Thomas Aquinas on Human Free Will

Exactly how it is that man operates with free moral agency within the sovereignty of God has been a subject at the forefront of theological dialogue for centuries. Before Thomas Aquinas addressed the conundrum, the teachings of Arianism, Pelagianism, and Manichaeism had their influence. A prevailing doctrine was the Augustinian understanding that Aquinas, at times, refuted (1). To ascertain Aquinas’ understanding of the matter depends on understanding his reasoning process and the authority he esteemed true. Aquinas believed the sovereignty of God superseded the liberty of man’s will, but not to its detriment of exercise. Aquinas pointed out— while alluding to John 14:6—that truth is of God and “that He is truth itself (2).” Therefore, all truth proceeds from God and is not subject to honest contention. However, the method used to ascertain truth came under discussion before this affirmation by Aquinas.

 In his evaluation of “sacred doctrine,” Aquinas stated, “For our faith rests upon the revelation made to the apostles and prophets, who wrote the canonical books, and not on the revelations (if any such there are) made to other doctors (3).” Philosophy is a sort of knowledge that is obtained by reasoning, and “faith liberates reason in so far as it allows reason to attain correctly what it seeks to know and to place it within the ultimate order of things, in which everything acquires true meaning (4).” Divine revelation grants the “sacred doctrine” because it consists of “truths which exceed human reason (5).”  Therefore, “reason … is not asked to pass judgment on the contents of faith … since this is not its function. Its function is rather to find meaning, to discover explanations which might allow everyone to come to a certain understanding of the contents of faith (6).” The divine revelations that God gave man were for man’s pursuit of God and godliness in life (cf. 2 Tim. 3:16–17). Not all knowledge has been granted by divine revelation (cf. Deut. 29:29; Job 11:6–7), and God has given some through natural means (cf. Psalm 19:1; Isaiah 28:24–26; Rom. 1:19–20).

 Aquinas referred to a “natural light of the intelligence (7)” that consisted of what is known by reason. Whereas the “sacred doctrine” is given by God through divine revelation (i.e., prophecy), natural intelligence composes other sciences which are subordinate to theology (“sacred doctrine”). Since theology employs the lesser sciences, it does not indicate a deficiency in theology; rather, theology employs lesser sciences due to the insufficiency of man’s intelligence (8). The lesser sciences, among which is philosophy, are led through natural reason to that which is higher than reason: namely “sacred doctrine.” Therefore, philosophy, or natural reason, and theology were authoritative for Aquinas; the latter was favored over all other sources while philosophy aided with the understanding of the theology: “The content of Revelation can never debase the discoveries and legitimate autonomy of reason (9).” Keep in mind that scholasticism was not regarded as a great approach by all, but it was Aquinas’ school of thought.

That Aquinas could esteem theology as authoritative is understandable to any Western Protestant since it proceeds from God. However, Aquinas believed that reason was a gift from God (cf. Isaiah 1:18). The knowledge of God is given partly through theology, but “not only so far as He can be known through creatures just as philosophers knew Him—That which is known of God is manifest in them (Rom. 1:19) (10).” That the philosophers knew God through creatures or the effects of creation suggested that philosophy was an integral part of authoritatively establishing the truth. Aquinas later wrote that God’s existence could only be demonstrated by his effects (11). Without theology, it is possible for philosophy to serve authoritatively through reason; hence his distinction between truths of reason and truths of faith. Having established that all truth proceeds from God and is authoritative primarily through the scriptures and secondarily through philosophy the reconciliation of man’s liberty to God’s sovereignty may be thus argued.


When addressing the topic of free will and sovereignty, one is prone to enter a quagmire of semantics. Simply put: man has freedom of will, and God’s sovereignty is such that it cannot be thwarted by man’s volition. However, God’s sovereign will does not negate man’s freedom in such a way that God is depicted as playing the puppeteer that pulls the strings of man. When a man is exposed to God’s sovereign will, he is at liberty to accept it or reject it without God’s forcing him toward either choice (cf. Ezek. 33:11). This is man’s response to God. Man’s freedom to choose is within the omniscience of God. Therefore, since God is omniscient, he has thus arranged his will according to his soteriological purpose, so that man’s freedom within his will does not undermine his purpose.

