Critique of Pure Reason

by Immanuel Kant

  Nothing therefore is gained by the analysis of the consciousness of myself, in thought in general, towards the knowledge of myself as an object. The logical analysis of thinking in general is simply mistaken for a metaphysical determination of the object.

  It would be a great, nay, even the only objection to the whole of our critique, if there were a possibility of proving a priori that all thinking beings are by themselves simple substances, that as such (as a consequence of the same argument) personality is inseparable from them, and that they are conscious of their existence as distinct from all matter. For we should thus have made a step beyond the world of sense and entered into the field of noumena, and after that no one could dare to question our right of advancing further, of settling in it, and, as each of us is favoured by luck, taking possession of it. The proposition that every thinking being is, as such, a simple substance, is synthetical a priori, because, first, it goes beyond the concept on which it rests, and adds to act of thinking in general the mode of existence; and secondly, because it adds to that concept a predicate (simplicity) which cannot be given in any experience. Hence synthetical propositions a priori would be not only admissible, as we maintained, in reference to objects of possible experience, and then only as principles of the possibility of that experience, but could be extended to things in general and to things by themselves, a result which would put an end to the whole of our critique, and bid us to leave everything as we found it. However, the danger is not so great, if only we look more closely into the matter.

  In this process of rational psychology, there lurks a paralogism, which may be represented by the following syllogism.

  That which cannot be conceived otherwise than as a subject, does not exist otherwise than as a subject, and is therefore a substance.

  A thinking being, considered as such, cannot be conceived otherwise than as a subject.

  Therefore it exists also as such only, that is, as a substance.

  In the major they speak of a being that can be thought in every respect, and therefore also as it may be given in intuition. In the minor, however, they speak of it only so far as it considers itself, as subject, with respect to the thinking and the unity of consciousness only, but not at the same time in respect to the intuition whereby this unity is given as an object of thinking. The conclusion, therefore, has been drawn by a sophism, and more especially by sophisma figurae dictionis.29

  That we are perfectly right in thus resolving that famous argument into a paralogism, will be clearly seen by referring to the general note on the systematical representation of the principles, and to the section on the noumena, for it has been proved there that the concept of a thing, which can exist by itself as a subject, and not as a mere predicate, carries as yet no objective reality, that is, that we cannot know whether any object at all belongs to it, it being impossible for us to understand the possibility of such a mode of existence. It yields us therefore no knowledge at all. If such a concept is to indicate, under the name of a substance, an object that can be given, and thus become knowledge, it must be made to rest on a permanent intuition, as the indispensable condition of the objective reality of a concept, that is, as that by which alone the object can be given. In internal intuition, however, we have nothing permanent, for the Ego is only the consciousness of my thinking; and if we do not go beyond this thinking, we are without the necessary condition for applying the concept of substance, that is, of an independent subject, to the self, as a thinking being. Thus the simplicity of the substance entirely disappears with the objective reality of the concept: and is changed into a purely logical qualitative unity of self-consciousness in thinking in general, whether the subject be composite or not.

  Refutation of Mendelssohn's Proof of the Permanence of the Soul

  This acute philosopher perceived very quickly how the ordinary argument that the soul (if it is once admitted to be a simple being) cannot cease to exist by decomposition, was insufficient to prove its necessary continuance, because it might cease to exist by simply vanishing. He therefore tried, in his Phædon, to prove that the soul was not liable to that kind of perishing which would be a real annihilation, by endeavouring to show that a simple being cannot cease to exist, because as it could not be diminished, and thus gradually lose something of its existence, and be changed, by little and little, into nothing (it having no parts, and therefore no plurality in itself), there could be no time between the one moment in which it exists, and the other in which it exists no longer; and this would be impossible.

  He did not consider, however, that, though we might allow to the soul this simple nature, namely, that it contains nothing manifold, nothing by the side of each other, and therefore no extensive quantity, yet we could not deny to it, as little as to any other existing thing, intensive quantity, i.e. a degree of reality with respect to all its faculties, nay, to all which constitutes its existence. Such a degree of reality might diminish by an infinite number of smaller degrees, and thus the supposed substance (the thing, the permanence of which has not yet been established), might be changed into nothing, not indeed through decomposition, but through a gradual remission of its powers, or, if I may say so, through elanguescence. For even consciousness has always a degree, which admits of being diminished,30 and therefore also the faculty of being conscious of oneself, as well as all other faculties.

  The permanence of the soul, therefore, considered merely as an object of the internal sense, remains undemonstrated and undemonstrable, though its permanence in life, while the thinking being (as man) is at the same time to itself an object of the external senses, is clear by itself. But this does not satisfy the rational psychologist, who undertakes to prove, from mere concepts, the absolute permanence of the soul, even beyond this life.31

  If now we take the above propositions in synthetical connection, as indeed they must be taken, as valid for all thinking beings, in a system of rational psychology, and proceed from the category of relation, with the proposition, all thinking beings, as such, are substances, backwards through the series till the circle is completed, we arrive in the end at their existence, and this, according to that system, they are not only conscious of, independently of external things, but are supposed to be able to determine it even of themselves (with respect to that permanence which necessarily belongs to the character of substance). Hence it follows, that in this rationalistic system idealism is inevitable, at least problematical idealism, because, if the existence of external things is not required at all for the determination of one's own existence in time, their existence is really a gratuitous assumption of which no proof can ever be given.

