Traditionally, the main interest in ethics has been theories of right action — that is, theories about what makes an action right. The two major types of theories are consequentialist (or teleological) and formalist (or deontological).

Consequentialist moral theories claim that the rightness of an action depends on its consequences. Utilitarianism is a consequentialist theory because right actions are supposed to result in more happiness than other possible actions.

Formalist moral theories claim that the rightness of an action depends on the action’s form. Here the consequences of an action don’t matter (or matter very little), but the form, or nature, of the action, does. Such a theory might claim, for example, that killing an innocent person is always wrong because of the nature of that action, and this would be so whether or not the killing resulted in a great deal of good such as saving the lives of a hundred people. By this definition, the Ten Commandments moral code is a formalist theory.

All humanist theories are nonreligious, and they can be either consequentialist or formalist. Not all nonreligious theories, however, can be plausibly considered humanist. Humanism as a worldview has traditionally incorporated a respect or concern for the welfare and the rights of human individuals. So utilitarianism earns the label of humanism because the crux of the theory is maximizing the happiness or pleasure of other human beings.

But the secular theory known as ethical egoism can’t plausibly be called humanist. It’s the view that right actions are those that promote one’s own self-interest — a kind of moral self-absorption that is alien to humanist views of humanity. Ethical egoism also permits all manner of heinous acts as long as they are in the best interests of one’s self, acts that humanism would not condone.

Religious theories of morality depend in some way on ideas about theistic or supernatural states of affairs. Secular moral theories leave out such ideas. As already mentioned, the differences between the two types of theories can be stark. But in some cases, a reference to the theistic or supernatural is the only substantial contrast between some religious and secular theories.

An influential religious theory of morality is the divine command theory (DCT), the view that an action is right if God commands or wills it. One version of this theory says that God’s commands are spelled out in rules stated clearly in scripture or made plain in nature. This is the divine command theory as a kind of legalism. A prime example is the Ten Commandments theory.

Another version of the DCT says that God’s commands are expressed not in a set of unbendable rules, but in the dynamics of each moral situation. Christian ethics, though it can take many forms, is usually construed as a type of DCT in which the commandments are those of Christ’s teachings, especially of the injunction to “love thy neighbor.”

Secular theories of morality have a much longer history than Christian ethics, dating back to the early Greek philosophers, Confucius, and other ancients. These include consequentialist theories such as utilitarianism and ethical egoism, as well as formalist theories such as Immanuel Kant’s duty-based ethical system and W.D. Ross’ hierarchy of moral duties. (These views and others will be examined in the next two modules of this course.)