Deontological Ethics [Ethics Theory]


Deontological ethics (from the Greek deon, meaning duty) is a duty-basic ethical theory that instead of concerning itself with the consequences of actions holds that some actions are either right or wrong because of what they are.

Deontologists therefore hold to moral rules that are binding and absolute. For example, it is always wrong to murder, to physically abuse children, to take advantage of the weak, and to lie. There are no exceptions to these. It is one’s duty to prevent themselves from engaging in immoral actions and to strive to do what is right.

Deontological ethics is opposed to consequentialism which proposes that the right thing to do would be that which produces the best consequences overall. According to the deontologist, however, it is morally wrong to murder a child because such an act would end the life of the child. It is morally wrong for no reason other than this alone, which means that it is not immoral because murdering a child would give a family much sorrow or take away future talent that could benefit the world. Similarly, to make up a lie about a person is morally wrong because it is purposely deceptive. It is not wrong because it harms that other person’s reputation. These examples illustrate that deontologists do not emphasize the consequences of an action, but rather the absolute rule or standard that must not be breached.

A major proponent of this perspective was Immanuel Kant (1724-1804). Kant proposed the categorical imperative, which is a set of requirements that a motivation has to pass through in order for an action to be considered a moral obligation. It was Kant’s attempt to formulate a general and universally applicable principle by which pure practical reason could distinguish right from wrong. The categorical imperative is “imperative” because it is a command that is addressed to agents (human beings) and it is “categorical” because it applies unconditionally and universally without reference to any ends (consequences) or ulterior motives that human beings might or might not have. One way Kant stated this is to “Act only according to that maxim by which you can at the same time will that it should become a universal law” (1). One’s action must thus be good in and of itself without qualification. Kant also contended that since humans are rational beings we can acknowledge that moral laws exist and that we ought to obey them. Such laws would be broad, apply to all humans, and even to other rational beings: “The supreme principle of morality would have an extremely wide scope: one that extended not only to all rational human beings but to any other rational beings who might exist – for example, God, angels, and intelligent extraterrestrials” (2).

A challenge is that because deontological ethics is absolute it leaves little room for further contemplation concerning exceptions to the rule. A deontologist might argue that killing a person is always, absolutely wrong and that this ought to be a universal law that should never be broken. However, other ethicists would counter that under certain circumstances it is permissible and necessary to kill another person, perhaps if it was in defense of one’s own life, family, or country. This is a difficulty for deontology because it maintains, as Professor Aaron Levine writes, “that the relevant rules may not be violated under any circumstances” (3). There are no exceptions. But as some have argued, given that deontological ethics does not take the consequences of actions into account, it may negatively impact happiness in the world. Continuing with the example above, if to kill a person is always, absolutely wrong and one therefore avoids ever killing another person, it might actually cause pain to millions of people in the world because of what that person will do in the future. Deontological ethics may in such a case severely reduce world happiness, which makes it “hard to believe”, as one philosopher wrote, “that it could ever be a duty deliberately to produce less good when we could produce more” (4).


1. Kant, Immanuel. 1998. Foundations of the Metaphysics of Morals. Edited by Mary Gregor. Cambridge: Cambridge University Press. p. 31.

2. Kerstein, Samuel. 2002. Kant’s Search for the Supreme Principle of Morality. Cambridge: Cambridge University Press. p. 2.

3. Levine, Aaron. 2012. Economic Morality and Jewish Law. USA: Oxford University Press. p. 25.

4. Ewing, Alfred. 1947. The Definition of Good. p. 188.



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