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BY 4.0 license Open Access Published online by De Gruyter January 18, 2022

The Highest Good and Its Crisis in Kant’s Thought

Luca Fonnesu


The article has the aim to show that Kant’s “standard” conception of the highest good does not represent his last word about the problem. Kant moves from a conception of the highest good close connected with the metaphysical tradition and with the aim of a new, moral justification of traditional metahysical concepts such as God and immortality of the soul. This view does find many difficulties and oscillations in the Critiques, looking for different formulations of a moral “proof” for the metaphysical concepts, grounded upon the need of justice and of a rational solution to the question of theodicy. The failure of this project is apparent with the essay on theodicy (1791). In the last decade of Kant’s intellectual activity, the expression “highest good” occurs few times and the concept looses its systematic relevance, as shown by the last works up to the Opus postumum.

1 Introduction

In 1963 – more than 20 years after his great work on Kant’s transcendental deduction (1934) – the prominent Kant scholar Hermann Jean de Vleeschauwer published a now-neglected article devoted to the Critique of Pure Reason (de Vleeschauwer 1963). The main claim of the article was that the Dialectic and not the Analytic of the first Critique is its most fundamental part, against the Neokantian interpretation of the Marburg School, but I shall not deal with that here. What interests me rather is de Vleeschauwer’s illustration of how and how much the heritage of modern metaphysical tradition does play a role in the Critique of Pure Reason. De Vleeschauwer shows that Kant’s work deals with the main questions of the tradition that began with Suarez and Descartes and was later systematized by Christian Wolff. The relationship with the philosophical tradition does not weaken – of course – the importance of Kant’s philosophical revolution, because he offers a completely new analysis – and combination – of the various elements of modern metaphysics, putting them in the new framework of the Critique. If the Analytic deals with what Wolff called the metaphysica generalis or ontology, stressing first of all its limits,[1] the Transcendental Dialectic critically discusses the concepts of the metaphysica specialis such as soul, world and God, showing their problematic status as objects of possible knowledge, but explaining at the same time their indispensable function as “regulative” principles. However, the concepts of metaphysics or ideas of reason do not play a role only because of their regulative function. To the contrary, their most important meaning emerges from the moral point of view, as proved by the concept of highest good presented for the first time in the Canon of the first Critique and by its systematic relevance between this work and the Critique of the Power of Judgment.

Generally speaking, Kant’s highest good is that state of affairs or that ‘world’ in which the greatest happiness corresponds to the greatest morality. The highest good is therefore a world in which happiness plays a great role: it is a further proof – by the way – of the importance of this central concept of the eighteenth century in Kant’s thought, notwithstanding his antieudemonistic attitude. The metaphysical tradition is still in play, because the model for this world of moral perfection is not so difficult to identify, looking at the debate on Leibniz’ mundus optimus, the best possible world, which was one of the most important themes of discussion in German Enlightenment after the publication of Leibniz’ Essays on Theodicy (cf. Lorenz 1997). Leibniz’ legacy in fact constitutes the model, the source and the framework of Kant’s conception of the highest good, which may be seen as the moral version of Leibniz’ thesis. Its importance in Kant’s biography is well known: Kant joined the discussion on the optimism of Leibniz and Pope launched by the Academy of Sciences of Berlin in 1753, and wrote even in 1759 some Considerations on optimism.[2] Furthermore, the question of optimism is discussed in the lectures on metaphysics and in some notes on the same subject. The derivation of the concept of the highest good from Leibniz’ idea of a best possible world is explicitly declared by Kant, e.g. in the Danziger Rationaltheologie: “The theory of the best world is an undispensable hypothesis for morality, because in morals I have to think that in the world also the greatest happiness agrees with the greatest morality”.[3]

The problem of the highest good concerns the moral need of a retribution of morality with happiness, or of a just world. It is therefore also Kant’s answer to – and interpretation of – the problem of justice in the world or, again in Leibniz’ language, to the problem of theodicy in a special (moral) restriction of its meaning. What cannot be accepted in Kant’s eyes, from the moral point of view, is the impossibility for morally good human beings to hope for happiness as the just retribution of their morality. Hence the metaphysical implications. The best moral world, the highest good, is a world in which happiness is distributed in proportion to moral merit, but this distribution does not seem possible without certain conditions, which are exactly the objects of the metaphysical tradition: the existence of a (morally just) God and the immortality of the individual soul. The objects of the metaphysica specialis criticized in the Transcendental Dialectic are in this way justified from the moral point of view – with some kind of “moral” proof – and can be the basis of a faith which Kant calls rational (Vernunftglaube) because it is derived from the need of justice of practical reason.

