Kant on the ‘Wise Adaptation’ of Our Cognitive Faculties: The Limits of Knowledge and the Possibility of the Highest Good

Abstract

This article provides a new reconstruction and evaluation of Kant’s argument in §IX of the second Critique’s Dialectic. Kant argues that our cognitive faculties are wisely adapted to our practical vocation since their failure to supply theoretical knowledge of God and the immortal soul is a condition of possibility for the highest good. This new reconstruction improves upon past efforts by greater fidelity to the form and content of Kant’s argument. I show that evaluating Kant’s argument requires settling various other issues in the interpretation of his moral philosophy, e.g. his account of moral psychology, motivation, education, and development.

1. Introduction

In the first Critique’s B-Preface, Kant declares that work’s aim: ‘Thus I had to deny knowledge in order to make room for faith’ (Bxxx).¹ Kant means that he had to deny theoretical knowledge of God, freedom, and immortality – three ideas of reason or concepts of the unconditioned – to make room for a practical faith in the same. At first glance, Kant’s declaration is puzzling. Why make room for faith? Surely knowledge of the freedom of the will, the immortality of the soul, and the existence of God would be better than faith, were it possible? But apart from the fact that it is not possible, in the final section of the second Critique’s Dialectic of Pure Practical Reason – §IX. On the Wise Adaptation of the Human Being’s Cognitive Faculties to his Practical Vocation – Kant argues that this knowledge would in fact be much worse than faith. Specifically, Kant argues that theoretical knowledge of God and the immortal soul would make the highest good impossible. His argument proceeds roughly as follows. Knowledge of God and immortality would entail knowledge of God’s reward and punishment for our virtue and vice, respectively. If we possessed this latter knowledge, we would always act solely from the motive of inclination regarding God’s reward and punishment, never from the moral motive of duty. So, our actions would never have moral worth since – for Kant – actions have moral worth if and only if they are performed from the motive of duty. Now, the highest good consists in perfect moral virtue and the perfect correspondence of virtue and happiness: it requires that we make ourselves worthy of happiness through the moral worthiness of our person. But if none of our actions have moral worth, then our person could never become worthy of happiness, and the highest good would be impossible. Therefore, it is morally beneficial that our cognitive faculties are constituted such that we cannot have knowledge of God and immortality. Since we cannot have this knowledge, it is possible to act from the motive of duty, and so the highest good remains possible (KpV, 5: 146–8). With this argument, it becomes clear why Kant had to deny knowledge in the first Critique: it is only by limiting theoretical reason’s capacity for knowledge of the unconditioned that Kant can secure the possibility of genuine moral action, and thereby the possibility of the highest good itself.²

To be sure, this puts significant weight on the argument of §IX of the second Critique. This argument has received comparatively little attention from Kant’s readers. For those who have given it attention, it has often seemed unconvincing. In recent years, some Kant scholars have developed a renewed interest in the argument. But these scholars disagree over what Kant’s argument is meant to be, and whether it succeeds. Eric Watkins (2009, 2010a) thinks that Kant is making a moral argument for the conclusion that we lack theoretical knowledge of God and that this argument fails on Kantian grounds. Watkins’ primary objection is that knowledge of God’s reward and punishment need not preclude us from acting from the motive of duty: Kant himself seems to be committed to the view that it is always possible to act from duty, no matter what our inclinations may be. Tyler Paytas (2017, 2019) thinks that Kant is arguing for the conclusion that God’s hiddenness is consistent with His perfect rationality and that this argument succeeds. Paytas responds to Watkins’ objection by invoking Kant’s account of respect for the moral law. On Paytas’ reading of this account, we can act from duty only once respect for the moral law has been awakened by an experience of conflict between duty and inclination. With knowledge of God, we would never experience such conflict, and so we would never acquire respect for the moral law. Paytas draws on Jens Timmermann (2015), who offers a similar reply to Watkins’ objection via Kantian respect. But Timmermann sees the structure of Kant’s argument differently, taking it as a reductio of the claim that knowledge of God would have been morally beneficial for us, assuming that Nature has endowed us with the right faculties to pursue the highest good. So, on the whole, even among those who are sympathetic to Kant’s broader project, the structure, aim, and viability of his argument in §IX remains disputed.

The purpose of this article is to offer a new reconstruction and evaluation of the argument in conversation with these prior debates. First, I will show that past reconstructions of Kant’s argument have not faithfully captured its genuine structure. Kant’s conclusion is not that we lack theoretical knowledge of God (Watkins 2009), nor that God’s hiddenness is compatible with His rationality (Paytas 2017), though he endorses these claims. Rather, per the title of §IX, Kant’s conclusion is that our cognitive faculties are wisely adapted to our practical vocation. By this, he means that our cognitive faculties are constituted such that they do not make the highest good impossible. Thus, a new reconstruction of Kant’s argument is needed, which faithfully tracks the conclusion for which Kant is arguing and the premises he uses to argue for it. The next task will be to evaluate this new reconstruction of Kant’s argument, using resources from prior debates, while also introducing new ones. The debate between Watkins on the one hand, and Paytas and Timmerman on the other, is invaluable for bringing out the significance of Kantian respect for §IX, and it will be instructive to weigh the merits of both sides. But a complete evaluation of Kant’s argument requires incorporating a number of further Kantian doctrines, including: the ideal of moral perfection as doing one’s duty ‘gladly’ (KpV, 5: 84), the distinction between sensible reform and intelligible revolution in moral development (RGV, 6: 47), and the view that the moral individual sees the moral law ‘as if’ it were God’s command (KpV, 5: 129).

This article has the following structure. In section 2, I provide an overview of Kant’s argument in KpV §IX. In section 3, I critically examine the existing reconstructions of the argument. I rehearse the debates over its structure and success, while motivating the need for a new reconstruction. In section 4, I offer a new reconstruction of Kant’s argument, explaining why he takes the premises to be true, and why he takes the conclusion to follow from the premises. I evaluate this new reconstruction on Kant’s own terms in light of prior debates, while also introducing new considerations. Ultimately, I do not make a final determination on the soundness of the argument since that would require settling several controversial issues in Kant-interpretation, which this article must leave open. Nevertheless, as I intend to show, this new reconstruction makes a noticeable improvement over prior efforts, significantly advancing the debate.

