Kant’s critique of perfectionism in the Groundwork of the Metaphysics of Morals launches lively debate on the limits of coercion and the requisites for free action, foundational for post-Kantian perfectionism. The Critique of Practical Reason reformulates the Leibnizian concept of spontaneity as a ‘true apology for Leibniz’, salvaging what is most vital in his thought. Spontaneous freedom does not externalise a unique content, as in Leibniz, but now conceived as negative liberty, signifies the will’s ability to abstract from external causes or to admit them selectively according to rational criteria. Spontaneity is the condition for an order of right, as the sphere of compatible external actions among juridical subjects. Here Kant effects a second modification of Leibniz, in the idea of mutual causality or reciprocity. The Metaphysics of Morals of 1797 elaborates the distinction between pure and empirical practical reason, freedom and happiness, and delineates the sphere of rightful interaction. Neither happiness nor virtue are subject to constraint, but in the sphere of right coercion or mutual limitation is the condition that assures and generalises freedom.

Leibniz is the genuine initiator of German Idealism, developing ideas of freedom as spontaneity or self-originating action, and linking freedom with justice and progress in ways that are decisive for Kant and later idealists. Rethinking spontaneity as negative freedom, Kant criticises the paternalistic perfectionism and Enlightened absolutism of Christian Wolff, a distinct development from Leibniz, but opens the way for a new perfectionism of freedom. The origins of perfectionism in Aristotle and the Stoics are surveyed, and the various formulations of post-Kantian perfectionism from Humboldt to Marx are outlined.

Kant repeatedly describes the moral theory and practice of the Stoics as “sublime,” indeed as eliciting “the most sublime sentiments that have ever existed.” This is often understood as an expression of approval, since what is sublime is said to arouse our admiration. I argue, however, that the description is not a generic expression of approval, but a specific description of Stoic moral theories and their peculiar appeal. For however much we admire the thoughts and actions Kant calls “sublime,” our attraction to them is always accompanied with repulsion. To be sure, attraction and repulsion both belong to Kant’s representation of moral duty, which elevates us as it humiliates our self-conceit. Its very name he calls “sublime.” Yet in the end, moral goodness is not so much sublime as beautiful. In coming to appreciate this, we may deepen our appreciation of Kant’s interpretation of the Stoics, and his distance from them.

The Feyerabend lectures (1784) anticipate many fundamental theses of Kant’s political thought in the published writings of the 1790s. In three fundamental topics – 1) the transition from the state of nature to the civil state, 2) the conception of sovereignty and of the division of powers, 3) the infallibility of the sovereign, with the related topics of the non-coercibility of the executive and the denial of the right to rebel – Kant has the basic structure of his political thought already clear and his intellectual debt to Achenwall is limited. These lecture notes also include a fundamental distinction between two senses of legislative power: understood as constituent and operative in the defining moment of the constitution of the state (what Achenwall would call the moment yielding fundamental laws) and understood as the specification of the fundamental laws agreed upon in their hypothetical origin. This distinction is never fully spelled out by Kant but is absolutely crucial to making sense of his body of political thought and addressing some apparent difficulties, including a proper understanding of his (in)famous denial of people’s right to rebel.

“Everyone has a price at which he sells himself”: Immanuel Kant quotes this remark in the 1793 Religion within the Bounds of Reason Alone, attributing it to “a member of English Parliament.” This chapter argues, however, that the context of the quotation in the Religion alludes to the arresting pedagogical practices of the Stoic philosopher Epictetus, who famously said that “different people sell themselves at different prices.” The chapter argues that there are two sides of Epictetus’ pedagogical strategies: a jolting side meant to expose self-deception and practical inconsistency; and an uplifting side meant to arouse the resources by which it is possible to progress towards virtue – specifically, our sense of kinship with the divine insofar as we are rational. This chapter argues that Kant develops a conception of self-respect in later practical works that plausibly draws on Epictetus, and his distinctive version of the traditional Stoic account of rational agency.

The introduction addresses questions about Kant’s access to Stoic philosophy and other matters about Stoicism in his immediate intellectual context. After this biographical and historical contextualisation, the individual chapters are introduced.

The question explored in this chapter is this: Is there a foothold, or even a toehold, in Stoic and Kantian texts that gives us purchase for developing an account of moral anger? I answer “yes,” although the positive argument in both Stoic and Kantian texts is not obvious. In the Stoic tradition, the overall normative demand is modeled on the character and conduct of a good and wise person, that is, the sage. Can the Stoic sage feel moral anger as part of how full virtue is expressed? The Stoic sage is typically modeled on concrete historical examples that display a fuller gamut of emotions than is often acknowledged. Moral anger and vicarious distress are, I argue, Stoic “good emotions” compatible with the rational desires and emotions characteristic of full virtue. Despite Kant’s Stoicizing tendencies at various junctures, he leaves room for moral anger as a way we express our duties of sympathy and become aware of the constraints of the moral law.

At least since Pauline Kleingeld’s defining work, scholars recognize that Kant’s aims in his philosophy of history are practical as well as theoretical: not just to describe history, but also to provide a view of it that supports moral action. Often scholars understand this support to be similar to that provided by the postulates of practical reason: the progressive view of history Kant articulates is taken to be a belief necessarily presupposed in moral agency, supporting the more general belief that the agent’s moral ends are realizable. Prompted by Kant’s description of his view as “consoling,” this chapter considers whether his view in Idea for a Universal History with a Cosmopolitan Aim may instead be interpreted as a form of Stoic consolation on the model of Seneca’s consolatory writings, with a different practical import: to relieve the moral agent from grief concerning large-scale historical events, thereby freeing her to act effectively within her own sphere.

Kant and the Stoics both rely on a momentous argument, set out in Plato’s dialogues, for the conclusion that nothing is unconditionally good but wisdom, yet they differ on how to interpret it. The Stoics identify this wisdom with the perfection of technical or productive knowledge of nature, and they regard it as the sole good. Kant identifies this wisdom with the perfection of practical knowledge of the good, and, analyzing this knowledge along the hylomorphic lines implicitly suggested in Plato’s argument, he locates wisdom’s unconditional goodness – its morality, or moral goodness – in its agreement not with the object it produces but with its form, morality’s principle. Two contrasting accounts of morality’s relation to perfection thus emerge. The Stoics see perfection in the knowledge of nature as entailing moral goodness, whereas Kant argues that moral goodness is the condition of all other goodness, including that of perfection.

Heidegger’s subordination of reason to “care” in Being and Time has exposed him to the charge of irrationalism. Against this view, I argue that Being and Time offers a “normativity-first” account in which reason, as reason-giving (logon didonai), is an ineluctable demand constitutive of authentic selfhood. Examining Heidegger’s rejection of the neo-Kantian equation of reason with logic in his 1929 Kantbuch, I explain the threads that connect what Heidegger calls “pure sensible reason” to his extensive phenomenological account, in Being and Time, of the “everyday” and “authentic” modes of Dasein’s care-structure. As authenticity’s discursive mode, the “call of conscience” is Dasein’s portal into normative space. As the essay “On the Essence of Ground” makes plain, Dasein’s response to the call involves answerability for what it holds to be best in its practical life, hence reason-giving. Such an origin of reason contrasts with rationalism only in eschewing any principle of sufficient reason.