In the lectures on ethics, Kant’s discussion of the highest good leads him to a discussion of ancient moral philosophy, because with the moderns – he writes in the second Critique – “the question of the highest good seems to have gone out of use or at least to have become a secondary matter” (Kant 1788/1996, 64), although the ancients too did not give the correct answer to the question. Also in this context Kant’s attitude is directed towards a metaphysical solution. At the beginning of the lectures, Kant discusses the ancient ethics moving from the interpretation of the highest good given by ancient philosophers: not only stoics and epicureans – the philosophical schools explicitly discussed in the second Critique – but also Diogenes as supporter of a cynic ideal, which in Kant’s eyes has been recently resumed by Rousseau (an ethics of “nature”), and Plato as supporter of a mystic or visionary ethics.[4] The common and symmetrical, though opposite, error of Stoics and Epicureans is to believe in the reducibility of happiness to morality in the case of the former and of morality to happiness in the case of the latter, as Kant explains also in the Critique of practical reason.[5] On the contrary, Kant thinks that “happiness and morality are two specifically quite different elements of the highest good” (Kant 1788/1996, p. 112), and this is in fact the problem. If they are different values, how can they be unified in a highest good, in a morally perfect world as a realm of justice where morality is rewarded with happiness? For Kant the right answer can have only metaphysical traits. The limit of ancient schools such as Stoics and Epicureans is exactly in their failure to understand the essential role of God for the realization of the highest good.[6] Kant repeats several times that the best representation of the greatest moral perfection as highest good is given by the ideal offered in the gospel: the rational justification of the Christian ideal would be Kant’s answer to the problem of justice in the world.[7]

What I want to question is that the just outlined theory of the highest good is Kant’s last word about the problem, because I maintain that it is not. The aim of this article is therefore to show that although Kant moves from an ideal of highest good closely connected with the metaphysical tradition and basis of a rational faith in its objects – God and the immortality of the soul –, his intellectual development[8] shows the difficulties of this project and consequently the crisis both of the ideal of the highest good and of its systematic function. Kant’s development represents progressive liberation from the metaphysical legacy towards an ethico-political, wordly conception of the activity of human beings in human history.[9] I’ll outline the problematic presentation of the concept of highest good in the Critiques, showing its difficulties in this framework and its crisis in the essay on theodicy (1791), when Kant’s attempt at a rational justification of the problem of theodicy shows its collapse even in the title – On the miscarriage (Misslingen) of all philosophical trials in theodicy. In the last decade of his intellectual activity, Kant looks for a different solution of the problem of realization of morality, and the highest good is no longer a central concept of his philosophical horizon, having lost its systematic relevance.

2 The Highest Good in the Critiques

Although with the very same constitutive elements – happiness and morality – Kant’s presentation of the notion of highest good is very different in the three Critiques and proves the difficulty of dealing with this concept and with the consequences which can be derived from it.

In the sketch of a moral philosophy presented in the Canon of the Critique of Pure Reason, morality is closely connected with happiness even in its definition, because the moral law is that law, writes Kant introducing it, “that has no other motive (Bewegungsgrund) than the worthiness to be happy” (Kant 1781–1787/1998, A 806 B 834), so that the answer to the question “If I do what I should, what may I then hope?” will be that

Everyone has cause to hope for happiness in the same measure as he has made himself worthy of it in its conduct, and that the system of morality is therefore inseparably combined with the system of happiness, though only in the idea of pure reason (Kant 1781–1787/1998, A 809 B 837).

The hope does therefore concern a retribution of morality with happiness which can be the object of hope. At this point Kant seems to introduce a system of self-rewarding (sich selbst lohnend) morality that does not need any further element for its realization. This is the idea of a moral world which is an intelligible one, in which

freedom, partly moved and partly restricted by moral laws, would itself be the cause of general happiness, and rational beings, under the guidance of such principles, would themselves be the authors of their own enduring welfare and at the same time that of others, though only in the idea of pure reason (Kant 1781–1787/1998, A 809 B 837).