  If, on the contrary, we proceed analytically, taking the proposition, I think, which involves existence (according to the category

  of modality) as given, and analyse it, in order to find our whether, and how, the Ego determines its existence in space and time by it alone, the propositions of rational psychology would not start from the concept of a thinking being, in general, but from a reality, and the inference would consist in determining from the manner in which that reality is thought, after everything that is empirical in it has been removed, what belongs to a thinking being in general. This may be shown by the following Table.

  1.

  I think,

  2.

  3.

  as Subject,

  as simple Subject,

  4.

  as identical Subject,

  in every state of my thought.

  As it has not been determined in the second proposition, whether I can exist and be conceived to exist as a subject only, and not also as a predicate of something else, the concept of subject is here taken as logical only, and it remains undetermined whether we are to understand by it a substance or not. In the third proposition, however, the absolute unity of apperception, the simple I, being the representation to which all connection or separation (which constitute thought) relate, assumes its own importance, although nothing is determined as yet with regard to t
he nature of the subject, or its subsistence. The apperception is something real, and it is only possible, if it is simple. In space, however, there is nothing real that is simple, for points (the only simple in space) are limits only, and not themselves something which, as a part, serves to constitute space. From this follows the impossibility of explaining the nature of myself, as merely a thinking subject, from the materialistic point of view. As, however, in the first proposition, my existence is taken for granted, for it is not said in it that every thinking being exists (this would predicate too much, namely, absolute necessity of them), but only, I exist, as thinking, the proposition itself is empirical, and contains only the determinability of my existence, in reference to my representations in time. But as for that purpose again I require, first of all, something permanent, such as is not given to me at all in internal intuition, so far as I think myself, it is really impossible by that simple self-consciousness to determine the manner in which I exist, whether as a substance or as an accident. Thus, if materialism was inadequate to explain my existence, spiritualism is equally insufficient for that purpose, and the conclusion is, that, in no way whatsoever can we know anything of the nature of our soul, so far as the possibility of its separate existence is concerned.

  And how indeed should it be possible by means of that unity of consciousness which we only know because it is indispensable to us for the very possibility of experience, to get beyond experience (our existence in life), and even to extend our knowledge to the nature of all thinking beings in general, by the empirical, but, with reference to every kind of intuition, undetermined proposition, I think.

  There is, therefore, no rational psychology, as a doctrine, furnishing any addition to our self-knowledge, but only as a discipline, fixing unpassable limits to speculative reason in this field, partly to keep us from throwing ourselves into the arms of a soulless materialism, partly to warn us against losing ourselves in a vague, and, with regard to practical life, baseless spiritualism. It reminds us at the same time to look upon this refusal of our reason to give a satisfactory answer to such curious questions, which reach beyond the limits of this life, as a hint to turn our self-knowledge away from fruitless speculations to a fruitful practical use—a use which, though directed always to objects of experience only, derives its principle from a higher source, and so regulates our conduct, as if our destination reached far beyond experience, and therefore far beyond this life.

  We see from all this, that rational psychology owes its origin to a mere misunderstanding. The unity of consciousness, on which the categories are founded, is mistaken for an intuition of the subject as object, and the category of substance applied to it. But that unity is only the unity in thought, by which alone no object is given, and to which, therefore, the category of substance, which always presupposes a given intuition, cannot be applied, and therefore the subject cannot be known. The subject of the categories, therefore, cannot, by thinking them, receive a concept of itself, as an object of the categories; for in order to think the categories, it must presuppose its pure self-consciousness, the very thing that had to be explained. In like manner the subject, in which the representation of time has its original source, cannot determine by it its own existence in time; and if the latter is impossible, the former, as a determination of oneself (as of a thinking being in general) by means of the categories, is equally so.32

  Thus vanishes, as an idle dream, that knowledge which was to go beyond the limits of possible experience, and was connected no doubt with the highest interests of humanity, so far at least as speculative philosophy was to supply it. Yet no unimportant service has thus been rendered to reason by the severity of our criticism, in proving, at the same time, the impossibility of settling anything dogmatically with reference to an object of experience, beyond the limits of experience, and thus securing it against all possible assertions to the contrary. This can only be done in two ways, either by proving one's own proposition apodictically, or, if that does not succeed, by trying to discover the causes of that failure, which, if they lie in the necessary limits of our reason, must force every opponent to submit to exactly the same law of renunciation with reference to any claims to dogmatic assertion.

