Critique of Pure Reason

by Immanuel Kant

  3 Read nimmt instead of nehmen, and können instead of könne.

  4 The passage from 'It seems to be' to 'objective concepts' is left out in the Second Edition, and replaced by a short note, see Supplement XXIII.

  5 The passage from 'Appearances' to 'given to me in intuition' is left out in the Second Edition, and replaced by Supplement XXIV.

  6 Read welches instead of welcher.

  7 Addition of the Second Edition.

  8 An additional note in the Second Edition is given in Supplement XXV.

  | Go to Table of Contents |

  Appendix

  Of the Amphiboly of Reflective Concepts, Owing to the Confusion of the Empirical with the Transcendental Use of the Understanding

  Reflection (reflexio) is not concerned with objects themselves, in order to obtain directly concepts of them, but is a state of the mind in which we set ourselves to discover the subjective conditions under which we may arrive at concepts. It is the consciousness of the relation of given representations to the various sources of our knowledge by which alone their mutual relation can be rightly determined. Before saying any more of our representations, the first question is, to which faculty of knowledge they may all belong; whether it is the understanding or the senses by which they are connected and compared. Many a judgment is accepted from mere habit, or made from inclination, and as no reflection precedes or even follows it critically, the judgment is supposed to have had its origin in the understanding. It is not all judgments that require an investigation, that is, a careful attention with regard to the grounds of their truth; for if they are immediately certain, as for instance, that between two points there can be only one straight line, no more immediately certain marks of their truth than that which they themselves convey could be discovered. But all judgments, nay, all comparisons, require reflection, that is, a discrimination of the respective faculty of knowledge to which any given concepts belong. The act by which I place in general the comparison of representations by the side of the faculty of knowledge to which that comparison belongs, and by which I determine whether these representations are compared with each other as belonging to the pure understanding or to sensuous intuition, I call transcendental reflection. The relation in which the two concepts may stand to each other in one state of the mind is that of identity and difference, of agreement and opposition, of the internal and external, and finally of the determinable and the determination (matter and form). The right determination of that relation depends on the question in which faculty of knowledge they subjectively belong to each other, whether in sensibility or in the understanding. For the proper distinction of the latter is of great importance with regard to the manner in which the former must be considered.

  Before proceeding to form any objective judgments, we have to compare the concepts with regard to the identity (of many representations under one concept) as the foundation of general judgments, or with regard to their difference as the foundation of particular judgments, or with regard to their agreement and opposition serving as the foundations of affirmative and negative judgments, etc. For this reason it might seem that we ought to call these concepts concepts of comparison (conceptus comparationis). But as, when the contents of concepts and not their logical form must be considered, that is, whether the things themselves are identical or different, in agreement or in opposition, etc., all things may have a twofold relation to our faculty of knowledge, namely, either to sensibility or to the understanding, and as the manner in which they belong to one another depends on the place to which they belong, it follows that the transcendental reflection, that is the power of determining the relation of given representations to one or the other class of knowledge, can alone determine their mutual relation. Whether the things are identical or different, in agreement or opposition, etc., cannot be established at once by the concepts themselves by means of a mere comparison (comparatio), but first of all by a proper discrimination of that class of knowledge to which they belong, that is, by transcendental reflection. It might therefore be said, that logical reflection is a mere comparison, because it takes no account of the faculty of knowledge to which any given representations belong, and treats them, so far as they are all found in the mind, as homogeneous, while transcendental reflection (which refers to the objects themselves) supplies the possibility of an objective comparison of representations among themselves, and is therefore very different from the other, the faculty of knowledge to which they belong not being the same. This transcendental reflection is a duty from which no one can escape who wishes to form judgments a priori. We shall now take it in hand, and may hope thus to throw not a little light on the real business of the understanding.

  I. Identity and Difference

  When an object is presented to us several times, but each time with the same internal determinations (qualitas et quantitas), it is, so long as it is considered as an object of the pure understanding, always one and the same, one thing, not many (numerica identitas). But if it is a phenomenon, a comparison of the concepts is of no consequence, and though everything may be identical with regard to the concepts, yet the difference of the places of this phenomenon at the same time is a sufficient ground for admitting the numerical difference of the object (of the senses). Thus, though there may be no internal difference whatever (either in quality or quantity) between two drops of water, yet the fact that they may be seen at the same time in different places is sufficient to establish their numerical difference. Leibniz took phenomena to be things by themselves, intelligibilia, that is, objects of the pure understanding (though, on account of the confused nature of their representations, he assigned to them the name of phenomena), and from that point of view his principle of their indiscernibility (principium identitas indiscernibilium) could not be contested. As, however, they are objects of sensibility, and the use of the understanding with regard to them is not pure, but only empirical, their plurality and numerical diversity are indicated by space itself, as the condition of external phenomena. For one part of space, though it may be perfectly similar and equal to another, is still outside it, and for this very reason a part of space different from the first which, added to it, makes a larger space: and this applies to all things which exist at the same time in different parts of space, however similar or equal they may be in other respects.

