In moral philosophy, deontology is the view that morality either forbids or permits actions, which is done through moral norms. For example, a deontological moral theory might hold that lying is wrong, even if it produces good consequences. Historically, the most influential deontological theory of morality was developed by the German philosopher Immanuel Kant, who introduced the idea of the categorical imperative.
Contrasted with consequentialist moral theories
Deontological theories of morality are frequently contrasted to consequentialist theories such as utilitarianism. While deontological moral theories typically hold that certain actions are either forbidden or wrong per se, consequentialist theories usually maintain that the rightness or wrongness of an action depends on the consequences of the act and hence on the circumstances in which it is performed.
As described by John Rawls, the distinction is between the right and the good: under deontology, what actions are right and what things are good are at least partially independent, whereas under consequentialism, an act is right if and only if it maximises the good.
Another way of distinguishing consequentialism and deontology, as done by Shelly Kagan, is to note that, under deontology, individuals are bound by constraints (such as the requirement not to kill) but are also given options (such as the right not to give money to charity, if they do not wish to). Strict consequentialism recognises neither - instead, one must maximise the good by any and all means necessary.
Contrasted with aretaic moral theories
Aretaic theories often maintain that character as opposed to actions or their consequences should be the focal point of ethical theory. An example is virtue ethics, which tries to describe what characteristics a virtuous person has.
Examples of deontological theories
The most famous deontological theory is that advanced by the German philosopher Immanuel Kant. Kant's theory included the idea of a categorical imperative. One expression of the categorical imperative is: "Act so that the maxim [determining motive of the will] may be capable of becoming a universal law for all rational beings." One example of a contemporary deontological moral theory is the contractualism developed by the American philosopher Thomas Scanlon.
- Deontology, edited by Stephen Darwall (Oxford: Blackwell, 2002). ISBN 0631231129. This is a collection of essays on deontological moral theory.
- Entry on Duties and Deontological Ethics in the Internet Encyclopedia of Philosophy (http://www.iep.utm.edu/e/ethics.htm#Duty%20Theories)