Deontological (or "duty-based") Ethics
1. The chief characteristic of deontological theories is: (moral) right (one's duty, how one should act) is defined independently of (moral) good. Deontological theories necessarily generate "categorical imperatives" (that is, duties independent of any theory of good). Here, the emphasis on acts rather than (as in utilitarianism) on outcomes.
2. Chief problem for deontological theory: defining right without appeal to good. Examples of how this problem might be solved:
a. Right is what God commands. (Divine Command Theory)
b. Right is what one's society commands. (Moral Relativism)
3. Deontological theories are not necessarily:
a. rule-based (God might, for example, issue commands case by case);
b. universalist (one society may command what another society forbids); or
c. absolutist (God or society might, for example, lay down general rules allowing exceptions).
4. What's distinctive about Kant's deontology? Kant claims to derive morality from reason--without appeal to any theory of the good. Morality limits what can properly be done rather than commanding conduct. Morality is a "side constraint" on conduct. (Compare utilitarianism's "demandingness".)
5. Kant's method offers at least three ways to test an act to see whether it is morally permissible (all—supposedly—equivalent):
a. Universalizability: act only on those maxims one can will to be universal laws.
b. Human dignity: act only on those maxims consistent with treating each person as an end, not merely as a means.
c. Moral legislation: act only on those maxims that all rational persons could adopt as universal rules governing all.
6. Recent deontologists? Marcus Singer, Generalization in Ethics (1961), Alan Gewirth, Reason and Morality (1978). [out of favor in 1980s and 1990s]
1) Identify your act (what you are actually proposing to do), for example, tell someone something you believe to be false.
2) Identify the end you have in view (your motive, what is actually moving you to do the act in question), for example, getting something without paying for it.
3) Consider whether (assuming the world otherwise remains as you believe it to be) you could still achieve that end in the way you propose:
a) if everyone were permitted to act the same whenever they had the same end in view (universalizability test);
b) if everyone knew you were permitted to act as you propose (disclosure or pre-publicity test, derived from acknowledging the dignity of others, that is, their status as agents with ends of their own); or
c) if your doing so required every rational person to approve a general rule permitting actions of that kind (moral legislation test).
4) Reject the act if you find it would fail any of the three tests above. (You may do any act passing all three tests.)
Rachels, James. Elements of Moral Philosophy. 4th ed. Boston: McGraw-Hill, 2003. pp. 122-143 (Kant)
This book is an extremely good introduction to major moral concepts and theories. In this section, the author gives a very succinct and clear description of the theory of Kant’s Categorical Imperative, some of the arguments against this theory, and ways of addressing these arguments.
Optional Further Reading :
Kant, Immanuel. Groundwork of the Metaphysics of Morals (1785). (Also entitled, Fundamental Principles of the Metaphysics of Morals, depending on translation)
An online version of this work is available at Project Gutenberg.