The World as Will and Idea (Vol. 2 of 3)

“The combination of the manifold of perception” is repeatedly given as the essential operation of the understanding, by means of its twelve categories. Yet this is never adequately explained, nor is it shown what this manifold of perception is before it is combined by the understanding. But time and space, the latter in all its three dimensions, are continua, i. e., all their parts are originally not separate but combined. Thus, then, everything that exhibits itself in them (is given) appears originally as a continuum, i. e., its parts appear already combined and require no adventitious combination of a manifold. If, however, some one should seek to interpret that combining of the manifold of perception by saying that I refer the different sense-impressions of one object to this one only – thus, for example, perceiving a bell, I recognise that what affects my eye as yellow, my hand as smooth and hard, my ear as sounding, is yet only one and the same body, – then I reply that this is rather a consequence of the knowledge a priori of the causal nexus (this actual and only function of the understanding), by virtue of which all those different effects upon my different organs of sense yet lead me only to one common cause of them, the nature of the body standing before me, so that my understanding, in spite of the difference and multiplicity of the effects, still apprehends the unity of the cause as a single object, which just on that account exhibits itself in perception. In the beautiful recapitulation of his doctrine which Kant gives at p. 719-726 or V. 747-754 of the “Critique of Pure Reason,” he explains the categories, perhaps more distinctly than anywhere else, as “the mere rule of the synthesis of that which empirical apprehension has given a posteriori.” It seems as if here he had something in his mind, such as that, in the construction of the triangle, the angles give the rule for the composition of the lines; at least by this image one can best explain to oneself what he says of the function of the categories. The preface to the “Metaphysical First Principles of Natural Science” contains a long note which likewise gives an explanation of the categories, and says that they “differ in no respect from the formal acts of the understanding in judging,” except that in the latter subject and predicate can always change places; then the judgment in general is defined in the same passage as “an act through which given ideas first become knowledge of an object.” According to this, the brutes, since they do not judge, must also have no knowledge of objects. In general, according to Kant, there are only conceptions of objects, no perceptions. I, on the contrary, say: Objects exist primarily only for perception, and conceptions are always abstractions from this perception. Therefore abstract thinking must be conducted exactly according to the world present in perception, for it is only their relation to this that gives content to conceptions; and we must assume for the conceptions no other a priori determined form than the faculty of reflection in general, the nature of which is the construction of conceptions, i. e., of abstract non-perceptible ideas, which constitutes the sole function of the reason, as I have shown in the first book. I therefore require that we should reject eleven of the categories, and only retain that of causality, and yet that we should see clearly that its activity is indeed the condition of empirical perception, which accordingly is not merely sensuous but intellectual, and that the object so perceived, the object of experience, is one with the idea, from which there remains nothing to distinguish except the thing in itself.

After repeated study of the “Critique of Pure Reason” at different periods of my life, a conviction has forced itself upon me with regard to the origin of the Transcendental Logic, which I now impart as very helpful to an understanding of it. Kant's only discovery, which is based upon objective comprehension and the highest human thought, is the apperçu that time and space are known by us a priori. Gratified by this happy hit, he wished to pursue the same vein further, and his love of architectonic symmetry afforded him the clue. As he had found that a pure intuition or perception a priori underlay the empirical perception as its condition, he thought that in the same way certain pure conceptions as presuppositions in our faculty of knowledge must lie at the foundation of the empirically obtained conceptions, and that real empirical thought must be only possible through a pure thought a priori, which, however, would have no objects in itself, but would be obliged to take them from perception. So that as the Transcendental Æsthetic establishes an a priori basis of mathematics, there must, he supposed, also be a similar basis for logic; and thus, then for the sake of symmetry, the former received a pendant in a Transcendental Logic. From this point onwards Kant was no more free, no more in the position of purely, investigating and observing what is present in consciousness; but he was guided by an assumption and pursued a purpose – the purpose of finding what he assumed, in order to add to the Transcendental Æsthetic so happily discovered a Transcendental Logic analogous to it, and thus symmetrically corresponding to it, as a second storey. Now for this purpose he hit upon the table of judgments, out of which he constructed, as well as he could, the table of categories, the doctrine of twelve pure a priori conceptions, which are supposed to be the conditions of our thinking those very things the perception of which is conditioned by the two a priori forms of sensibility: thus a pure understanding now corresponded symmetrically to a pure sensibility. Then another consideration occurred to him, which offered a means of increasing the plausibility of the thing, by the assumption of the schematism of the pure conceptions of the understanding. But just through this the way in which his procedure had, unconsciously indeed, originated betrayed itself most distinctly. For because he aimed at finding something a priori analogous to every empirical function of the faculty of knowledge, he remarked that between our empirical perception and our empirical thinking, conducted in abstract non-perceptible conceptions, a connection very frequently, though not always, takes place, because every now and then we try to go back from abstract thinking to perception; but try to do so merely in order really to convince ourselves that our abstract thought has not strayed far from the safe ground of perception, and perhaps become exaggeration, or, it may be, mere empty talk; much in the same way as, when we are walking in the dark, we stretch out our hand every now and then to the guiding wall. We go back, then, to the perception only tentatively and for the moment, by calling up in imagination a perception corresponding to the conceptions which are occupying us at the time – a perception which can yet never be quite adequate to the conception, but is merely a temporary representative of it. I have already adduced what is needful on this point in my essay on the principle of sufficient reason, § 28. Kant calls a fleeting phantasy of this kind a schema, in opposition to the perfected picture of the imagination. He says it is like a monogram of the imagination, and asserts that just as such a schema stands midway between our abstract thinking of empirically obtained conceptions, and our clear perception which comes to us through the senses, so there are a priori schemata of the pure conceptions of the understanding between the faculty of perception a priori of pure sensibility and the faculty of thinking a priori of the pure understanding (thus the categories). These schemata, as monograms of the pure imagination a priori, he describes one by one, and assigns to each of them its corresponding category, in the wonderful “Chapter on the Schematism of the Pure Conceptions of the Understanding,” which is noted as exceedingly obscure, because no man has ever been able to make anything out of it. Its obscurity, however, vanishes if it is considered from the point of view here indicated, but there also comes out more clearly in it than anywhere else the intentional nature of Kant's procedure, and of the determination formed beforehand of finding what would correspond to the analogy, and could assist the architectonic symmetry; indeed this is here the case to such a degree as to be almost comical. For when he assumes schemata of the pure (empty) a priori conceptions of the understanding (categories) analogous to the empirical schemata (or representatives through the fancy of our actual conceptions), he overlooks the fact that the end of such schemata is here entirely wanting, For the end of the schemata in the case of empirical (real) thinking is entirely connected with the material content of such conceptions. For since these conceptions are drawn from empirical perception, we assist and guide ourselves when engaged in abstract thinking by now and then casting a momentary glance back at the perception out of which the conceptions are framed, in order to assure ourselves that our thought has still real content. This, however, necessarily presupposes that the conceptions which occupy us are sprung from perception, and it is merely a glance back at their material content, indeed a mere aid to our weakness. But in the case of a priori conceptions which as yet have no content at all, clearly this is necessarily omitted. For these conceptions are not sprung from perception, but come to it from within, in order to receive a content first from it. Thus they have as yet nothing on which they could look back. I speak fully upon this point, because it is just this that throws light upon the secret origin of the Kantian philosophising, which accordingly consists in this, that Kant, after the happy discovery of the two forms of intuition or perception a priori, exerted himself, under the guidance of the analogy, to prove that for every determination of our empirical knowledge there is an a priori analogue, and this finally extended, in the schemata, even to a mere psychological fact. Here the apparent depth and the difficulty of the exposition just serve to conceal from the reader that its content remains a wholly undemonstrable and merely arbitrary assumption. But he who has penetrated at last to the meaning of such an exposition is then easily induced to mistake this understanding so painfully attained for a conviction of the truth of the matter. If, on the contrary, Kant had kept himself here as unprejudiced and purely observant as in the discovery of a priori intuition or perception, he must have found that what is added to the pure intuition or perception of space and time, if an empirical perception arises from it, is on the one hand the sensation, and on the other hand the knowledge of causality, which changes the mere sensation into objective empirical perception, but just on this account is not first derived and learned from sensation, but exists a priori, and is indeed the form and function of the pure understanding. It is also, however, its sole form and function, yet one so rich in results that all our empirical knowledge rests upon it. If, as has often been said, the refutation of an error is only complete when the way it originated has been psychologically demonstrated, I believe I have achieved this, with regard to Kant's doctrine of the categories and their schemata, in what I have said above.

