The Critique of Pure Reason · Immanuel Kant
APPENDIX
The great utility of this critique of conclusions arrived at by the processes of mere reflection consists in its clear demonstration of the nullity of all conclusions respecting objects which are compared with each other in the understanding alone, while it at the same time confirms what we particularly insisted on, namely, that, although phenomena are not included as things in themselves among the objects of the pure understanding, they are nevertheless the only things by which our cognition can possess objective reality, that is to say, which give us intuitions to correspond with our conceptions. When we reflect in a purely logical manner, we do nothing more than compare conceptions in our understanding, to discover whether both have the same content, whether they are self-contradictory or not, whether anything is contained in either conception, which of the two is given, and which is merely a mode of thinking that given. But if I apply these conceptions to an object in general (in the transcendental sense), without first determining whether it is an object of sensuous or intellectual intuition, certain limitations present themselves, which forbid us to pass beyond the conceptions and render all empirical use of them impossible. And thus these limitations prove that the representation of an object as a thing in general is not only insufficient, but, without sensuous determination and independently of empirical conditions, self-contradictory; that we must therefore make abstraction of all objects, as in logic, or, admitting them, must think them under conditions of sensuous intuition; that, consequently, the intelligible requires an altogether peculiar intuition, which we do not possess, and in the absence of which it is for us nothing; while, on the other hand phenomena cannot be objects in themselves. For, when I merely think things in general, the difference in their external relations cannot constitute a difference in the things themselves; on the contrary, the former presupposes the latter, and if the conception of one of two things is not internally different from that of the other, I am merely thinking the same thing in different relations. Further, by the addition of one affirmation (reality) to the other, the positive therein is really augmented, and nothing is abstracted or withdrawn from it; hence the real in things cannot be in contradiction with or opposition to itself—and so on.
The true use of the conceptions of reflection in the employment of the understanding has, as we have shown, been so misconceived by Leibnitz, one of the most acute philosophers of either ancient or modern times, that he has been misled into the construction of a baseless system of intellectual cognition, which professes to determine its objects without the intervention of the senses. For this reason, the exposition of the cause of the amphiboly of these conceptions, as the origin of these false principles, is of great utility in determining with certainty the proper limits of the understanding. It is right to say whatever is affirmed or denied of the whole of a conception can be affirmed or denied of any part of it (dictum de omni et nullo); but it would be absurd so to alter this logical proposition as to say whatever is not contained in a general conception is likewise not contained in the particular conceptions which rank under it; for the latter are particular conceptions, for the very reason that their content is greater than that which is cogitated in the general conception. And yet the whole intellectual system of Leibnitz is based upon this false principle, and with it must necessarily fall to the ground, together with all the ambiguous principles in reference to the employment of the understanding which have thence originated.
Leibnitz’s principle of the identity of indiscernibles or indistinguishables is really based on the presupposition that, if in the conception of a thing a certain distinction is not to be found, it is also not to be met with in things themselves; that, consequently, all things are completely identical (numero eadem) which are not distinguishable from each other (as to quality or quantity) in our conceptions of them. But, as in the mere conception of anything abstraction has been made of many necessary conditions of intuition, that of which abstraction has been made is rashly held to be non-existent, and nothing is attributed to the thing but what is contained in its conception. The conception of a cubic foot of space, however I may think it, is in itself completely identical. But two cubic feet in space are nevertheless distinct from each other from the sole fact of their being in different places (they are numero diversa); and these places are conditions of intuition, wherein the object of this conception is given, and which do not belong to the conception, but to the faculty of sensibility. In like manner, there is in the conception of a thing no contradiction when a negative is not connected with an affirmative; and merely affirmative conceptions cannot, in conjunction, produce any negation. But in sensuous intuition, wherein reality (take for example, motion) is given, we find conditions (opposite directions)—of which abstraction has been made in the conception of motion in general—which render possible a contradiction or opposition (not indeed of a logical kind)—and which from pure positives produce zero = 0. We are therefore not justified in saying that all reality is in perfect agreement and harmony, because no contradiction is discoverable among its conceptions.[39] According to mere conceptions, that which is internal is the substratum of all relations or external determinations.
When, therefore, I abstract all conditions of intuition, and confine myself solely to the conception of a thing in general, I can make abstraction of all external relations, and there must nevertheless remain a conception of that which indicates no relation, but merely internal determinations. Now it seems to follow that in everything (substance) there is something which is absolutely internal and which antecedes all external determinations, inasmuch as it renders them possible; and that therefore this substratum is something which does not contain any external relations and is consequently simple (for corporeal things are never anything but relations, at least of their parts external to each other); and, inasmuch as we know of no other absolutely internal determinations than those of the internal sense, this substratum is not only simple, but also, analogously with our internal sense, determined through representations, that is to say, all things are properly monads, or simple beings endowed with the power of representation. Now all this would be perfectly correct, if the conception of a thing were the only necessary condition of the presentation of objects of external intuition. It is, on the contrary, manifest that a permanent phenomenon in space (impenetrable extension) can contain mere relations, and nothing that is absolutely internal, and yet be the primary substratum of all external perception.
By mere conceptions I cannot think anything external, without, at the same time, thinking something internal, for the reason that conceptions of relations presuppose given things, and without these are impossible. But, as an intuition there is something (that is, space, which, with all it contains, consists of purely formal, or, indeed, real relations) which is not found in the mere conception of a thing in general, and this presents to us the substratum which could not be cognized through conceptions alone, I cannot say: because a thing cannot be represented by mere conceptions without something absolutely internal, there is also, in the things themselves which are contained under these conceptions, and in their intuition nothing external to which something absolutely internal does not serve as the foundation. For, when we have made abstraction of all the conditions of intuition, there certainly remains in the mere conception nothing but the internal in general, through which alone the external is possible. But this necessity, which is grounded upon abstraction alone, does not obtain in the case of things themselves, in so far as they are given in intuition with such determinations as express mere relations, without having anything internal as their foundation; for they are not things in themselves, but only phenomena.
