The refutation of rational psychology is much fuller and more thorough in the first edition of the “Critique of Pure Reason” than in the second and following editions, and therefore upon this point we must make use of the first edition exclusively. This refutation has as a whole very great merit and much truth. Yet I am clearly of the opinion that it was merely from his love of symmetry that Kant deduced as necessary the conception of the soul from the paralogism of substantiality by applying the demand for the unconditioned to the conception substance, which is the first category of relation, and accordingly maintained that the conception of a soul arose in this way in every speculative reason. If this conception really had its origin in the presupposition of a final subject of all predicates of a thing, one would have assumed a soul not in men alone, but also just as necessarily in every lifeless thing, for such a thing also requires a final subject of all its predicates. Speaking generally, however, Kant makes use of a quite inadmissible expression when he talks of something which can exist only as subject and not as predicate (e.g., Critique of Pure Reason, p. 323; V. 412; Prolegomena, § 4 and [pg 101] 47); though a precedent for this is to be found in Aristotle's “Metaphysics,” iv. ch. 8. Nothing whatever exists as subject and predicate, for these expressions belong exclusively to logic, and denote the relations of abstract conceptions to each other. Now their correlative or representative in the world of perception must be substance and accident. But then we need not look further for that which exists always as substance and never as accident, but have it directly in matter. It is the substance corresponding to all properties of things which are their accidents. It is, in fact, if one wishes to retain the expression of Kant which has just been condemned, the final subject of all predicates of that empirically given thing, that which remains after the abstraction of all its properties of every kind. And this holds good of man as of a brute, a plant, or a stone, and is so evident, that in order not to see it a determined desire not to see is required. That it is really the prototype of the conception substance, I will show soon. But subject and predicate are related to substance and accident rather as the principle of sufficient reason in logic to the law of causality in nature, and the substitution or identification of the former is just as inadmissible as that of the latter. Yet in the “Prolegomena,” § 46, Kant carries this substitution and identification to its fullest extent in order to make the conception of the soul arise from that of the final subject of all predicates and from the form of the categorical syllogism. In order to discover the sophistical nature of this paragraph, one only needs to reflect that subject and predicate are purely logical determinations, which concern abstract conceptions solely and alone, and that according to their relation in the judgment. Substance and accident, on the other hand, belong to the world of perception and its apprehension in the understanding, and are even there only as identical with matter and form or quality. Of this more shortly.
The antithesis which has given occasion for the assumption [pg 102] of two fundamentally different substances, body and soul, is in truth that of objective and subjective. If a man apprehends himself objectively in external perception, he finds a being extended in space and in general merely corporeal; but if, on the other hand, he apprehends himself in mere self-consciousness, thus purely subjectively, he finds himself a merely willing and perceiving being, free from all forms of perception, thus also without a single one of the properties which belong to bodies. Now he forms the conception of the soul, like all the transcendental conceptions called by Kant Ideas, by applying the principle of sufficient reason, the form of all objects, to that which is not an object, and in this case indeed to the subject of knowing and willing. He treats, in fact, knowing, thinking, and willing as effects of which he seeks the cause, and as he cannot accept the body as their cause, he assumes a cause of them entirely different from the body. In this manner the first and the last of the dogmatists proves the existence of the soul: Plato in the “Phædrus” and also Wolf: from thinking and willing as the effects which lead to that cause. Only after in this way, by hypostatising a cause corresponding to the effect, the conception of an immaterial, simple, indestructible being had arisen, the school developed and demonstrated this from the conception of substance. But this conception itself they had previously constructed specially for this purpose by the following artifice, which is worthy of notice.
