Kant on the Rationality of Morality – GUYER (M)

GUYER, Paul. Kant on the Rationality of Morality. Cambridge University Press, 2019. 73pp. Resenha de: CARVALHO, Vinicius. Manuscrito, Campinas, v.43 n.2 Apr./June 2020.

In his contribution to the Cambridge Elements: The Philosophy of Immanuel Kant series, Paul Guyer contends that Kant derives the fundamental principle of morality (in this case, the formulas of the categorical imperative) and the object of morality (the highest good) from the application of the most fundamental principles of reason: the principle of noncontradiction, of sufficient reason, and, to a lesser extent, the principle of excluded middle. The fundamental fact that ought not to be denied by any rational agent – on pain of self-contradiction – is that oneself and others have a free will, in other words, that they have the capacity to freely set and pursue their own ends. Guyer argues that Kant grounds his whole moral theory upon this fact, and that the application of the fundamental principles of reason to it gives us the principle and the object of morality. In what follows, I will summarize each of the book’s chapters, discussing some of its claims when I see fit.

In the second chapter – Reasons, Reasoning and Reason as Such, the first chapter being the introduction  Guyer discusses past approaches about the relation between the fundamental principles of morality and reason for Kant. For instance, philosophers such as Christine Korsgaard and Allen Wood emphasize that rational actions are actions based on reasons, and that genuine reasons are universally valid norms, valid for everyone, everywhere. Kant would have gotten the requirement to act on universally valid reasons from the observation that this is what characterizes rational action. Onora O’Neill also emphasizes the same requirement for universalizability, though she supports her reading not by appealing to the notion of a reason in particular, but to the notion of reasoning in general, in her well-known account of Kant’s conception of reason in the Canon of Pure Reason from the first Critique2. In my view, Guyer correctly criticizes an aspect of O’Neill’s reading on this point: it is not the case that we “invent and construct standards for reasoned thinking and acting”3all the way downPace O’Neill, Guyer argues that it is certainly the case that Kant did not believe that the application of the principles of rationality were sufficient to arrive at substantive metaphysical conclusions: this is one of the features of dogmatism he so fiercely denounced. But he certainly regarded some formal principles of reason as “necessary conditions of reasoning because they are the fundamental principles of reason” (p. 9). So, even though Guyer agrees with these interpreters about the importance of the requirement of universality when it comes to morality, his argument will be that this requirement is the result of the application of some even more fundamental principles, beginning with that of noncontradiction.

The third chapter – From Noncontradiction to Universalizability – shows exactly how that is so. First, Guyer shows that Kant followed the philosophical tradition of his time in accepting the principle of noncontradiction as the first principle of reason (and the principle of sufficient reason as the second). Indeed, Kant is quite clear on this matter in his lectures on Logic (especially in the Jäsche Logik) and at some points in the first Critique4. But to which concepts and pairs of judgment need we apply this principle to derive the principle of morality? In the preface to the Groundwork, Kant says that for any moral law, its “ground of obligation” must be sought “a priori simply in concepts of pure reason” (GMS, AA 04: 389), and in the second section of the work he clarifies that this a priori concept is the concept of a rational being (GMS, AA 04: 412). More precisely even, it is the concept of a rational agent, which is a rational being with the capacity to act according to the representation of certain laws, for the sake of certain ends (GMS, AA 04: 426-7). According to Guyer:

Kant’s argument will then be that the fundamental principle of morality can be derived from the application of the principle of noncontradiction to the concept of a rational agent as one capable of setting its own ends. This capacity must be affirmed of any rational agent and cannot be denied without contradiction. (p. 17)

Guyer’s point is that a maxim is immoral whenever its proposed action entails some belief that contradicts the fact that agents have free will. Take the lying promise situation – in which an agent makes a promise with no intention of keeping it – as an example. Kant says that in such a world, in which everyone makes lying promises whenever it suits their interests, no one would accept promises at all. The practice of making promises in general would cease to exist because one of its necessary conditions (i.e., that the promisee trusts the promisor) is gone. Thus, in making a false promise an agent virtually robs the possibility of everyone else making any promises. It undermines their freedom by making it impossible for them to take part in a social practice in which they have chosen to participate5. It treats other people as if they were not fully free agents. According to Guyer, this shows that “the necessity of avoiding contradiction between a proposed maxim and its universalization is a consequence of the necessity of avoiding contradicting the nature of rational beings as persons with free will” (p. 24). Although Kant does not explicitly say this in the Groundwork, Guyer takes as textual evidence (a) the fact that Kant says of immoral maxims that when universalized they either contradict themselves, or that they entail practices that are inconsistent with some fundamental characteristic of rational agents (see GMS, AA 04: 423-4), and (b) Kant’s treatment of the duties not to commit suicide, to help others in need, and to develop one’s talents in the Metaphysics of Morals (see MS, AA 06: 451; 453).