  II. Agreement and Opposition

  When reality is represented by the pure understanding only (realitas noumenon), no opposition can be conceived between realities, that is, no such relation that, if connected in one subject, they should annihilate the effects one of the other, as for instance 3 - 3 = 0. The real in the phenomena, on the contrary (realitas phenomenon), may very well be in mutual opposition, and if connected in one subject, one may annihilate completely or in part the effect of the other, as in the case of two forces moving in the same straight line, either drawing or impelling a point in opposite directions, or in the case of pleasure, counterbalancing a certain amount of pain.

  III. The Internal and the External

  In an object of the pure understanding that only is internal which has no relation whatever (as regards its existence) to anything different from itself. The inner relations, on the contrary, of a substantial phenomenon in space are nothing but relations, and the substance itself a complex of mere relations. We only know substances in space through the forces which are active in a certain space, by either drawing others near to it (attraction) or by preventing others from penetrating into it (repulsion and impenetrability). Other properties constituting the concept of a substance appearing in space, and which we call matter, are unknown to us. As an object of the pure understanding, on the contrary, every substance must have internal determinations and forces bearing on the internal reality. But what other internal accidents can I think except those which my own internal sense presents to me, namely, something which is either itself thought, or something analogous to it? Hence Leibniz represented all substances (as he conceived them as noumena), even the component
parts of matter (after having in thought removed from them everything implying external relation, and therefore composition also), as simple subjects endowed with powers of representation, in one word, as monads.

  IV. Matter and Form

  These are two concepts which are treated as the foundation of all other reflection, so inseparably are they connected with every act of the understanding. The former denotes the determinable in general, the latter its determination (both in a purely transcendental meaning, all differences in that which is given and the mode in which it is determined being left out of consideration). Logicians formerly called the universal, matter; the specific difference, form. In every judgment the given concepts may be called the logical matter (for a judgment); their relation, by means of the copula, the form of a judgment. In every being its component parts (essentialia) are the matter; the mode in which they are connected in it, the essential form. With respect to things in general, unlimited reality was regarded as the matter of all possibility, and the limitation thereof (negation) as that form by which one thing is distinguished from another, according to transcendental concepts. The understanding demands first that something should be given (at least in concept) in order to be able afterwards to determine it in a certain manner. In the concept of the pure understanding therefore, matter comes before form, and Leibniz in consequence first assumed things (monads), and within them an internal power of representation, in order afterwards to found thereon their external relation, and the community of their states, that is, of their representations. In this way space and time were possible only, the former through the relation of substances, the latter through the connection of their determinations among themselves, as causes and effects. And so it would be indeed, if the pure understanding could be applied immediately to objects, and if space and time were determinations of things by themselves. But if they are sensuous intuitions only, in which we determine all objects merely as phenomena, then it follows that the form of intuition (as a subjective quality of sensibility) comes before all matter (sensations), that space and time therefore come before all phenomena, and before all data of experience, and render in fact all experience possible. As an intellectual philosopher Leibniz could not endure that this form should come before things and determine their possibility: a criticism quite just when he assumed that we see things as they are (though in a confused representation). But as sensuous intuition is a peculiar subjective condition on which all perception a priori depends, and the form of which is original and independent, the form must be given by itself, and so far from matter (or the things themselves which appear) forming the true foundation (as we might think, if we judged according to mere concepts), the very possibility of matter presupposes a formal intuition (space and time) as given.

  Note on the Amphiboly of Reflective Concepts

  I beg to be allowed to call the place which we assign to a concept, either in sensibility or in the pure understanding, its transcendental place. If so, then the determination of this position which belongs to every concept, according to the difference of its use, and the directions for determining according to rules that place for all concepts, would be called transcendental topic; a doctrine which would thoroughly protect us against the subreptitious claims of the pure understanding and the errors arising from it, by always distinguishing to what faculty of knowledge each concept truly belongs. Every concept, or every title to which many kinds of knowledge belong, may be called a logical place. Upon this is based the logical topic of Aristotle, of which orators and schoolmasters avail themselves in order to find under certain titles of thought what would best suit the matter they have in hand, and thus to be able, with a certain appearance of thoroughness, to argue and wrangle to any extent.

  Transcendental topic, on the contrary, contains no more than the above-mentioned four titles of all comparison and distinction, which differ from the categories because they do not serve to represent the object according to what constitutes its concept (quantity, reality, etc.), but only the comparison of representations, in all its variety, which precedes the concept of things. This comparison, however, requires first a reflection, that is, a determination of the place to which the representations of things which are to be compared belong, namely, whether they are thought by the pure understanding or given as phenomena by sensibility.