After Kant had thus introduced such great errors into the first simple outlines of a theory of the faculty of perception, he adopted a variety of very complicated assumptions. To these belongs first of all the synthetic unity of apperception: a very strange thing, very strangely explained. “The I think must be able to accompany all my ideas.” Must – be able: this is a problematic-apodictic enunciation; in plain English, a proposition which takes with one hand what it gives with the other. And what is the meaning of this carefully balanced proposition? That all knowledge of ideas is thinking? That is not the case: and it would be dreadful; there would then be nothing but abstract conceptions, or at any rate a pure perception free from reflection and will, such as that of the beautiful, the deepest comprehension of the true nature of things, i. e., of their Platonic Ideas. And besides, the brutes would then either think also, or else they would not even have ideas. Or is the proposition perhaps intended to mean: no object without a subject? That would be very badly expressed by it, and would come too late. If we collect Kant's utterances on the subject, we shall find that what he understands by the synthetic unity of apperception is, as it were, the extensionless centre of the sphere of all our ideas, whose radii converge to it. It is what I call the subject of knowing, the correlative of all ideas, and it is also that which I have fully described and explained in the 22d chapter of the Supplements, as the focus in which the rays of the activity of the brain converge. Therefore, to avoid repetition, I now refer to that chapter.

That I reject the whole doctrine of the categories, and reckon it among the groundless assumptions with which Kant burdened the theory of knowledge, results from the criticism given above; and also from the proof of the contradictions in the Transcendental Logic, which had their ground in the confusion of perception and abstract knowledge; also further from the proof of the want of a distinct and definite conception of the nature of the understanding and of the reason, instead of which we found in Kant's writings only incoherent, inconsistent, insufficient, and incorrect utterances with regard to these two faculties of the mind. Finally, it results from the explanations which I myself have given of these faculties of the mind in the first book and its Supplements, and more fully in the essay on the principle of sufficient reason, § 21, 26, and 34, – explanations which are very definite and distinct, which clearly follow from the consideration of the nature of our knowledge, and which completely agree with the conceptions of those two faculties of knowledge that appear in the language and writings of all ages and all nations, but were not brought to distinctness. Their defence against the very different exposition of Kant has, for the most part, been given already along with the exposure of the errors of that exposition. Since, however, the table of judgments, which Kant makes the foundation of his theory of thinking, and indeed of his whole philosophy, has, in itself, as a whole, its correctness, it is still incumbent upon me to show how these universal forms of all judgment arise in our faculty of knowledge, and to reconcile them with my exposition of it. In this discussion I shall always attach to the concepts understanding and reason the sense given them in my explanation, which I therefore assume the reader is familiar with.

An essential difference between Kant's method and that which I follow lies in this, that he starts from indirect, reflected knowledge, while I start from direct or intuitive knowledge. He may be compared to a man who measures the height of a tower by its shadow, while I am like him who applies the measuring-rule directly to the tower itself. Therefore, for him philosophy is a science of conceptions, but for me it is a science in conceptions, drawn from knowledge of perception, the one source of all evidence, and comprehended and made permanent in general conceptions. He passes over this whole world of perception which surrounds us, so multifarious and rich in significance, and confines himself to the forms of abstract thinking; and, although he never expressly says so, this procedure is founded on the assumption that reflection is the ectype of all perception, that, therefore, all that is essential in perception must be expressed in reflection, and expressed in very contracted forms and outlines, which are thus easily surveyed. According to this, what is essential and conformable to law in abstract knowledge would, as it were, place in our hands all the threads by which the varied puppet-show of the world of perception is set in motion before our eyes. If Kant had only distinctly expressed this first principle of his method, and then followed it consistently, he would at least have been obliged to separate clearly the intuitive from the abstract, and we would not have had to contend with inextricable contradictions and confusions. But from the way in which he solves his problem we see that that fundamental principle of his method was only very indistinctly present to his mind, and thus we have still to arrive at it by conjecture even after a thorough study of his philosophy.

Now as concerns the specified method and fundamental maxim itself, there is much to be said for it, and it is a brilliant thought. The nature of all science indeed consists in this, that we comprehend the endless manifold of perceptible phenomena under comparatively few abstract conceptions, and out of these construct a system by means of which we have all those phenomena completely in the power of our knowledge, can explain the past and determine the future. The sciences, however, divide the wide sphere of phenomena among them according to the special and manifold classes of the latter. Now it was a bold and happy thought to isolate what is absolutely essential to the conceptions as such and apart from their content, in order to discover from these forms of all thought found in this way what is essential to all intuitive knowledge also, and consequently to the world as phenomenon in general; and because this would be found a priori on account of the necessity of those forms of thought, it would be of subjective origin, and would just lead to the ends Kant had in view. Here, however, before going further, the relation of reflection to knowledge of perception ought to have been investigated (which certainly presupposes the clear separation of the two, which was neglected by Kant). He ought to have inquired in what way the former really repeats and represents the latter, whether quite pure, or changed and to some extent disguised by being taken up into its special forms (forms of reflection); whether the form of abstract reflective knowledge becomes more determined through the form of knowledge of perception, or through the nature or constitution which unalterably belongs to itself, i. e., to reflective knowledge, so that even what is very heterogeneous in intuitive knowledge can no longer be distinguished when it has entered reflective knowledge, and conversely many distinctions of which we are conscious in the reflective method of knowledge have also sprung from this knowledge itself, and by no means point to corresponding differences in intuitive knowledge. As the result of this investigation, however, it would have appeared that knowledge of perception suffers very nearly as much change when it is taken up into reflection as food when it is taken into the animal organism whose forms and compounds are determined by itself, so that the nature of the food can no longer be recognised from the result they produce. Or (for this is going a little too far) at least it would have appeared that reflection is by no means related to knowledge of perception as the reflection in water is related to the reflected objects, but scarcely even as the mere shadow of these objects stands to the objects themselves; which shadow repeats only a few external outlines, but also unites the most manifold in the same form and presents the most diverse through the same outline; so that it is by no means possible, starting from it, to construe the forms of things with completeness and certainty.