Notably, Kant’s argument bears upon several more general philosophical issues regarding God, morality, freedom, etc. Most obviously, it speaks to the problem of divine hiddenness, i.e. why the God of classical theism would not make His existence undeniably clear to everyone.³ As others have pointed out, Kant’s argument offers a novel moral justification for divine hiddenness: God does not reveal Himself because it would eliminate the moral worth of human action. Paytas (2019) even claims that Kant – against his own official intentions – thereby gives us the resources for a complete theodicy: God allows evil so that His existence will be hidden, for the moral reasons already cited.⁴ Despite this broader interest, this article will only be concerned with whether Kant’s argument works on intra-Kantian grounds. Though others (e.g. Watkins 2009) have sought to make it plausible or even convincing to non-Kantians, I do not have this ambition here. To make the argument convincing generally would require defending Kant’s whole moral theory. To make it plausible, it would perhaps be enough to get the non-Kantian to accept some basic moral assumptions, e.g. that the moral worth of actions is determined by their motive rather than their consequences. But I will not try to defend these assumptions in any general way. Rather, I will be investigating whether Kant is justified in drawing the conclusion he does on the basis of his own philosophical commitments.

2. Kant’s argument in KpV §IX

Before examining the key passages, consider the place of §IX within the Dialectic of Pure Practical Reason. In §I, The Antinomy of Practical Reason, Kant argues that practical reason faces an antinomy in its search for its unconditioned object, the highest good. The highest good is perfect virtue and the perfect correspondence of virtue and happiness, which generates the following antinomy. For the highest good to be possible, one of two things must be true: either happiness grounds virtue (Thesis) or virtue grounds happiness (Antithesis). The Thesis is absolutely false since acting for the sake of one’s happiness contradicts the moral motive of duty, required for virtue. The Antithesis is conditionally false, on condition that we consider only the sensible world of Nature since Nature is indifferent to our moral conduct (KpV, 5: 113–14).⁵

In §§II–VIII, Kant develops his famous critical resolution of this antinomy. He argues that virtue would ground happiness – i.e. the Antithesis would be true – if God and the immortal soul existed. The immortal soul would give us the infinite duration needed for the moral development necessary to become worthy of happiness through perfect virtue. God, the moral Author of Nature, would guarantee that virtue is rewarded with happiness and vice punished with unhappiness. The problem is, as demonstrated in the first Critique, that our theoretical reason cannot attain knowledge of God and immortality. Thankfully, practical reason comes to the rescue. Kant argues that the moral law of practical reason supplies practical grounds for faith in God and immortality. Since the moral law unconditionally commands that we ought to realize the highest good, it must be possible to do so.⁶ We are therefore justified in adopting a practical faith in the conditions of possibility of this realization, God and the immortal soul. Kant’s primacy of the practical means that practical reason is able to ‘fill the gaps’ left by theoretical reason, grounding practical faith in the unconditioned objects of which the first Critique denied us theoretical knowledge. The highest good is possible after all (KpV, 5: 114–46).

It is here that §IX, the Dialectic’s final section, enters the fray. In the first paragraph, Kant raises the problem that the section’s argument will address:

If human nature is called to strive for the highest good, it must also be assumed that the measure of its cognitive faculties, especially their relation to one another, is suitable to this end. Now, the Critique of pure speculative reason proves its utter insufficiency for solving, conformably with this end, the most important problems that are proposed to it, although the Critique does not fail to recognize the natural hints of this same reason, which are not to be overlooked, nor the great steps that it can take to approach this great goal that is set before it, which, however, it can never reach of itself, even with the aid of the greatest cognition of nature. Nature then seems here to have provided for us only in a stepmotherly fashion with the faculty needed for our end. (KpV, 5: 146)

Kant starts here with another application of ‘ought implies can’. Since we ought to realize the highest good, it must be possible to do so. Whereas earlier sections of the Dialectic dealt with God and immortality as conditions of possibility for the highest good, §IX asks whether and how our cognitive faculties render the highest good possible or impossible. If our cognitive faculties are constituted such that the highest good is possible, then they are ‘wisely adapted’ to our practical vocation; if they render the highest good impossible, then they are unwisely adapted. In the second sentence, Kant begins to investigate this question. The first Critique showed that our faculty of theoretical (speculative) reason cannot provide knowledge of God and immortality. So, it appears Nature has been ‘stepmotherly’ in apportioning our cognitive faculties: she has withheld knowledge of the conditions of the highest good. But it is not yet clear why this should be a problem. We still have our faculty of practical reason, which grounds practical faith in God and immortality, and this seems sufficient for our moral purposes. Granted, we might think that things would be easier had we been allotted the theoretical knowledge we lack, but this lack poses no immediate threat to our practical vocation.

As it turns out, Kant’s real worry is not about the consequences of our lack of knowledge, but about what would follow if we did have this knowledge:

Assuming now that nature had here complied with our wish and given us that capacity for insight or that enlightenment which we would like to possess or which some believe erroneously they actually do possess, what would, as far as we can tell, be the result of it? Unless our whole nature were at the same time changed, the inclinations, which always have the first word, would first demand their satisfaction and, combined with reasonable reflection, their greatest possible and most lasting satisfaction under the name of happiness; the moral law would afterward speak, in order to keep them within their proper limits and even to subject them all to a higher end which has no regard to inclination. But instead of the conflict that the moral disposition now has to carry on with the inclinations, in which, though after some defeats, moral strength of soul is to be gradually acquired, God and eternity with their awful majesty would stand unceasingly before our eyes (for what we can prove perfectly holds as much certainty for us as what we are assured of by our sight). Transgression of the law would, no doubt, be avoided: what is commanded would be done; but because the disposition from which actions ought to be done cannot be instilled by any command, and because the spur to activity in this case would be promptly at hand and external, reason would have no need to work itself up so as to gather strength to resist the inclinations by a lively representation of the dignity of the law: hence most actions conforming to the law would be done from fear, only a few from hope, and none at all from duty, and the moral worth of actions, on which alone in the eyes of supreme wisdom the worth of the person and even that of the world depends, would not exist at all. As long as human nature remains as it is, human conduct would thus be changed into mere mechanism in which, as in a puppet show, everything would gesticulate well but there would be no life in the figures. (KpV, 5: 146–7)

We will consider several reconstructions of Kant’s argument in this passage, but here is a rough gloss. Kant considers a scenario: suppose our cognitive faculties were constituted such that we had theoretical knowledge of God and immortality. What would happen? Kant argues that our knowledge of God’s reward and punishment for virtue and vice would mean we would always act from the motive of inclination vis-à-vis this reward and punishment since we would never experience the conflict between inclination and duty necessary to develop our reason. Since actions have moral worth only if they are performed from the motive of duty, and since our own person has moral worth only if our actions have moral worth, it follows that our person would have no worth. Since the highest good requires that we cultivate perfect virtue, becoming worthy of happiness through the moral worth of our own person, it follows that knowledge of God and immortality would make the highest good impossible.

