Some ethical theories are teleological - what is right or wrong depends on the end or outcome of an action - for utlitarians, pleasure, happiness or 'the greatest good'; for Aristotle, 'Eudaimonia'. Other theories are deontological - doing what is right means doing your duty or following the rules - for Kant, the categorical imperative; in Natural Law, the secondary precepts. It is easy to think of teleological theories as relativist and deontological theories as absolutist, but it it not that simple. Apart from Kantian Ethics (thoroughly absolutist and deontological) and Situation Ethics (clearly relativist and teleological), ethics seems to involve an uneasy mix.
Absolutist ethical theories
Kant and the Categorical Imperative
Kant says that we should act according to maxims that we would want to see as universal laws. These laws are absolutist - we can work them out logically prior to experience; they are not verified through experience (they are known 'a priori').
The consequences of our actions are irrelevant to whether they are right or wrong - evil actions may have unintended good consequences, and someone might act heroically without any guarantee that the consequences will be good. No character quality is absolutely good (good without exception) - for example, it is possible to act kindly but do the wrong thing. The only good thing is a good will that does what is logically the right thing to do.
Natural Law is often described as deontological because, in practice, it leads to a set of rules that people have a duty to follow. These rules are absolutist, because they know of no exception. For example, using contraception to prevent conception is absolutely wrong, regardless of consequences such as the spread of AIDS, unwanted pregnancies etc.
However, Aquinas' Natural Law Theory says we should try to fulfil our God-given purpose. This is teleological, as it is interested in our design or 'end…