Divine command theory (also known as theological voluntarism) is a meta-ethical theory which proposes that an action’s status as morally good is equivalent to whether it is commanded by God. The theory asserts that what is moral is determined by what God commands, and that for a person to be moral is to follow his commands. Followers of both monotheistic and polytheistic religions in ancient and modern times have often accepted the importance of God’s commands in establishing morality. Numerous variants of the theory have been presented: historically, figures including Saint Augustine, Duns Scotus, and Thomas Aquinas have presented various versions of divine command theory; more recently, Robert Merrihew Adams has proposed a “modified divine command theory” based on the omnibenevolence of God in which morality is linked to human conceptions of right and wrong. Paul Copan has argued in favour of the theory from a Christian viewpoint, and Linda Zagzebski’s divine motivation theory proposes that God’s motivations, rather than commands, are the source of morality.
Semantic challenges to divine command theory have been proposed; the philosopher William Wainwright argued that to be commanded by God and to be morally obligatory do not have an identical meaning, which he believed would make defining obligation difficult. He also contended that, as knowledge of God is required for morality by divine command theory, atheists and agnostics could not be moral; he saw this as a weakness of the theory. Others have challenged the theory on modal grounds by arguing that, even if God’s command and morality correlate in this world, they may not do so in other possible worlds. In addition, the Euthyphro dilemma, first proposed by Plato, presented a dilemma which threatened either to leave morality subject to the whims of God, or challenge his omnipotence. Divine command theory has also been criticised for its apparent incompatibility with the omnibenevolence of God, moral autonomy and religious pluralism, although some scholars have attempted to defend the theory from these challenges.