Since Kant’s treatment of duties in that latter work relies more heavily on the Formula of Humanity (FH) rather than the Formula of Universal Law (FUL), because the nature of rational agents as free agents (ends-in-themselves) is explicit in the former formula, Guyer says: “Thus Kant’s requirement of universalizability follows from the formula of humanity and is ultimately grounded in the law of noncontradiction because the latter is.” (p. 23). I believe this deserved a bit more clarification by the author, though, for the question “how could the requirement of universalizability expressed by FUL follow from FH if the latter is presented after and as a ‘development’ of the first formula?” comes straight to the reader’s mind. A possible answer would be that the derivation of FUL already relies upon the premise that rational agents are free agents, who express their freedom in their adoption of maxims. The evidence for this is Kant’s distinction, already at the beginning of the derivation, between imperfect and perfect wills (GMS, AA 04: 412). It is precisely because rational agents with imperfect wills are free to adopt whatever maxims they propose to themselves that the principle of morality – to choose only maxims apt for universal legislation – is presented as an imperative. In any case, I believe this point should have been more fully developed by the author. The chapter ends with a brief treatment of Kant’s deduction of the freedom of the will at the third section of the Groundwork, where Kant argues that we cannot but regard ourselves as beings with free will when we apply the distinction (argued for in the first Critique) between world of sense and intellectual world. The fact that we know that we are free agents (from the practical point of view) is what produces a self-contradiction whenever we adopt a maxim that entails some belief or other that is inconsistent with this knowledge.

The fourth chapter – The Principle of Sufficient Reason and the Idea of the Highest Good – shows how Kant got his conception of the highest good through the application of the second fundamental principle of reason, that is, the principle of sufficient reason, according to which there is an adequate explanation for every fact. Guyer first discusses how Kant refuses the traditional use of this principle as it was employed by the rationalists, for the application of this principle is warranted only within the limits of possible experience. But, according to Guyer, he accepted the use of this principle when it came to matters of morality. More precisely, Kant claimed that the application of this principle lets us theorize about the “unconditional”, which, in this case, means that we can apply this principle to think about the complete and systematic consequences of morality. For Kant, this means that we are drawn to the idea of the highest good, a condition in which “universal happiness [is] combined with and in conformity with the purest morality throughout the world.” (TP, AA 08: 279).

Throughout the chapter, Guyer defends his interpretation on how to read Kant’s conception of the highest good and his argument for it. He shows that Kant applies this principle in two ways: first, to show that morality is a condition on the pursuit of happiness. Kant does not ground moral worth in possible or actual good consequences of actions. Some action might bring a great deal of happiness (whatever we understand ‘happiness’ to mean), but its accomplishment is constrained by moral considerations, such as if it respects the nature of those involved as ends-in-themselves. In the second case, happiness is conceived as the complete object of morality: since happiness is the satisfaction of all possible ends (GMS, AA 04: 418; KpV, AA 05: 25) and the nature of rational agents is that they set themselves their ends, then “the moral command to preserve and promote the capacity to set ends is in fact equivalent to a moral command to promote happiness … [happiness is] what morality commands in the first instance, but not, as it turns out, all that it commands” (p. 37). This is why, in Kant’s words, “pure practical reason … seeks the unconditioned totality of the object of pure practical reason, under the name of the highest good” (KpV, AA 05: 108). It is important to keep in mind here that happiness commanded by morality under the concept of the highest good is not happiness simpliciter, that is, the mere satisfaction of contingent ends, but that it is limited by moral considerations. This conception of the highest good as the object of morality also leads Kant to develop what he thinks to be the necessary conditions for the attainment of this object. The three ideas of pure reason that were discussed in the Dialectic of the first Critique now receive the status of postulates of practical reason: the immortality of the soul, freedom of the will and the existence of God are propositions that, for Kant, cannot be theoretically proven, but which we must accept because they are necessary conditions to the realization of morality’s object, the highest good. The end of the chapter is devoted to show how Kant eventually shifted position regarding the role of the postulates, especially in his latter writings from the 1790’s.

