The Conclusion of the Critique of pure reason¹

It is well known that the fundamental problem of Kant's Critique of pure reason is that of the possibility of metaphysics as science. It is the issue raised by the guiding question of the book: how are synthetic a priori judgments possible? What is much less known and infinitely less evident, is Kant's answer to this cardinal problem whose urgency he so well signified. How is metaphysics actually viable according to Kant? Where does Kant answer in a clear and distinct fashion the question concerning the grounds for synthetic a priori judgments?

The uncertainty that bears on this matter can certainly account for the diversity of interpretations that have been suggested of Kant's solution to the dilemma of metaphysics. I will single out four major trends in the Kant literature. For some, Kant appeared mostly as the philosopher who wanted to liquidate metaphysics altogether as he defied metaphysicians to justify the validity claim of their so-called science. This iconoclastic reading has endured ever since Mendelssohn coined the phrase about the "alles zermalmenden" Kant, that is Kant as the rebell who wanted to do away with two millennia of metaphysics. This reading is maintained, to quote one of its most recent instances, by the russian interpret Arsenij Gulyga, who writes: "In fact, Kant never gave an answer to his question at the beginning of the Critique, «how is metaphysics as science possible?» His transcendental dialectic destroyed all dogmatic claims in this sphere"² . According to a second line of interpretation, Kant did jettison classical metaphysics, but he replaced it by something like a theory of science, one which would reflect solely on the principles at the root of scientific knowledge or, more generally, of our perception of reality or what has been dubbed our "conceptual framework". One could speak here, following Paton's quasi-paradoxical formulation, of a "metaphysics of experience". A third reading of Kant's solution took its departure from Kant's famous passage where he confessed he had to suppress knowledge to make way for faith, a metaphysical faith based on the ressources of pure practical reason. Kant's moral philosophy would thus be the new form of metaphysics. This reading has been suggested by Gerhard Krüger and more recently, albeit in a different vein, by Manfred Riedel³. Finally, there have been interpretations suggesting that Kant actually wanted to save the tenets of aristotelian-leibnizian metaphysics, that laid claim to a knowledge that surpasses the shallow dimension of experience. This has been called the metaphysical interpretation of Kant.

So many, often conflicting, interpretations have not come about randomly. They certainly have something to do with the fact that Kant never seems to give a concluding response to the issue of the possibility of metaphysics and its synthetic a priori judgments. In clear, there is no text in the first Critique that would spell out in a straightforward manner: here is how the problem of metaphysics is to be solved, here is how synthetic a priori judgments by pure reason are possible. One does not find, in short, a "conclusion" to Kant's Critique of pure reason, or, what is more customary in his writings, some kind of Schlussbemerkung, where Kant would make a summary of his research and condense his answer to the inaugural question of his work so well stated in its masterly Introduction.

Nevertheless, such a response, such a "conclusion", must be found somewhere in the Critique of pure reason, since it is precisely to solve the problem of the possibility of metaphysics that the first Critique has been written in the first place. Instituted as a propedeutics to metaphysics, the Critique has no other goal than to sort out the possibility of synthetic a priori cognitions. Its raison d'être consists in establishing the credibility of some form of rational metaphysics. Kant writes very specifically in the Introduction: "It is upon this inquiry, which should be entitled not a doctrine, but only a transcendental critique, that we are now engaged. Its purpose is not to extend knowledge, but only to correct it and to supply a touchstone of the value, or lack of value, of all knowledge a priori. Such a critique is therefore a preparation so far as may be possible, for an organon; and should this turn out not to be possible, then at least for a canon of pure reason, according to which, in due course, the complete system of the philosophy of pure reason (...) might be carried into execution"⁴. The complete system of pure reason, which Kant announces in this context under the heading of a "transcendental philosophy", is what should come after the transcendental critique which is the Critique of pure reason, understood as the propedeutic destined to deliver the touchstone for a system of metaphysics. "Such a system might be called", says Kant in the conditional tense, "a transcendental philosophy". But, he cautions: "that is still at this stage too large an undertaking"⁵. It is too much, because one does not yet know how such a metaphysical or transcendental knowledge is possible. Thus the necessity, Kant argues, of a propedeutic to transcendental philosophy, that is of a "transcendental critique" that would lay the groundwork for a transcendental philosophy" or a metaphysics, that has yet to be developped. - Today, one often understands under "transcendental philosophy" a reflection on the "conditions of possibility" of this or that. For Kant this type of reflection belongs specially to a transcendental critique. For a transcendental philosophy, as Kant understands it, the question of its "conditions of possibility" has, in principle, already been resolved.

