I.2.2. The Concepts of Pure Reason

Whatever we may have to decide as to the possibility of the concepts derived from pure reason, it is at least true that they are not to be obtained by mere reflection but only by inference. Concepts of understanding are also thought a priori antecedently to experience and for the sake of experience, but they contain nothing more than the unity of reflection upon appearances, in so far as these appearances must necessarily belong to a possible empirical consciousness. Through them alone is knowledge and the determination of an object possible. They first provide the material required for making inferences, and they are not preceded by any a priori concepts of objects from which they could be inferred. On the other hand, their objective reality is founded solely on the fact that, since they constitute the intellectual form of all experience, it must always be possible to show their application in experience.

The title ‘concept of reason’ already gives a preliminary indication that we are dealing with something which does not allow of being confined within experience, since it concerns a knowledge of which any empirical knowledge (perhaps even the whole of possible experience or of its empirical synthesis) is only a part. No actual experience has ever been completely adequate to it, yet to it every actual experience belongs. Concepts of reason enable us to conceive, concepts of understanding to understand—([as employed in reference to] perceptions). If the concepts of reason contain the unconditioned, they are concerned with something to which all experience is subordinate, but which is never itself an object of experience—something to which reason leads in its inferences from experience, and in accordance with which it estimates and gauges the degree of its empirical employment, but which is never itself a member of the empirical synthesis. If, none the less, these concepts possess objective validity, they may be called conceptus ratiocinati (rightly inferred concepts); if, however, they have no such validity, they have surreptitiously obtained recognition through having at least an illusory appearance of being inferences, and may be called conceptus ratiocinantes (pseudo-rational concepts). But since this can be established only in the chapter on the dialectical inferences of pure reason, we are not yet in a position to deal with it. Meantime, just as we have entitled the pure concepts of understanding categories, so we shall give a new name to the concepts of pure reason, calling them transcendental ideas. This title we shall now explain and justify.

Despite the great wealth of our languages, the thinker often finds himself at a loss for the expression which exactly fits his concept, and for want of which he is unable to be really intelligible to others or even to himself. To coin new words is to advance a claim to legislation in language that seldom succeeds; and before we have recourse to this desperate expedient it is advisable to look about in a dead and learned language, to see whether the concept and its appropriate expression are not already there provided. Even if the old-time usage of a term should have become somewhat uncertain through the carelessness of those who introduced it, it is always better to hold fast to the meaning which distinctively belongs to it (even though it remain doubtful whether it was originally used in precisely this sense) than to defeat our purpose by making ourselves unintelligible.

For this reason, if there be only a single word the established meaning of which exactly agrees with a certain concept, then, since it is of great importance that this concept be distinguished from related concepts, it is advisable to economise in the use of the word and not to employ it, merely for the sake of variety, as a synonym for some other expression, but carefully to keep to its own proper meaning. Otherwise it may easily happen that the expression ceasing to engage the attention in one specific sense, and being lost in the multitude of other words of very different meaning, the thought also is lost which it alone could have preserved.

Plato made use of the expression ‘idea’ in such a way as quite evidently to have meant by it something which not only can never be borrowed from the senses but far surpasses even the concepts of understanding (with which Aristotle occupied himself), inasmuch as in experience nothing is ever to be met with that is coincident with it. For Plato ideas are archetypes of the things themselves, and not, in the manner of the categories, merely keys to possible experiences. In his view they have issued from highest reason, and from that source have come to be shared in by human reason, which, however, is now no longer in its original state, but is constrained laboriously to recall, by a process of reminiscence (which is named philosophy), the old ideas, now very much obscured. I shall not engage here in any literary enquiry into the meaning which this illustrious philosopher attached to the expression. I need only remark that it is by no means unusual, upon comparing the thoughts which an author has expressed in regard to his subject, whether in ordinary conversation or in writing, to find that we understand him better than he has understood himself. As he has not sufficiently determined his concept, he has sometimes spoken, or even thought, in opposition to his own intention.