The whole of reflective knowledge, or the reason, has only one chief form, and that is the abstract conception. It is proper to the reason itself, and has no direct necessary connection with the world of perception, which therefore exists for the brutes entirely without conceptions, and indeed, even if it were quite another world from what it is, that form of reflection would suit it just as well. But the combination of conceptions for the purpose of judging has certain definite and normal forms, which have been found by induction, and constitute the table of judgments. These forms are for the most part deducible from the nature of reflective knowledge itself, thus directly from the reason, because they spring from the four laws of thought (called by me metalogical truths) and the dictum de omni et nullo. Certain others of these forms, however, have their ground in the nature of knowledge of perception, thus in the understanding; yet they by no means point to a like number of special forms of the understanding, but can all be fully deduced from the sole function which the understanding has – the direct knowledge of cause and effect. Lastly, still others of these forms have sprung from the concurrence and combination of the reflective and intuitive modes of knowledge, or more properly from the assumption of the latter into the former. I shall now go through the moments of the judgment one by one, and point out the origin of each of them in the sources referred to; and from this it follows of itself that a deduction of categories from them is wanting, and the assumption of this is just as groundless as its exposition was found to be entangled and self-conflicting.

1. The so-called Quantity of judgments springs from the nature of concepts as such. It thus has its ground in the reason alone, and has absolutely no direct connection with the understanding and with knowledge of perception. It is indeed, as is explained at length in the first book, essential to concepts, as such, that they should have an extent, a sphere, and the wider, less determined concept includes the narrower and more determined. The latter can therefore be separated from the former, and this may happen in two ways, – either the narrower concept may be indicated as an indefinite part of the wider concept in general, or it may be defined and completely separated by means of the addition of a special name. The judgment which carries out this operation is in the first case called a particular, and in the second case an universal judgment. For example, one and the same part of the sphere of the concept tree may be isolated through a particular and through an universal judgment, thus – “Some trees bear gall-nuts,” or “All oaks bear gall-nuts.” One sees that the difference of the two operations is very slight; indeed, that the possibility of it depends upon the richness of the language. Nevertheless, Kant has explained this difference as disclosing two fundamentally different actions, functions, categories of the pure understanding which determines experience a priori through them.

Finally, a concept may also be used in order to arrive by means of it at a definite particular idea of perception, from which, as well as from many others, this concept itself is drawn; this happens in the singular judgment. Such a judgment merely indicates the boundary-line between abstract knowledge and knowledge of perception, and passes directly to the latter, “This tree here bears gall-nuts.” Kant has made of this also a special category.

After all that has been said there is no need of further polemic here.

2. In the same way the Quality of the judgment lies entirely within the province of reason, and is not an adumbration of any law of that understanding which makes perception possible, i. e., it does not point to it. The nature of abstract concepts, which is just the nature of the reason itself objectively comprehended, carries with it the possibility of uniting and separating their spheres, as was already explained in the first book, and upon this possibility, as their presupposition, rest the universal laws of thought of identity and contradiction, to which I have given the name of metalogical truths, because they spring purely from the reason, and cannot be further explained. They determine that what is united must remain united, and what is separated must remain separate, thus that what is established cannot at the same time be also abolished, and thus they presuppose the possibility of the combination and separation of spheres, i. e., of judgment. This, however, lies, according to its form, simply and solely in the reason, and this form has not, like the content of the judgments, been brought over from the perceptible knowledge of the understanding, and therefore there is no correlative or analogue of it to be looked for there. After the perception has been brought about through the understanding and for the understanding, it exists complete, subject to no doubt nor error, and therefore knows neither assertion nor denial; for it expresses itself, and has not, like the abstract knowledge of the reason, its value and content in its mere relation to something outside of it, according to the principle of the ground of knowing. It is, therefore, pure reality; all negation is foreign to its nature, can only be added on through reflection, and just on this account remains always in the province of abstract thought.

To the affirmative and negative Kant adds the infinite judgment, making use of a crotchet of the old scholastics, an ingeniously invented stop-gap, which does not even require to be explained, a blind window, such as many others he made for the sake of his architectonic symmetry.

3. Under the very wide conception of Relation Kant has brought three entirely different properties of judgments, which we must, therefore, examine singly, in order to recognise their origin.

(a.) The hypothetical judgment in general is the abstract expression of that most universal form of all our knowledge, the principle of sufficient reason. In my essay on this principle, I already showed in 1813 that it has four entirely different meanings, and in each of these originally originates in a different faculty of knowledge, and also concerns a different class of ideas. It clearly follows from this, that the source of the hypothetical judgment in general, of that universal form of thought, cannot be, as Kant wishes to make it, merely the understanding and its category of causality; but that the law of causality which, according to my exposition, is the one form of knowledge of the pure understanding, is only one of the forms of that principle which embraces all pure or a priori knowledge – the principle of sufficient reason – which, on the other hand, in each of its meanings has this hypothetical form of judgment as its expression. We see here, however, very distinctly how kinds of knowledge which are quite different in their origin and significance yet appear, if thought in abstracto by the reason, in one and the same form of combination of concepts and judgments, and then in this form can no longer be distinguished, but, in order to distinguish them, we must go back to knowledge of perception, leaving abstract knowledge altogether. Therefore the path which was followed by Kant, starting from the point of view of abstract knowledge, to find the elements and the inmost spring of intuitive knowledge also, was quite a wrong one. For the rest, my whole introductory essay on the principle of sufficient reason is, to a certain extent, to be regarded merely as a thorough exposition of the significance of the hypothetical form of judgment; therefore I do not dwell upon it longer here.

(b.) The form of the categorical judgment is nothing but the form of judgment in general, in its strictest sense. For, strictly speaking, judging merely means thinking, the combination of, or the impossibility of combining, the spheres of the concepts. Therefore the hypothetical and the disjunctive combination are properly no special forms of the judgment; for they are only applied to already completed judgments, in which the combination of the concepts remains unchanged the categorical. But they again connect these judgments, for the hypothetical form expresses their dependence upon each other, and the disjunctive their incompatibility. Mere concepts, however, have only one class of relations to each other, those which are expressed in the categorical judgment. The fuller determination, or the sub-species of this relation, are the intersection and the complete separateness of the concept-spheres, i. e., thus affirmation and negation; out of which Kant has made special categories, under quite a different title, that of quality. Intersection and separateness have again sub-species, according as the spheres lie within each other entirely, or only in part, a determination which constitutes the quantity of the judgments; out of which Kant has again made a quite special class of categories. Thus he separates what is very closely related, and even identical, the easily surveyed modifications of the one possible relation of mere concepts to each other, and, on the other hand, unites what is very different under this title of relation.