Kant ends the section by explaining how things actually stand, given that our cognitive faculties do not provide knowledge of God and immortality:

Now, when it is quite otherwise with us; when with all the effort of our reason we have only a very obscure and ambiguous view into the future; when the governor of the world allows us only to conjecture his existence and his grandeur, not to behold them or prove them clearly; when, on the other hand, the moral law within us, without promising or threatening anything with certainty, demands of us disinterested respect; and when, finally, this respect alone, become active and ruling, first allows us a view into the realm of the supersensible, though only with weak glances; then there can be a truly moral disposition, devoted immediately to the moral law, and a rational creature can become worthy of the highest good in conformity with the moral worth of his person and not merely with his actions. Thus what the study of nature and of the human being teaches us sufficiently elsewhere may well be true here also: that the inscrutable wisdom by which we exist is not less worthy of veneration in what it has denied us than in what it has granted us. (KpV, 5: 147–8)

Since we lack knowledge of God and immortality, we can and do experience a conflict between inclination and duty. This makes it possible to develop respect for the moral law, and thereby come to act from the motive of duty. By acting from duty, our actions and our person can have moral worth. Therefore, the highest good is possible after all. It turns out, then, that our cognitive faculties have been wisely adapted to our practical vocation in their denial of knowledge of God and immortality. What had seemed like Nature’s ‘stepmotherliness’ is really a condition of possibility of the highest good. As Kant poetically puts it: the inscrutable wisdom by which we exist is worthy of veneration in what it has denied us. By this I take him to mean that there is wisdom in the limitations of our cognitive faculties. If the ‘inscrutable wisdom’ by which we exist had made our cognitive faculties unwisely adapted to our practical vocation, it could not be called ‘wisdom’ and would certainly not be worthy of veneration. Here, the Dialectic of Pure Practical Reason concludes.⁷

3. Reconstructing Kant’s argument

Is Kant’s argument sound? To address this question, let us first look at the reconstructions of the argument offered in the scholarship. Watkins gives the following reconstruction:

• P1. If we had knowledge of everything, then we would have knowledge of God’s existence and of his promise of eternal reward and his threat of eternal punishment for our good and bad actions (respectively).

• P2. If we had knowledge of God’s existence and of his promise of eternal reward and his threat of eternal punishment for our good and bad actions (respectively), then (a) we would have to act out of hope or fear (or a combination thereof) and (b) we could not act out of respect for the moral law.

• P3. If (a) we would have to act out of hope or fear (or a combination thereof) and (b) we could not act out of respect for the moral law, none of our actions could have moral worth.

• P4. At least some of our actions could have moral worth.

• C1. We do not have knowledge of everything, specifically, of God’s existence and of his promise of eternal reward and his threat of eternal punishment for our good and bad actions.

• (Watkins 2009: 88)

While this reconstruction captures some dimensions of Kant’s argument, it faces a number of problems. Consider C1: Watkins takes the conclusion of Kant’s argument to be that we do not have knowledge of God’s existence, etc. While Kant certainly does hold this view, the plain sense of Kant’s text here is that this lack of knowledge is a premise in his argument, not its conclusion. Indeed, this is the point of the question the argument is addressing: given that our cognitive faculties deny us knowledge of God and immortality, are these faculties wisely or unwisely adapted to our practical vocation? The argument then reasons from this lack of knowledge to the conclusion that our faculties are wisely adapted to our practical vocation. In fact, Watkins does not mention our cognitive faculties nor the substance of our practical vocation, the highest good. He stops short at the moral worth of our actions, without following Kant’s further reasoning to the moral worth of our person, and then to the highest good’s possibility. Without these further steps, we lose the full significance of this argument for the Dialectic, which is concerned with the possibility of the highest good. (There are also other problems: Watkins only considers knowledge of God’s existence, not immortality. He takes Kant’s imagined scenario to involve knowledge of ‘everything’, whereas Kant is only considering knowledge of God and immortality.)⁸

That said, Watkins judges this argument to be unsound. His central objection is that P2 is false. Watkins argues, on Kantian grounds, that knowledge of God’s existence and of His reward and punishment does not entail that we would always act out of hope or fear rather than respect for the moral law. He gives two reasons for this. First, Kant’s justification for P2 seems to be that, without conflict between inclination and duty, we would have no need to develop our reason to combat our inclinations, and so we would not in fact develop it. Watkins maintains that this last move is unjustified: the fact that our inclinations provide aLink sufficient motive to act in conformity with the moral law does not entail that we would in fact never develop our reason. He suggests that such development is precisely what happens in normal human development from childhood to maturity: while children are initially motivated to act morally from inclination (hope and fear), their reason is able to gradually develop until they become capable of acting from duty (2009: 86). Second, Watkins claims that the whole question of moral development is beside the point. Kant is committed to the view that we are always capable of acting from duty, no matter what our inclinations may be. Even when faced with the ‘awful majesty’ of God and consequent inclinations regarding His reward and punishment, we would not lose our transcendental freedom to act from respect for the moral law. We always have the capacity to be motivated to do our duty for duty’s sake, irrespective of whatever reward or punishment would follow (2009: 91–2). So, in Watkins’ view, Kant’s argument fails.⁹

In reply to Watkins’ objections, Paytas and Timmermann come to Kant’s defence. While it is true, Paytas admits, that Kantian moral agents are capable of acting on the motive of duty in cases where duty happens to align with inclination, they would not be capable of so acting if they always aligned. This is because, on Paytas’ account of Kant’s moral psychology, moral agents can only become aware of their freedom to act out of respect for the moral law via determinate experiences of conflict between inclination and duty. Paytas uses Kant’s Gallows Man example, where an individual comes to recognize their own capacity to act out of respect for the moral law through the experience of choosing between bearing false witness and summary execution. This individual realizes that since they ought to speak the truth, it follows they can – they can disregard their inclination for self-preservation and act out of duty (KpV, 5: 30). (Whether they will is a different question.) Since knowledge of God would ensure that our inclinations were never in conflict with duty, we would never experience the conflict necessary to awaken respect, and so would always act solely from inclination (Paytas 2019: 61–2).¹⁰ Timmermann gives a similar reply to Watkins. It is only thanks to an experience of conflict between inclination and duty that ‘we realize for the first time that we are not enthralled by inclination, that there is something within us that is active and radically free. This inspires respect for the law that limits the claims of inclination, which in turn enables us to act independently of self-regarding considerations just because the law requires it’ (Timmermann 2015: 236). Again, since knowledge of God (and immortality) would prevent this conflict, we would never become enabled to act from respect for the moral law.