The transcendental critique of 1781 thus aims at the clarification of the legitimate metaphysical use of pure reason to make way for the establishment of a metaphysics. The preface to the second edition will therefore define the critique as a "treatise of method", as a Traktat von der Methode, which, Kant insists, is "not yet a system of science itself"⁶ – as metaphysics or transcendental philosophy promises to be. The Critique thus recommends itself as an attempt (Versuch), "to change the procedure (Verfahren) adopted hitherto in metaphysics, accomplishing in it a total revolution"⁷. In itself, the project of a transcendental critique that would function as prolegomena to any future metaphysics is of a remarkable transparence. What is less clear meanwhile, is its realization, its solution, its conclusion, in one word, the exact meaning of the transformation that has to be carried through in the method extolled thus far in metaphysics. What is the meaning of this new method of pure reason?

Our search for this "conclusion" of the Critique has to start with Kant's initial formulation of the problem: how are synthetic a priori judgments possible? As we all know, this problem is subdivided, for the Critique of 1781 as for the Prolegomena of 1783, into three sub-questions: how are synthetic a priori judgments possible 1. in pure mathematics, 2. in pure physics and 3. in metaphysics. This threefold question can also espouse the following form: how are pure mathematics, physics and metaphysics possible? In the presentation of the Prolegomena, which in this respect corresponds fairly well to the architecture of the Critique, the first question is delt with in the transcendental Aesthetic, the second in the Analytic, the third in the Dialectic. As as matter of fact, the Aesthetic does account for the possibility of pure synthetic cognition in mathematics by relying on the mediating instance of the pure intuition of space and time, in which the synthetic a priori assertions of mathematics can be construed and verified, because pure time and space allow for some sort of ideal illustration. In a much more complex argument, that we cannot analyse here⁸, the Analytic attempts to justify the synthetic a priori cognitions of pure physics by appealing to the "third term" of "possible experience". As for the Dialectic, it is, to be sure, concerned with the genuinely metaphysical pretensions of pure reason. But the case of the Dialectic is somewhat particular insofar as it doesn't reach, as was the case in the Aesthetic and the Analytic, a really positive result, i.e. a solution to the problem of the legitimacy of metaphysics as science. Kant admits it unabatedly, and in many ways. First of all, when he divides his transcendental Logic in an Analytic and a Dialectic, he unmistakingly specifies that the former offers a Logic of truth and the second a "Logic of illusion". Does that entail that metaphysics can only be illusory? Is the realm of the a priori knowable limited to pure mathematics and physics? Furthermore, Kant often concedes that the task of his Dialectic is for all intents and purposes merely negative, since it deals with the world of illusion or Schein ⁹.

Does one have to conclude that metaphysics is then unredeemable? This would most certainly be the case if the Dialectic was the last word, or the last section, of the Critique of pure reason. But it isn't. After the Dialectic comes a Methodology (Methodenlehre). I would now like to argue that this transcendental theory of method, far from being a mere appendix to the Critique, as it is often thought to be, represents the genuine outcome of Kant's critical undertaking. It serves, so to speak, as the positive counterpart to the Dialectic, as the arena where one has to find Kant's original solution to the problem of metaphysics. Without this positive outcome, the question of the possibility of synthetic a priori judgments remains without any answer.