Categorical judgments have as their metalogical principle the laws of thought of identity and contradiction. But the ground of the connection of the concept-spheres which gives truth to the judgment, which is nothing but this connection, may be of very different kinds; and, according to this, the truth of the judgment is either logical, or empirical, or metaphysical, or metalogical, as is explained in the introductory essay, § 30-33, and does not require to be repeated here. But it is apparent from this how very various the direct cognitions may be, all of which exhibit themselves in the abstract, through the combination of the spheres of two concepts, as subject and predicate, and that we can by no means set up the sole function of the understanding as corresponding to them and producing them. For example, the judgments, “Water boils, the sine measures the angle, the will resolves, business distracts, distinction is difficult,” express through the same logical form the most different kinds of relations; but from this we obtain the right, however irregular the beginning may be, of placing ourselves at the standpoint of abstract knowledge to analyse direct intuitive knowledge. For the rest, the categorical judgment springs from knowledge of the understanding proper, in my sense, only when causation is expressed by it; this is, however, the case in all judgments which refer to a physical quality. For if I say, “This body is heavy, hard, fluid, green, sour, alkaline, organic, &c., &c.,” this always refers to its effect, and thus is knowledge which is only possible through the pure understanding. Now, after this, like much which is quite different from it (for example, the subordination of very abstract concepts), has been expressed in the abstract through subject and predicate, these mere relations of concepts have been transferred back to knowledge of perception, and it has been supposed that the subject and predicate of the judgment must have a peculiar and special correlative in perception, substance and accident. But I shall show clearly further on that the conception substance has no other true content than that of the conception matter. Accidents, however, are quite synonymous with kinds of effects, so that the supposed knowledge of substance and accident is never anything more than the knowledge of cause and effect by the understanding. But the special manner in which the idea of matter arises is explained partly in § 4 of the first book, and still more clearly in the essay on the principle of sufficient reason at the end of § 21, p. 77 (3d ed., p. 82), and in some respects we shall see it still more closely when we investigate the principle of the permanence of substance.

(c.) Disjunctive judgments spring from the law of thought of excluded third, which is a metalogical truth; they are, therefore, entirely the property of the reason, and have not their origin in the understanding. The deduction of the category of community or reciprocity from them is, however, a glaring example of the violence which Kant sometimes allowed to be done to truth, merely in order to satisfy his love of architectonic symmetry. The illegitimacy of that deduction has already often been justly condemned and proved upon various grounds, especially by G. E. Schulze in his “Kritik der theoretischen Philosophie,” and by Berg in his “Epikritik der Philosophie.” What real analogy is there, indeed, between the problematical determination of a concept by disjunctive predicates and the thought of reciprocity? The two are indeed absolutely opposed, for in the disjunctive judgment the actual affirmation of one of the two alternative propositions is also necessarily the negation of the other; if, on the other hand, we think two things in the relation of reciprocity, the affirmation of one is also necessarily the affirmation of the other, and vice versa. Therefore, unquestionably, the real logical analogue of reciprocity is the vicious circle, for in it, as nominally in the case of reciprocity, what is proved is also the proof, and conversely. And just as logic rejects the vicious circle, so the conception of reciprocity ought to be banished from metaphysics. For I now intend, quite seriously, to prove that there is no reciprocity in the strict sense, and this conception, which people are so fond of using, just on account of the indefiniteness of the thought, is seen, if more closely considered, to be empty, false, and invalid. First of all, the reader must call to mind what causality really is, and to assist my exposition, see upon this subject § 20 of the introductory essay, also my prize-essay on the freedom of the will, chap. iii. p. 27 seq., and lastly the fourth chapter of the second book of this work. Causality is the law according to which the conditions or states of matter which appear determine their position in time. Causality has to do merely with conditions or states, indeed, properly, only with changes, and neither with matter as such, nor with permanence without change. Matter, as such, does not come under the law of causality, for it neither comes into being nor passes away; thus neither does the whole thing, as we commonly express ourselves, come under this law, but only the conditions or states of matter. Further, the law of causality has nothing to do with permanence, for where nothing changes there is no producing of effects and no causality, but a continuing quiet condition or state. But if, now, such a state is changed, then the new state is either again permanent or it is not, but immediately introduces a third state, and the necessity with which this happens is just the law of causality, which is a form of the principle of sufficient reason, and therefore cannot be further explained, because the principle of sufficient reason is the principle of all explanation and of all necessity. From this it is clear that cause and effect stand in intimate connection with, and necessary relation to, the course of time. Only because the state A. precedes in time the state B., and their succession is necessary and not accidental, i. e., no mere sequence but a consequence – only because of this is the state A. cause and the state B. effect. The conception reciprocity, however, contains this, that both are cause and both are effect of each other; but this really amounts to saying that each of the two is the earlier and also the later; thus it is an absurdity. For that both states are simultaneous, and indeed necessarily simultaneous, cannot be admitted, because, as necessarily belonging to each other and existing at the same time, they constitute only one state. For the permanence of this state there is certainly required the continued existence of all its determinations, but we are then no longer concerned with change and causality, but with duration and rest, and nothing further is said than that if one determination of the whole state be changed, the new state which then appears cannot continue, but becomes the cause of the change of all the other determinations of the first state, so that a new third state appears; which all happens merely in accordance with the simple law of causality, and does not establish a new law, that of reciprocity.

I also definitely assert that the conception reciprocity cannot be supported by a single example. Everything that one seeks to pass off as such is either a state of rest, to which the conception of causality, which has only significance with reference to changes, finds no application at all, or else it is an alternating succession of states of the same name which condition each other, for the explanation of which simple causality is quite sufficient. An example of the first class is afforded by a pair of scales brought to rest by equal weights. Here there is no effect produced, for there is no change; it is a state of rest; gravity acts, equally divided, as in every body which is supported at its centre of gravity, but it cannot show its force by any effect. That the taking away of one weight produces a second state, which at once becomes the cause of the third, the sinking of the other scale, happens according to the simple law of cause and effect, and requires no special category of the understanding, and not even a special name. An example of the second class is the continuous burning of a fire. The combination of oxygen with the combustible body is the cause of heat, and heat, again, is the cause of the renewed occurrence of the chemical combination. But this is nothing more than a chain of causes and effects, the links of which have alternately the same name. The burning, A., produces free heat, B., this produces new burning, C. (i. e., a new effect which has the same name as the cause A., but is not individually identical with it), this produces new heat, D. (which is not really identical with the effect B., but only according to the concept, i. e., it has the same name), and so on indefinitely. A good example of what in ordinary life is called reciprocity is afforded by a theory about deserts given by Humboldt (Ansichten der Natur, 2d ed., vol. ii. p. 79). In the sandy deserts it does not rain, but it rains upon the wooded mountains surrounding them. The cause is not the attraction of the clouds by the mountains; but it is the column of heated air rising from the sandy plain which prevents the particles of vapour from condensing, and drives the clouds high into the heavens. On the mountains the perpendicular rising stream of air is weaker, the clouds descend, and the rainfall ensues in the cooler air. Thus, want of rain and the absence of plants in the desert stand in the relation of reciprocity; it does not rain because the heated sand-plain sends out more heat; the desert does not become a steppe or prairie because it does not rain. But clearly we have here again, as in the example given above, only a succession of causes and effects of the same names, and throughout nothing essentially different from simple causality. This is also the case with the swinging of the pendulum, and indeed also with the self-conservation of the organised body, in which case likewise every state introduces a new one, which is of the same kind as that by which it was itself brought about, but individually is new. Only here the matter is complicated, because the chain no longer consists of links of two kinds, but of many kinds, so that a link of the same name only recurs after several others have intervened. But we always see before us only an application of the single and simple law of causality which gives the rule to the sequence of states, but never anything which must be comprehended by means of a new and special function of the understanding.

