Total depravity (also called radical corruption or pervasive depravity) is a Protestant theological doctrine derived from the concept of original sin. It teaches that, as a consequence of man's fall, every person born into the world is enslaved to the service of sin as a result of their fallen nature and, apart from the efficacious (irresistible) or prevenient (enabling) grace of God, is completely unable to choose by themselves to follow God, refrain from evil, or accept the gift of salvation as it is offered.
The doctrine is advocated to various degrees by many Protestant denominations, including some Lutheran synods, and all Calvinist churches. Arminian denominations, such as Methodists, believe and teach total depravity, but with distinct differences, the most important of which is the distinction between irresistible grace and prevenient grace.
In opposition to Pelagius, who believed that after The Fall people are able to choose not to sin, and contrary to all prior early church fathers, Augustine of Hippo argued that, since the Fall, all humanity is in a self-imposed bondage to sin. All people are inescapably predisposed to evil prior to making any actual choice, and are unable to refrain from sin. Free will is not taken away in the sense of the ability to choose between alternatives, but people are unable to make these choices in service to God rather than self. Thomas Aquinas also taught that people are not able to avoid sin after the Fall, and that this entailed a loss of original righteousness or sinlessness, as well as concupiscence or selfish desire. Duns Scotus, however, modified this interpretation, and only believed that sin entailed a lack of original righteousness. During the Protestant Reformation, the Reformers took Scotus's position to be the Catholic position and argued that it made sin only a defect or privation of righteousness rather than an inclination toward evil. Martin Luther, John Calvin and other Reformers used the term "total depravity" to articulate what they claimed to be the Augustinian view that sin corrupts the entire human nature.