Determinism Free will and Predestination

Thomas Aquinas (1225–1274) attempted to harmonize Augustine's account of predestination and human freedom with Aristotle's understanding of human action. Following John Damascene, Aquinas describes the will as a rational appetite. Although humans cannot choose whether to desire the ultimate end, namely happiness, they can choose between different proximate goods. He distinguishes the liberty of exercise from the liberty of specification. The liberty of specification is that freedom that has its root in reason's ability to consider alternative courses of action. The liberty of exercise rests in the will's ability to act or not to act. Scholars disagree over how significantly Aquinas's account of free choice differs from Aristotle's account of intentional action.

Like Aristotle, Aquinas thought that deliberation must be about contingent events that are not knowable as future. Unlike Aristotle, Aquinas clearly held that God is omniscient and omnipotent. How does God know future contingents? Following the early Christian writer Boethius (c. 475–525), Aquinas held that God knows future contingents not as future but as they are present to him eternally. Even God could not know them as future. How does God's providence extend to contingent events such as free human acts? God causes necessary events to happen in a necessary way and contingent events to happen in a contingent way. God is the complete universal cause of a free act, even though the agent is its complete proximate cause. Following Augustine, in his later writings Aquinas clearly states that predestination is antecedent to any foreseen merits and that original sin has made it impossible to live a fully virtuous life without grace. There is no reason on the part of the individual why God chooses to save him and allow another to sin and be damned.

Stephen Tempier, bishop of Paris, and many theologians were concerned that the reception of Aristotle's works was leading to an intellectual determinism that compromised human freedom. In particular, Franciscan theologians regarded the will as the ultimate root of human free choice, although many Dominicans followed their brother Thomas's emphasis on the intellect. Although the Franciscan John Duns Scotus (c. 1266–1308) broadly agreed with Aquinas's account of predestination and God's eternal knowledge, he had a weaker understanding of original sin and emphasized the will over the intellect. Like Aquinas, Scotus thought that the will has an inclination to the good, but he distinguishes between the inclination toward the just and the inclination toward the advantageous. Freedom results from the ability to choose between the two.

The Franciscan William of Ockham (c. 1285–c. 1349) comes much closer to the modern understanding of "free will," according to which an agent has a liberty of indifference whereby he can make any choice whatsoever. Moreover, Ockham adopts an alternative understanding of predestination according to which at least some are predestined on account of their foreseen merits. He thinks that God has knowledge of future contingents from the perspective of the past, and that both God and the agent are immediate partial causes of a free action. Consequently, God cannot internally move the will of even the great saints but must either put them in suitable circumstances or withhold his causal action when they would sin. Ockham's views on predestination were influential throughout the later medieval period, and they led to a medieval Augustinian reaction. But the greatest reaction was to occur during the Protestant Reformation.