Kant opens in this way the space for a perfect moral world which could be the model for the real world, because this seems to be the role of an idea, a “mere” but “yet practical idea, which really can and should have its influence on the sensible world, in order to make it agree as far as possible with this idea. The idea of a moral world thus has objective reality” in this practical sense (Kant 1781–1787/1998, A 808 B 836). After this suggestion of a normative function of the idea of a moral world as an ideal system of self-rewarding morality which should guide actions in the sensible world with the aim of its transformation, Kant weakens this normative force of the “idea”, stressing that its realization is possible only if everybody does what he should, i.e. if «all actions of rational beings occur as if they arose from a highest will that comprehends all private choice in or under itself» (Kant 1781–1787/1998, A 810 B 838). Kant’s argument is in this way reoriented towards a metaphysical solution: a highest reason becomes the only possible guarantee of a connection between happiness and morality, being in fact excluded the possibility of an immanent solution of the problem:

The necessary connection of the hope of being happy with the unremitting effort to make oneself worthy of happiness that can be adduced cannot be cognized through reason if it is grounded merely in nature, but may be hoped for only if it is at the same time grounded on a highest reason (höchste Vernunft) which commands in accordance with moral laws, as at the same time the cause of nature (Kant 1781–1787/1998, A 810 B 838).

The metaphysical shift from a self-rewarding morality to the necessity of a highest reason even for the hope in happiness as a retribution of morality makes it possible to introduce the concept of highest good, because the highest reason itself is – declares Kant – the highest original good, while the connection of morality and happiness is only a highest derived good, which we have to accept as a future consequence of our behaviour in the real world and which will be possible only with the presuppositions of God and of a future life.

But not only that: “God and a future life are two presuppositions that are not separated from the obligation that pure reason imposes on us on the principles of the very same reason” (Kant 1781–1787/1998, A 809 B 837).[10] In fact, God and a future life are not necessary presuppositions of the obligation of the moral law, but just of the motivation to act. The first Critique is, in this regard, completely different from Kant’s other works on morality. Moral laws as such do not depend on elements other than reason. There are moral laws that command a priori and absolutely,[11] but in the Critique of pure reason Kant stresses the necessity of incentives which move human beings to action, a motivation which can be given only by divine promotion or deterrence of actions through promises and threats. Otherwise moral principles would be mere “empty figments of the brain” (Kant 1781–1787/1998, A 812 B 840):

Thus without a God and a world that is now not visible to us but is to hope for, the majestic ideas of morality are, to be sure, objects of approbation and admiration, but not incentives (Triebfeder) for resolve and realization, because they would not fulfil the whole end that is natural for every rational being and determined a priori and necessarily through the very same pure reason (Kant 1781–1787/1998, A 813 B 841).

In this framework, God and a future life are therefore constitutive elements of the exercise of morality, because Kant’s theory of motivation is still grounded upon God’s authority. On the one hand, this is a limit of Kant’s position, because the moral theory is still dependent on a theological presupposition, but on the other hand, the metaphysical conditions of the realization of the highest good – God and immortality – are justified as necessary, indispensable elements of morality. The claim of the necessity of the perspective of a highest good is fully justified.

The role of the highest good for the theory of motivation is still at work in the lectures on the philosophy of religion in 1783–1784, but disappears in the Groundwork of 1785, and not so much – or not only – because Kant in this work does not discuss the question of the highest good,[12] but because he presents a new, autonomous theory of motivation based upon the idea of respect for the law (Kant 1785, 400). In the new framework, neither the highest good nor its metaphysical conditions – God and a future life – seem to be necessary anymore for moral action. Morality is now self-sufficient, both for its rational principle and for the motivation of action. However, this new self-sufficiency does not have the implications which one could expect. On the contrary – and this fact surprised Kant’s contemporaries – the importance of the highest good and the necessity to give to this concept a new configuration will be an important element in the project and in the drafting of the Critique of Practical Reason. The metaphysical horizon is still important and Kant considers explicitly the doctrine of postulates as a central element of the second Critique. Announcing the upcoming printing of the book, he stresses in a letter of June 1787 just the role of the dialectic of pure practical reason:

I am so far along with my Critique of practical reason that I intend to send it to Halle to printing next week. This work will better demonstrate and make comprehensible the possibility of supplementing, by pure practical reason, that which I denied to speculative reason (Kant 1999, p. 490).[13]