  Concepts may be logically compared without our asking any questions as to what place their objects belong, whether as noumena to the understanding, or to sensibility as phenomena. But if with these concepts we wish to proceed to the objects themselves, a transcendental reflection is necessary first of all, in order to determine whether they are meant to be objects for the pure understanding or for sensibility. Without this reflection our use of these concepts would be very uncertain, and synthetical propositions would spring up which critical reason cannot acknowledge, and which are simply founded on transcendental amphiboly, that is, on our confounding an object of the pure understanding with a phenomenon.

  For want of such a transcendental topic, and deceived by the amphiboly of reflective concepts, the celebrated Leibniz erected an intellectual system of the world, or believed at least that he knew the internal nature of things by comparing all objects with the understanding only and with the abstract formal concepts of his thought. Our table of reflective concepts gives us the unexpected advantage of being able to exhibit clearly the distinctive features of his system in all its parts, and at the same time the leading principle of this peculiar view which rested on a simple misunderstanding. He compared all things with each other by means of concepts only, and naturally found no other differences but those by which the understanding distinguishes its pure concepts from each other. The conditions of sensuous intuition, which carry their own differences, are not considered by him as original and independent; for sensibility was with him a confused mode of representation only, and not a separate source of representations. According to him a phenomenon was the representation of a thing by itself, though different, in its logical form, from knowledge by means of the understanding, because the phenomenon, in the ordinary absence of analysis, brings a certain admixture of collateral representations into the concept of a thing which the understanding is able to separate. In one word, Leibniz intellectualised phenomena, just as Locke, according to his system of Noogony (if I may use such an expression), sensualised all concepts of the understanding, that is, represented them as nothing but empirical, though abstract, reflective concepts. Instead of regarding the understanding and sensibility as two totally distinct sources of representations, which however can supply objectively valid judgments of things only in conjunction with each other, each of these great men recognised but one of them, which in their opinion applied immediately to things by themselves, while the other did nothing but to produce either disorder or order in the representations of the former.

  Leibniz accordingly compared the objects of the senses with each other as things in general and in the understanding only. He did this,

  First, so far as they are judged by the understanding to be either identical or different. As he considers their concepts only and not their place in intuition, in which alone objects can be given, and takes no account of the transcendental place of these concepts (whether the object is to be counted among phenomena or among things by themselves), it could not happen otherwise than that he should extend his principle of indiscernibility, which is valid with regard to concepts of things in general only, to objects of the senses also (mundus phaenomenon), and imagine that he thus added no inconsiderable extension to our knowledge of nature. No doubt, if I know a drop of water as a thing by itself in all its internal determinations, I cannot allow that one is different from the other, when their whole concepts are identical. But if the drop of water is a phenomenon in space, it has its place not only in the understanding (among concepts), but in the sensuous external intuition (in space), and in this case the physical place is quite indifferent with regard to the inner determinations of things, so that
a place B can receive a thing which is perfectly similar or identical with another in place A, quite as well as if it were totally different from it in its internal determinations. Difference of place by itself and without any further conditions renders the plurality and distinction of objects as phenomena not only possible, but also necessary. That so-called law of Leibniz therefore is no law of nature, but only an analytical rule, or a comparison of things by means of concepts only.

  Secondly. The principle that realities (as mere assertions) never logically contradict each other, is perfectly true with regard to the relation of concepts, but has no meaning whatever either as regards nature or as regards anything by itself (of which we can have no concept whatever).1 The real opposition, as when A—B = 0, takes place everywhere wherever one reality is united with another in the same subject and one annihilates the effect of the other. This is constantly brought before our eyes in nature by all impediments and reactions which, as depending on forces, must be called realitates phaenomena. General mechanics can even give us the empirical condition of that opposition in an a priori rule, by attending to the opposition of directions; a condition of which the transcendental concept of reality knows nothing. Although Leibniz himself did not announce this proposition with all the pomp of a new principle, he yet made use of it for new assertions, and his followers expressly inserted it in their system of the Leibniz-Wolfian philosophy. According to this principle all evils, for example, are nothing but the consequences of the limitations of created beings, that is, they are negations, because these can be the only opposites of reality (which is perfectly true in the mere concept of the thing in general, but not in things as phenomena). In like manner the followers of Leibniz consider it not only possible, but even natural, to unite all reality, without fearing any opposition, in one being; because the only opposition they know is that of contradiction (by which the concept of a thing itself is annihilated), while they ignore that of reciprocal action and reaction, when one real cause destroys the effect of another, a process which we can only represent to ourselves when the conditions are given in sensibility.