One must first recall that the Methodology represents the second major section of the Critique, as a whole, after the transcendental theory of elements (that contains the Aesthetic and the Logic, Analytic and Dialectic). This is not meaningless. The inaugural division of Kant's transcendental critique is that between a theory of elements and a theory of method. If the Methodology has the honor of being the last section of the book, it is because the very idea of a theory of method is intimately linked to the original project of a Critique of pure reason. The Critique defined itself, we remember, as a "treatise on method" that aims at a fundamental revolution in metaphysics by exposing the corner stone of metaphysical cognitions. In its very conception, the Critique of pure reason has no other task than to revolutionize metaphysics by proposing a new methodology that could lay the foundations for a rigorous metaphysics. It then seems appropriate to learn anew to see in the methodology the logical outcome of Kant's critical investigation. By exagerating only slightly, one could claim that the transcendental theory of elements had no other object than to sort out the elements of pure reason. The original import of the Critique could then be found in its methodology. What is undoubtable is that the institution of a new metaphysics did not take place anywhere in the transcendental theory of elements.

Kant defines the transcendental theory of method as the "determination of the formal conditions of a complete system of pure reason"¹⁰, which has yet to be developped under the title of a metaphysics. It aims at clarifying the conditions for the legitimate use of pure reason with view to this metaphysics. The Critique of pure reason doesn't have a more urgent task. After defining its purpose, Kant lays out the plan of his methodology: "Toward this end [i.e. the determination of the formal conditions for a complete system of pure reason] we will deal with a discipline, a canon, an architectonic and finally a history of pure reason"¹¹. After going through the Dialectic, one can easily grasp why the Methodology will open on a discipline of pure reason. Since metaphysical reason naturally falls pray to transcendental illusion, a pure reason keen on its proper method needs a discipline before anything alse, that is an instruction with a negative purpose, following Kant's own expression¹². To this extent the discipline can be said to duplicate the therapeutical and critical effort, in the negative meaning of the word, of the Dialectic. It is not in this Discipline that one will find a positive answer to the inquiry on the possibility of metaphysics.

It is only in its second act, in the Canon of pure reason, that the Methodology will draw out the new foundations of metaphysics. The idea of a "canon" of pure reason had already been broached in the Introduction of the Critique, at one of its most strategic junctures, where the project of Kant's Critique was in the process of defining itself. Let's quote again the relevant portion of the text: "such a critique is therefore a preparation... for a canon of a priori cognitions, according to which... the complete system of the philosophy of pure reason might someday be presented"¹³. Where should we find this "canon" of the legitimate use of pure reason, the avowed goal of the first Critique, if not in its Canon of pure reason?
Kant offers a general, but limpid definition of what is to be understood under a canon: "I understand by canon the whole (Inbegriff) of the a priori principles of the legitimate use of certain faculties of knowledge"¹⁴. If this faculty of knowledge is pure reason itself, as is here the case, its Canon will necessarily indicate the a priori principles of the legimate use of pure reason. This earmarking associates in striking fashion the Canon to the original purpose of a critique of pure reason. Does the Critique have a more precise objective than the sorting out of the a priori principles of the correct employment of pure reason?

Yet did we not learn from the Dialectic that it is vain to expect any kind of metaphysical knowledge? Did it not consign all the possibilities of the sophistic arguments of metaphysics "in the archives of human reason in order to prevent similar errors in the future"¹⁵? Certainly, but Kant now says that this failure only concerns pure theoretical or speculative reason, the reason that rests solely on the syllogisms of pure reason to obtain a priori knowledge. This failure of theorerical reason is inexorable and Kant insists that there can be absolutely no canon for this reason, but only a negative discipline¹⁶. If there is a canon of pure reason at all, it will only deal with the practical use of reason, which Kant introduces here as an entirely new outcome that he is setting out to explore: "Consequently, if there be any correct employment of pure reason, in which case there must be a canon of this reason, the canon will not deal with the speculative, but merely with the practical employment, which we shall now proceed to investigate"¹⁷. This passage makes quite clear that if there shall be a legitimate use of pure reason, there must be a canon for it. The determination of the justified employment of pure reason, goal of the Critique, has to be found in its canon.

Kant immediately underscores the urgency of his inquiry by giving the first section of the Canon the title: "On the ultimate end of the pure employment of reason". Without any doubt, one is also reaching the final end, the culmination point of the entire Critique of Pure reason that will link the possibility of metaphysics to the practical interest of pure reason. Kant's argumentation starts with a recollection of the three objects of reason as they emerged from the Dialectic: the freedom of the will, the immortality of the soul and the existence of God¹⁸.

