This book traces the alleged incoherences to attempts to assimilate Kant's ethical writings to modern conceptions of rationality, actions and rights.A reconsideration of Kant's conceptions of philosophical method, reason, freedom, autonomy and action, progresses to an interpretation of the Categorical Imperative and a comparative analysis of Kant and Kantian ethics.A reconsideration of Kant's conceptions of philosophical method, reason, freedom, autonomy and action, progresses to an interpretation of the Categorical Imperative and a comparative analysis of Kant and Kantian ethics.Two centuries after they were published, Kant's ethical writings are as much admired and imitated as they have ever been, yet serious and long-standing accusations of internal incoherence remain unresolved. Onora O'Neill traces the alleged incoherences to attempts to assimilate Kant's ethical writings to modern conceptions of rationality, action and rights. When the temptation to assimilate is resisted, a strikingly different and more cohesive account of reason and morality emerges. Kant offers a constructivist vindication of reason and a moral vision in which obligations are prior to rights and in which justice and virtue are linked. O'Neill begins by reconsidering Kant's conceptions of philosophical method, reason, freedom, autonomy and action. She then moves on to the more familiar terrain of interpretation of the Categorical Imperative, while in the last section she emphasizes differences between Kant's ethics and recent Kantian ethics, including the work of John Rawls and other contemporary liberal political philosophers.Part I. Reason and Critique: 1. Reason and politics in the Kantian enterprise; 2. The public use of reason; 3. Reason and autonomy in Grundlegung III; 4. Action, anthropology and autonomy; Part II. Maxims and Obligations: 5. Consistency in action; 6. Between consenting adults; 7. Universal laws and ends in themselves; 8. Kant after virtue; Part III. Kant'sl³$