Before considering what Watkins could say in his defence, we should examine Paytas’ own reconstruction of Kant’s argument:

1. (1) The development of virtue requires an experience of conflict between self-interest and the moral law.

2. (2) God’s revealing himself would preclude all experience of conflict between self-interest and the moral law.

3. (3) God’s revealing himself would preclude the possibility of virtue. (From 1 to 2)

4. (4) Without the possibility of virtue, human existence would be meaningless.

5. (5) God’s revealing himself would render human existence meaningless. (From 3 to 4)

6. (6) A perfectly rational deity would not choose to render human existence meaningless.

7. (7) God’s keeping himself hidden is consistent with his perfect rationality. (From 5 to 6)

8. (Paytas 2017: 136; 2019: 65)

Paytas’ reconstruction improves on Watkins’ in some ways, making explicit additional premises that Watkins has bundled together. Paytas clarifies that Kant is concerned with the development of virtue through an experience of conflict between self-interest (inclination) and the moral law (duty), which Watkins left implicit in his P2. But there are also several problems that Paytas’ and Watkins’ reconstructions share. Like Watkins, Paytas does not mention our cognitive faculties or the highest good. If, as I suggested, the aim of Kant’s argument is to demonstrate that our cognitive faculties are suitable to the realization of the highest good, this is a notable omission. Indeed, it seems to me that, like Watkins, Paytas has not supplied the correct conclusion to Kant’s argument. Paytas takes the conclusion to be that God’s hiddenness is consistent with His rationality, an idea that is certainly connected with the concerns of KpV §IX. But the problem Kant is addressing in KpV §IX is not, in the first instance, whether God’s hiddenness is consistent with His rationality, but whether our own cognitive faculties are consistent with our practical vocation. Granted, these are related, but a faithful reconstruction of Kant’s argument ought to track the question he is trying to answer, rather than other related questions. (Paytas has also elected to use non-Kantian terminology such as ‘human existence’ and its ‘meaning’, rather than following Kant’s reasoning from the moral worth of actions, to the moral worth of persons, to the highest good’s possibility.)

Addressing these issues will have to wait until the new reconstruction of Kant’s argument in the next section. Before that, we should examine Timmermann’s position. He does not provide a premise-conclusion reconstruction of the argument, but he makes several crucial contributions to the discussion of KpV §IX. Importantly, unlike Watkins and Paytas, he takes Kant’s argument to be primarily concerned with our cognitive faculties and the highest good, rather than divine hiddenness or rationality. (He also recognizes that Kant is concerned with knowledge of God and immortality.) Still, Paytas is right to identify his affinity with Timmermann’s readings of Kant’s argument on other grounds, namely, that they both make the development of respect the hinge of the argument, using this to respond to Watkins’ objections. Nevertheless, Timmermann seems to have a quite different view of the structure of Kant’s argument. Timmermann writes that the argument ‘takes the shape of a reductio of the thesis that practical reason would have stood anything to gain from theoretical cognition of God and immortality’ (2015: 232). It of course follows that the conclusion of Kant’s argument is supposed to be the negation of this thesis: practical reason would not have stood anything to gain from theoretical cognition of God and immortality. Now, in my view, this conclusion is nearly there, assuming we treat this as equivalent to the assertion that our cognitive faculties are wisely adapted to our practical vocation. But Timmermann’s conclusion remains too weak: Kant argues not only that practical reason would have nothing to gain by knowledge of God and immortality, but that it would have everything to lose: it would lose the possibility of the highest good.

Timmermann explains Kant’s reductio: ‘The first step is to assume the truth of this thesis: “Assuming now that Nature has complied with our wish in this, and given us that capacity for insight or that illumination (Erleuchtung) which we would like to possess or which some fancy that they actually do possess, what would, as far as we can tell, be the result of it?” [KpV, 5: 146]’ (2015: 232). This thesis is quite different from that which Timmermann had previously told us is the target of Kant’s reductio. If the thesis is now meant to be that our cognitive faculties are capable of knowledge of God and immortality, then a reductio will yield the conclusion that our cognitive faculties are not capable of this knowledge. This would give Timmermann’s reconstruction the same conclusion as Watkins’, but as I argued above, this is an implausible account of Kant’s conclusion. Yet Timmermann then explains Kant’s strategy in a still different way: ‘Kant’s basic strategy is clear. He will argue that illumination [i.e. knowledge of God and immortality] would render virtue impossible, and along with it the highest good (of which it is the primary constituent) and any objective value that the world may now contain. This result directly contradicts our initial assumption, that human beings have been endowed with just the right rational powers to pursue the highest good. Nature was therefore right to deny us direct theoretical knowledge of the two metaphysical objects in question. God and immortality must remain hidden’ (2015: 232). Here Timmermann seems to be saying that the argument works by assuming that our cognitive faculties are constituted such that the highest good is not impossible (and then deriving a contradiction from the further thesis that we possess knowledge of God and immortality). But I take it that Kant wants to argue for the claim that our cognitive faculties do not make the highest good impossible, not assume it.

In any event, while Timmermann’s contribution is important for highlighting the significance of our cognitive faculties and the highest good to Kant’s argument, more work is needed to reconstruct the argument.

4. A new reconstruction and evaluation

Having identified certain lingering problems in previous reconstructions of Kant’s argument in KpV §IX, I want to propose a new reconstruction. I will present it in premise-conclusion form, then walk through each step, evaluating the argument in light of the issues raised above.

• P1. If we had theoretical knowledge of God and the immortal soul, then we would have theoretical knowledge that we will receive God’s reward and punishment for our virtue and vice, respectively.