All those objects are of the utmost interest to us, says Kant, but that interest is not really of theoretical nature¹⁹. By that he means that those objects, could they be known, would be of no utility "in concreto, that is in the study of nature"²⁰. The interest we attach to those ideas, Kant contends, is genuinely practical. And "practical means that which is possible through freedom"²¹. Kant's argument is that there are conditions of freedom that are not only of an empirical import (if not, moral philosophy would amount to a mere empirical anthropology). There are also moral laws that originally belong to reason and that compell us in an unconditional and universal manner. There is thus an "efficiency" of pure reason that is not of theoretical nature and about which a canon will be possible. Kant writes: "Pure practical laws, whose end is given through reason completely a priori, and which are prescribed to us not in an empirically conditionned, but in an absolute manner, would be products of pure reason. Such are moral laws and these alone, therefore, belong to the practical employment of pure reason, and allow of a canon"²²

The practical interest we associate to the three ideas of reason, towards which "all the preparations of reason are oriented in the realm of what one can call pure philosophy", only wants to sort out "what is to be done, if our will is free, if there is a God and a future life"²³. Claiming here that practical freedom can be confirmed by experience, a thesis that is far from constant in Kant, and that it belongs as such to speculative philosophy, Kant limits, as early as the first Critique, the scope of his canon of pure practical reason, to two objects: "we have therefore in a canon of pure reason to deal with only two questions, which relate to the practical interest of pure reason, and in regard to which a canon of its employment must be possible: Is there a God? Is there a future life?"²⁴. The practical, if not existential object of the Canon is concisely circumscribed.

It also echoes Kant's basic concern in his inquiry on the possibility of metaphysics. The metaphysics that Kant looks for in the Critique does not aim at the establishment of a scholastic system that would produce a priori definitions of all concepts through the run down of a caracteristica universalis. Kant's metaphysics is an "interested" metaphysics from the outset. It hopes to answer the original metaphysical preoccupations of man, the questions that constitute what Kant calls the metaphysica naturalis, that has always existed and that will always continue to exist as a natural disposition. Its essential qualms are the existence of God and the immortality of the soul. Can this metaphysics ever acquire scientific status? Can there be a rigorous science regarding the most elementary metaphysical aspirations of man, which can never be content, Kant writes, with that which is merely temporal²⁵? This metaphysical thirst can be condensated in the twofold question: is there a God? is there a future life?

Even if those questions concern more closely what Kant calls the practical use of reason, one must nevertheless never lose sight of the theoretical ambition of Kant's inquiry on practical reason in the first Critique. Kant is indeed still looking for the touchstone of a metaphysics. Kant readily acknowledges it at the very beginning of the Canon: "however (indessen) there must be some source of positive cognitions (einen Quell von positiven Erkenntnissen) that belong to the domain of pure reason, but that only give occasion to error solely owing to misunderstanding, while yet in actual fact they form the goal of reason's zeal"²⁶. Even if Kant is only discussing the practical employment of reason, one will nonetheless discover in this usage the source (Quell) or the touchstone for positive cognitions in a metaphysics out of pure reason. It is this foundation or touchstone that the Critique of pure reason has to put into light in order to edify a metaphysics. The road that leads to a metaphysical cognition, whose synthetic a priori claim would be legitimate, passes through the study of the principles of pure practical reason. This, I submit, is the sense of the methodological revolution Kant attempts to carry through in the method hitherto observed in metaphysics.