Or is it perhaps advanced in support of the conception of reciprocity that action and reaction are equal? But the reason of this is what I urge so strongly and have fully explained in the essay on the principle of sufficient reason, that the cause and the effect are not two bodies, but two successive states of bodies, consequently each of the two states implicates all bodies concerned; thus the effect, i. e., the newly appearing state, for example, in the case of an impulse, extends to both bodies in the same proportion; therefore the body impelled produces just as great a change in the body impelling as it itself sustains (each in proportion to its mass and velocity). If one pleases to call this reciprocity, then absolutely every effect is a reciprocal effect, and no new conception is introduced on this account, still less does it require a new function of the understanding, but we only have a superfluous synonym for causality. But Kant himself, in a moment of thoughtlessness, exactly expressed this view in the “Metaphysical First Principles of Natural Science” at the beginning of the proof of the fourth principle of mechanics: “All external effect in the world is reciprocal effect.” How then should different functions lie a priori in the understanding for simple causality and for reciprocity, and, indeed, how should the real succession of things only be possible and knowable by means of the first, and their co-existence by means of the second? According to this, if all effect is reciprocal effect, succession and simultaneity would be the same thing, and therefore everything in the world would take place at the same moment. If there were true reciprocity, then perpetual motion would also be possible, and indeed a priori certain; but it is rather the case that the a priori conviction that there is no true reciprocity, and no corresponding form of the understanding, is the ground of the assertion that perpetual motion is impossible.

Aristotle also denies reciprocity in the strict sense; for he remarks that two things may certainly be reciprocal causes of each other, but only if this is understood in a different sense of each of them; for example, that one acts upon the other as the motive, but the latter acts upon the former as the cause of its movement. We find in two passages the same words: Physic., lib. ii. c. 3, and Metaph., lib. v. c. 2. Εστι δε τινα και αλληλων αιτια; οἱον το πονειν αιτιον της ευεξιας, και αὑτη του πονειν; αλλ᾽ ου τον αυτον τροπον, αλλα το μεν ὡς τελος, το δε ὡς αρχη κινησεως. (Sunt præterea quæ sibi sunt mutuo causæ, ut exercitium bonæ habitudinis, et hæc exercitii: at non eodem modo, sed hæc ut finis, aliud ut principium motus.) If, besides this, he had accepted a reciprocity proper, he would have introduced it here, for in both passages he is concerned with enumerating all the possible kinds of causes. In the Analyt. post., lib. ii. c. 11, he speaks of a circle of causes and effects, but not of reciprocity.

4. The categories of Modality have this advantage over all others, that what is expressed through each of them really corresponds to the form of judgment from which it is derived; which with the other categories is scarcely ever the case, because for the most part they are deduced from the forms of judgment with the most capricious violence.

Thus that it is the conceptions of the possible, the actual, and the necessary which occasion the problematic, assertatory, and apodictic forms of judgment, is perfectly true; but that those conceptions are special, original forms of knowledge of the understanding which cannot be further deduced is not true. On the contrary, they spring from the single original form of all knowledge, which is, therefore, known to us a priori, the principle of sufficient reason; and indeed out of this the knowledge of necessity springs directly. On the other hand, it is only because reflection is applied to this that the conceptions of contingency, possibility, impossibility, and actuality arise. Therefore all these do not by any means spring from one faculty of the mind, the understanding, but arise through the conflict of abstract and intuitive knowledge, as will be seen directly.

I hold that to be necessary and to be the consequent of a given reason are absolutely interchangeable notions, and completely identical. We can never know, nor even think, anything as necessary, except so far as we regard it as the consequent of a given reason; and the conception of necessity contains absolutely nothing more than this dependence, this being established through something else, and this inevitable following from it. Thus it arises and exists simply and solely through the application of the principle of sufficient reason. Therefore, there is, according to the different forms of this principle, a physical necessity (the effect from the cause), a logical (through the ground of knowing, in analytical judgments, syllogisms, &c.), a mathematical (according to the ground of being in time and space), and finally a practical necessity, by which we intend to signify not determination through a pretended categorical imperative, but the necessary occurrence of an action according to the motives presented, in the case of a given empirical character. But everything necessary is only so relatively, that is, under the presupposition of the reason from which it follows; therefore absolute necessity is a contradiction. With regard to the rest, I refer to § 49 of the essay on the principle of sufficient reason.

The contradictory opposite, i. e., the denial of necessity, is contingency. The content of this conception is, therefore, negative – nothing more than this: absence of the connection expressed by the principle of sufficient reason. Consequently the contingent is also always merely relative. It is contingent in relation to something which is not its reason. Every object, of whatever kind it may be – for example, every event in the actual world – is always at once necessary and contingent, necessary in relation to the one condition which is its cause: contingent in relation to everything else. For its contact in time and space with everything else is a mere coincidence without necessary connection: hence also the words chance, συμπτωμα, contingens. Therefore an absolute contingency is just as inconceivable as an absolute necessity. For the former would be simply an object which stood to no other in the relation of consequent to its reason. But the inconceivability of such a thing is just the content of the principle of sufficient reason negatively expressed, and therefore this principle must first be upset before we can think an absolute contingency; and even then it itself would have lost all significance, for the conception of contingency has meaning only in relation to that principle, and signifies that two objects do not stand to each other in the relation of reason and consequent.

In nature, which consists of ideas of perception, everything that happens is necessary; for it proceeds from its cause. If, however, we consider this individual with reference to everything else which is not its cause, we know it as contingent; but this is already an abstract reflection. Now, further, let us abstract entirely from a natural object its causal relation to everything else, thus its necessity and its contingency; then this kind of knowledge comprehends the conception of the actual, in which one only considers the effect, without looking for the cause, in relation to which one would otherwise have to call it necessary, and in relation to everything else contingent. All this rests ultimately upon the fact that the modality of the judgment does not indicate so much the objective nature of things as the relation of our knowledge to them. Since, however, in nature everything proceeds from a cause, everything actual is also necessary, yet only so far as it is at this time, in this place; for only so far does determination by the law of causality extend. Let us leave, however, concrete nature and pass over to abstract thinking; then we can present to ourselves in reflection all the natural laws which are known to us partly a priori, partly only a posteriori, and this abstract idea contains all that is in nature at any time, in any place, but with abstraction from every definite time and place; and just in this way, through such reflection, we have entered the wide kingdom of the possible. But what finds no place even here is the impossible. It is clear that possibility and impossibility exist only for reflection, for abstract knowledge of the reason, not for knowledge of perception; although it is the pure forms of perception which supply the reason with the determination of the possible and impossible. According as the laws of nature, from which we start in the thought of the possible and impossible, are known a priori or a posteriori, is the possibility or impossibility metaphysical or physical.

