Pelagius, a British monk (ca. 360–420 C.E.), defended the view that even after Adam and Eve's original sin mankind retained the ability not to sin. We are born, Pelagius said, “without virtue as without vice, and before the activity of our personal will there is nothing in man but what God has stored in him” (Bettensen 1954, 75). This view was attacked by Saint Augustine and condemned as heretical in the Synod of Carthage (418 C.E.). A related view, which came to be known as “Semi-Pelagian,” held that the beginning of saving faith lies in an unconditioned act of free will (see Pohle 1913).

Behind the Pelagian controversy lies a theological puzzle that may never be entirely solved. If divine grace is given independently of our will, as Saint Augustine and his followers down the centuries have held, it seems to lead to the doctrine that people are predestined by God to either salvation or damnation, before they have a chance to act or even to exercise their own will. On the other hand, if the Pelagians are correct, and salvation depends on, or at least begins with, a free act of the human will, it is unclear why the sacrificial death of Jesus Christ was necessary at all, since even without it people could in principle have pleased God by willing to do whatever was necessary for their salvation. Orthodox Catholicism has always been committed both to free will and to the priority and necessity of grace, but the two halves of orthodox doctrine have never been reconciled so convincingly as to keep Pelagianism from resurfacing.

In the heated religious battles of the seventeenth century, Pelagianism became one of the “stock accusations” theological controversialists hurled at each other and at philosophers, particularly when they dared to expound novel ideas (Davies 2001, 136). Protestants condemned the entire Roman Catholic Church of their day as Pelagian, while both the Catholic and Protestant communities were also internally divided on the issue. Within the Roman Catholic faith, Jansenists and Dominicans attributed Pelagianism to the Jesuits, while Dutch Calvinists detected it among the Arminians.

Descartes’ novel doctrine of the infinity of the human will, which he develops in the Fourth Meditation, was occasionally rumored to be Pelagian.