The "ultimate end of the pure employment of reason" (title of the first section) has now been determined. It lies in the question: is there a God and a future life? It will be up to the second section of the Canon to explain more precisely in what this new method of practical reason consists, the only one still open to rational metaphysics. It is entitled: "On the Ideal of the highest good as a determining ground of the ultimate end of pure reason". Its first paragraph sums up the path of reason throughout the transcendental Dialectic. Reason has led us to speculative ideas, but those ideas have redirected us toward experience in a certainly useful manner, but which nonetheless doesn't correspond to our expectations²⁷. In other words, the result of the Dialectic is quite honorable, but it didn't really satisfy our expectations since it left unresolved the question of the possibility of metaphysics, thus failing to answer the most vital questions of reason, regarding God and the immortality of the soul. It is at this strategic juncture that the perspective of a practical metaphysics will begin to unfold: "Only one more attempt remains to be undertaken: to see whether pure reason may not also be met in the practical sphere, and whether it may not there conduct us to ideas which reach the highest ends of pure reason that we have just stated and whether, therefore, reason may not be able to supply to us from the standpoint of its practical interest what it altogether refuses to supply in respect of its speculative interest"²⁸. At this decisive step of the argument where he alludes to the interest of reason, Kant puts forward the three famous questions that express this interest of reason: what can I know? what should I do? what may I hope for? The first question is only speculative (bloss spekulativ), Kant contends. He prides himself of having exhausted all possible answers to this question in his Critique, but, then again, "we remain as far away from the two great ends towards which all the effort of pure reason strives"²⁹ - the two great ends coined in the question "is there a God? is there a future life". Kant then goes on to set aside rather swiftly the second question that expresses the interest of reason: what should I do? Resorting to almost the same terms he used to diminish the urgency of the first question, he declares: "the second question is only practical (bloss praktisch). As such, it doesn't belong to the scope of pure reason. It is not a transcendental, but a moral matter, that doesn't have to concern our Critique". The second question (what should I do?) is thus provisionally discarded from the discussion of the "ground for the determination of the ultimate end of reason" in the Canon.

Kant's entire attention will be devoted to the third question: "if I do what I ought to, what may I hope for?" This question, he says, has the advantage of being both practical and theoretical, since hope invests every action we undertake, but it is also theoretical, then what is hoped for or hoped "in" entails a certain kind of cognition, that has yet to be circumscribed. What evidently appeals to Kant, is that the practical here serves as a kind of a relay to the theoretical concerns of reason, in such a way that "the practical can lead as a guiding thread to the solution of the theoretical question"³⁰. What Kant here envisions is, without any doubt, a solution to the theoretical question through the practical use of pure reason.

The text of the Canon stresses quite clearly this passage from the practical to the theoretical: "I maintain that just as the moral principles are necessary according to reason, in its practical employment, it is in the view of reason, in the field of its theoretical employment, no less necessary to assume that everyone has ground to hope for happiness in the measure in which he has rendered himself by his conduct worthy of it"³¹. One can find in this relaying of theoretical reason through practical reason the main thrust of Kant's solution to the possibility of metaphysics. It is in itself revealing that the entire second section of the Canon will only deal with the third question concerning the interest of reason, the question of hope. It contains the key to Kant's initial problem.

What does hope strive for? Kant answers, in the simplest of terms: "all hope strives towards happiness"³². Realistically or pessimistically, Kant believes however that our quest for happiness will never be fully satisfied under empirical conditions (and who could claim that he is wrong?). The supreme happiness that everyone is striving for is not one which could be realized in our terrestrial existence. It is appropriate, I think, to translate the word Glückseligkeit employed here by Kant through something like a "happiness of felicity", a Glück of the Seligen. What our reason truly hopes for is not a greater enjoyment or a merely material well-being, but a peace of soul that is not only of this world. To be sure, we cannot generate this felicity, this Glückseligkeit, by ourselves. The only thing we can do, and hope for, is to make us worthy of such a happiness of felicity.

By this means, Kant does give an answer to the question "what ought I do?" that he claimed to avert in his transcendental enquiry: "you ought to do what will make you worthy of happiness"³³. And to make oneself worthy of happiness is to act, as much as we can, according to the spirit of the moral law provided by pure practical reason. The ultimate intent of our hope can therefore only consist for pure reason in the allocation of such an eternal happiness that would be proportional to the morality of our actions (or our maxims of action). Such a hope only makes sense, clearly, if one admits the existence of a supreme intelligence that is capable of securing this "necessary link between the hope for happiness and the unremitting effort to make oneself worthy of happiness"³⁴. It is this link between the hope of reason and its accomplishment that constitutes the ideal of the highest good in the first Critique³⁵. One easily recognizes here the well-known doctrine of the postulates of practical reason that crowns the second Critique. The essential tenets of this doctrine can already be found however in the Critique of 1781, where they form its proper conclusion.

