a term usually employed to designate the aggregate of the moral principles of an individual or a community as evinced in its conduct in comparison with the acknowledged rules of morality. The various general relations of this subject are so fully discussed in the articles ETHICS (See Ethics) , Moral Law (See Moral Law) , etc., that we here bring together only some special distinctions under the head of Duty, the fulfilment of which is the ultimate criterion of public and private morals.
Baumgarten defines duties to be actions which one is bound to perform, and Christian August Crusius coincides with this opinion when he defines duty as the application of the principles of morality to individual cases, and with Opitz, who calls it the inward knowledge of what one must do or abstain from doing in order to lead a religious life. Reinhard defines duty as the moral necessity of doing or not doing a certain thing, resulting from our perception of right (System d. christl. Moral, part 2, 196). This is the view taken by many others, even by Roman Catholic moralists (see Riegler, Christl. Moral, part 1, 124 sq.). This, however, considers only the outward part of duty, as manifested in action; its scope was afterwards enlarged by connecting it with the conscience ( (See Moral Sense) ), which Crusius understands to be the inborn impulse by which we recognise the obligation of subjecting all our thoughts and actions to the will of God. Paley stands almost alone in making virtue consist in Utility, and those who resolve it into "the fitness of things" do but indirectly refer it to the will of God, who has ordained the constitution of the universe. All our duties to God are comprised in the expression, Honor God (Walch), or Love God. For to fear God and keep his commandments is the whole duty of man ( Ecclesiastes 12:13). It was already presented as such in the O.T., but in the N.T. this is put in the first place, as the one important principle: unlimited love towards God, and to one's neighbor as the image of God, as well as of one's self ( Matthew 22:37-40; Romans 13:8-10; Deuteronomy 6:4-9; Leviticus 19:14; Leviticus 19:17-18, etc.).
As the Kantian philosophy, abandoning the cognition of a thing Per Se, placed the power of truth entirely in the consciousness of obligation (categorical imperative), duty, as that commanded by it. acquired in that system an extraordinary significance. Will nothing, and do nothing which it cannot be lawful for entire mankind to do; or, As ye would that men should do to: you, do ye also to them likewise ( Matthew 7:12; Luke 6:31). The total submission to the categoric imperative arising from pure regard for the law is the highest morality; while that arising from love, a sort of subjective satisfaction in it, is less pure, since the motive is akin to egotism. Thus morality resolved itself into the doctrine of law and duty, while previously it was considered as almost exclusively a question of good. Indeed, Paley made morality itself consist in seeking the high-est good, a theory not far removed from the purer form, of ancient Epicureanism. The modern philosophy, however, has justly repudiated this utilitarian text, and thrown the subject back for solution upon the deeper convictions of mankind as expressed in the instinctive discriminations of conscience. (See Moral Philosophy).