  Nothing is lost, however, by this with regard to the right, nay, the necessity of admitting a future life, according to the principles of practical, as connected with the speculative employment of reason. It is known besides, that a purely speculative proof has never been able to exercise any influence on the ordinary reason of men. It stands so entirely upon the point of a hair, that even the schools can only keep it from falling so long as they keep it constantly spinning round like a top, so that, even in their own eyes, it yields no permanent foundation upon which anything could be built. The proofs which are useful for the world at large retain their value undiminished, nay, they gain in clearness and natural power, by the surrender of those dogmatical pretensions, placing reason in its own peculiar domain, namely, the system of ends, which is, however, at the same time the system of nature; so that reason, as a practical faculty by itself, without being limited by the conditions of nature, becomes justified in extending the system of ends, and with it, our own existence, beyond the limits of experience and of life. According to the analogy with the nature of living beings in this world, in which reason must necessarily admit the principle that no organ, no faculty, no impulse, can be found, as being either superfluous or disproportionate to its use, and therefore purposeless, but that everything is adequate to its destination in life, man, who alone can contain in himself the highest end of all this, would be the only creature excepted from it. For, his natural dispositions, not only so far as he uses them according to his talents and impulses, but more especially the moral law within him, go so far beyond all that is useful and advantageous in this life, that he is taught thereby, in the absence of all advantages, even of the shadowy hope of posthumous fame, to esteem the mere consciousness of righteousness beyond everything else, feeling an inner call, by his conduct in this world and a surrender of many advantages, to render himself fit to become the citizen of a better world, which exists in his idea only. This powerful and incontrovertible proof, accompanied by our constantly increasing recognition of a design pervading all that we see around us, and by a contemplation of the immensity of creation, and therefore also by the consciousness of an unlimited possibility in the extension of our knowledge, and a desire commensurate therewith, all this remains and always will remain, although we must surrender the hope of ever being able to understand, from the mere theoretical knowledge of ourselves the necessary continuance of our existence.

  Conclusion of the Solution of the Psychological Paralogism

  The dialectical illusion in rational psychology arises from our confounding an idea of reason (that of a pure intelligence) with the altogether indefinite concept of a thinking being in general. What we are doing is, that we conceive ourselves for the sake of a possible experience, taking no account, as yet, of any real experience, and thence conclude that we are able to become conscious of our existence, independently of experience and of its empirical conditions. We are, therefore, confounding the possible abstraction of our own empirically determined existence with the imagined consciousness of a possible separate existence of our thinking self, and we bring ourselves to believe that we know the substantial within us as the transcendental subject, while what we have in our thoughts is only the unity of consciousness, on which, as on the mere form of knowledge, all determination is based.

  The task of explaining the community of the soul with the body does not properly fall within the province of that psychology of which we are here speaking, because that psychology tries to prove the personality of the soul, apart also from that community (after death), being therefore transcendent, in the proper sense of that word, inasmuch as, though dealing with an object of experience, it deals with it only so far as it has ceased to be an object of experience. According to our doctrine, however, a sufficient answer may be retu
rned to that question also. The difficulty of the task consists, as is well known, in the assumed heterogeneousness of the object of the internal sense (the soul), and the objects of the external senses, the formal condition of the intuition with regard to the former being time only, with regard to the latter, time and space. If we consider, however, that both kinds of objects thus differ from each other, not internally, but so far only as the one appears externally to the other, and that possibly what is at the bottom of phenomenal matter, as a thing by itself, may not be so heterogeneous after all as we imagine, that difficulty vanishes, and there remains that one difficulty only, how a community of substances is possible at all; a difficulty which it is not the business of psychology to solve, and which, as the reader will easily understand, after what has been said in the Analytic of fundamental powers and faculties, lies undoubtedly beyond the limits of all human knowledge.

  General Note on the Transition from Rational Psychology to Cosmology

  The proposition, I think, or, I exist thinking, is an empirical proposition. Such a proposition is based on an empirical intuition, and its object is phenomenal: so that it might seem as if, according to our theory, the soul was changed altogether, even in thinking, into something phenomenal, and our consciousness itself, as merely phenomenal, would thus indeed refer to nothing.

  Thinking, taken by itself, is a logical function only, and therefore pure spontaneity, in connecting the manifold of a merely possible intuition. It does not represent the subject of consciousness, as phenomenal, for the simple reason, that it takes no account whatsoever of the manner of intuition, whether it be sensuous or intellectual. I do not thereby represent myself to myself, either as I am, or as I appear to myself, but I only conceive of myself, as of any other object, without taking account of the manner of intuition. If thereby I represent myself as the subject of my thoughts, or as the ground of thinking, these modes of representation are not the categories of substance or cause, because these are functions of thought (judgment) as applied already to our sensuous intuition, such sensuous intuition being necessary, if I wish to know myself. But I only wish to become conscious of myself as thinking, and as I take no account of what my own self may be as a phenomenon, it is quite possible that it might be a phenomenon only to me, who thinks, but not to me, so far as I am thinking. In the consciousness of myself in mere thinking I am the substance itself, but of that substance nothing is thus given me for thinking.