• P2. If we had theoretical knowledge that we will receive God’s reward and punishment for our virtue and vice, respectively, then inclination (i.e. hope and fear for God’s reward and punishment, respectively) would always be a sufficient motive to act in conformity with the moral law.

• P3. If inclination is always a sufficient motive to act in conformity with the moral law, then we would never experience conflict between inclination and duty.

• P4. If we never experience conflict between inclination and duty, then we would never need to develop our reason to resist our inclinations.

• P5. If we never need to develop our reason to resist our inclinations, then we would in fact never develop our reason.

• P6. If we in fact never develop our reason, then we would always act only from the motive of inclination and never act from the motive of duty.

• C1. ∴ If we had theoretical knowledge of God and the immortal soul, then we would always act only from the motive of inclination and never act from the motive of duty. [P1, P2, P3, P4, P5, P6]

• P7. If we always act from the motive of inclination and never act from the motive of duty, then none of our actions could ever have moral worth.

• P8. If none of our actions could ever have moral worth, then our person could not have moral worth.

• P9. If our person cannot have moral worth, then the highest good would be impossible.

• C2. ∴ If we had theoretical knowledge of God and the immortal soul, then the highest good would be impossible. [C1, P7, P8, P9]

• P10. If our cognitive faculties (in a given respect) gave us theoretical knowledge of God and the immortal soul, then our cognitive faculties (in the same respect) would make the highest good impossible. [C2]

• P11. Our cognitive faculties (in a given respect) are wisely adapted to our practical vocation if and only if our cognitive faculties (in the same respect) do not make the highest good impossible.

• P12. Our cognitive faculties do not give us theoretical knowledge of God and the immortal soul. [The first Critique’s Transcendental Dialectic]

• P13. Our cognitive faculties (with respect to theoretical knowledge of God and the immortal soul) do not make the highest good impossible. [P10, P12]

• C3. ∴ Our cognitive faculties (with respect to theoretical knowledge of God and the immortal soul) are wisely adapted to our practical vocation. [P11, P13]

In general, this new reconstruction has several advantages over prior attempts. It faithfully tracks the primary subject matter of Kant’s argument, viz. our cognitive faculties and the possibility of the highest good. It adduces the genuine conclusion of the argument: our cognitive faculties are wisely adapted to our practical vocation. To reach this conclusion, it uses our lack of knowledge of God and immortality as one of its premises. At each step, this new reconstruction spells out each of Kant’s moves, making explicit what was left implicit in prior reconstructions, and all the while sticking with Kant’s own concepts.

The reconstruction has three main parts. First, using Kant’s account of moral motivation, we draw out a series of entailments from knowledge of God and immortality, reaching the sub-conclusion that this knowledge would mean that we would always act from inclination and never from duty (C1). Then, using Kant’s account of moral worth, we draw out further entailments from C1, reaching the second sub-conclusion that this knowledge would make the highest good impossible (C2). Finally, we demonstrate that since our cognitive faculties do not give us knowledge of God and immortality, they do not make the highest good impossible in this respect, and so we conclude: our cognitive faculties (with respect to theoretical knowledge of God and the immortal soul) are wisely adapted to our practical vocation (C3). Let us now walk through the reconstructed argument.

P1. In KpV §IX, Kant considers what would happen were we to have knowledge of God and immortality. P1 begins by establishing the first consequence of this knowledge: the further knowledge that we will receive God’s reward and punishment for our virtue and vice. Why would knowledge of God and immortality entail this further knowledge? For Kant, the moral law requires that virtue be rewarded with happiness and vice punished with unhappiness. Kant further holds that God, were He to exist, would have the requisite power (omnipotence), knowledge (omniscience), and morality (perfect justice) to bring about this state of affairs: God knows our moral merits, has the power to administer reward and punishment, and would be morally motivated to do so. But an immortal soul is also necessary since in the sensible world of Nature this connection between virtue and happiness is absent. God’s reward and punishment will not be dispensed until we have shuffled off our mortal coil.

Watkins raises a concern about Kant’s reasoning from knowledge of God to knowledge of His reward and punishment. It seems that Kant thinks that God’s ontological predicates can be separated from His moral predicates.¹¹ For example, it is conceivable that one might know that there exists a metaphysical ground of all possibilities (God as ens realissimum) without knowing that this ground is the moral judge of humanity. If so, knowledge of God’s existence might not entail knowledge of His reward and punishment (Watkins 2009: 92–3). But Watkins admits that this objection is uncertain since others have argued that Kant actually holds that God’s ontological and moral predicates are inseparable (e.g. Kain 2021). One might also think that knowledge of God’s ontological predicates without His moral predicates would not constitute knowledge of God per se, but only knowledge of some part of God. Finally, if Kant’s argument is meant to be dialectically effective against the dogmatic rationalist metaphysician, who is committed to the view that knowledge of God includes His moral attributes, then Kant would be licensed to adopt this commitment in combatting his opponent.

This raises a further concern: Why is Kant convinced that the only morally relevant feature of God is His reward and punishment? Why are no other moral predicates relevant? For example, if knowledge of God includes knowledge of God’s moral predicates, it would include knowledge of God’s holy will. (This is required for knowledge of God’s reward and punishment since it is only thanks to His holy will that we can be certain that He will act as righteous judge.) Kant elsewhere maintains that, given God’s holy will, the moral individual can regard the moral law ‘as if’ it were God’s command (KpV, 5: 129; RGV, 6: 153–4.)¹² Would knowledge of this fact perhaps have a different effect on our moral motivations than knowledge of God’s reward and punishment? To be sure, Kant is clear that acting in conformity with the moral law because it is God’s command is heteronomous. But might there be some sense in which knowledge of God’s holy will could awaken our respect for the moral law, making possible action from the motive of duty? We will have to defer these questions to the discussion of moral motivation below.

In sum, there is a reasonable Kantian case for P1, though there are also some unresolved issues, which will be further explored as we continue through the argument.