Plato very well realised that our faculty of knowledge feels a much higher need than merely to spell out appearances according to a synthetic unity, in order to be able to read them as experience. He knew that our reason naturally exalts itself to forms of knowledge which so far transcend the bounds of experience that no given empirical object can ever coincide with them, but which must none the less be recognised as having their own reality, and which are by no means mere fictions of the brain.

Plato found the chief instances of his ideas in the field of the practical, that is, in what rests upon freedom, which in its turn rests upon modes of knowledge that are a peculiar product of reason. Whoever would derive the concepts of virtue from experience and make (as many have actually done) what at best can only serve as an example in an imperfect kind of exposition, into a pattern from which to derive knowledge, would make of virtue something which changes according to time and circumstance, an ambiguous monstrosity not admitting of the formation of any rule. On the contrary, as we are well aware, if anyone is held up as a pattern of virtue, the true original with which we compare the alleged pattern and by which alone we judge of its value is to be found only in our minds. This original is the idea of virtue, in respect of which the possible objects of experience may serve as examples (proofs that what the concept of reason commands is in a certain degree practicable), but not as archetype. That no one of us will ever act in a way which is adequate to what is contained in the pure idea of virtue is far from proving this thought to be in any respect chimerical. For it is only by means of this idea that any judgment as to moral worth or its opposite is possible; and it therefore serves as an indispensable foundation for every approach to moral perfection—however the obstacles in human nature, to the degree of which there are no assignable limits, may keep us far removed from its complete achievement.

The Republic of Plato has become proverbial as a striking example of a supposedly visionary perfection, such as can exist only in the brain of the idle thinker; and Brucker has ridiculed the philosopher for asserting that a prince can rule well only in so far as he participates in the ideas. We should, however, be better advised to follow up this thought, and, where the great philosopher leaves us without help, to place it, through fresh efforts, in a proper light, rather than to set it aside as useless on the very sorry and harmful pretext of impracticability. A constitution allowing the greatest possible human freedom in accordance with laws by which the freedom of each is made to be consistent with that of all others—I do not speak of the greatest happiness, for this will follow of itself—is at any rate a necessary idea, which must be taken as fundamental not only in first projecting a constitution but in all its laws. For at the start we are required to abstract from the actually existing hindrances, which, it may be, do not arise unavoidably out of human nature, but rather are due to a quite remediable cause, the neglect of the pure ideas in the making of the laws. Nothing, indeed, can be more injurious, or more unworthy of a philosopher, than the vulgar appeal to so-called adverse experience. Such experience would never have existed at all, if at the proper time those institutions had been established in accordance with ideas, and if ideas had not been displaced by crude conceptions which, just because they have been derived from experience, have nullified all good intentions. The more legislation and government are brought into harmony with the above idea, the rarer would punishments become, and it is therefore quite rational to maintain, as Plato does, that in a perfect state no punishments whatsoever would be required. This perfect state may never, indeed, come into being; none the less this does not affect the rightfulness of the idea, which, in order to bring the legal organisation of mankind ever nearer to its greatest possible perfection, advances this maximum as an archetype. For what the highest degree may be at which mankind may have to come to a stand, and how great a gulf may still have to be left between the idea and its realisation, are questions which no one can, or ought to, answer. For the issue depends on freedom; and it is in the power of freedom to pass beyond any and every specified limit.

But it is not only where human reason exhibits genuine causality, and where ideas are operative causes (of actions and their objects), namely, in the moral sphere, but also in regard to nature itself, that Plato rightly discerns clear proofs of an origin from ideas. A plant, an animal, the orderly arrangement of the cosmos—presumably therefore the entire natural world—clearly show that they are possible only according to ideas, and that though no single creature in the conditions of its individual existence coincides with the idea of what is most perfect in its kind—just as little as does any human being with the idea of humanity, which he yet carries in his soul as the archetype of his actions—these ideas are none the less completely determined in the Supreme Understanding, each as an individual and each as unchangeable, and are the original causes of things. But only the totality of things, in their interconnection as constituting the universe, is completely adequate to the idea. If we set aside the exaggerations in Plato’s methods of expression, the philosopher’s spiritual flight from the ectypal mode of reflecting upon the physical world-order to the architectonic ordering of it according to ends, that is, according to ideas, is an enterprise which calls for respect and imitation. It is, however, in regard to the principles of morality, legislation, and religion, where the experience, in this case of the good, is itself made possible only by the ideas—incomplete as their empirical expression must always remain—that Plato’s teaching exhibits its quite peculiar merits. When it fails to obtain recognition, this is due to its having been judged in accordance with precisely those empirical rules, the invalidity of which, regarded as principles, it has itself demonstrated. For whereas, so far as nature is concerned, experience supplies the rules and is the source of truth, in respect of the moral laws it is, alas, the mother of illusion! Nothing is more reprehensible than to derive the laws prescribing what ought to be done from what is done, or to impose upon them the limits by which the latter is circumscribed.