In the fifth chapter – Rationality and the System of Duties -, Guyer argues that Kant’s treatment of duties show that he also took the ideal of systematicity to be part of his conception of reason and rationality. That this ideal is essential to Kant’s philosophy is clear from the Appendix to the Transcendental Dialectic (see KrV A 642/B 670), and in his practical philosophy we can see this ideal at work in many occasions. First, there is the requirement that an agent adopts not only one maxim apt for universal legislation, but that all his maxims satisfy this requirement (GMS, AA 04: 432). Second, there is the requirement that all ends of all agents be compatible, as well as that each agent be treated as an end-in-itself, as expressed in the Formula of the Realm of Ends (GMS, AA 04: 433). And third, there is the suggestion that the supreme principle of morality must be able to offer a complete division and characterization of the generally recognized classes of duties6, that is, into (a) perfect and imperfect duties (GMS, AA 04: 423-4), and (b) both duties of virtue (noncoercively enforceable) as well as duties of right (coercively enforceable). Granted, Kant seems to use in general two different principles to derive these duties, focusing on FUL in the Groundwork and on FH in the Metaphysics of Morals. But, as Guyer argues, these principles are supposed to be interchangeable and at least coextensive when it comes to the duties they entail. The most important point of the chapter, however, is the explanation of why we might need a system of duties. Showing that Kant followed in important aspects George F. Meier’s treatment of duties, Guyer argues that the systematic classification of duties, combined with the application of the principles of noncontradiction and excluded middle – the principle that ought implies can as well, but this one is not usually explicitly stated by Kant – are what allows Kant to deny the possibility of conflict of duties, in other words, genuine moral dilemmas. Thus, Guyer says:

Here is where Kant might have brought in the principle of the excluded middle as well as that of noncontradiction: whereas the latter principle tells us that two contrary duties, that is, duties to perform two incompatible acts at the same time, cannot both be duties (on the ground that we cannot have an obligation to perform the impossible), the former would tell us that we have to perform one of these duties. (p. 47)

This chapter ends with a discussion of Kant’s ideal of systematicity both in the theoretical and in the practical uses of reason as presented mainly in the third Critique.

The sixth chapter – Reason as Motivation – explains how, for Kant, pure reason can motivate action. Guyer shows that Kant’s disagreement with Hume about the role of reason in action, though substantial, is not complete. Whereas Hume thought that reason was motivationally inert and could not lead us to action – only sentiments and “passions” could -, Kant thought that pure reason could be practical. Indeed, this is necessary for any action to have moral worth: “What is essential to any moral worth of actions is that the moral law determine the will immediately” (KpV, AA 05: 71). But this does not mean that reason motivates us to action without any feelings being involved, for Kant also says that “every determination of choice proceeds from the representation of a possible action to the deed through the feeling of pleasure and displeasure, taking an interest in the action or its effect” (MS, AA 06: 399). Guyer explains this apparent inconsistency by arguing that we must place Kant’s theory of motivation within his transcendental idealism, specifically the distinction between noumenal and phenomenal selves. The moral law does determine the will immediately because this happens when we choose to adopt the moral law as our “fundamental maxim” (RGV, AA 06: 36) and when we are conscious of it “whenever we draw up maxims of the will for ourselves” (KpV, AA 05: 29). But when it comes to choosing particular maxims, this happens through the intermediation of the feeling of respect, which is a self-wrought feeling, caused by reason, that acts as a counterweight in favor of the moral law against the motivational pull of inclinations (GMS, AA 04: 401). Thus, Guyer says that “reason produces action – this is Kant’s disagreement with Hume – but it does so through the production or modification of feeling – here is Kant’s agreement with Hume” (p. 53). In the rest of the chapter, Guyer discusses Kant’s fuller theory of motivation as presented in the Metaphysics of Morals, which involves the exercise and cultivation of a class of feelings that are sensible to the determination for action through the concept of duty, namely: moral feeling, conscience, love of others or sympathy, and self-respect or self-esteem. Thus, Guyer joins others who have consistently pointed out that any interpretation that represents Kant’s ethics as devoid of any place for feelings and emotions is seriously flawed.

In the seventh chapter – Kantian Constructivism -, Guyer discusses the metaethical implications of his interpretation, especially in the realism versus antirealism debate concerning Kant’s moral theory. Appropriately, the author first makes sure to distinguish semantic realism from ontological realism. This fundamental distinction is unfortunately not always drawn in discussions of Kant’s metaethics, causing many unnecessary disagreements. Guyer claims that Kant is clearly a semantic realist: for him, judgments about right and wrong, good or bad, are not indeterminate in their truth-value, and they can be correctly inferred from previous moral judgments and principles. In other words, there are correct and incorrect answers to moral questions, i.e., questions of permissibility, worthiness, etc. The real hornet’s nest is when it comes to the following problem: in virtue of what are some moral judgments true? Is it due to some metaphysical fact independent of us, or is it the result of the application of some constructive procedure?

