Deontological ethics

Deontology is often defined by contrasting it with one of its chief competitors, consequentialism. In its simplest form, consequentialism claims that we only have one moral duty: to do as much good as possible. Deontology (the word comes from the Greek deon meaning ‘one must’) denies this, and asserts that there are several distinct duties, not all of which depend for their status as duties on considerations of value alone.

Deontological duties are divided into two classes: constraints and duties of special relationship. The former govern the way we treat others regardless of our relationships to them. Some ways of treating people, such as torturing them, are ruled out, even to prevent others doing worse deeds. The latter govern our actions toward those to whom we stand in special relations such as friendship. You are required to do certain things for your friends, even if you could make the world better by abandoning them.

In addition to constraints and duties of relationship, some deontologists claim that there is a requirement to do good whenever there is no other duty more pressing. Others are less demanding, requiring only that we do some good in addition to fulfilling our other obligations. The least demanding deontology would incorporate no moral requirement to do good, and claim that provided we breach no duty we are permitted to live as we see fit.

Some deontologists attempt to justify the various duties they propose by appeal to some more fundamental and unifying principle(s). Other deontologists deny that such unifying justification is available. Deontologists, then, may agree about surface features, such as the extent of our duties, while disagreeing about the possibility of an underlying rationale.