What we cognize in matter is nothing but relations (what we call its internal determinations are but comparatively internal). But there are some self-subsistent and permanent, through which a determined object is given. That I, when abstraction is made of these relations, have nothing more to think, does not destroy the conception of a thing as phenomenon, nor the conception of an object in abstracto, but it does away with the possibility of an object that is determinable according to mere conceptions, that is, of a noumenon. It is certainly startling to hear that a thing consists solely of relations; but this thing is simply a phenomenon, and cannot be cogitated by means of the mere categories: it does itself consist in the mere relation of something in general to the senses. In the same way, we cannot cogitate relations of things in abstracto, if we commence with conceptions alone, in any other manner than that one is the cause of determinations in the other; for that is itself the conception of the understanding or category of relation. But, as in this case we make abstraction of all intuition, we lose altogether the mode in which the manifold determines to each of its parts its place, that is, the form of sensibility (space); and yet this mode antecedes all empirical causality.
But in this sense the conception of a noumenon is problematical, that is to say, it is the notion of a thing of which we can neither say that it is possible, nor that it is impossible, inasmuch as we do not know of any mode of intuition besides the sensuous, or of any other sort of conceptions than the categories—a mode of intuition and a kind of conception neither of which is applicable to a non-sensuous object. We are on this account incompetent to extend the sphere of our objects of thought beyond the conditions of our sensibility, and to assume the existence of objects of pure thought, that is, of noumena, inasmuch as these have no true positive signification. For it must be confessed of the categories that they are not of themselves sufficient for the cognition of things in themselves and, without the data of sensibility, are mere subjective forms of the unity of the understanding. Thought is certainly not a product of the senses, and in so far is not limited by them, but it does not therefore follow that it may be employed purely and without the intervention of sensibility, for it would then be without reference to an object.
And we cannot call a noumenon an object of pure thought; for the representation thereof is but the problematical conception of an object for a perfectly different intuition and a perfectly different understanding from ours, both of which are consequently themselves problematical. The conception of a noumenon is therefore not the conception of an object, but merely a problematical conception inseparably connected with the limitation of our sensibility. That is to say, this conception contains the answer to the question: “Are there objects quite unconnected with, and independent of, our intuition?”—a question to which only an indeterminate answer can be given. That answer is: “Inasmuch as sensuous intuition does not apply to all things without distinction, there remains room for other and different objects.” The existence of these problematical objects is therefore not absolutely denied, in the absence of a determinate conception of them, but, as no category is valid in respect of them, neither must they be admitted as objects for our understanding.
Understanding accordingly limits sensibility, without at the same time enlarging its own field. While, moreover, it forbids sensibility to apply its forms and modes to things in themselves and restricts it to the sphere of phenomena, it cogitates an object in itself, only, however, as a transcendental object, which is the cause of a phenomenon (consequently not itself a phenomenon), and which cannot be thought either as a quantity or as reality, or as substance (because these conceptions always require sensuous forms in which to determine an object)—an object, therefore, of which we are quite unable to say whether it can be met with in ourselves or out of us, whether it would be annihilated together with sensibility, or, if this were taken away, would continue to exist. If we wish to call this object a noumenon, because the representation of it is non-sensuous, we are at liberty to do so. But as we can apply to it none of the conceptions of our understanding, the representation is for us quite void, and is available only for the indication of the limits of our sensuous intuition, thereby leaving at the same time an empty space, which we are competent to fill by the aid neither of possible experience, nor of the pure understanding.
The critique of the pure understanding, accordingly, does not permit us to create for ourselves a new field of objects beyond those which are presented to us as phenomena, and to stray into intelligible worlds; nay, it does not even allow us to endeavour to form so much as a conception of them. The specious error which leads to this—and which is a perfectly excusable one—lies in the fact that the employment of the understanding, contrary to its proper purpose and destination, is made transcendental, and objects, that is, possible intuitions, are made to regulate themselves according to conceptions, instead of the conceptions arranging themselves according to the intuitions, on which alone their own objective validity rests. Now the reason of this again is that apperception, and with it thought, antecedes all possible determinate arrangement of representations. Accordingly we think something in general and determine it on the one hand sensuously, but, on the other, distinguish the general and in abstracto represented object from this particular mode of intuiting it. In this case there remains a mode of determining the object by mere thought, which is really but a logical form without content, which, however, seems to us to be a mode of the existence of the object in itself (noumenon), without regard to intuition which is limited to our senses.
Before ending this transcendental analytic, we must make an addition, which, although in itself of no particular importance, seems to be necessary to the completeness of the system. The highest conception, with which a transcendental philosophy commonly begins, is the division into possible and impossible. But as all division presupposes a divided conception, a still higher one must exist, and this is the conception of an object in general—problematically understood and without its being decided whether it is something or nothing. As the categories are the only conceptions which apply to objects in general, the distinguishing of an object, whether it is something or nothing, must proceed according to the order and direction of the categories. 1. To the categories of quantity, that is, the conceptions of all, many, and one, the conception which annihilates all, that is, the conception of none, is opposed. And thus the object of a conception, to which no intuition can be found to correspond, is = nothing. That is, it is a conception without an object (ens rationis), like noumena, which cannot be considered possible in the sphere of reality, though they must not therefore be held to be impossible—or like certain new fundamental forces in matter, the existence of which is cogitable without contradiction, though, as examples from experience are not forthcoming, they must not be regarded as possible.
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