From this exposition, which requires no proof because it rests directly upon the knowledge of the principle of sufficient reason and upon the development of the conceptions of the necessary, the actual, and the possible, it is sufficiently evident how entirely groundless is Kant's assumption of three special functions of the understanding for these three conceptions, and that here again he has allowed himself to be disturbed by no reflection in the carrying out of his architectonic symmetry.

To this, however, we have to add the other great mistake, that, certainly according to the procedure of earlier philosophy, he has confounded the conceptions of necessity and contingency with each other. That earlier philosophy has applied abstraction to the following mistaken use. It was clear that that of which the reason is given inevitably follows, i. e., cannot not be, and thus necessarily is. But that philosophy held to this last determination alone, and said that is necessary which cannot be otherwise, or the opposite of which is impossible. It left, however, the ground and root of such necessity out of account, overlooked the relativity of all necessity which follows from it, and thereby made the quite unthinkable fiction of an absolute necessity, i. e., of something the existence of which would be as inevitable as the consequent of a reason, but which yet was not the consequent of a reason, and therefore depended upon nothing; an addition which is an absurd petitio, for it conflicts with the principle of sufficient reason. Now, starting from this fiction, it explained, in diametrical opposition to the truth, all that is established by a reason as contingent, because it looked at the relative nature of its necessity and compared this with that entirely imaginary absolute necessity, which is self-contradictory in its conception.[5 - Cf. Christian Wolf's “Vernünftige Gedanken von Gott, Welt und Seele,” § 577-579. It is strange that he only explains as contingent what is necessary according to the principle of sufficient reason of becoming, i. e., what takes place from causes, and on the contrary recognises as necessary that which is so according to the other forms of the principle of sufficient reason; for example, what follows from the essentia (definition), thus analytical judgments, and further also mathematical truths. The reason he assigns for this is, that only the law of causality gives infinite series, while the other kinds of grounds give only finite series. Yet this is by no means the case with the forms of the principle of sufficient reason in pure space and time, but only holds good of the logical ground of knowledge; but he held mathematical necessity to be such also. Compare the essay on the principle of sufficient reason, § 50.] Now Kant adheres to this fundamentally perverse definition of the contingent and gives it as explanation. (Critique of Pure Reason, V. p. 289-291, 243. V. 301, 419. V. 447, 486, 488.) He falls indeed into the most evident contradiction with himself upon this point, for on p. 301 he says: “Everything contingent has a cause,” and adds, “That is contingent which might possibly not be.” But whatever has a cause cannot possibly not be: thus it is necessary. For the rest, the source of the whole of this false explanation of the necessary and the contingent is to be found in Aristotle in “De Generatione et Corruptione,” lib. ii. c. 9 et 11, where the necessary is explained as that which cannot possibly not be: there stands in opposition to it that which cannot possibly be, and between these two lies that which can both be and not be, – thus that which comes into being and passes away, and this would then be the contingent. In accordance with what has been said above, it is clear that this explanation, like so many of Aristotle's, has resulted from sticking to abstract conceptions without going back to the concrete and perceptible, in which, however, the source of all abstract conceptions lies, and by which therefore they must always be controlled. “Something which cannot possibly not be” can certainly be thought in the abstract, but if we go with it to the concrete, the real, the perceptible, we find nothing to support the thought, even as possible, – as even merely the asserted consequent of a given reason, whose necessity is yet relative and conditioned.

I take this opportunity of adding a few further remarks on these conceptions of modality. Since all necessity rests upon the principle of sufficient reason, and is on this account relative, all apodictic judgments are originally, and according to their ultimate significance, hypothetical. They become categorical only through the addition of an assertatory minor, thus in the conclusion. If this minor is still undecided, and this indecision is expressed, this gives the problematical judgment.

What in general (as a rule) is apodictic (a law of nature), is in reference to a particular case only problematical, because the condition must actually appear which brings the case under the rule. And conversely, what in the particular as such is necessary (apodictic) (every particular change necessary through the cause), is again in general, and predicated universally, only problematical; because the causes which appear only concern the particular case, and the apodictic, always hypothetical judgment, always expresses merely the general law, not the particular case directly. All this has its ground in the fact that possibility exists only in the province of reflection and for the reason; the actual, in the province of perception and for the understanding; the necessary, for both. Indeed, the distinction between necessary, actual, and possible really exists only in the abstract and according to the conception; in the real world, on the other hand, all three fall into one. For all that happens, happens necessarily, because it happens from causes; but these themselves have again causes, so that the whole of the events of the world, great and small, are a strict concatenation of necessary occurrences. Accordingly everything actual is also necessary, and in the real world there is no difference between actuality and necessity, and in the same way no difference between actuality and possibility; for what has not happened, i. e., has not become actual, was also not possible, because the causes without which it could never appear have not themselves appeared, nor could appear, in the great concatenation of causes; thus it was an impossibility. Every event is therefore either necessary or impossible. All this holds good only of the empirically real world, i. e., the complex of individual things, thus of the whole particular as such. If, on the other hand, we consider things generally, comprehending them in abstracto, necessity, actuality, and possibility are again separated; we then know everything which is in accordance with the a priori laws which belong to our intellect as possible in general; that which corresponds to the empirical laws of nature as possible in this world, even if it has never become actual; thus we distinguish clearly the possible from the actual. The actual is in itself always also necessary, but is only comprehended as such by him who knows its cause; regarded apart from this, it is and is called contingent. This consideration also gives us the key to that contentio περι δυνατων between the Megaric Diodorus and Chrysippus the Stoic which Cicero refers to in his book De Fato. Diodorus says: “Only what becomes actual was possible, and all that is actual is also necessary.” Chrysippus on the other hand says: “Much that is possible never becomes actual; for only the necessary becomes actual.” We may explain this thus: Actuality is the conclusion of a syllogism to which possibility gives the premises. But for this is required not only the major but also the minor; only the two give complete possibility. The major gives a merely theoretical, general possibility in abstracto, but this of itself does not make anything possible, i. e., capable of becoming actual. For this the minor also is needed, which gives the possibility for the particular case, because it brings it under the rule, and thereby it becomes at once actual. For example:

Maj. All houses (consequently also my house) can be destroyed by fire.

Min. My house is on fire.

Concl. My house is being destroyed by fire.

For every general proposition, thus every major, always determines things with reference to actuality only under a presupposition, therefore hypothetically; for example, the capability of being burnt down has as a presupposition the catching fire. This presupposition is produced in the minor. The major always loads the cannon, but only if the minor brings the match does the shot, i. e., the conclusion, follow. This holds good throughout of the relation of possibility to actuality. Since now the conclusion, which is the assertion of actuality, always follows necessarily, it is evident from this that all that is actual is also necessary, which can also be seen from the fact that necessity only means being the consequent of a given reason: this is in the case of the actual a cause: thus everything actual is necessary. Accordingly, we see here the conceptions of the possible, the actual, and the necessary unite, and not merely the last presuppose the first, but also the converse. What keeps them apart is the limitation of our intellect through the form of time; for time is the mediator between possibility and actuality. The necessity of the particular event may be fully seen from the knowledge of all its causes; but the concurrence of the whole of these different and independent causes seems to us contingent; indeed their independence of each other is just the conception of contingency. Since, however, each of them was the necessary effect of its causes, the chain of which has no beginning, it is evident that contingency is merely a subjective phenomenon, arising from the limitation of the horizon of our understanding, and just as subjective as the optical horizon at which the heavens touch the earth.