The latter position was famously defended by John Rawls, who labeled the method employed in his political philosophy Kantian Constructivism. Defenders of a constructivist reading of Kant’s metaethics claim that he derived the principles of morality from a mere conception of practical reason or reason in general. On the other hand, those who prefer the (ontological) realist view say that what ultimately grounds morality and from which Kant derives its principles is the fact that rational agents are ends in themselves, “or that human freedom is intrinsically valuable” (p. 64). As Guyer points out, and I am in very much agreement with him on this point, the method by which Kant derives particular moral duties constitutes a form of constructivism: we infer particular duties by applying the different formulas of the moral law to our specific circumstances7. Therefore, we can say that Kant is a normative constructivist.8 But it is not so clear whether he is a metaethical constructivist. Some argue that what grounds the moral law is the fact that rational agents are free, which gives them an irreducible value, outside the purview of construction, upon which morality is grounded9. For Guyer, Kant’s position regarding the nature of the fundamental principle of morality should be seen as a realist position: this fundamental principle is ultimately derived from the application of the principle of noncontradiction to the fact that rational agents have free wills, a fact that obtains independently of any procedure of construction. But he claims that this does not fit well with what we contemporarily regard as moral realism, for this fact is not a specific moral one, nor is it Kant’s position that there is something of value in the world independent of evaluative attitudes. About this, Guyer says:

This is a fact, in Kant’s own words a “fact of reason”, but it is not a mysterious moral fact, or a value that somehow exists in the universe independently of our act of valuing it. It is simply a fact that cannot be denied on pain of self-contradiction, since, Kant assumes, in some way we always recognize it even when by our actions we would deny it. Whether Kant succeeded in demonstrating this fact is a question; but there is no question that he regards our possessions of wills as a fact from which moral theory must begin. Thus we can say that as regards its fundamental principle, Kant’s moral philosophy is a form of realism, though not specifically moral realism. (p. 64)

As the author points out both in this last chapter and in the second, it is one thing for Kant to show how the principles and the final object of morality are derived from the fact that we are free agents combined with the requirement to respect the fundamental principles of reason; it is quite another thing for him to demonstrate that we are, indeed, free agents. That would be the subject of a much longer and detailed study, which falls out of the scope of the book, let alone of this review. Kant on the Rationality of Morality is a short but insightful book. Its discussions bridge Kant’s theoretical and practical philosophies, and they offer an original argument for one of the most important interpretative problems of the Groundwork, the derivation of the principles of morality. I recommend it especially to those who prefer to read Kant’s ethics as not so dependent on the significant metaphysical and epistemological theses of his transcendental idealism; as well, of course, to those interested in moral theory in general.


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1This work was supported by grant 2019/21992-8, São Paulo Research Foundation (FAPESP).

2 O’Neill, 1989.

3 O’Neill, 2004, p. 187.

4Log, AA 9: 51 and KrV, A 150/B 189; A 151-2/B 191. References to Kant’s texts follow the standard: abbreviation of the work, followed by their number in the Akademie volumes and their corresponding pagination. Except for the Critique of Pure Reason, quoted with reference to the pagination of its first (A) and second (B) editions. All quotations of Kant are taken from the Cambridge editions.

5 Barbara Herman (1993, p. 215) gives a similar explanation: “A condition of choice that could not be accepted by all rational agents would be: doing x where the possibility of x-ing depends on other rational agents similarly situated not doing x. This is the condition standardly found to be the ground of choice of the deceitful-promise maxim”.

6Right after stating FUL, Kant says: “Now, if from this one imperative all imperatives of duty can be derived as from their principle, then, even though we leave it unsettled whether what is called duty is not such an empty concept, we shall at least be able to indicate what we think by it and what the concept means” (GMS, AA 04: 421). For an argument that FUL cannot adequately provide a general classification of duties, see Timmons (2004).

7“ … moral philosophy … gives him [the human being], as a rational being, laws a priori; which of course still require a power of judgment sharpened by experience <durch Erfahrung geschärfte Urtheilskraft>, partly to distinguish in what cases they are applicable, partly to obtain for them access to the will of a human being and momentum for performance …” (GMS, AA 04: 389). See also MS, AA 06: 217.

8I am borrowing this notion from Street (2008).

9For such a realist reading of Kant, see Schönecker and Schmidt (2018).

Vinicius Carvalho – University of Campinas Department of Philosophy Campinas – S.P. Brazil [email protected]

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