Immanuel Kant: Ethics

The ethical theory of Immanuel Kant (b. 1724–d. 1804) exerted a powerful influence on the subsequent history of philosophy and continues to be a dominant approach to ethics, rivaling consequentialism and virtue ethics. Kant’s ethical thought continues to be studied in itself, as a part of his critical system of philosophy, in its historical context, and in relation to particular practical questions. Kant’s writings and lectures display the influence of the Stoics, Rousseau, Crusius, Wolff, Hutcheson, Hume, and others; Fichte, Hegel, Nietzsche, Bradley, Greene, Habermas, and Rawls are among the many philosophers whose moral philosophies can be read (in part) as responses to Kant. Salient foundational features of Kant’s ethics include: its a priori method, its conception of the will as autonomous, its categorical imperative, its theory of freedom, and its account of moral motivation. Kant maintained that foundational moral principles must be a priori, not based on observation or experience. Kant takes the moral law to be legislated by the will to itself. Unlike holy beings, human beings experience morality as a constraint upon our wills. For us, the moral law is a categorical imperative. All ethical duties are ultimately grounded in this supreme moral principle. If we are bound to obey the moral law, we must be capable of doing so; Kant holds that, even assuming causal determinism in the phenomenal world, morality reveals our (noumenal) freedom to us. Kant attributes moral worth only to action done from duty (i.e., from respect for the law), not from inclination. Significant aspects of Kant’s fully developed ethical theory include its rich theory of virtue and the virtues, its taxonomy of duties (which include duties to oneself as well as to others), its distinctive conceptions of the highest good and human evil, and its connections with Kant’s philosophies of history, religion, and human nature. Many of Kant’s own discussions of particular duties, virtues, and vices are controversial. For example, Kant appears to condemn all lies as violations of a duty to oneself. This entry focuses on Kant’s ethics rather than Kantian ethics more broadly. Despite that, it includes a number of pieces that apply, extend, or revise Kant’s ethics in some ways, as well as interpretations of Kant’s ethics that some commentators may object stray too far from Kant’s own stated views. Kant’s political philosophy is discussed only peripherally here, save for the section on the Doctrine of Right of the Metaphysics of Morals.