But though the following out of these considerations is what gives to philosophy its peculiar dignity, we must meantime occupy ourselves with a less resplendent, but still meritorious task, namely, to level the ground, and to render it sufficiently secure for moral edifices of these majestic dimensions. For this ground has been honeycombed by subterranean workings which reason, in its confident but fruitless search for hidden treasures, has carried out in all directions, and which threaten the security of the superstructures. Our present duty is to obtain insight into the transcendental employment of pure reason, its principles and ideas, that we may be in a position to determine and estimate its influence and true value. Yet, before closing these introductory remarks, I beseech those who have the interests of philosophy at heart (which is more than is the case with most people) that, if they find themselves convinced by these and the following considerations, they be careful to preserve the expression ‘idea’ in its original meaning, that it may not become one of those expressions which are commonly used to indicate any and every species of representation, in a happy-go-lucky confusion, to the consequent detriment of science. There is no lack of terms suitable for each kind of representation, that we should thus needlessly encroach upon the province of any one of them. Their serial arrangement is as follows. The genus is representation in general (repraesentatio). Subordinate to it stands representation with consciousness (perceptio). A perception which relates solely to the subject as the modification of its state is sensation (sensatio), an objective perception is knowledge (cognitio). This is either intuition or concept (intuitus vel conceptus). The former relates immediately to the object and is single, the latter refers to it mediately by means of a feature which several things may have in common. The concept is either an empirical or a pure concept. The pure concept, in so far as it has its origin in the understanding alone (not in the pure image of sensibility), is called a notion A concept formed from notions and transcending the possibility of experience is an idea or concept of reason. Anyone who has familiarised himself with these distinctions must find it intolerable to hear the representation of the colour, red, called an idea. It ought not even to be called a concept of understanding, a notion.

The Transcendental Analytic has shown us how the mere logical form of our knowledge may in itself contain original pure a priori concepts, which represent objects prior to all experience, or, speaking more correctly, indicate the synthetic unity which alone makes possible an empirical knowledge of objects. The form of judgments (converted into a concept of the synthesis of intuitions) yielded categories which direct all employment of understanding in experience. Similarly, we may presume that the form of syllogisms, when applied to the synthetic unity of intuitions under the direction of the categories, will contain the origin of special a priori concepts, which we may call pure concepts of reason, or transcendental ideas and which will determine according to principles how understanding is to be employed in dealing with experience in its totality.

The function of reason in its inferences consists in the universality of knowledge [which it yields] according to concepts, the syllogism being itself a judgment which is determined a priori in the whole extent of its conditions. The proposition, ‘Caius is mortal’, I could indeed derive from experience by means of the understanding alone. But I am in pursuit of a concept (in this case, the concept ‘man’) that contains the condition under which the predicate (general term for what is asserted) of this judgment is given; and after I have subsumed the predicate under this condition taken in its whole extension (‘All men are mortal’), I proceed, in accordance therewith, to determine the knowledge of my object (‘Caius is mortal’).

