In This Article Expand or collapse the "in this article" section Immanuel Kant: Ethics

  • Introduction
  • General Overviews
  • Reference Works
  • Anthologies
  • Bibliographies
  • Groundwork of the Metaphysics of Morals
  • Critique of Practical Reason
  • Lectures on Ethics
  • Freedom
  • Practical Reason
  • Moral Motivation
  • Virtue
  • The Highest Good
  • Radical Evil
  • Historical Perspectives
  • Constructivism

Philosophy Immanuel Kant: Ethics
Lara Denis
  • LAST REVIEWED: 10 November 2022
  • LAST MODIFIED: 30 September 2013
  • DOI: 10.1093/obo/9780195396577-0225


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.

General Overviews

Readers who wish to understand Kant’s ethics within the context of his philosophy as a whole will find Guyer 2006 an illuminating introduction. Several chapters are devoted to Kant’s moral and political philosophy, as well as to aspects of Kant’s philosophy of religion, history, and nature that bear on his ethics. The book is accessible enough for advanced undergraduates and other readers new to Kant. Other selections suitable for those new to Kant are Johnson 2012, Schneewind 1992, and Uleman 2010. Uleman 2010 is the most comprehensive and detailed, and written with advanced undergraduates in mind. Like Guyer 2006, Uleman 2010 can serve as a textbook. Johnson 2012 is available online and periodically updated. It provides an overview that focuses on the foundational doctrines of the Groundwork of the Metaphysics of Morals, though it is not limited to them. Schneewind 1992 is particularly informative with respect to Kant’s influences and intellectual context and development. The remaining four selections are highly influential books. Paton 1947 is especially worth reading on the categorical imperative and its formulations. O'Neill 1975 is especially important when it comes to topics of maxim formulation and the contradiction tests of the first formulation of the categorical imperative. Allison 1990 is particularly valuable for the discussion of freedom. Wood 1999 is the most wide ranging and the most interested in drawing on Kant’s work in practical anthropology.

  • Allison, Henry. Kant’s Theory of Freedom. Cambridge, UK: Cambridge University Press, 1990.

    DOI: 10.1017/CBO9781139172295

    Highly influential treatment of Kant’s moral theory, treating topics ranging from freedom, reason, and will, to virtue, character, and evil.

  • Guyer, Paul. Kant. New York: Routledge, 2006.

    Accessible enough for undergraduates, but sufficiently distinctive in its interpretations as to be of interest to more advanced readers. Brings Kant’s philosophies of nature, history, and religion to bear on his ethics; discusses Kant’s philosophy of right in addition to his theory of virtue. Overview of Kant’s entire philosophical system.

  • Johnson, Robert. “Kant’s Moral Philosophy.” In The Stanford Encyclopedia of Philosophy. Edited by Edward N. Zalta. 2012.

    A brief, clear, and accessible introduction to Kant’s ethics, focused on Kant’s foundational positions on the nature of moral philosophy, the categorical imperative and its formulations, the good will and moral motivation, and autonomy. Includes bibliography and links to other Internet resources, including but not limited to related Stanford Encyclopedia of Philosophy entries. Updated every few years.

  • O'Neill, Onora. Acting on Principle: An Essay in Kantian Ethics. New York: Columbia University Press, 1975.

    A highly influential work on Kant’s ethics. Much attention is focused on the formula of universal law, its contradiction tests, and related issues regarding ends, maxims, and intentions. Other topics include Kant’s taxonomy of duties, moral worth, supererogation, and conflicts of duty. Concise and systematic.

  • Paton, H. J. The Categorical Imperative: A Study in Kant’s Moral Philosophy. London: Hutchinson’s University Library, 1947.

    Focuses on such foundational topics as the critical method, the good will, duty, reverence for the law, the intelligible world, and freedom—and especially the categorical imperative. Its influence on English-language Kant scholarship would be difficult to overstate.

  • Schneewind, J. B. “Autonomy, Obligation, and Virtue: An Overview of Kant’s Moral Philosophy.” In The Cambridge Companion to Kant. Edited by Paul Guyer, 309–341. Cambridge, UK: Cambridge University Press, 1992.

    DOI: 10.1017/CCOL0521365872

    A philosophically and historically informative introduction. Sets Kant’s moral philosophy in the contexts of Kant’s broader philosophy and its development. Also situates Kant’s moral philosophy in relation to significant influences as Wolff, Crusius, Rousseau, and Hutcheson.

  • Uleman, Jennifer K. An Introduction to Kant’s Moral Philosophy. Cambridge, UK: Cambridge University Press, 2010.

    DOI: 10.1017/CBO9780511801082

    Geared toward advanced undergraduates, graduate students, and above. A sophisticated introduction to Kant’s moral theory. Main topics include practical reason; will, choice, and desire; freedom and its place in nature; the categorical imperative; and the goodness of a good will.

  • Wood, Allen W. Kant’s Ethical Thought. Cambridge, UK: Cambridge University Press, 1999.

    DOI: 10.1017/CBO9781139173254

    Five chapters concern the “metaphysical foundations” of Kant’s ethics; the focus here falls on the categorical imperative, its formulations, and their applications. The focus of the other four main chapters is the relation of morality to human nature. Topics here include practical anthropology, history, inclinations and passions, and radical evil.

back to top

Users without a subscription are not able to see the full content on this page. Please subscribe or login.

How to Subscribe

Oxford Bibliographies Online is available by subscription and perpetual access to institutions. For more information or to contact an Oxford Sales Representative click here.