Deontology

Also known as: Kantian Ethics

framework · philosophy · philosophical-tradition

Ethics grounded in duty and universalizable maxims, independent of consequences.

Deontology (from Greek deon, 'duty') is the family of normative ethical theories holding that the moral status of an action is determined by features intrinsic to the action itself — particularly its conformity to duty, principle, or right — rather than by its consequences. The dominant articulation is Immanuel Kant's, presented in the Groundwork of the Metaphysics of Morals (1785) and Critique of Practical Reason (1788), grounded in the Categorical Imperative with three principal formulations: act only on maxims you could will to be universal laws (Universal Law); treat humanity, in yourself and others, always as an end and never merely as a means (Humanity); and act as if legislating universal laws for a kingdom of ends (Autonomy). Kant's framework grounds duties in pure practical reason, holding that moral worth attaches to acts done from duty rather than from inclination, even when consequences are favorable. Contemporary deontological positions include W.D. Ross's pluralistic prima facie duties, threshold deontology, and Kantian constructivism (Korsgaard, O'Neill). Deontology stands in contrast to consequentialism on the question of whether intrinsic act-features or outcomes are morally fundamental.

Originators

Immanuel Kant (foundational); W.D. Ross (pluralistic deontology); contemporary figures including Christine Korsgaard, Onora O'Neill, Frances Kamm high

Year / Decade

1785 (Kant's Groundwork); ongoing tradition through W.D. Ross (1930) and contemporary Kantianism high

Primary sources

Kant, I. (1785). Groundwork of the Metaphysics of Morals, Kant, I. (1788). Critique of Practical Reason, Ross, W.D. (1930). The Right and the Good high

Core components

Duty as moral foundation
Categorical Imperative (Kant) with three formulations: Universal Law, Humanity (as end not merely means), Autonomy/Kingdom of Ends
Distinction between perfect and imperfect duties
Moral worth from acting from duty rather than inclination
W.D. Ross's prima facie duties (fidelity, reparation, gratitude, justice, beneficence, self-improvement, non-maleficence)
Threshold deontology (rules can be overridden at sufficient stakes)
Distinction from consequentialism

Primary use case

Normative ethical theory in academic philosophy; foundation for human-rights discourse and international law; bioethics (informed consent, truth-telling); business ethics; professional ethics; basis for arguments against utilitarian calculations that treat persons as fungible aggregators of welfare.

Common criticisms

Rule-conflict problems: when duties conflict (truth-telling vs preventing harm), strict deontology offers limited guidance
counterintuitive consequences in specific cases (the famous Murderer at the Door problem — strict Kant says don't lie, even to a murderer asking where his intended victim is hiding)
abstraction from consequences seems to permit catastrophic outcomes when 'principles' are followed regardless
the Universal Law formulation has been critiqued as too permissive (almost any maxim can be universalized with enough specification) or too restrictive
cross-cultural variation in what counts as duty raises relativism concerns
tension between Kant's universalism and his historically embedded views on race and gender, which contemporary Kantianism has had to confront.

Lineage

Siblings: Consequentialism, Virtue Ethics, Contractualism