Accordingly, in the conclusion of a syllogism we restrict a predicate to a certain object, after having first thought it in the major premiss in its whole extension under a given condition. This complete quantity of the extension in relation to such a condition is called universality (universalitas). In the synthesis of intuitions we have corresponding to this the allness (universitas) or totality of the conditions. The transcendental concept of reason is, therefore, none other than the concept of the totality of the conditions for any given conditioned. Now since it is the unconditioned alone which makes possible the totality of conditions, and, conversely, the totality of conditions is always itself unconditioned, a pure concept of reason can in general be explained by the concept of the unconditioned, conceived as containing a ground of the synthesis of the conditioned.

The number of pure concepts of reason will be equal to the number of kinds of relation which the understanding represents to itself by means of the categories. We have therefore to seek for an unconditioned, first, of the categorical synthesis in a subject] secondly, of the hypothetical synthesis of the members of a series] thirdly, of the disjunctive synthesis of the parts in a system.

There is thus precisely the same number of kinds of syllogism, each of which advances through prosyllogisms to the unconditioned: first, to the subject which is never itself a predicate; secondly, to the presupposition which itself presupposes nothing further; thirdly, to such an aggregate of the members of the division of a concept as requires nothing further to complete the division. The pure concepts of reason—of totality in the synthesis of conditions—are thus at least necessary as setting us the task of extending the unity of understanding, where possible, up to the unconditioned, and are grounded in the nature of human reason. These transcendental concepts may, however, be without any suitable corresponding employment in concreto, and may therefore have no other utility than that of so directing the understanding that, while it is extended to the uttermost, it is also at the same time brought into complete consistency with itself.

But while we are here speaking of the totality of conditions and of the unconditioned, as being equivalent titles for all concepts of reason, we again come upon an expression with which we cannot dispense, and which yet, owing to an ambiguity that attaches to it through long-standing misuse, we also cannot with safety employ. The word ‘absolute’ is one of the few words which in their original meaning were adapted to a concept that no other word in the same language exactly suits. Consequently its loss, or what amounts to the same thing, looseness in its employment, must carry with it the loss of the concept itself. And since, in this case, the concept is one to which reason devotes much of its attention, it cannot be relinquished without greatly harming all transcendental philosophy. The word ‘absolute’ is now often used merely to indicate that something is true of a thing considered in itself, and therefore of its inward nature. In this sense the absolutely possible would mean that which in itself (interne) is possible—which is, in fact, the least that can be said of an object. On the other hand, the word is also sometimes used to indicate that something is valid in all respects, without limitation, e.g. absolute despotism, and in this sense the absolutely possible would mean what is in every relation (in all respects) possible—which is the most that can be said of the possibility of a thing. Now frequently we find these two meanings combined. For example, what is internally impossible is impossible in any relation, and therefore absolutely impossible. But in most cases the two meanings are infinitely far apart, and I can in no wise conclude that because something is in itself possible, it is therefore also possible in every relation, and so absolutely possible. Indeed, as I shall subsequently show, absolute necessity is by no means always dependent on inner necessity, and must not, therefore, be treated as synonymous with it. If the opposite of something is internally impossible, this opposite is, of course, impossible in all respects, and the thing itself is therefore absolutely necessary. But I cannot reverse the reasoning so as to conclude that if something is absolutely necessary its opposite is internally impossible, i.e., that the absolute necessity of things is an inner necessity. For this inner necessity is in certain cases a quite empty expression to which we cannot attach any concept whatsoever, whereas the concept of the necessity of a thing in all relations (to everything possible) involves certain quite special determinations. Since the loss of a concept that is of great importance for speculative science can never be a matter of indifference to the philosopher, I trust that the fixing and careful preservation of the expression, on which the concept depends, will likewise be not indifferent to him.

It is, then, in this wider sense that I shall use the word ‘absolute’, opposing it to what is valid only comparatively, that is, in some particular respect. For while the latter is restricted by conditions, the former is valid without restriction.

