Thomas Aquinas

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Aquinas, Thomas


Born 1225 or 1226, in the castle of Roccasecca, near Aquino, southern Italy; died Mar. 7, 1274, in the monastery of Fossanuova, southern Italy. Medieval philosopher and theologian. Known for his formulation of orthodox Scholasticism as a system. Founder of Thomism.

Thomas attended the University of Naples from 1239 to 1244 and became a Dominican monk in 1244; he then studied under Albertus Magnus at the University of Paris from 1245 to 1248 and at the University of Cologne from 1248 to 1252. In 1257 he became a doctor of the University of Paris. He lectured at Paris, Cologne, Rome, and Naples. Thomas was made a saint of the Catholic Church in 1323, and in 1567 he was recognized as the fifth doctor of the church.

In his principal works—the monumental Summa theologiae (consisting of close to 3,000 articles and left uncompleted) and Summa contra gentiles—Thomas presented a summary of the rationalist theological thinking of High Scholasticism, which attempted to clothe the doctrines of faith in the vestments of common sense. Following in the footsteps of Albertus Magnus, Thomas went back to Aristotle as a source for his concepts—namely, Aristotle’s “common sensibles” and the idea of a system of “natural” reason as the underpinning of “supernatural” dogma.

The task that Thomas set for himself was to create a systematic order of the many within the one, rather than to contemplate the one in isolation from the many; he sought, as it were, to deduce the existence of god from the existence of things. In this respect, Thomas’ thinking is in contrast to the abstract speculation of early Scholasticism (as exemplified by Anselm of Canterbury)—a school of thought that was in line with Plato, Neoplatonism, and Augustine. Under the rubrics of the Summa theologiae, the same schemes of thought are imposed on an infinite variety of specific questions, ranging from the five proofs of the existence of god to a definition of the limits of what is or is not permissible in the conduct of financial affairs.

Thomas Aquinas’ ontology, which can be traced back to Aristotle, is based on the antithesis of what is potential, or possible, and what is actual, or real. The potential is that which is uncompleted, unfixed, subject to changes and variations, and thus imperfect. Matter—the weakest form of existence—represents pure potentiality, being only a passive receptacle that is acted upon. The actual, on the other hand, is what has been realized, brought into being, completed, and therefore perfect. Form, as opposed to matter, represents actuality—form being the principle of order and clarity, or intelligibility. God—the source from which everything has taken shape—is the absolute actuality, excluding all that is potential. Form, with its inherent ideal universality, is given concrete specificity by matter, which injects the principle of individuation. Following Aristotle, Thomas makes a distinction between subsfance (essence) and accident in everything that is real. Thomas’ ontology, reflecting a characteristic of medieval philosophy in general, is value-laden; in his view, “the real and the good are interchangeable concepts” (Summa theologiae, 11:18.3).

Thomas’ anthropology, which had a particularly close relation to the acute ideological conflicts of his time, is based on the notion of the human individual as a personal union of soul and body. While the soul is both immaterial and real, it is only through the body that it achieves ultimate actualization. Thomas defended this idea against the spiritualism of Plato and Augustine as well as against the Averroism of Siger of Brabant, with its doctrine of a single impersonal intellectual soul in all thinking creatures of the universe. In Thomas’ view, Origen’s doctrine of the essential identity of angelical and human nature was fallacious. The human soul must not simply be considered the body’s “mover,” but rather its essential form. This concept was resisted by Thomas’ Augustinian and Franciscan opponents, until it was accepted as orthodox doctrine by the Catholic Church at a council held in Vienne in 1314.

Averroism was regarded by Thomas Aquinas as a subversion of Christian eschatology, insofar as the latter is concerned with the destiny of the human soul. The individual, in Thomas’ view, is “the noblest thing in all reasoning nature” (ibid., 1:20.1). The intellect, inasmuch as it is always an individual human intellect, is not the prime moving principle; rather, it is a part of the whole. God alone is endowed with intellect as essence, while intellect in man is the potential of essence; thus it is not intellect which thinks—it is man who thinks through the medium of the intellect. Proceeding from the premises of Christian dogma, Thomas denies the absoluteness of the intellect and views it as a part of the individual’s spiritual and bodily entity; at the same time, he asserts the primacy of intellect over will. According to Thomas, reason is in its nature higher than the will—but with the reservation that, on the plane of human life, love of god is more important than knowledge of god.

In his ethical teachings, Thomas Aquinas represents “natural law,” which is implanted by god in the human heart, in the spirit of Aristotle’s ethics; “divine law” stands above and surpasses natural law but cannot contradict it. In his treatise on kingship, De regno, Thomas combines the dogmas of Christianity and the doctrine of the pope’s supreme authority with such Aristotelian concepts as the idea of man as a social being, the common good as a goal of the state, and morality as the middle point between the fallacy of the extremes. With some reservations, Thomas acknowledges the people’s right to rise up against a tyrant who practices the perversion of justice.

In the 14th century the philosophical and theological system of Thomas Aquinas was taken up and used by the Dominican schoolmen in their disputes with the Augustinians and the Franciscan followers of John Duns Scotus. Since the 16th century, Thomism has been actively propagated by the Jesuits; among the commentaries and later versions of Thomism are those of F. Suárez and other Jesuit theologians. The teachings of Thomas Aquinas gave rise to neo-Thomism in the second half of the 19th century.


Opera omnia, vols. 1–25. Parma, 1852–73. (Reprinted, New York, 1948.)
Opera omnia, vols. 1–34. Paris, 1871–80.
Opera omnia, vols. 1–16. Rome, 1882. (Incomplete ed.)
In Russian translation:
In Antologiia mirovoi filosofii, vol. 1. Moscow, 1969. Pages 823–62.


Bronzov, A. A. Aristotel’ i Foma Akvinskii v otnoshenii k ikh ucheniiu o nravstvennosti. St. Petersburg, 1884.
Borgosz, J. Foma Akvinskii, 2nd ed. Moscow, 1975. (Translated from Polish.)
Garadzha, V. I. “Problemy very i znaniia v tomizme.” Voprosy filosofii, 1963, no. 9.
Maritain, J. Le Docteur Angélique. Paris, 1930.
Grabmann, M. Thomas von Aquin, 8th ed. Munich, 1949.
Pieper, J. Über Thomas von Aquin, 2nd ed. Munich, 1949.
Chesterton, G. K. St. Thomas Aquinas. New York, 1956.
Gilson, E. Le Thomisme: Introduction à la philosophie de St. Thomas d’Aquin, 6th ed. Paris, 1965.