With the first class of ideas, i.e., the real world of perception, the idea of matter is also given; because the law governing this class of ideas, the law of causality, determines the change of the states or conditions, and these conditions themselves presuppose something permanent, whose changes they are. When speaking above of the principle of the permanence of substance, I showed, by reference to earlier passages, that this idea of matter arises because in the understanding, for which alone it [pg 103] exists, time and space are intimately united, and the share of space in this product exhibits itself as the permanence of matter, while the share of time appears as the change of states. Purely in itself, matter can only be thought in abstracto, and not perceived; for to perception it always appears already in form and quality. From this conception of matter, substance is again an abstraction, consequently a higher genus, and arose in this way. Of the conception of matter, only the predicate of permanence was allowed to remain, while all its other essential properties, extension, impenetrability, divisibility, &c., were thought away. Like every higher genus, then, the concept substance contains less in itself than the concept matter, but, unlike every other higher genus, it does not contain more under it, because it does not include several lower genera besides matter; but this remains the one true species of the concept substance, the only assignable thing by which its content is realised and receives a proof. Thus the aim with which in other cases the reason produces by abstraction a higher conception, in order that in it several subordinate species may be thought at once through common determinations, has here no place; consequently that abstraction is either undertaken idly and entirely without aim, or it has a secret secondary purpose. This secret purpose is now brought to light; for under the conception substance, along with its true sub-species matter, a second species is co-ordinated—the immaterial, simple, indestructible substance, soul. But the surreptitious introduction of this last concept arose from the fact that the higher concept substance was framed illogically, and in a manner contrary to law. In its legitimate procedure the reason always frames the concept of a higher genus by placing together the concepts of several species, and now comparing them, proceeds discursively, and by omitting their differences and retaining the qualities in which they agree, obtains the generic concept which includes them all but has a smaller content. From this [pg 104] it follows that the concepts of the species must always precede the concept of the genus. But, in the present case, the converse is true. Only the concept matter existed before the generic concept substance. The latter was without occasion, and consequently without justification, as it were aimlessly framed from the former by the arbitrary omission of all its determinations except one. Not till afterwards was the second ungenuine species placed beside the concept matter, and so foisted in. But for the framing of this second concept nothing more was now required than an express denial of what had already been tacitly omitted in the higher generic concept, extension, impenetrability, and divisibility. Thus the concept substance was framed merely to be the vehicle for the surreptitious introduction of the concept of the immaterial substance. Consequently, it is very far from being capable of holding good as a category or necessary function of the understanding; rather is it an exceedingly superfluous concept, because its only true content lies already in the concept of matter, besides which it contains only a great void, which can be filled up by nothing but the illicitly introduced species immaterial substance; and, indeed, it was solely for the purpose of containing this that it was framed. Accordingly, in strictness, the concept substance must be entirely rejected, and the concept matter everywhere put in its place.
The categories were a procrustean bed for every possible thing, but the three kinds of syllogisms are so only for the three so-called Ideas. The Idea of the soul was compelled to find its origin in the form of the categorical syllogism. It is now the turn of the dogmatic ideas concerning the universe, so far as it is thought as an object in itself, between two limits—that of the smallest (atom), and that of the largest (limits of the universe in time and space). These must now proceed from the form of the hypothetical [pg 105] syllogism. Nor for this in itself is any special violence necessary. For the hypothetical judgment has its form from the principle of sufficient reason, and not the cosmological alone but all those so-called Ideas really have their origin in the inconsiderate and unrestricted application of that principle, and the laying aside of it at pleasure. For, in accordance with that principle, the mere dependence of an object upon another is ever sought for, till finally the exhaustion of the imagination puts an end to the journey; and thus it is lost sight of that every object, and indeed the whole chain of objects and the principle of sufficient reason itself, stand in a far closer and greater dependence, the dependence upon the knowing subject, for whose objects alone, i.e., ideas, that principle is valid, for their mere position in space and time is determined by it. Thus, since the form of knowledge from which here merely the cosmological Ideas are derived, the principle of sufficient reason, is the source of all subtle hypostases, in this case no sophisms need be resorted to; but so much the more is sophistry required in order to classify those Ideas according to the four titles of the categories.
(1.) The cosmological Ideas with regard to time and space, thus of the limits of the world in both, are boldly regarded as determined through the category of quantity, with which they clearly have nothing in common, except the accidental denotation in logic of the extent of the concept of the subject in the judgment by the word quantity, a pictorial expression instead of which some other might just as well have been chosen. But for Kant's love of symmetry this is enough. He takes advantage of the fortunate accident of this nomenclature, and links to it the transcendent dogmas of the world's extension.