Now the transcendental concept of reason is directed always solely towards absolute totality in the synthesis of conditions, and never terminates save in what is absolutely, that is, in all relations, unconditioned. For pure reason leaves everything to the understanding—the understanding [alone] applying immediately to the objects of intuition, or rather to their synthesis in the imagination. Reason concerns itself exclusively with absolute totality in the employment of the concepts of the understanding, and endeavours to carry the synthetic unity, which is thought in the category, up to the completely unconditioned. We may call this unity of appearances the unity of reason, and that expressed by the category the unity of understanding, Reason accordingly occupies itself solely with the employment of understanding, not indeed in so far as the latter contains the ground of possible experience (for the concept of the absolute totality of conditions is not applicable in any experience, since no experience is unconditioned), but solely in order to prescribe to the understanding its direction towards a certain unity of which it has itself no concept, and in such manner as to unite all the acts of the understanding, in respect of every object, into an absolute whole. The objective employment of the pure concepts of reason is, therefore, always transcendent, while that of the pure concepts of understanding must, in accordance with their nature, and inasmuch as their application is solely to possible experience, be always immanent.

I understand by idea a necessary concept of reason to which no corresponding object can be given in sense-experience. Thus the pure concepts of reason, now under consideration, are transcendental ideas. They are concepts of pure reason, in that they view all knowledge gained in experience as being determined through an absolute totality of conditions. They are not arbitrarily invented; they are imposed by the very nature of reason itself, and therefore stand in necessary relation to the whole employment of understanding. Finally, they are transcendent and overstep the limits of all experience; no object adequate to the transcendental idea can ever be found within experience. If I speak of an idea, then as regards its object, viewed as an object of pure understanding, I am saying a great deal, but as regards its relation to the subject, that is, in respect of its actuality under empirical conditions, I am for the same reason saying very little, in that, as being the concept of a maximum, it can never be correspondingly given in concreto. Since in the merely speculative employment of reason the latter [namely, to determine the actuality of the idea under empirical conditions] is indeed our whole purpose, and since the approximation to a concept, which yet is never actually reached, puts us in no better position than if the concept were entirely abortive, we say of such a concept—it is only an idea. The absolute whole of all appearances—we might thus say—is only an idea; since we can never represent it in image, it remains a problem to which there is no solution. But since, on the other hand, in the practical employment of understanding, our sole concern is with the carrying out of rules, the idea of practical reason can always be given actually in concreto, although only in part; it is, indeed, the indispensable condition of all practical employment of reason. The practice of it is always limited and defective, but is not confined within determinable boundaries, and is therefore always under the influence of the concept of an absolute completeness. The practical idea is, therefore, always in the highest degree fruitful, and in its relation to our actual activities is indispensably necessary. Reason is here, indeed, exercising causality, as actually bringing about that which its concept contains; and of such wisdom we cannot, therefore, say disparagingly it is only an idea. On the contrary, just because it is the idea of the necessary unity of all possible ends, it must as an original, and at least restrictive condition, serve as standard in all that bears on the practical.

Although we must say of the transcendental concepts of reason that they are only ideas this is not by any means to be taken as signifying that they are superfluous and void. For even if they cannot determine any object, they may yet, in a fundamental and unobserved fashion, be of service to the understanding as a canon for its extended and consistent employment. The understanding does not thereby obtain more knowledge of any object than it would have by means of its own concepts, but for the acquiring of such knowledge it receives better and more extensive guidance. Further—what we need here no more than mention—concepts of reason may perhaps make possible a transition from the concepts of nature to the practical concepts, and in that way may give support to the moral ideas themselves, bringing them into connection with the speculative knowledge of reason. As to all this, we must await explanation in the sequel.

In accordance with our plan we leave aside the practical ideas, and consider reason only in its speculative, or rather, restricting ourselves still further, only in its transcendental employment. Here we must follow the path that we have taken in the deduction of the categories; we must consider the logical form of knowledge through reason, to see whether perhaps reason may not thereby be likewise a source of concepts which enable us to regard objects in themselves as determined synthetically a priori, in relation to one or other of the functions of reason.