The second Critique is in fact Kant’s most important – and problematic – work as regards the highest good. Here Kant deals widely with this concept and gives to it an essential systematic role with the doctrine of the postulates of practical reason. In fact, the whole Dialectic of Pure Practical Reason is devoted to the doctrine of postulates grounded upon the thesis of the highest good, after that in the Analytic the principle of happiness has been criticized as a principle of morality. In the Dialectic, happiness receives (suddenly) a new role. Here emerges in the clearest way even the function of the highest good for Kant’s answer to the aspect of the most important problem of theodicy, the question of retributive justice. This perspective emerges clearly in the presentation of the highest good, with Kant’s insistence upon the insufficiency of virtue alone in the different but converging views of existential, moral and theological kind, i.e. the hope of the individual, the view of an “impartial spectator” and, above all, God’s view:

That virtue (as worthiness to be happy) is the supreme condition of whatever can even seem to us desirable and hence of all our pursuit of happiness and that it is therefore the supreme good has been proved in the Analytic. But it is not yet, on that account, the whole and complete good as the object of the faculty of desire of rational finite beings; for this, happiness is also required, and that not merely in the partial eyes of a person who makes himself an end but even in the judgment of an impartial reason, which regards a person in the world generally as an end in itself. For, to need happiness, to be also worthy of it, and yet not to participate in it cannot be consistent with the perfect volition of a rational being that would at the same time have all power, even if we think of such a being only for the sake of the experiment (Kant 1788/1996, p. 110).

Moving from this starting point, Kant develops a theory of the highest good which does need for its realization the postulates of metaphysical conditions: God’s existence and the immortality of the soul. The postulates derive from what Kant calls a need (Bedürfnis) of pure practical reason, which is different from both the need of inclination and the need of theoretical reason. As regards the former, Kant replies to a critique, which questions the force of the argument of a mere need for the justification of the existence of the object of the need, distinguishing a need of inclination from a need of reason:

the late Wizenmann… disputes the authorization to conclude from a need to the objective reality of its object and illustrates the point by the example of a man in love, who, having fooled himself into an idea of beauty that is merely a chimera of his own brain, would like to conclude that such an object really exists somewhere. I grant that he is perfectly correct in this, in all cases where the need is based upon inclination, which cannot necessarily postulate the existence of its object even for the one affected by it, much less can it contain a requirement valid for everyone, and therefore it is a merely subjective ground of the wish. But in the present case it is need of reason arising from an objective determining ground of the will, namely the moral law, which necessarily binds every rational being and therefore justifies him a priori in presupposing in nature the conditions befitting it and makes the latter inseparable from the complete practical use of reason (Kant 1788/1996, p. 143 n.).

The connection with moral law is the indispensable argument even for the distinction between the need of speculative reason and the need of pure practical reason:

a need of pure reason in its speculative use leads only to hypotheses, that of pure practical reason, however, to postulates… a need of pure practical reason is based on a duty, that of making something (the highest good) the object of my will so as to promote it with all my powers; and thus I must suppose its possibility and so too the conditions for this, namely God, freedom, and immortality, because I cannot prove these by my speculative reason, although I can also not refute them.” (Kant 1788/1996, p. 142)

In fact, the highest good is in the second Critique not only something that can be the object of hope, but also something which has to be the object of will: there is now a proper duty to promote the highest good, though Kant never does deduce it[14]: “It is a priori (morally) necessary to produce the highest good through the freedom of the will” (Kant 1788/1996, p. 113) …“the promotion of the highest good, which contains this connection [of happiness and virtue] in its concept, is an a priori necessary object of our will and inseparably bound up with the moral law (Kant 1788/1996, p. 114). This is a first important difference from the Critique of Pure Reason. In that work, after the presentation of the hypothesis of a moral, intelligible, perfect world, Kant did shift towards the metaphysical solution of a highest original good that was the source of the highest derived good. The only human contribution to the highest good was morality as a condition of the hope for a just retribution. In the Critique of Practical Reason, the active aspect of human beings consists also in their dutiful promotion of a just proportion between morality and happiness, even if it is not clear what this promotion should consist in, since, to say the least, human beings cannot understand other beings’ and not even their own morality. Kant is not clear on the point,[15] but it does not seem possible to see this duty having the same binding force as the moral law, because it derives from it and the latter is independent, in its validity, from the former and from every other supposition:

