matter, is thus limited to the form, and leaves the matter untouched, which therefore exists in our consciousness as the foundation of all things, which is not subject to becoming or passing away, which has therefore always been and will always continue to be. A deeper proof of the permanence of substance, drawn from the analysis of our perception of the empirical world in general, is to be found in the first book of this work, § 4, where it is shown that the nature of matter consists in the absolute union of space and time, a union which is only possible by means of the idea of causality, consequently only for the understanding, which is nothing but the subjective correlative of causality. Hence, also, matter is never known otherwise than as producing effects, i. e., as through and through causality; to be and to act are with it one, which is indeed signified by the word actuality. Intimate union of space and time – causality, matter, actuality – are thus one, and the subjective correlative of this one is the understanding. Matter must bear in itself the conflicting properties of both factors from which it proceeds, and it is the idea of causality which abolishes what is contradictory in both, and makes their co-existence conceivable by the understanding, through which and for which alone matter is, and whose whole faculty consists in the knowledge of cause and effect. Thus for the understanding there is united in matter the inconstant flux of time, appearing as change of the accidents, with the rigid immobility of space, which exhibits itself as the permanence of substance. For if the substance passed away like the accidents, the phenomenon would be torn away from space altogether, and would only belong to time; the world of experience would be destroyed by the abolition of matter, annihilation. Thus from the share which space has in matter, i. e., in all phenomena of the actual – in that it is the opposite and counterpart of time, and therefore in itself and apart from the union with the latter knows absolutely no change – the principle of the permanence of substance, which recognises everything as a priori certain, had to be deduced and explained; but not from mere time, to which for this purpose and quite erroneously Kant has attributed permanence.
In the essay on the principle of sufficient reason, § 23, I have fully explained the incorrectness of the following proof of the a priori nature and of the necessity of the law of causality from the mere succession of events in time; I must, therefore, content myself here by referring to that passage.6 This is precisely the case with the proof of reciprocity also, the concept of which I was obliged to explain above as invalid. What is necessary has also been said of modality, the working out of the principles of which now follows.
There are still a few points in the further course of the transcendental analytic which I should have to refute were it not that I am afraid of trying the patience of the reader; I therefore leave them to his own reflection. But ever anew in the “Critique of Pure Reason” we meet that principal and fundamental error of Kant's, which I have copiously denounced above, the complete failure to distinguish abstract, discursive knowledge from intuitive. It is this that throws a constant obscurity over Kant's whole theory of the faculty of knowledge, and never allows the reader to know what he is really speaking about at any time, so that instead of understanding, he always merely conjectures, for he alternately tries to understand what is said as referring to thought and to perception, and remains always in suspense. In the chapter “On the Division of all Objects into Phenomena and Noumena,” Kant carries that incredible want of reflection as to the nature of the idea of perception and the abstract idea, as I shall explain more fully immediately, so far as to make the monstrous assertion that without thought, that is, without abstract conceptions, there is no knowledge of an object; and that perception, because it is not thought, is also not knowledge, and, in general, is nothing but a mere affection of sensibility, mere sensation! Nay, more, that perception without conception is absolutely void; but conception without perception is yet always something (p. 253; V. 309). Now this is exactly the opposite of the truth; for concepts obtain all significance, all content, only from their relation to ideas of perception, from which they have been abstracted, derived, that is, constructed through the omission of all that is unessential: therefore if the foundation of perception is taken away from them, they are empty and void. Perceptions, on the contrary, have in themselves immediate and very great significance (in them, indeed, the thing in itself objectifies itself); they represent themselves, express themselves, have no mere borrowed content like concepts. For the principle of sufficient reason governs them only as the law of causality, and determines as such only their position in space and time; it does not, however, condition their content and their significance, as is the case with concepts, in which it appears as the principle of the ground of knowing. For the rest, it looks as if Kant really wished here to set about distinguishing the idea of perception and the abstract idea. He objects to Leibnitz and Locke that the former reduced everything to abstract ideas, and the latter everything to ideas of perception. But yet he arrives at no distinction; and although Locke and Leibnitz really committed these errors, Kant himself is burdened with a third error which includes them both – the error of having so mixed up knowledge of perception and abstract knowledge that a monstrous hybrid of the two resulted, a chimera of which no distinct idea is possible, and which therefore necessarily only confused and stupefied students, and set them at variance.
Certainly thought and perception are separated more in the chapter referred to “On the Division of all Objects into Phenomena and Noumena” than anywhere else, but the nature of this distinction is here a fundamentally false one.
With my refutation of the Kantian proof may be compared the earlier attacks upon it by Feder,
