SIN (O. Eng. syn: a common Teutonic word, cf. Dutch zonde, Ger. Sünde), a general term for wickedness or a wicked act. As psychology recognizes a distinction of pleasure and pain, and metaphysics of good and evil, so morality assumes the difference between right and wrong in action, good and bad in character; but the distinction in psychology and metaphysics applies to what is, the difference in morality is based on a judgment of what is by what ought to be. When the act or the character does not correspond with the standard, this want of correspondence may in different relations be variously described. In relation to human society, and the rules it imposes on its members, action that ought not to be done is crime; a habit which is injurious to a man's own moral nature, especially if it involves evil physical consequences, is described as vice. If man is thought of as under the authority of God, any transgression of or want of conformity to the law of God is defined as sin. Crime is a legal, vice a moral, and sin a religious term. Sin may be distinguished from guilt as follows: guilt is the liability to penalty, that is, to the suffering conceived not as the natural consequence, but as the expression of the divine displeasure, which sin as a breach of divine law involves. Sin is a term applied not only to actions, but also to dispositions and motives. In the theological phrase original sin it means the inherited tendency to do wrong.

There have been two great controversies in the Christian Church on this question, the Augustinian-Pelagian and the Calvinistic-Arminian, one in the 5th century and the other in the 17th. Pelagius declared the capacity of every man to become virtuous by his own efforts, and summoned the members of the Church in Rome to enter on the way of perfection in monasticism. His friend Caelestius was in 412 charged with and excommunicated for heresy because he regarded Adam as well as all his descendants as naturally mortal, denied the racial consequences of Adam's fall, asserted the entire innocence of the new-born, recognized sinless men before the coming of Christ. Pelagius himself desired to avoid controversy, and with mental reservations denied these statements of his friend; but he did not escape suspicion, and his condemnation in 418 was the signal for a literary polemic, which lasted ten years, and in which Julian of Eklanum was the most brilliant but reckless combatant on the side of Pelagius. In the East the freedom of the will was so insisted on, that one may regard Greek theology as essentially Pelagian. In the West there was unanimity only on three points: the necessity of baptism for the remission of sins, the inheritance of sin as a result of Adam's fall, and the indispensableness of the divine grace in the attainment of goodness. Pelagius insisted that sin was an act, not a state, an abuse of the freedom of the will, and that each man was responsible and liable to punishment only for his own acts. This extreme individualism he qualified only in two respects, he admitted a principle of imitation, the influence of bad example, habit and customs, may be inherited and communicated. Divine grace is not necessary for human virtue. It is granted only according to act, and merits as the law in enlightening, warning or promising reward. To this Augustine opposed the view that Adam's sin is, as its penalty, transmitted to all his descendants, both as guilt and as weakness. The transmission is not by imitation, but by propagation. The essence and mode of operation of original sin is concupiscence, which, as of the devil, subjects man in his natural state to the devil's dominion. Even infants are involved in Adam's condemnation. Sin is a necessity in each individual, and there is a total corruption of man's nature, physically as well as morally. Into the details of the controversy it is not necessary to go any further. While the authority of Augustine received lip-homage, the doctrine of the Roman Catholic Church became more Pelagian, and in the Tridentine decrees and still more in the ethics of the Jesuits, in spite of the opposition of Jansenism, Pelagianism at last triumphed.

The Reformation restored the teaching of Augustine; in Calvinism especially the sovereignty of the divine and the impotence of the human will were emphasized; and against this exaggeration Arminianism was a protest. Of the five articles of the Remonstrance of 1610 only two now concern us: the possibility of resisting the grace which is indispensable to salvation, and the possibility of falling away from grace even after conversion. The Arminian system was an attempt to modify the Calvinistic theory in a moral interest, so as to maintain human responsibility, good and ill desert; but to this moral interest the system sacrificed the religious interest in the sufficiency and the sovereignty of divine grace. Its adherents necessarily laid emphasis on human freedom. As regards original sin they taught that the inclinations to evil inherited from Adam are not themselves blameworthy, and only consent to them involves real guilt. It is not just, however, to Arminianism to identify it with Pelagianism, as it does strive to make clear man's need of divine grace to overcome sin and reach holiness. In the Evangelical Revival of the 18th century Arminianism was represented by Wesley, and Calvinism by Whitefield.