This duty [to promote the highest good] is based on something that is indeed quite independent of these suppositions and of itself apodictically certain, namely the moral law; and so far it needs no further support by theoretical opinions as to the inner character of things, the secret aim of the order of the world, or a ruler presiding over it, in order to bind us most perfecly to actions unconditionally conformed to the law” (Kant 1788/1996, p. 142f.).[16]

There is another “active” aspect of human beings which is evidentiated by Kant in the second Critique and which was not present in the Critique of Pure Reason. The postulates of God’s existence and of the immortality of the soul are still the metaphysical conditions of the realization for the highest good, but the justification of immortality is now different. Since the retribution of morality can take place – writes Kant in the second Critique – only for a perfect morality, for holiness, and since this state cannot be reached by finite rational beings, the only way to the highest good is in infinite perfectioning, because holiness “can only be found in an endless progress toward that complete conformity” (Kant 1788/1996, p. 122). The justification of immortality does consist in this process of perfectioning with the aim of holiness. In this direction, it seems that the proportion between happiness and morality can be only of a single kind, that of a proportion between beatitude and holiness, but this view would exclude most aspects of a just retribution (e.g. punishment for bad beings) and would contrast with Kant’s insistence, in the Critique of Practical Reason, on the natural dimension of happiness and of highest good itself.[17]

A third aspect of the Critique of Practical Reason which has to be pointed out is exactly a new role of nature. In the Critique of Pure Reason, the realization of the highest good can take place only in an afterlife, in a future intelligible world, while in the second Critique it seems that nature can or even must play a role. This emerges already in the presentation of the question: that happiness causes morality is absolutely impossible, but the other way around it is not impossible in the same way and is only conditionally false (Kant 1788/1996, p. 114), because morality can be the cause of happiness in an indirect way:

it is not impossible[18] that morality of disposition should have a connection, and indeed a necessary connection, as cause with happiness as effect in the sensible world, if not immediately yet mediately (by means of an intelligible author of nature), a connection which, in a nature that is merely an object of the senses, can never occur except contingently and cannot suffice for the highest good (Kant 1788/1996, p. 115).

The realization of the highest good seems here and elsewhere to take place in nature, not in an intelligible world, although through the mediation of its author. The hypothesis that the highest good could take place in nature even without the mediation of its author is nevertheless suggested by Kant himself in the difficult section VIII of the Dialectic of pure practical reason, devoted to the need of reason as a basis of rational faith. This section shows all Kant’s difficulty in dealing both with the highest good and with the consequent faith. Faith cannot certainly be commanded (this would be an Unding, nonsense or absurdity, Kant 1788/1996, p. 144), while what can be commanded is the duty to promote the highest good. What is important in Kant’s eyes is that a proportion of happiness and morality, i.e. a just retribution, is not thought of as impossible: “no one can want to maintain that a worthiness of rational beings in the world to be happy in conformity with the moral law combined with a possession of this happiness proportioned to it is impossible in itself” (Kant 1788/1996, p. 144). The need of a moral retribution cannot be questioned because it depends on the moral law, but Kant has to recognize that for its realization in the world it is possible to consider different options. The one which he declares to prefer is that of a faith in the existence of a moral, just God, because “in accordance with a mere course of nature in the world, happiness in exact conformity with moral worth is not to be expected and is to be held impossible, and that therefore the possibility of the highest good on this side can be granted only on the presupposition of a moral author of the world” (Kant 1788/1996, p. 145). Nevertheless, this impossibility is not a logical one and has to do with the limits of our own reason, which does not understand how the highest good could be possible without a God. This is so true that the very same human reason cannot even prove the impossibility of a – so to speak – immanent solution to the question of the highest good, also because the transcendent solution of the author of the world cannot be commanded, so that doubt is always possible and allowed “even in the well-disposed (Wohlgesinnten)”, while what is not permitted is the Unglaube, unbelief (Kant 1788/1996, p. 146). Kant’s difficulty is apparent even in his oscillations regarding the solution to the question. On the one hand, Kant stresses the indispensable role of the postulates and of a transcendent solution for the realization of the highest good, while on the other, a worldly solution is explicitly declared as not impossible, because one has to consider good human beings that do not believe in a God or in a future life. The moral “proof” leaves space for different solutions.

