A deductive argument is an argument whose conclusion follows necessarily from its premises. This contrasts to various kinds of inductive arguments, which offer only a degree of probability to support their conclusion.

Any position in ethics which claims that the rightness or wrongness of actions depends on whether they correspond to our duty or not. The word derives from the Greek word for duty, deon. In deontological ethics the rightness or wrongness of an act is intrinsic to the act (intinsic means inside, such as the intention which I have when doing it), whereas with teleological ethics, it is extrinsic (outside) the act, lying in the consequences of the action. Kantian ethics is an example of a deontological ethical theory.

Any position in ethics which claims that the rightness or wrongness of actions depends on whether they correspond to God's commands or not.