Reason, considered as the faculty of a certain logical form of knowledge, is the faculty of inferring, i.e. judging mediately (by the subsumption of the condition of a possible judgment under the condition of a given judgment). The given judgment is the universal rule (major premiss). The subsumption of the condition of another possible judgment under the condition of the rule is the minor premiss. The actual judgment which applies the assertion of the rule to the subsumed case is the conclusion. The rule states something universally, subject to a certain condition. The condition of the rule is found to be fulfilled in an actual case. What has been asserted to be universally valid under that condition is therefore to be regarded as valid also in the actual case, which involves that condition. It is very evident, therefore, that reason arrives at knowledge by means of acts of the understanding which constitute a series of conditions. Thus if I arrive at the proposition that all bodies are alterable, only by beginning with the more remote knowledge (in which the concept of body does not occur, but which nevertheless contains the condition of that concept), namely, that everything composite is alterable; if I then proceed from this to a proposition which is less remote and stands under the condition of the last-named proposition, namely, that bodies are composite; and if from this I finally pass to a third proposition, which connects the more remote knowledge (alterable) with the knowledge actually before me, and so conclude that bodies are alterable—by this procedure I have arrived at knowledge (a conclusion) by means of a series of conditions (the premisses). Now every series the exponent of which is given (in categorical or hypothetical judgment) can be continued; consequently this same activity of reason leads to ratiocinatio polysyllogistica, which is a series of inferences that can be prolonged indefinitely on the side either of the conditions per prosyllogismos; or of the conditioned (per episyllogismos).

But we soon become aware that the chain or series of prosyllogisms, that is, of inferred knowledge on the side of the grounds or conditions of a given knowledge, in other words, of the ascending series of syllogisms, must stand in a different relation to the faculty of reason from that of the descending series, that is, of the advance of reason in the direction of the conditioned, by means of episyllogisms. For since in the former case the knowledge (conclusio) is given only as conditioned, we cannot arrive at it by means of reason otherwise than on the assumption that all the members of the series on the side of the conditions are given (totality in the series of the premisses); only on this assumption is the judgment before us possible a priori: whereas on the side of the conditioned, in respect of consequences, we only think a series in process of becoming, not one already presupposed or given in its completeness, and therefore an advance that is merely potential. If, therefore, knowledge be viewed as conditioned, reason is constrained to regard the series of conditions in the ascending line as completed and as given in their totality. But if the same knowledge is viewed as a condition of yet other knowledge, and this knowledge as constituting a series of consequences in a descending line, reason can be quite indifferent as to how far this advance extends a parte posteriori, and whether a totality of the series is possible at all. For it does not need such a series in order to be able to draw its conclusion, this being already sufficiently determined and secured by its grounds a parte priori. The series of premisses on the side of the conditions may have a first member, as its highest condition, or it may have no such member, in which case it is without limits a parte priori. But however this may be, and even admitting that we can never succeed in comprehending a totality of conditions, the series must none the less contain such a totality, and the entire series must be unconditionally true if the conditioned, which is regarded as a consequence resulting from it, is to be counted as true. This is a requirement of reason, which announces its knowledge as being determined a priori and as necessary, either in itself, in which case it needs no grounds, or, if it be derivative, as a member of a series of grounds, which itself, as a series, is unconditionally true.

We are not at present concerned with logical dialectic, which abstracts from all the content of knowledge and confines itself to exposing the fallacies concealed in the form of syllogisms, but with a transcendental dialectic which has to contain, completely a priori, the origin of certain modes of knowledge derived from pure reason as well as of certain inferred concepts, the object of which can never be given empirically and which therefore lie entirely outside [the sphere of] the faculty of pure understanding. From the natural relation which the transcendental employment of our knowledge, alike in inferences and in judgments, must bear to its logical employment, we have gathered that there can be only three kinds of dialectical inference, corresponding to the three kinds of inference through which reason can arrive at knowledge by means of principles, and that in all of these its business is to ascend from the conditioned synthesis, to which understanding always remains restricted, to the unconditioned, which understanding can never reach.

The relations which are to be universally found in all our representations are (1) relation to the subject; (2) relation to objects, either as appearances or as objects of thought in general. If we combine the subdivision with the main division, all relation of representations, of which we can form either a concept or an idea, is then threefold: (1) the relation to the subject; (2) the relation to the manifold of the object in the [field of] appearance; (3) the relation to all things in general.