The Critique of the Power of Judgment offers Kant’s last attempt to give a systematic meaning to the concept of the highest good. Kant’s argument is presented even in the title of several sections and in text as having the demonstrative structure of a “proof”.[19] Nevertheless, the anthropological relativization of the validity of the “proof” is apparent here too. The idea of a realization of the highest good in the world through our actions and as a duty is still declared by Kant,[20] but the ambiguity of the preceding works does not disappear. Putting aside his usual caution in discussing metaphysical and theological questions, the highest good becomes in the third Critique even the final end (Endzweck) of creation, although as a matter of faith (Glaubenssache) and its status depends on the constitution of human reason and does not have an absolute value:

the highest final end that is to be realized by us, that through which alone we can become worthy of being ourselves the final end of a creation, is an idea that has objective reality for us in a practical relation, and is an object, but since we cannot provide objective reality for this concept from a theoretical point of view, a mere matter of faith of pure reason, together with God and immortality, as the conditions under which alone we can, given the constitution of our (human) reason, conceive of the possibility of that effect of the lawful use of our freedom (Kant 1790/2000, p. 469f., cf. p. 455).

God as the author of the world does play in fact a fundamental role in this context, while the immortality of the soul, grounded in the Critique of Practical Reason upon the questionable idea of holiness as moral perfection, is certainly mentioned – as in the quoted passage and elsewhere[21] – but has lost every systematic meaning. A postulate of the immortality of the soul is not even mentioned.

3 The Collapse of Theodicy

If the theory of the highest good is Kant’s answer to the problem of theodicy – and I think that it is so – or at least to the aspect of the problem of theodicy which is for him the most important – a just retribution – the short article on theodicy published by Kant just one year after the third Critique is a turning point of Kant’s philosophy even for the problem of the highest good. Already the title is remarkable in this direction, being devoted to the failure or miscarriage of theodicy, better, of all theodicies: Über das Misslingen aller philosophischen Versuche in der Theodizee. Kant’s text can be considered as the expression of a critical attitude which does not concern only past philosophical, i.e. rationalist theodicies, but even, at least in the interpretation followed here, Kant’s own attempt to offer, with the highest good, a rationalist solution to the question.

Theodicy is first of all a general question which does concern the counterpurposive or the Zweckwidrig, what tradition did call evil, i.e. every aspect of reality which appears as negative in front of the presupposition of the existence of a superior wisdom: “By ‘theodicy’ we understand the defense of the highest wisdom of the creator against the charge which reason brings against it for whatever is counterpurposive in the world” (Kant 1791/1996, p. 255). As we know from our preceding discussion, there is an aspect of the problem of theodicy which is in Kant’s eyes of the utmost importance, that of justice or retribution. He explicitly highlights the question:

It is remarkable that of all the difficulties in reconciling the course of world events with the divinity of their creator, none imposes itself on the mind as starkly as that of the semblance in them of a lack of justice. If it comes about (although it seldom happens) that an unjust, especially violent, villain does not escape unpunished from the world, then the impartial spectator rejoices, now reconciled with heaven (Kant 1791/1996, p. 260n.).

The defense of the highest wisdom in front of the different forms of evil is in Kant’s eyes a failure, even for the described most important form of injustice, that of the failure of a just retribution for the good man and even more, it seems, for the bad. This failure shows the impossibility of a rational theodicy:

Now the outcome of this juridical process before the forum of philosophy is this: Every previous theodicy has not performed what it promised, namely the vindication of the moral wisdom of the world-government against the doubts raised against it on the basis of what the experience of this world teaches (Kant 1791/1996, p. 263).

The failure of every possibility of a rational answer to the question of evil and in particular to the question of retribution is confirmed by the second part of Kant’s essay on theodicy, where he presents the concept of an authentic theodicy. Bearing in mind the theory of the highest good, the new approach is to say the least surprising. Kant’s moral theology in the Critiques is built upon the thesis of a homogeneity between man and God from the moral point of view. God himself is the result of a procedure which moves from the moral law and understands his will as perfectly adequate to it: it is the Kantian version of rationalist theology, against every form of voluntarism. On the contrary, the model of an authentic theodicy presented through the figure of Job is characterized by a strong form of theological voluntarism. Kant’s point is here to stress the limits of human reason, which do concern even the human practical reason, which seems to have lost its epistemological primacy. What was so far from Kant’s theological rationalism and from his theory of the highest good is now understood as an authentic theodicy: “Job declares himself for the system of unconditional divine decision. ‘He has decided,’ Job says, ‘He does as he wills’” (Kant 1791/1996, p. 265).[22] The moral dimension of Job’s faith does not have rational traits anymore, but has to do with his sincerity, which is here declared as “the principal requirement in matters of faith” (Kant 1791/1996, p. 267). The problem of faith seems to be now a moral problem of sincerity with ourselves and with others, not a question of its rational justification, as it was across the Critiques.