P2. This premise follows from Kant’s moral psychology, in combination with his views on God’s reward and punishment. For Kant, inclination and duty are the only possible determining grounds of the will or ‘motives’ (Motive) for action: inclination stems from our natural-sensible side and is directed towards our self-interest, while duty stems from our rational-intelligible side and is directed towards the moral law. While there are as many different particular ends as objects of inclination, still ‘happiness’ is the name for ‘their greatest possible and most lasting satisfaction’ (KpV, 5: 147). In other words, as a whole, our inclinations are directed towards our own happiness. Now, God’s reward consists in happiness proportioned to virtue, and punishment unhappiness proportioned to vice. Thus, if we had knowledge of God’s reward and punishment, the inclination towards our future happiness (hope for reward) and away from our future unhappiness (fear of punishment) would always constitute a sufficient motive to act in conformity with the moral law. In any given situation, we would know that the ‘greatest possible and most lasting satisfaction’ of our inclinations (happiness) would follow from acting in conformity with the moral law, and this would be enough to motivate us to act in such a way.

It is important for the remainder of Kant’s argument that God’s reward and punishment generates a motive merely to act in conformity with the moral law, rather than out of respect for the moral law – the motive of inclination rather than duty. Still, one might wonder why this is. Timmermann (2015: 240) raises a worry: knowledge of God’s reward and punishment would presumably include knowledge that only actions from duty make us worthy of God’s reward. Would this not motivate us to abandon inclination – and inclination-determined action merely in conformity with the moral law – in favour of duty for duty’s sake (respect for the moral law)? But Kant would have a reasonable reply: if the only reason we turned away from inclination towards duty was an inclination for our own happiness, then our actions from duty would really be from the motive of inclination after all. In other words, acting out of duty in order to get God’s reward is not really acting out of duty at all. There would need to be some other way to get the motive of duty going – but as Kant will argue, knowledge of God’s reward and punishment prevents this.

One might have the further worry that Kant’s view of the consequences for our conduct of knowledge of God’s reward and punishment is implausible. Is it really the case that this knowledge would always make inclination (towards reward and punishment) alone a sufficient motive to act in conformity with the moral law? It seems that there are many examples of theistic believers who nevertheless act immorally; it is hard to see why knowledge of God would not similarly allow for immoral action. Moreover, there would seem to be plenty of examples of individuals who act contrary to their long-term self-interest in order to satisfy their short-term desires. So, even if knowledge of God’s reward and punishment convinced us incontrovertibly that moral conduct best serves our long-term self-interest (i.e. our happiness), this could be outweighed in a given instance by some other immoral short-term inclination. Now, Timmermann (2015: 233–5) argues that Kant’s view is otherwise: for Kant, the strength of our concern with our overall happiness would outweigh other inclinations here. But one could have reasonable philosophical doubts over whether this is truly the case. (An advantage of Paytas’ reconstruction of Kant’s argument is that it does not include Kant’s claim that knowledge of God and immortality would make immoral conduct impossible, lending the argument a greater plausibility. But this comes at the cost of some loss of fidelity to the details of Kant’s position – a price that is perhaps worth paying in this case.)

P3. Kant’s idea here is that, if we were always sufficiently motivated by inclination to act in conformity with the moral law, then we would never face a situation in which our inclinations conflicted with our duty – they would both always point in the same direction. Is this right? Even with knowledge of God’s reward and punishment, would we not still be subject to all sorts of other natural desires pulling us away from conformity with the moral law? As I noted in response to a worry regarding P2 above, Timmermann (2015: 233–5) again supplies the Kantian response: while we would indeed still be subject to these other inclinations pulling us away from the moral law, Kant’s view is that, all things considered, our inclinations as a whole would not pull us away. This is because, as we saw, Kant regards happiness as the sum-total object of our inclinations. Were I to have a particular inclination that strayed from the moral law, the countervailing inclination stemming from my knowledge of God’s punishment would infinitely outweigh whatever weight the first immoral inclination might have. So, no genuine conflict between inclination and duty could ever arise. (While one could certainly raise philosophical objections to this picture of moral psychology, I think Timmermann is right to attribute it to Kant.)

P4. The textual basis for this premise comes from Kant’s account in KpV §IX of what would follow from knowledge of God and immortality: ‘Transgression of the law would, no doubt, be avoided … but … because the spur to activity in this case would be promptly at hand and external, reason would have no need to work itself up so as to gather strength to resist the inclinations by a lively representation of the dignity of the law’ (KpV, 5: 147). Without experiencing conflict between inclination and duty, we would never need to develop our reason since inclination alone would always provide a sufficient motive for compliance with the moral law. But what kind of ‘need’ is this? Surely we would still have a moral need to develop our reason since this would be the only way to make ourselves worthy of happiness? Kant’s point seems to be that we would have no need to develop our reason in order to act in conformity with the moral law – and as he will argue, this entails that we would in fact never develop our reason.

P5. As we saw above, Watkins (2009: 86) provides the basis for an objection to this premise: even if we never had a need to develop our reason to resist our inclinations, there is no reason why we could not still in fact develop our reason. Watkins suggests that this is precisely what happens in ordinary cases of moral education: children are educated to strengthen their reason and have respect for the moral law, irrespective of whatever direction their inclinations may be pushing or pulling them. (On Kant’s own account of moral education, we begin by teaching children to act morally out of hope and fear for reward and punishment, only later introducing the motive of duty (KpV, 5: 152).) In other words, the moral law demands respect no matter what our inclinations are – even if our inclinations are in total harmony with the moral law – and there is always room for us to recognize this, even if this is not ‘needed’ for conformity with the moral law.

But as we further saw, Paytas and Timmermann respond to Watkins’ objection by contending that the development of our reason is impossible without an experience of conflict between inclination and duty. Since knowledge of God and immortality would preclude this experience, it follows not only that we would never need to develop our reason, but that we would never in fact do so. They take the justification for this to be Kant’s account of the moral feeling of respect. Kant seems to hold that respect can only be awakened through a determinate experience of conflict, without which it would lie inactive or dormant. Kant explains the process by which we develop respect with the Gallows Man example, discussed above. A man threatened with hanging on the gallows if he does not testify falsely against another innocent man becomes aware of his freedom to do what he ought to do out of respect for the moral law, even at the price of his own death (KpV, 5: 30).

