Kantian ethics

Part of a series on
Immanuel Kant
Major works Critique of Pure Reason Prolegomena to​ Any Future Metaphysics "Answering the​ Question: What Is Enlightenment?" Groundwork of the Metaphysic of Morals Critique of Practical Reason Critique of Judgment Religion within the Bounds of Bare Reason Perpetual Peace The Metaphysics of Morals "On a Supposed Right to Tell Lies from​ Benevolent Motives" Opus Postumum
Kantianism • Kantian ethics Transcendental idealism Critical philosophy Sapere aude Thing-in-itself Schema A priori and a posteriori Analytic–synthetic distinction Noumenon Category Categorical imperative Hypothetical imperative "Kingdom of Ends" Political philosophy
People J. G. Fichte G. W. F. Hegel David Hume F. H. Jacobi Arthur Schopenhauer Baruch Spinoza
Related topics German idealism Neo-Kantianism
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Kantian ethics refers to a deontological ethical theory developed by German philosopher Immanuel Kant that is based on the notion that "I ought never to act except in such a way that I could also will that my maxim should become a universal law.” It is also associated with the idea that “[i]t is impossible to think of anything at all in the world, or indeed even beyond it, that could be considered good without limitation except a good will." The theory was developed in the context of Enlightenment rationalism. It states that an action can only be moral if it is motivated by a sense of duty, and its maxim may be rationally willed a universal, objective law.

Central to Kant's theory of the moral law is the categorical imperative. Kant formulated the categorical imperative in various ways. His principle of universalizability requires that, for an action to be permissible, it must be possible to apply it to all people without a contradiction occurring. Kant's formulation of humanity, the second formulation of the categorical imperative, states that as an end in itself, humans are required never to treat others merely as a means to an end, but always as ends in themselves. The formulation of autonomy concludes that rational agents are bound to the moral law by their own will, while Kant's concept of the Kingdom of Ends requires that people act as if the principles of their actions establish a law for a hypothetical kingdom.

The tremendous influence of Kant's moral thought is evident both in the breadth of appropriations and criticisms it has inspired and in the many real world contexts in which it has found application.