Some actions seem wrong even when they would produce good results: breaking a solemn promise, using someone as a pawn, punishing an innocent person. Deontology (from the Greek word for duty) is the family of theories holding that morality is about duties and constraints, not only outcomes. Its greatest figure is the German philosopher Immanuel Kant (1724 to 1804).
The good will
Kant's Groundwork of the Metaphysics of Morals (1785) begins by claiming that nothing is good without qualification except a good will. Intelligence, courage and even happiness can serve evil ends. What gives an action moral worth is not its results but its motive: doing the right thing because it is right, which Kant called acting from duty. A shopkeeper who gives correct change only because honesty is good for business acts in line with duty, but not from duty.
Hypothetical and categorical imperatives
A hypothetical imperative says what to do if you want something: if you want to pass the exam, study. A categorical imperative applies whatever you want. Moral rules, Kant argued, are categorical: “do not lie” does not depend on whether lying would get you what you want. He held that reason reveals one supreme principle, the categorical imperative, which he expressed in several formulations.
The formula of universal law
In T.K. Abbott's nineteenth-century English translation, the first formulation reads: “Act only on that maxim whereby thou canst at the same time will that it should become a universal law.” A maxim is the personal rule behind your action. The test: could you consistently will that everyone act on your rule?
Kant's example is a lying promise. Suppose I borrow money, promising to repay it while knowing I cannot. My maxim is “when I need money, I will promise falsely to repay it.” If everyone acted on this, promises would become meaningless and no one would accept them, so the maxim defeats itself. That shows the act is wrong.
The formula of humanity
The second formulation, in the same translation, is perhaps the most influential: “So act as to treat humanity, whether in thine own person or in that of any other, in every case as an end withal, never as means only.” Note the word “only.” We use people as means all the time, as when we pay a cashier. What is wrong is treating someone merely as a tool, ignoring their capacity to make their own choices, as deception and coercion do. Kant held that rational beings have dignity, a worth beyond any price, which cannot be traded off against benefits to others.
Autonomy
For Kant, the moral law is not imposed from outside, by God or society. Rational agents give it to themselves through their own reason. This idea of autonomy, or self-legislation, lies at the root of modern ideas of human dignity and respect for persons.
Strengths
Kantian ethics explains why individuals may not be sacrificed for the greater good, grounds human rights in the dignity of persons, and captures the sense that morality binds everyone equally, regardless of their desires.
Criticisms
- Rigidity. Kant held that lying is always wrong, even to a murderer asking where your friend is hiding. Most people find this conclusion very hard to accept.
- Conflicting duties. When two strict duties clash, such as keeping a promise and preventing harm, the theory gives little guidance on which wins.
- Slippery maxims. Depending on how a maxim is described, harmless acts can seem to fail the universal law test and harmful ones to pass it.
- Coldness. Acting from duty rather than love can seem to miss something. Visiting a sick friend “because it is my duty” sounds strange.
Worked example: informed consent
From 1932 to 1972, the US Public Health Service ran a study in Tuskegee, Alabama, observing hundreds of Black men with syphilis. The men were not told they had the disease, and they were not offered penicillin even after it became the standard cure in the 1940s. Researchers wanted to learn how the untreated disease progressed. Many men died, and wives and children were infected.
A utilitarian would condemn the study for the enormous suffering it caused. But Kant's formula of humanity identifies what was wrong even apart from the outcome: the men were used merely as means. They were deceived about their condition, so they could not make their own choices about their bodies and lives. Their rational agency was bypassed, not respected.
Modern research ethics is largely Kantian on this point. The rule of informed consent says people may be research subjects only if they understand the risks and freely agree. Consent makes the difference between legitimate and illegitimate use. A volunteer in a vaccine trial is also a means to scientific knowledge, but not merely a means, because they have chosen to take part for reasons they accept.
Apply the universal law test too. Could researchers consistently will a world in which scientists routinely deceive their subjects whenever it serves research? In such a world no one would trust medicine or volunteer for studies, and the practice would undermine itself.