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Definition: Thomas Aquinas from Merriam-Webster's Collegiate(R) Dictionary

Saint Thomas Aquinas 1224(or 1225)–1274 It. Tommaso d'Aquino Ital. religious & philos.

Summary Article: Thomas Aquinas (1225–74)
From Evangelical Dictionary of Theology
Life and Works

Thomas Aquinas is one of the most influential theologians in Christian history, and his legacy continues in the twenty-first century. He was born to a noble family in southern Italy (thus the name “Aquino”). He studied in Naples (from 1239), and then was sent to Paris (in 1245) to study under Albertus Magnus. After following Albertus to Cologne (1248) as an assistant in forming a new studium generale, he was sent back to Paris (1252) for further study. As a master in Paris, he wrote biblical commentary and held forth on disputed questions (both ordinary and public). Following his stay in Paris, he returned to Italy (1259). After serving in Naples and Orvieto, he moved to Rome (1265) before returning to Paris (1268). Finally, he was sent from Paris to Naples (1272) to found another studium. Saying Mass on December 6, 1273, he encountered something that left him unable to continue writing theology. Following what must be considered an intense mystical experience, he explained that everything he had produced seemed like straw in comparison with the object of his encounter. Several weeks later he died (March 7, 1274). He was canonized as a saint by Pope John XXII (1323) and declared a Doctor of the Church by Pius V (1567). He is buried in Toulouse.

By all accounts both a quiet and very large man, he produced a simply massive literary corpus, astounding in breadth and depth of analysis. He wrote commentaries and lectures on prominent biblical texts; Isaiah, Jeremiah, Lamentations, Psalms, Job, Matthew, John, and the Epistles of Paul received detailed attention. In addition, Thomas wrote commentaries on Boethius, Pseudo-Dionysius, and Lombard's Sentences as well as Aristotle's On the Soul, Physics, Politics, Nicomachean Ethics, De Interratatione, Metaphysics, and Posterior Analytics (plus other minor works). He also wrote occasional treatises such as polemics against Greek Orthodoxy and Muslim Averroist theology. Beyond all this, he wrote a shorter Compendium of Theology as well as discussions of disputed questions (e.g., on truth, evil, angels, the virtues, discipline, and the incarnation). Above all these, however, stand his two most influential works: the Summa contra Gentiles and, ultimately, the Summa Theologica. Throughout we see astute engagement with Aristotle (though deeply respectful, he is not afraid to disagree with “The Philosopher” about many important matters), an astonishing bank of quotations from patristic theologians (both Latin and Greek), and above all unswerving commitment to the authority of divine revelation and the truth of Christian doctrine.


Thomas is convinced that knowledge of God is available; God has made himself known. He thinks that it is acceptable for someone to “start” with belief in God; in today's language, it may be “properly basic.” But he also thinks that God's existence may be demonstrated. Some genuine knowledge of God is available to all, and this is reflected in truths found in Muslim and Jewish theology. But our knowledge of God, while genuine, is always limited and partial rather than exhaustive, and proper language for God is always analogical rather than univocal (or equivocal). While some knowledge may be available through reflecting on divine action in creation (the “Five Ways”), some truths about God can be known only through special revelation (e.g., doctrines of the Trinity and the incarnation).

Who is this God revealed to humans? God is simple, not composed of parts or pieces in any way whatsoever. God is immutable, not subject to change. God is impassible, not subject to vicissitudes and threats of emotional life. God is omnipotent, omniscient, and eternal: all-powerful, all-knowing, and unchanging while unlimited by temporal constraints. God is perfect, pure act (actus purus). God's goodness is perfect in every way, expressed as both justice and mercy (as well as the other ways that Scripture speaks of God). For Thomas, in a sense these perfections culminate in the doctrine of the Trinity: God's perfect and undivided life just is the triune life of love shared between Father, Son, and Holy Spirit. God's goodness just is the pure and simple goodness of the Trinity. Therefore we should understand divine action in creation to be for the purpose of sharing that goodness (so far as it can be communicated to creatures).

Humans are created in the image of God. A human person is a composite of body and soul. Humans are created to share in goodness and thus are made for happiness. They act with responsibility and thus with freedom, and they are called to exercise that freedom in ways that exemplify the virtues. Sin and evil have disrupted this world and brought ruin upon God's creation; Thomas clearly sees evil as a privation and sin or vice as both “contrary to nature” and, ultimately, opposed to God. Sin is “original,” and it is actual. All sin brings death, and mortal sin results in damnation.

God has not, however, abandoned humanity to sin's consequences. Instead, God providentially uses sin and suffering to judge and discipline the sinner; while not sin's cause, God nonetheless is able to turn evil into good. For sinners’ salvation, the Son of God became incarnate as the man Jesus Christ. Thomas's Christology accepts and defends the received creedal tradition, explicated according to a “concretist” and hylomorphic account: the person who is the divine Logos takes upon himself a body-soul composite and in so doing “hypostasizes” it. This incarnate person remains fully divine even as he is fully human, and Thomas says that we should think about the attributes or properties peculiar to each nature as properly predicated of the person (though not of the other nature); accordingly, we should not say that “Christ is a creature” simpliciter, but we can and should say that “Christ is a creature according to his human nature.” The incarnate Son is so thoroughly and indissolubly united to his Father that he enjoys the beatific vision throughout his earthly ministry and even during his passion. He makes atonement for human sinners, and his work changes not only their legal standing before God but their very nature as well. This change occurs not in a vacuum but in the community of the church, happening as Christ's real presence is manifest in the Eucharist. Such real and radical transformation is evidenced in cultivation of the virtues, involving the entire person: thought, word, and deed; heart, mind, and strength.

See also Aristotle, Aristotelianism; Neo-Thomism; Roman Catholicism; Scholasticism; Thomism

  • Davies, B. , The Thought of Thomas Aquinas;.
  • B. Davies; E. Stump, eds., The Oxford Handbook of Aquinas;.
  • Emery, G. , The Trinitarian Theology of St Thomas Aquinas;.
  • Stump, E. , Aquinas;.
  • Torrell, J.-P. , Saint Thomas Aquinas, vol. 1, The Person and His Work.
  • T. H. McCall
    © 2017 by Baker Publishing Group

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