(2.) Yet more boldly does Kant link to quality, i.e., the affirmation or negation in a judgment, the transcendent Ideas concerning matter; a procedure which has not even an accidental similarity of words as a basis. For it is just [pg 106] to the quantity, and not to the quality of matter that its mechanical (not chemical) divisibility is related. But, what is more, this whole idea of divisibility by no means belongs to those inferences according to the principle of sufficient reason, from which, however, as the content of the hypothetical form, all cosmological Ideas ought to flow. For the assertion upon which Kant there relies, that the relation of the parts to the whole is that of the condition to the conditioned, thus a relation according to the principle of sufficient reason, is certainly an ingenious but yet a groundless sophism. That relation is rather based upon the principle of contradiction; for the whole is not through the part, nor the parts through the whole, but both are necessarily together because they are one, and their separation is only an arbitrary act. It depends upon this, according to the principle of contradiction, that if the parts are thought away, the whole is also thought away, and conversely; and by no means upon the fact that the parts as the reason conditioned the whole as the consequent, and that therefore, in accordance with the principle of sufficient reason, we were necessarily led to seek the ultimate parts, in order, as its reason, to understand from them the whole. Such great difficulties are here overcome by the love of symmetry.
(3.) The Idea of the first cause of the world would now quite properly come under the title of relation; but Kant must reserve this for the fourth title, that of modality, for which otherwise nothing would remain, and under which he forces this idea to come by saying that the contingent (i.e., according to his explanation, which is diametrically opposed to the truth, every consequent of its reason) becomes the necessary through the first cause. Therefore, for the sake of symmetry, the conception of freedom appears here as the third Idea. By this conception, however, as is distinctly stated in the observations on the thesis of the third conflict, what is really meant is only that Idea of the cause of the world which alone is admissible [pg 107] here. The third and fourth conflicts are at bottom tautological.
About all this, however, I find and assert that the whole antinomy is a mere delusion, a sham fight. Only the assertions of the antitheses really rest upon the forms of our faculty of knowledge, i.e., if we express it objectively, on the necessary, a priori certain, most universal laws of nature. Their proofs alone are therefore drawn from objective grounds. On the other hand, the assertions and proofs of the theses have no other than a subjective ground, rest solely on the weakness of the reasoning individual; for his imagination becomes tired with an endless regression, and therefore he puts an end to it by arbitrary assumptions, which he tries to smooth over as well as he can; and his judgment, moreover, is in this case paralysed by early and deeply imprinted prejudices. On this account the proof of the thesis in all the four conflicts is throughout a mere sophism, while that of the antithesis is a necessary inference of the reason from the laws of the world as idea known to us a priori. It is, moreover, only with great pains and skill that Kant is able to sustain the thesis, and make it appear to attack its opponent, which is endowed with native power. Now in this regard his first and constant artifice is, that he does not render prominent the nervus argumentationis, and thus present it in as isolated, naked, and distinct a manner as he possibly can; but rather introduces the same argument on both sides, concealed under and mixed up with a mass of superfluous and prolix sentences.
The theses and antitheses which here appear in such conflict remind one of the δικαιος and αδικος λογος which Socrates, in the “Clouds” of Aristophanes, brings forward as contending. Yet this resemblance extends only to the form and not to the content, though this would gladly be asserted by those who ascribe to these most speculative of all questions of theoretical philosophy an influence upon morality, and therefore seriously regard the thesis as the [pg 108] δικαιος, and the antithesis as the αδικος λογος. I shall not, however, accommodate myself here with reference to such small, narrow, and perverse minds; and, giving honour not to them, but to the truth, I shall show that the proofs which Kant adduced of the individual theses are sophisms, while those of the antitheses are quite fairly and correctly drawn from objective grounds. I assume that in this examination the reader has always before him the Kantian antinomy itself.