It is to be noted that Kant's perspective in 1781 differs on a crucial point from the doctrine presented in 1788. Whereas the Critique of practical reason will consider the respect for the moral law, unter complete disregard from any future reward, as the sole legitimate motive of morality, the Canon of 1781 still sees in the promise of a future felicity a necessary mobile of moral action. Much less rigorous than the second Critique, the Critique of pure reason sides more closely with classical ethics: "Thus without a God and without a world invisible to us now, but hoped for, the glorious ideas of morality are indeed objects of approval and admiration, but not motives (Triebfedern) of purpose and action because they don't fulfil in its completeness that end which is natural to every rational being and which is determined a priori; and rendered necessary by that same pure reason"³⁶. The first Critique openly espouses a "system of morality that rewards itself"³⁷, ein System der sich selbst lohnenden Moralität. This system contends that the supposition of a wise world ruler is a "practical necessity" in order to "give moral laws their effectivity"³⁸. Reason, Kant claims in 1781, is compelled "either to admit such a being and with it a life in a world that we have to consider as future, or to regard moral laws as vain hallucinations (leere Hirngespinste)"³⁹.

We can now comprehend to what extent the highest good, understood in the perspective of 1781, can provide a positive answer to the twofold query of pure reason: is there a God? is there a future life? A positive answer is defensible, Kant argues, since they are necessary conditions to ensure the coherence of the system of morality. From here we can fully grasp the meaning of the title of the second section of the Canon: "The ideal of the highest good as a determining principle for the ultimate end of reason". The hope rendered possible by the principle of the highest good enables us to ground on the basis of pure practical reason what Kant insistingly calls the "two cardinal propositions of our pure reason: there is a God, there is a future life"⁴⁰. This is, in the Critique of pure reason, the clearest of answers to the fundamental problem of metaphysics.
But, one might ask, have those two cardinal propositions really been "founded"? The propositions "there is a God, there is a future life" are evidently synthetic a priori judgments, that theoretical reason failed time and again to prove in the Dialectic. How can we justify such claims before the tribunal of a transcendental critique? We know that a mediating third term is necessary in order to account for the legitimacy of any synthetic a priori judgment. What is this tertium quid in the case of the postulates of practical reason? The first Critique, as far as we can see, does not squarely address this matter, content, as it is, with laying out the programme of a future metaphysics based on the reality of practical reason. On can find an answer to this question in the second Critique, where Kant writes: "In order to extend pure knowledge practically, an a priori purpose must be given, i.e., an end as an object (of the will) which, independently of all theoretical principles, is thought of as practically necessary through a categorical imperative directly determining the will. In this case, the object is the highest good"⁴¹. What here authorizes the a priori extension of knowledge in a practical horizon, is a purpose, an Absicht, an a priori interest of reason, linked to its cardinal thirst: is there a God? is there a future life? The possibility of what Kant labels, ackwardly enough, pure practical knowledge lies in the underlying purpose of the highest good.