Now all pure concepts in general are concerned with the synthetic unity of representations, but [those of them which are] concepts of pure reason (transcendental ideas) are concerned with the unconditioned synthetic unity of all conditions in general. All transcendental ideas can therefore be arranged in three classes, the first containing the absolute (unconditioned) unity of the thinking subject, the second the absolute unity of the series of conditions of appearance, the third the absolute unity of the condition of all objects of thought in general.

The thinking subject is the object of psychology, the sum-total of all appearances (the world) is the object of cosmology, and the thing which contains the highest condition of the possibility of all that can be thought (the being of all beings) the object of theology. Pure reason thus furnishes the idea for a transcendental doctrine of the soul (psychologia rationalis), for a transcendental science of the world (cosmologia rationalis), and, finally, for a transcendental knowledge of God (theologia transzendentalis). The understanding is not in a position to yield even the mere project of any one of these sciences, not even though it be supported by the highest logical employment of reason, that is, by all the conceivable inferences through which we seek to advance from one of its objects (appearance) to all others, up to the most remote members of the empirical synthesis; each of these sciences is an altogether pure and genuine product, or problem, of pure reason.

In what precise modes the pure concepts of reason come under these three headings of all transcendental ideas will be fully explained in the next chapter. They follow the guiding-thread of the categories. For pure reason never relates directly to objects, but to the concepts which understanding frames in regard to objects. Similarly it is only by the process of completing our argument that it can be shown how reason, simply by the synthetic employment of that very function of which it makes use in categorical syllogisms, is necessarily brought to the concept of the absolute unity of the thinking subject, how the logical procedure used in hypothetical syllogisms leads to the idea of the completely unconditioned in a series of given conditions, and finally how the mere form of disjunctive syllogism must necessarily involve the highest concept of reason, that of a being of all beings—a thought which, at first sight, seems utterly paradoxical.

No objective deduction, such as we have been able to give of the categories, is, strictly speaking, possible in the case of these transcendental ideas. Just because they are only ideas they have, in fact, no relation to any object that could be given as coinciding with them. We can, indeed, undertake a subjective derivation of them from the nature of our reason; and this has been provided in the present chapter.

As is easily seen, what pure reason alone has in view is the absolute totality of the synthesis on the side of the conditions (whether of inherence, of dependence, or of concurrence); it is not concerned with absolute completeness on the side of the conditioned. For the former alone is required in order to presuppose the whole series of the conditions, and to present it a priori to the understanding. Once we are given a complete (and unconditioned) condition, no concept of reason is required for the continuation of the series; for every step in the forward direction from the condition to the conditioned is carried through by the understanding itself. The transcendental ideas thus serve only for ascending, in the series of conditions, to the unconditioned, that is, to principles. As regards the descending to the conditioned, reason does, indeed, make a very extensive logical employment of the laws of understanding, but no kind of transcendental employment; and if we form an idea of the absolute totality of such a synthesis (of the progressus), as, for instance, of the whole series of all future alterations in the world, this is a creation of the mind (ens rationis) which is only arbitrarily thought, and not a necessary presupposition of reason. For the possibility of the conditioned presupposes the totality of its conditions, but not of its consequences. Such a concept is not, therefore, one of the transcendental ideas; and it is with these alone that we have here to deal.

Finally, we also discern that a certain connection and unity is evident among the transcendental ideas themselves, and that by means of them pure reason combines all its modes of knowledge into a system. The advance from the knowledge of oneself (the soul) to the knowledge of the world, and by means of this to the original being, is so natural that it seems to resemble the logical advance of reason from premisses to conclusion. Whether this is due to a concealed relationship of the same kind as subsists between the logical and the transcendental procedure, is one of the questions that await answer in the course of these enquiries. Indeed, we have already, in a preliminary manner, obtained an answer to the question, since in treating of the transcendental concepts of reason, which, in philosophical theory, are commonly confused with others, and not properly distinguished even from concepts of understanding, we have been able to rescue them from their ambiguous position, to determine their origin, and at the same time, in so doing, to fix their precise number (to which we can never add), presenting them in a systematic connection, and so marking out and enclosing a special field for pure reason.