4 Out of the Highest Good

Although there are few occurrences of the notion in the Religion and in the essay on Theory and Practice,[23] the notion of highest good does not play a systematic role anymore in the last decade of Kant’s intellectual activity.

In Kant’s system of morality, the Metaphysics of Morals, the highest good in its usual, metaphysical sense of the Critiques is not even mentioned, and it is possible to find an explanation for this absence. Morality does not need to look for a reward beyond itself, because it is self-rewarding, not with happiness, but with its own value:

The highest, unconditional end of pure practical reason (which is still a duty) consists in this: that virtue be its own end and, despite the benefits it confers on human beings, also its own reward (Kant 1797/1996, p. 396).

Kant’s last word on the reward of morality is therefore a kind of neostoic position. The echo of the discussion of the highest good can be found in Kant’s classification of duties, but without any metaphysical claim. The active components of the highest good in the Critique of Practical Reason were self-perfectioning as justification of immortality and the duty to promote the highest good as a retribution of morality with happiness. In the Metaphysics of Morals, the duties towards oneself are duties of moral self-perfectioning, while the general trait of duties towards others is the promotion of their happiness.

In the Doctrine of method, at the end of the book, it is possible to find a further echo of the preceding discussion of the highest good, but neither the expression nor a systematic relevance of the question, to say nothing of something like a “proof”:

we see in the works of nature, which we can judge, a wisdom so widespread and profound that we can explain it to ourselves only by the inexpressibly great art of a creator of the world. And with regard to the moral order, which is the highest adornment of the world, we have reason to expect a no less wise regime, such that if we do not make ourselves unworthy of happiness, by violating our duty, we can also hope to share in happiness (Kant 1797/1996, p. 482).

The last occurrences of the highest good are in the Anthropology, but Kant’s classification of its different forms does not even mention, here too, the old metaphysical meaning. If the highest physical good is “resting after work”, the highest moral-physical good, Kant now writes, their unity is a “moral happiness”, while “The way of thinking characteristic of the union of good living with virtue in social intercourse is humanity” (Kant 1798, 276f.).

To tell the truth, in the Metaphysics of Morals there is one occurrence of the expression “highest good”, but with a new meaning. The expression is used now to designate perpetual peace (Kant 1797/1996, p. 355). Kant’s suggestion is important: the realization of morality looks no more for metaphysical, but for political and institutional conditions, which has to be realized through human activity in history.[24]

At the end of Kant’s life, there is however even a metaphysical last word concerning the question of the highest good which does confirm the loss of its relevance, as Erich Adickes remarked in 1920. In Adickes’ eyes, Kant shows in the so called Opus postumum to have understood what was the main defect of his practical philosophy, i.e. the utilitarian point of view of the doctrine of the highest good which was in contradiction with Kant’s effort for a pure morality. At the same time, every demonstrative structure concerning God disappears from Kant’s philosophical horizon, even in a moral form.[25] Faith in God is an individual, private question, not the result of a proof, as already declared by Job. Adickes is right, but the crisis of the concept and of the function of the highest good is not something which suddenly reveals itself in the O. postumum. It was begun, in fact, some years before, after the third Critique, when Kant begun to look for new solutions to the problem of the realization of morality.[26]

Corresponding author: Luca Fonnesu, Dipartimento di Studi Umanistici, Università di Pavia, Pavia, Italy, E-mail:

Quotations from Kant’s texts are from the Cambridge edition, with the pagination of the Akademie-Ausgabe, with the exception of the Critique of Pure Reason (pagination of the first, A and of the second, B edition).


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Published Online: 2022-01-18

© 2022 Luca Fonnesu, published by De Gruyter, Berlin/Boston

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