Now, is it legitimate to conclude from a purpose to the reality of its object? Is man immortal simply because he happens to desire it? Is God's existence proven because it appears to be a necessary piece in the realization of the highest good conceived by reason? Does the philosopher who constantly warned us throughout the Dialectic not to take our metaphysical desires for realities fall prey to a similar illusion? Kant did not confront this objection in his Critique of 1781, but he did in an important footnote to the second Critique. Kant there refers to an argument raised by Wizenmann against the doctrine of the highest good. Wizenmann "disputes the right to argue from a need to the objective reality of the object of the need, and he illustrates his point by the example of a man in love, who has fooled himself with an idea of beauty which is merely a chimera of his own brain and who now tries to argue that such an object really exists somewhere"⁴². Wizenmann clearly aims at Kant's practical metaphysics adumbrated in the Canon of the first Critique, which he must have read very well. Kant agrees with Wizenmann as far as mere contingent or empirical desires are concerned: "I concede that he is right in all cases where the need is based on inclination, which cannot postulate the existence of its object even for him who is beset by it, and which even less contains a demand valid for everyone, and which is therefore a merely subjective ground of wishes"⁴³. From the desire to the reality of what is desired, the consequence is not cogent. But the purpose that leads us to postulate the existence of God and the immortality of the soul is not, Kant suggests, an inclination like any other else. We are not preoccupied here with a random subjective inclination, that would be particular and empirical, but with a Vernunftbedürfnis,"with a need of reason arising from an objective determining ground of the will, i.e., the moral law, which is necessarily binding on every rational being; this, therefore, justifies a priori the presupposition of suitable conditions in nature and makes them inseparable from the complete practical use of reason". In Kant's mind, the pure interest of reason is objective for it is universally shared by all rational beings, deriving from the only positive a priori of pure reason, the moral law that compells unconditionally. This unconditional command of reason has as its goal, its telos, the highest good. To jettison this universal aim of the moral law, would be tantamount to robbing reason of any efficiency and, ultimately, of any coherence. Why would reason enjoin us moral beings to seek the realization of an impossible ideal? To acquiesce to moral law as the principle of moral action entails that we assume at the same time its aim, the highest good and the two conditions of its actuality, that is the existence of God and the immortality of the soul. The objectivity of the postulates of practical reason stems from the unquestionable objectivity of moral law and the rationality it opens up to human existence. One has to see in this conclusion, in this logic of practical rationality, the real conclusion of Kant's Critique of pure reason, whose purpose was to appreciate the legitimate employment of pure reason with view to the establishment of a rigorous metaphysics.

This conclusion should not lead to any triumphalism of pure reason. The practical postulate of God's existence and of the immortality of the soul is the only positive content of a metaphysics based on the logic of practical hope. By paraphrasing a passage of the Paralogisms, one could say that the proposition "there is a God, there is a future life" constitutes the "only text" of Kant's practical metaphysics. But this conclusion will only appear modest to the rationalist schools who nurtured much higher ambitions in their pursuit of a priori knowledge. Nonetheless Kant feels that it suffices if one wants to answer - and philosophy has no other purpose - the questions raised by the interests of reason and entertained by every mortal. This will be the concluding words of Kant's Canon of pure reason and, consequently, of the first Critique: "But, it will be said, is this all that pure reason achieves in opening up prospects beyond the limits of experience? Nothing more than two articles of belief? Surely, the common understanding could have achieved as much, without appealing to philosophers for counsel in the matter". But, Kant counters, "do you really require that a mode of knowledge which concerns all men should transcend the common understanding, and should only be revealed to you by philosophers?"⁴⁴ Kant's metaphysics of the interests of reason doesn't want to transcend the scope of common sense, but to serve it and to justify the claims of its faith. Herein lies the consequence, and the novelty perhaps, of Kant's reorientation of metaphysics towards the requirements of practical reason, that serves as the bed-rock of his "cosmical" understanding of philosophy as the "science of the relation of all knowledge to the essential ends of human reason"⁴⁵. This philosophy, Kant concludes, does not "advance further than is possible under the guidance which nature has bestowed even upon the most ordinary understanding"⁴⁶. Those are the concluding words of Kant's Canon.

It is now time for our own reflection to conclude. The purpose of our enquiry was not to "invent" a conclusion for a book that doesn't have one in its table of contents. The issue of the conclusion of the Critique of pure reason that we wanted to call to attention is not a matter of literary composition, but a fundamental concern of any reader of Kant's first Critique. What is at stake is the true nature of Kant's answer to the possibility of metaphysics. The metaphysics Kant is aiming at would, if it is ever possible, offer an answer to the most essential, the most interested questions of pure reason: is there a God? is there a future life? It is to sort out the grounds for such an answer that Kant institutes a Critique of pure reason, designed as prolegomena to any future metaphysics. When he wrote his first Critique, Kant had no idea that he would go on to write two other Critiques. This means that in the perspective of 1781, the one we maintained throughout our argument, one Critique will be enough to yield the groundwork of metaphysics. As a treatise on method, the Critique indeed indicated a new path to future metaphysics. As early as 1781, this path is that of pure practical reason, effective and credible through its imperative command and in the coherence of its system of morality, that culminates in the ideal of the highest good. From the vantage point of this "principle", Kant will effectively attempt to answer the main problems of the metaphysica naturalis. It is then the Canon that solves the question of the possibility of metaphysics. This finds confirmation in the rather dramatic diction set forth in the Canon ("if there is any legitimate employment of reason, there must be a canon", also evident in its titles: "On the ultimate end of the pure use of reason", "On the ideal of the highest good as a determining ground for the ultimate end of reason", etc.). After this Canon, Kant will proceed to spell out an Architectonic and a History of pure reason, the last two sections of the Critique. They will indeed lay out in an extraordinarily sketchy fashion the plan for the system of metaphysics that the Canon has just made possible. One could thus consider those two ultimate chapters as an appendix to Kant's Critique of pure reason and its conclusion, the Canon of pure reason.