Since necessity is the same thing as following from given grounds, it must appear in a special way in the case of every form of the principle of sufficient reason, and also have its opposite in the possibility and impossibility which always arises only through the application of the abstract reflection of the reason to the object. Therefore the four kinds of necessity mentioned above stand opposed to as many kinds of impossibility, physical, logical, mathematical and practical. It may further be remarked that if one remains entirely within the province of abstract concepts, possibility is always connected with the more general, and necessity with the more limited concept; for example, “An animal may be a bird, a fish, an amphibious creature, &c.” “A nightingale must be a bird, a bird must be an animal, an animal must be an organism, an organism must be a body.” This is because logical necessity, the expression of which is the syllogism, proceeds from the general to the particular, and never conversely. In the concrete world of nature (ideas of the first class), on the contrary, everything is really necessary through the law of causality; only added reflection can conceive it as also contingent, comparing it with that which is not its cause, and also as merely and purely actual, by disregarding all causal connection. Only in this class of ideas does the conception of the actual properly occur, as is also shown by the derivation of the word from the conception of causality. In the third class of ideas, that of pure mathematical perception or intuition, if we confine ourselves strictly to it, there is only necessity. Possibility occurs here also only through relation to the concepts of reflection: for example, “A triangle may be right-angled, obtuse-angled, or equiangular; its three angles must be equal to two right-angles.” Thus here we only arrive at the possible through the transition from the perceptible to the abstract.

After this exposition, which presupposes the recollection of what was said both in the essay on the principle of sufficient reason and in the first book of the present work, there will, it is hoped, be no further doubt as to the true and very heterogeneous source of those forms which the table of judgments lays before us, nor as to the inadmissibility and utter groundlessness of the assumption of twelve special functions of the understanding for the explanation of them. The latter point is also supported by a number of special circumstances very easily noted. Thus, for example, it requires great love of symmetry and much trust in a clue derived from it, to lead one to assume that an affirmative, a categorical, and an assertatory judgment are three such different things that they justify the assumption of an entirely special function of the understanding for each of them.

Kant himself betrays his consciousness of the untenable nature of his doctrine of the categories by the fact that in the third chapter of the Analytic of Principles (phænomena et noumena) several long passages of the first edition (p. 241, 242, 244-246, 248-253) are omitted in the second – passages which displayed the weakness of that doctrine too openly. So, for example, he says there (p. 241) that he has not defined the individual categories, because he could not define them even if he had wished to do so, inasmuch as they were susceptible of no definition. In saying this he forgot that at p. 82 of the same first edition he had said: “I purposely dispense with the definition of the categories although I may be in possession of it.” This then was, sit venia verbo, wind. But this last passage he has allowed to stand. And so all those passages wisely omitted afterwards betray the fact that nothing distinct can be thought in connection with the categories, and this whole doctrine stands upon a weak foundation.

This table of the categories is now made the guiding clue according to which every metaphysical, and indeed every scientific inquiry is to be conducted (Prolegomena, § 39). And, in fact, it is not only the foundation of the whole Kantian philosophy and the type according to which its symmetry is everywhere carried out, as I have already shown above, but it has also really become the procrustean bed into which Kant forces every possible inquiry, by means of a violence which I shall now consider somewhat more closely. But with such an opportunity what must not the imitatores servum pecus have done! We have seen. That violence then is applied in this way. The meaning of the expressions denoted by the titles, forms of judgment and categories, is entirely set aside and forgotten, and the expressions alone are retained. These have their source partly in Aristotle's Analyt. priora, i. 23 (περι ποιοτητος και ποσοτητος των του συλλογισμου ὁρων: de qualitate et quantitate terminorum syllogismi), but are arbitrarily chosen; for the extent of the concepts might certainly have been otherwise expressed than through the word quantity, though this word is more suited to its object than the rest of the titles of the categories. Even the word quality has obviously been chosen on account of the custom of opposing quality to quantity; for the name quality is certainly taken arbitrarily enough for affirmation and negation. But now in every inquiry instituted by Kant, every quantity in time and space, and every possible quality of things, physical, moral, &c., is brought by him under those category titles, although between these things and those titles of the forms of judgment and of thought there is absolutely nothing in common except the accidental and arbitrary nomenclature. It is needful to keep in mind all the respect which in other regards is due to Kant to enable one to refrain from expressing in hard terms one's repugnance to this procedure. The nearest example is afforded us at once by the pure physiological table of the general principles of natural science. What in all the world has the quantity of judgments to do with the fact that every perception has an extensive magnitude? What has the quality of judgments to do with the fact that every sensation has a degree? The former rests rather on the fact that space is the form of our external perception, and the latter is nothing more than an empirical, and, moreover, entirely subjective feeling, drawn merely from the consideration of the nature of our organs of sense. Further, in the table which gives the basis of rational psychology (Critique of Pure Reason, p. 344; V. 402), the simplicity of the soul is cited under quality; but this is just a quantitative property, and has absolutely no relation to the affirmation or negation in the judgment. But quantity had to be completed by the unity of the soul, which is, however, already included in its simplicity. Then modality is forced in in an absurd way; the soul stands in connection with possible objects; but connection belongs to relation, only this is already taken possession of by substance. Then the four cosmological Ideas, which are the material of the antinomies, are referred to the titles of the categories; but of this we shall speak more fully further on, when we come to the examination of these antinomies. Several, if possible, still more glaring examples 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 - With my refutation of the Kantian proof may be compared the earlier attacks upon it by Feder, Ueber Zeit, Raum und Kausalität, § 28; and by G. E. Schulze, Kritik der theoretischen Philosophie, Bd. ii. S. 422-442.] 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. On p. 253; V. 309, it is said: “If I take away all thought (through the categories) from empirical knowledge, there remains absolutely no knowledge of an object, for through mere perception nothing at all is thought, and that this affection of sensibility is in me establishes really no relation of such ideas to any object.” This sentence contains, in some degree, all the errors of Kant in a nutshell; for it brings out clearly that he has falsely conceived the relation between sensation, perception, and thought, and accordingly identifies the perception, whose form he yet supposes to be space, and indeed space in all its three dimensions, with the mere subjective sensation in the organs of sense, but only allows the knowledge of an object to be given through thought, which is different from perception. I, on the contrary, say: Objects are first of all objects of perception, not of thought, and all knowledge of objects is originally and in itself perception. Perception, however, is by no means mere sensation, but the understanding is already active in it. The thought, which is added only in the case of men, not in the case of the brutes, is mere abstraction from perception, gives no fundamentally new knowledge, does not itself establish objects which were not before, but merely changes the form of the knowledge already won through perception, makes it abstract knowledge in concepts, whereby its concrete or perceptible character is lost, but, on the other hand, combination of it becomes possible, which immeasurably extends the range of its applicability. The material of our thought is, on the other hand, nothing else than our perceptions themselves, and not something which the perceptions did not contain, and which was added by the thought; therefore the material of everything that appears in our thought must be capable of verification in our perception, for otherwise it would be an empty thought. Although this material is variously manipulated and transformed by thought, it must yet be capable of being reduced to perception, and the thought traced back to this – just as a piece of gold can be reduced from all its solutions, oxides, sublimates, and combinations, and presented pure and undiminished. This could not happen if thought itself had added something, and, indeed, the principal thing, to the object.

