Kantian deontology is Immanuel Kant’s normative ethical theory that judges actions by rational duty, not consequences. An action is morally right when its maxim, or underlying rule, satisfies the categorical imperative.
The Reasoning / Mechanism
Kant argues that the only thing good without qualification is a good will: commitment to do what is right because it is right. Actions have moral worth when performed from duty, not merely from self-interest, emotion, or expected outcomes.
The categorical imperative is an unconditional command for every rational agent. A hypothetical imperative applies only if someone has a goal, such as “If you want high marks, revise.” Kant gives complementary formulations:
| Formulation | Moral test |
|---|---|
| Formula of Universal Law | Universalize the maxim. If its universal adoption is rationally contradictory or cannot be willed, reject it. |
| Formula of Humanity | Treat humanity, in yourself and others, always as an end and never merely as a means. |
| Formula of Autonomy | Act as a rational law-maker among equally rational agents. |
Consider the maxim “I may make a false promise whenever it benefits me.” Universalizing it would destroy trust in promises, making promising impossible. This contradiction in conception means false promises violate a perfect duty.
Imperfect duties, such as developing talents or helping others, allow flexibility in how and when they are fulfilled. Perfect duties strictly prohibit actions such as deception.
A common misconception is that Kant simply imposes rigid rules. More precisely, rational agents freely test their maxims through universality, autonomy, and respect for persons.
IB Exam Technique
In an IB Philosophy response, define deontology, explain the categorical imperative, and apply one formulation to a clear example. For evaluation, discuss whether excluding consequences creates inflexibility, balanced against Kant’s protection of human dignity and moral consistency.