One of Aquinas’ most profound expositions on the predestination of man is expressed like this: “But as He saved us, so He predestined that we should be saved.” The order that Aquinas placed predestination about salvation is theologically defined as sublapsarianism. Sublapsarianism differs from supralapsarianism in the order of God’s decrees. The former follows the decrial order of 1) creation of human beings, 2) authorization of the action of the fall of man, 3) providence of salvation for all, and 4) salvation of some and reprobation of others; this order as a whole presupposes the foreknowledge of God. The latter follows the decrial order of 1) salvation of some and condemnation of others, 2) creation of the elect and reprobate, 3) permission of the fall, and 4) providence of salvation only for the elect (12). The latter supposition expresses God’s sovereign will to the quenching of man’s liberty while the former allows for man’s liberty to serve in conjunction with God’s sovereign will.

Aquinas justified man’s freedom by reasoning that there would otherwise be no need or existence of commands, prohibitions, or rewards and punishments if free will did not exist (13). Furthermore, “the proper act of free will is choice (14).” The choice made by man is based either upon an appetitive intellect or an intellectual appetite. The one whose choice is appetitive intellect would be one who chooses based on sensory perception such as what tastes good (15). One who chooses based on intellectual appetite would be one whose choice is based on the knowledge that drives the appetite; such as what tastes good that may not be the best for one’s well-being. The latter proceeds from counsel, but the former is animalistic and instinctive. Therefore, “freedom is part of the act of faith: it is required (16).” Otherwise, “truth and freedom either go hand in hand or together they perish in misery (17).”

What must be considered when speaking about liberty and sovereignty, as already mentioned, is the omniscience of God: “But the end must first be known by men who are to direct their thoughts and actions to the end (18).” God’s will is such that it operates with the foreknowledge of man’s will since God can view through foreknowledge what will take place before it happens(19)—hence his ability to formulate a scheme of redemption (cf. Gal. 4:4). “There can be no other reason for predestination than the foreknowledge of merits (20).”

To be so concerned about the free will of humanity being such that it could undermine God’s will is to ignore the sovereignty of God. The two doctrines go hand-in-hand when properly understood. When God’s omniscience is ignored, humanity’s free will is weakened, but when one considers that God is omniscient, God does not thwart man’s will but works with it.


  1. Peter Kreeft, Summa of the Summa (San Francisco: Ignatius Press, 1990). All references to this work are based on the question (Q), and at times, the accompanying answer (A). See Q. 12; Q. 22, A. 2; Q. 23, A. 5; Q. 83, A.
  2. Summa Q. 16, A. 5.
  3. Ibid., Q. 1, A. 8.
  4. John Paul II, Fides et Ratio, 20.
  5. Cf. Summa Q. 1, A. 1.
  6. John Paul II, 42.
  7. Summa Q. 1, A. 2; cf. Q. 12, A. 12.
  8. Ibid., Q. 1, A. 5; cf. A. 9.
  9. John Paul II, 79.
  10. Summa Q. 1, A. 6.
  11. Ibid., Q. 2, A. 2.
  12. For a fuller treatment on these definitions see Millard Erickson, Christian Theology, 2d. ed. (Grand Rapids: Baker Academic, 1998), 842ff.
  13. Summa Q. 83, A. 1.
  14. Ibid., Q. 83, A. 3.
  15. Cf. Ibid., Q. 1, A. 9.
  16. John Paul II, 13.
  17. Ibid., 90.
  18. Summa Q. 1, A. 1.
  19. Cf. Conf. 11.1.
  20. Summa Q. 23, A. 4.

Steven Hunter (PhD, Faulkner University) is the preaching minister for the Glendale Road Church of Christ in Murray, KY. He's also authored several books for Start2Finish, and Classically Christian explores Christianity from a church-historical perspective. Steven enjoys reading books, drinking coffee, and is a practitioner of Goshin Ryu Jujutsu—a traditional Japanese martial art.