The whole of the chapter on the Amphiboly, which follows this, is merely a criticism of the Leibnitzian philosophy, and as such is on the whole correct, though the form or pattern on which it is constructed is chosen merely for the sake of architectonic symmetry, which here also is the guiding clue. Thus, to carry out the analogy with the Aristotelian Organon, a transcendental Topic is set up, which consists in this, that every conception is to be considered from four points of view, in order to make out to which faculty of knowledge it belongs. But these four points of view are quite arbitrarily selected, and ten others might be added to them with just as much right; but their fourfold number corresponds to the titles of the categories, and therefore the chief doctrine of Leibnitz is divided among them as best it may be. By this critique, also, to some extent, certain errors are stamped as natural to the reason, whereas they were merely false abstractions of Leibnitz's, who, rather than learn from his great philosophical contemporaries, Spinoza and Locke, preferred to serve up his own strange inventions. In the chapter on the Amphiboly of Reflection it is finally said that there may possibly be a kind of perception entirely different from ours, to which, however, our categories are applicable; therefore the objects of that supposed perception would be noumena, things which can only be thought by us; but since the perception which would give that thought meaning is wanting to us, and indeed is altogether quite problematical, the object of that thought would also merely be a wholly indefinite possibility. I have shown above by quotations that Kant, in utter contradiction with himself, sets up the categories now as the condition of knowledge of perception, now as the function of merely abstract thought. Here they appear exclusively in the latter sense, and it seems quite as if he wished to attribute them merely to discursive thought. But if this is really his opinion, then necessarily at the beginning of the Transcendental Logic, before specifying the different functions of thought at such length, he was necessarily bound to characterise thought in general, and consequently to distinguish it from perception; he ought to have shown what knowledge is given by mere perception, and what that is new is added by thought. Then we would have known what he was really speaking about; or rather, he would then have spoken quite differently, first of perception, and then of thought; instead of which, as it is, he is always dealing with something between the two, which is a mere delusion. There would not then be that great gap between the transcendental Æsthetic and the transcendental Logic, where, after the exposition of the mere form of perception, he simply dismisses its content, all that is empirically apprehended, with the phrase “It is given,” and does not ask how it came about, whether with or without understanding; but, with one spring, passes over to abstract thought; and not even to thought in general, but at once to certain forms of thought, and does not say a word about what thought is, what the concept is, what is the relation of abstract and discursive to concrete and intuitive, what is the difference between the knowledge of men and that of brutes, and what is reason.

Yet it was just this distinction between abstract knowledge and knowledge of perception, entirely overlooked by Kant, which the ancients denoted by φαινομενα and νοουμενα,[7 - See Sext. Empir. Pyrrhon. hypotyp., lib. i. c. 13, νοουμενα φαινομενοις αντετιθη Αναξαγορας (intelligibilia apparentibus opposuit Anaxagoras).] and whose opposition and incommensurability occupied them so much in the philosophemes of the Eleatics, in Plato's doctrine of Ideas, in the dialectic of the Megarics, and later the Scholastics in the controversy between Nominalism and Realism, the seed of which, so late in developing, was already contained in the opposite mental tendencies of Plato and Aristotle. But Kant, who, in an inexcusable manner, entirely neglected the thing to denote which the words φαινομενα and νοουμενα had already been taken, took possession of the words, as if they were still unappropriated, in order to denote by them his thing in itself and his phenomenon.

Since I have been obliged to reject Kant's doctrine of the categories, just as he rejected that of Aristotle, I wish here to indicate as a suggestion a third way of reaching what is aimed at. What both Kant and Aristotle sought for under the name of the categories were the most general conceptions under which all things, however different, must be subsumed, and through which therefore everything that exists would ultimately be thought. Just on this account Kant conceived them as the forms of all thought.

Grammar is related to logic as clothes to the body. Should not, therefore, these primary conceptions, the ground-bass of the reason, which is the foundation of all special thought, without whose application, therefore, no thought can take place, ultimately lie in those conceptions which just on account of their exceeding generality (transcendentalism) have their expression not in single words, but in whole classes of words, because one of them is thought along with every word whatever it may be, whose designation would therefore have to be looked for, not in the lexicon but in the grammar? In fact, should they not be those distinctions of conceptions on account of which the word which expresses them is either a substantive or an adjective, a verb or an adverb, a pronoun, a preposition, or some other particle – in short, the parts of speech? For undoubtedly these denote the forms which all thought primarily assumes, and in which it directly moves; accordingly they are the essential forms of speech, the fundamental constituent elements of every language, so that we cannot imagine any language which would not consist of at least substantives, adjectives, and verbs. These fundamental forms would then have subordinated to them those forms of thought which are expressed through their inflections, that is, through declension and conjugation, and it is unessential to the chief concern whether in denoting them we call in the assistance of the article and the pronoun. We will examine the thing, however, somewhat more closely, and ask the question anew: What are the forms of thought?

(1.) Thought consists throughout of judging; judgments are the threads of its whole web, for without making use of a verb our thought does not move, and as often as we use a verb we judge.

(2.) Every judgment consists in the recognition of the relation between subject and predicate, which it separates or unites with various restrictions. It unites them from the recognition of the actual identity of the two, which can only happen in the case of synonyms; then in the recognition that the one is always thought along with the other, though the converse does not hold – in the universal affirmative proposition; up to the recognition that the one is sometimes thought along with the other, in the particular affirmative proposition. The negative propositions take the opposite course. Accordingly in every judgment the subject, the predicate, and the copula, the latter affirmative or negative, must be to be found; even although each of these is not denoted by a word of its own, as is however generally the case. The predicate and the copula are often denoted by one word, as “Caius ages;” sometimes one word denotes all three, as concurritur, i. e., “the armies engage.” From this it is evident that the forms of thought are not to be sought for precisely and directly in words, nor even in the parts of speech, for even in the same language the same judgment may be expressed in different words, and indeed in different parts of speech, yet the thought remains the same, and consequently also its form; for the thought could not be the same if the form of thought itself were different. But with the same thought and the same form of thought the form of words may very well be different, for it is merely the outward clothing of the thought, which, on the other hand, is inseparable from its form. Thus grammar only explains the clothing of the forms of thought. The parts of speech can therefore be deduced from the original forms of thought themselves which are independent of all language; their work is to express these forms of thought in all their modifications. They are the instrument and the clothing of the forms of thought, and must be accurately adapted to the structure of the latter, so that it may be recognised in them.

(3.) These real, unalterable, original forms of thought are certainly those of Kant's logical table of judgments; only that in this table are to be found blind windows for the sake of symmetry and the table of the categories; these must all be omitted, and also a false arrangement. Thus: —

(a.) Quality: affirmation and negation, i. e., combination and separation of concepts: two forms. It depends on the copula.

(b.) Quantity: the subject-concept is taken either in whole or in part: totality or multiplicity. To the first belong also individual subjects: Socrates means “all Socrateses.” Thus two forms. It depends on the subject.