¹ This text was presented at a meeting of the North American Kant Society in New Orleans on April 26, 1990 and published in the Graduate Faculty Philosophy Journal 16 (1992), 165-178. A lengthier French version of it appeared in the Kant-Studien, 81, 1990, 129-144. We thank the Kant-Studien for their permission to publish a shortened translation.

² A. Gulyga, Immanuel Kant, Frankfurt am Main: Suhrkamp, 1985, p. 152.

³ G. Krüger, Philosophie und Moral in der kantischen Kritik, Tübingen: J.C.B. Mohr, 1931, 2. Aufl. 1967. M. Riedel, Urteilskraft und Vernunft. Kants ursprüngliche Fragestellung, Frankfurt am Main : Suhrkamp Verlag, 1989.

⁴ B 26; transl.: Critique of pure reason, transl. by N. Kemp Smith, New York: St. Martin's Press, 1965, p. 59

⁵ B 25, transl., p. 59.

⁶ BXXII; transl., p. 59

⁷ Ibid.

⁸ See chapter III of our inquiry Kant et le problème de la philosophie: l'a priori, Paris: Vrin, 1989

⁹ Compare A 63-4/B 88.

¹⁰ A 707-8/ B 735-6; transl., p. 573.

¹¹ A 708/ B 736.

¹² A 709/B 737.

¹³ B 26.

¹⁴ A 796/B 824

¹⁵ A 704/B 732

¹⁶ A 796/B 825

¹⁷ A 796-7/B 824-5; transl., p. 630 (modified).

¹⁸ A 798/B 826

¹⁹ Ibid.

²⁰ Ibid.

²¹ A 800/B828

²² A 800/B 828; transl., p. 639.

²³ Ibid.

²⁴ A 803/B 831; transl, p. 634.

²⁵ B XXXIII.

²⁶ A 795-6/B 823-4; transl., p. 629 (modified).

²⁷ A 804/B 832.

²⁸ Ibid; transl., p. 635 (modified).

²⁹ A 805/B 833.

³⁰ A 805/B 833.

³¹ A 809/B 837; transl., p. 638.

³² A 805/B 833; transl., p. 636.

³³ A 809/B 837.

³⁴ A 810/B 838.

³⁵ See A 810/B 838: "Ich nenne die Idee einer solchen Intelligenz, in welcher der moralisch vollkommenste Wille, mit der höchsten Seligkeit verbunden, die Ursache aller Glückseligkeit in der Welt ist, so fern sie mit der Sittlichkeit (als der Würdigkeit, glücklich zu sein) in genauem Verhältnisse steht, das Ideal des höchsten Guts".

³⁶ A 813/B 841; transl. p. 640.

³⁷ A 809/B 837.

³⁸ A 818/B 846.

³⁹ A 811/B B 839.

⁴⁰ A 741/B 769.

⁴¹ Kritik der praktischen Vernunft, Ak. V, 134; transl. Immanuel Kant, Critique of practical Reason And Other Writings in Moral Philosophy, transl. by L. W. Beck, Chicago: The University of Chicago Press, 1949 (repr. : New York and London: Garland Publishing, 1976), p. 236.

⁴² Ibid. Ak. V, 143-4 (English translation, p. 245).

⁴³ Ibid.

⁴⁴ A 830-1/B 858-9; transl. p. 651.

⁴⁵ A 839/B 867; transl., p. 657.

⁴⁶ A 831/B 859.