But is it really true that we must personally undergo such an experience to awaken respect for the moral law? Surely Kant cannot expect everyone to have an experience quite as dramatic as the Gallows Man. Perhaps less dire circumstances would suffice, as long as some conflict between duty and inclination occurred. But do we even need that? Why is it not enough to simply imagine the Gallows Man? After all, this is what Kant seems to want us to do by including this example in the second Critique. Granted, if we had knowledge of God and immortality, we would have to imaginatively bracket these, but that seems eminently possible. Indeed, in the second Critique’s Doctrine of the Method, Kant explains that moral education involves bringing forward historical examples of actions performed out of respect for the moral law at great personal cost (e.g. those who refused to give false testimony against Anne Boleyn), with the express purpose of awakening respect in students (KpV, 5: 155–6). Now, Paytas and Timmermann could perhaps respond: all these stories, imaginings, etc., can only have purchase on us if we already had at least some personal experience of conflict between duty and inclination. Without such experience, they would fall on deaf ears. But this reply is uncertain at best. Kant often speaks as if ‘the representation of the moral law’ alone is sufficient to awaken respect, insofar as the two are ‘inseparably connected’ (KpV, 5: 80). If so, no direct experience of conflict is required, only the representation of the moral law. To be sure, in KpV §IX, Kant writes: ‘reason would have no need to work itself up … by a lively representation of the dignity of the law’ (KpV, 5: 147). But to take Watkins’ line, the absence of a need to entertain this representation does not entail its impossibility.

Reaching a final determination on the truth of this premise, if only on Kant’s own terms, would require settling these complicated issues in his account of respect for the moral law, moral development, and moral psychology more generally. I cannot hope to do so here.¹³ But the next premise may render these issues moot anyway.

P6. Watkins (2009: 91–2) again provides the basis for an objection to this premise: by Kant’s own lights, we do not need to ‘develop’ our reason in order to act from duty instead of inclination. Rather, we can act from duty under any circumstances, at any time. No matter what our past experiences have been, no matter what our stage of moral development might presently be (e.g. a hardened criminal with a morally corrupt upbringing), we always have the transcendental freedom to do our duty for duty’s sake. But how can this be true, on Kant’s account? How can it be that we are capable of acting from duty at any time, given Kant’s emphasis on the need for gradual moral development over time? There seems to be a tension between these two Kantian claims.

I would propose to supplement Watkins’ objection by invoking the distinction in Kant’s Religion between sensible reform and intelligible revolution. While it is true we must undergo gradual moral reform in the sensible world, Kant argues that this moral development is a sensible appearance of a revolution in our intelligible moral character from evil to good, which transpires all-at-once in the intelligible world (RGV, 6: 47). Many philosophical puzzles arise from this conjunction of reform and revolution.¹⁴ But for our purposes, the consequences are clear enough: the revolution of intelligible character means that we can always make the moral law the determining ground of our will, no matter where we may be on the scale of moral progress in the sensible world. After all, if ought implies can, then since we ought to act from the motive of duty, it is always true that we can act from the motive of duty. Is the revolution in intelligible character nevertheless dependent on a determinate experience of conflict between inclination and duty within the sensible world, insofar as this experience is required to awaken respect? This would seem to have things backwards: it would make our intelligible character conditioned by sensible experiences, rather than unconditional obedience to the moral law. To be sure, this leaves open the question why an individual makes the revolution in their intelligible character – but Kant is happy to leave this a question lying beyond the bounds of reason. It is enough to say that since one ought to make this revolution, one can (RGV, 6: 47–8).

This supplement leads to a further worry. Suppose we have made the revolution in our intelligible character from evil to good. Further suppose that we have knowledge of God and immortality, entailing that our inclinations have become fully harmonized with the moral law. It seems to follow that there would no longer be any gradual moral reform necessary in the sensible world, since we do not have any inclinations to overcome. If we now act from the motive of duty, would our actions be devoid of moral worth, given that there are no inclinations to struggle against? Yet Kant holds that the complete harmony of duty and inclination constitutes the perfection of the moral disposition – a perfection which, under normal circumstances, remains an infinite goal towards which we can only endlessly strive – which, in the second Critique, he describes as doing one’s duty ‘gladly’ (KpV, 5:84). On the one hand, some of Kant’s statements about this infinite goal suggest that its achievement would do away with moral virtue: e.g. ‘the law … would then cease to be a command, and morality, having passed subjectively into holiness, would cease to be virtue’ (KpV, 5: 84). Thankfully, since this goal remains forever beyond reach, virtue always remains in place, and so too our worthiness to be happy. This lends credence to the view that gradual moral development is an irreducibly important part of our moral lives, rather than merely an expression of a single revolution in character. On the other hand, some other of Kant’s statements suggest that a creature who attained to holiness would be infinitely worthy of happiness.¹⁵

Once again, far be it from me to try to settle here these difficult issues on the relation between moral reform and revolution, or between moral imperfection (virtue) and perfection (holiness). My intention is just to draw out where the pressure-points of the argument lie. If, after further inquiry, it turns out that moral development is essential on the Kantian picture, then this premise will go through. If, on the contrary, it turns out the moral development is inessential, then this premise will fall short.

C1. This should be straightforward. We are chaining together the conditionals in the first six premises, by transitivity. We have thereby reached an important sub-conclusion: knowledge of God and immortality would have drastic, dire effects on our moral motivations, namely, always acting from inclination and never from duty.

P7. This should be an uncontroversial entailment from one of the most well-known components of Kant’s moral philosophy: our actions have moral worth if and only if they are performed from the motive of duty. Thus our actions cannot have moral worth if they are never performed from duty. (As already intimated above, there is some question over whether Kant would attribute moral worth to actions that are performed both from duty and inclination in cases where duty and inclination are in harmony, or whether this would even be the proper way to describe such actions. But in any event, Kant does not think such a situation would follow from knowledge of God and immortality.)

P8. The reasoning here simply follows some of the key tenets of Kant’s moral philosophy: the moral worth of our person is dependent on the moral worth of our actions. Our person earns moral worth – becoming worthy of happiness under the highest good – by acting from the motive of duty, i.e. through actions which themselves have moral worth.¹⁶ (Note again how this and the next few premises improve upon past reconstructions by drawing out each of Kant’s moves, and sticking to Kant’s own concepts rather than substituting them with others. For example: Watkins stops short at the moral worth of actions, without considering the moral worth of persons or the highest good. Paytas discusses the meaning of human existence, not moral worth.)

P9. This follows from Kant’s conception of the highest good. For the highest good to be possible, we must be capable of making ourselves worthy of happiness through the moral worth of our person. If it is not possible for our person to have moral worth, then the highest good would not be possible.¹⁷

C2. This should again be straightforward. We are again just chaining the conditional in C1 with three further conditionals (P7, P8, P9). In this second sub-conclusion, we have drawn out an even more drastic and dire consequence of knowledge of God and immortality: it would make the highest good impossible.

P10. This follows from C2 by conditional introduction. It is important that P10 is restricted to considering our cognitive faculties only in a given respect, since this sets up the later premises in which Kant will argue that, with respect to knowledge of God and immortality, our cognitive faculties do not make the highest good impossible. As I will suggest, I do not think Kant’s argument in KpV §IX can rule out the possibility that there might be other ways in which our cognitive faculties make the highest good impossible – though it seems that Kant’s considered view is that they do not. KpV §IX is restricted to the specific question of whether our cognitive faculties’ incapacity to provide knowledge of God and immortality is conducive to our practical vocation.

P11. This premise is true by Kant’s definition of our practical vocation and his stipulation of the meaning of ‘wisely adapted’. For Kant, our practical vocation is to realize the highest good, while being ‘wisely adapted’ here means ‘does not make impossible’. This might seem like a thin notion of wise adaptation. Would our cognitive faculties not be better adapted and hence wiser if they helped us to realize the highest good in some more determinate, positive way? But consider that Kant is dealing with a binary option: either our cognitive faculties give us knowledge of God and immortality, or they do not. In the former case, the highest good would be impossible. In the latter, the highest good would be possible. So ‘wise adaptation’ turns out to mean picking the case in which our cognitive faculties make the highest good possible (by denying us knowledge of God and immortality), over the case in which our cognitive faculties make it impossible. That is wise, indeed.

P12. This premise expresses Kant’s view that our cognitive faculties are limited in such a way that knowledge of God and immortality is impossible. As I began, there is a sense in which this view can be regarded as the fundamental result of the first Critique, as Kant declares: ‘Thus I had to deny knowledge in order to make room for faith’ (Bxxx). It is important to notice that this denial happens on several fronts. Most memorably, the Transcendental Dialectic shows that our faculty of theoretical reason cannot give us knowledge of God and immortality: all the traditional metaphysical arguments for God’s existence and the soul’s immortality are revealed as transcendental illusions, in the Ideal and Paralogisms of Pure Reason, respectively. Yet importantly, Kant also argues that God and the immortal soul lie beyond the bounds of a possible experience: since they cannot be given to our sensible intuition, no theoretical knowledge of them can be had through any combination of sensibility (intuition) and understanding (concept).¹⁸ Finally, while in principle knowledge of God and immortality could be had through a faculty of intellectual intuition, Kant argues that we do not possess this faculty. The picture Kant paints in KpV §IX might initially sound like an intuitive revelation of God – ‘God and eternity with their awful majesty would stand unceasingly before our eyes’ – but he immediately glosses this scenario with a parenthetical remark: ‘(for what we can prove perfectly holds as much certainty for us as what we are assured of by our sight)’ (KpV, 5:147). His point is that this argument should be taken to apply to all putative instances of theoretical knowledge of God and immortality, whether via sensible intuition, discursive theoretical reason, or intellectual intuition. Kant holds that none of the cognitive faculties we possess can give us knowledge of God and immortality – and if there are any other faculties that could provide this knowledge, we fail to possess them.

P13. This clearly follows from P10 and P12. Notice again that Kant’s argument does not rule out the possibility that there might be some other way(s) in which our cognitive faculties make the highest good impossible. But clearly Kant’s argument in KpV §IX only considers our cognitive faculties with respect to knowledge of God and immortality. Kant is specifically arguing against an opponent (e.g. a dogmatic rationalist metaphysician) who asserts that knowledge of God and immortality would be beneficial. Whether or not there is some other way our cognitive faculties might thwart our practical vocation, Kant does not address here. (This is true even though the title of KpV §IX might mislead the reader to think that Kant means to make an argument about our cognitive faculties being wisely adapted in every respect. But this reading is implausible.) Again, it is almost certain that Kant’s view is that there is no other way in which our cognitive faculties make the highest good impossible. But he does not argue for this more general view in KpV §IX. Instead, he limits the scope of his judgement of wise adaptation to this particular domain of the use of our cognitive faculties.

C3. This conclusion clearly follows from P11 and P13: since, with respect to theoretical knowledge of God and the immortal soul, our cognitive faculties do not make the highest good impossible, then – by virtue of the meaning of wise adaptation and our practical vocation – our cognitive faculties (in this same respect) are wisely adapted to our practical vocation. With this conclusion, Kant has defeated the worry raised in the first paragraph of KpV §IX, that our cognitive faculties seem to have been unwisely adapted, for ‘Nature … seems here to have provided for us only in a stepmotherly fashion with the faculty needed for our end’ (KpV, 5: 146). Kant’s argument has demonstrated that the opposite is true, as stated in the final sentence of §IX: ‘Thus what the study of Nature and of the human being teaches us sufficiently elsewhere may well be true here also: that the inscrutable wisdom by which we exist is not less worthy of veneration in what it has denied us than in what it has granted us’ (KpV, 5:148). In other words: there is wisdom in the constitution of our cognitive faculties – they have been wisely adapted to our practical vocation after all.

It seems to me that this conclusion is more faithful to the aims of Kant’s argument than previous reconstructions. The motivation for §IX is not a puzzle about divine hiddenness, even if it may incidentally offer a resolution to this puzzle as well, but rather about our cognitive faculties and their relation to the possibility of the highest good (i.e. our practical vocation). The conclusion of this new reconstruction reflects this Kantian point.

5. Conclusion

A final determination of the soundness of Kant’s argument in KpV §IX, even on Kantian grounds alone, will have to await settling a number of outstanding questions vis-à-vis the fine details of Kant’s account of moral motivation and moral psychology, not to mention addressing various further issues regarding the holy will, divine command, moral development and moral perfection, among others. But I take it that this new reconstruction has nevertheless significantly advanced the debate about Kant’s argument by giving a more comprehensive and faithful picture of that argument’s form and content. Per the above discussion, P1, P2, P5, and P6 seem to be particularly vulnerable to objections, but, as also indicated, there may very well be Kantian resources to respond to these objections. Of course, there may also be other objections to these or other premises. In any case, there is surely more discussion and debate that could be had on this Kantian argument, but I hope that this debate can now proceed on more solid ground with the account offered here.