Thomas Aquinas (1225–1274). Italian theologian and doctor of the church, born at Roccasecca near Aquino, Italy. He was inducted into a Benedictine monastery at age five but later was forcibly removed by his family and enrolled at the new secular University at Naples (1239), where he joined the Dominicans. Sometime after 1245 he began studies under Albert the Great at the Convent of St. James, Paris. In 1248 Aquinas and Albert started a school in Cologne. Aquinas returned to Paris in 1252 to teach at the university. From 1259 to 1268 he taught at the papal Curiae in Italy, where he met the translator William Moerbeke. The Latin Averroeist controversy called him back to Paris (1268–72). His final years were spent in Naples teaching in a Dominican house. He died at Fossanova on the way to the Council of Lyons, March 7, 1274.

Aquinas was canonized in 1326, made a doctor of the church in 1567, commended for study by Pope Leo XIII (Aeterni Patris) in 1879, and declared patron of Catholic schools in 1880.

Major Writings

Thomas is credited with some ninety-eight works, though nine are of doubtful authenticity. His writings were produced steadily from 1252 until the year of his death. The greatest and most influential of his works was Summa Theologica, a systematic presentation of Christian doctrine in philosophical terms. His system was declared the official teaching of the Catholic Church by Leo XIII.

Thought

The views of Aquinas cover most philosophical and theological categories.

Faith and Reason. Like Augustine, Aquinas believed faith was based in God’s revelation in Scripture. Support for faith was found in miracles and probable arguments. Although God’s existence is provable by reason, sin obscures human ability to know, and so belief (not proof) that God exists is necessary for most. Reason, however, is never the basis for faith in God. Demanding reasons for belief in God actually lessens the merit of one’s faith. Believers, nonetheless, should reason about and for their faith. There are five ways to demonstrate God’s existence by reason. (1) From motion to an Unmoved Mover, (2) from effects to a First Cause, (3) from contingent being to a Necessary Being, (4) from degrees of perfection to a Most Perfect Being, and (5) from design in nature to a Designer. There are, however, mysteries (e.g., Trinity, Incarnation) that cannot be known by human reason but only by faith.

Epistemology. Aquinas held that all knowledge begins in experience. We are, however, born with an a priori, innate capacity to know. Certainty about reality is possible by means of first principles: (1) identity—being is being, (2) noncontradiction—being is not nonbeing, (3) the excluded middle—either being or nonbeing, (4) causality—nonbeing cannot cause being, and (5) finality—every being acts toward an end. So nothing is in the mind that was not first in the senses—except the mind itself with its capacity to know by means of first principles. These first principles are self-evident once they are understood.

Metaphysics. Like Aristotle, Aquinas believed it was the function of the wise man to know order. The order reason produces in its own acts is logic. That which it produces through acts of will is ethics. The order produced by reason in external things is art. But the order reason contemplates (but does not produce) is nature. When nature is contemplated insofar as it is sensible, one is studying the physical sciences. Nature studied insofar as it is quantifiable is mathematics. But nature studied insofar as it is being is metaphysics.

The heart of Aquinas’s metaphysics is the real distinction between essence and existence in all finite beings. Aristotle had distinguished between actuality and potentiality, but he applied this only to form and matter, not to the order of being. Aquinas argued that only God is pure being, pure actuality, with no potentiality whatsoever. Hence, the central premise of Thomistic thought is “act in the order in which it is act is unlimited and unique, unless it is cojoined with passive potency.” God alone is pure act(uality) without form. Angels are completely actualized potentialities (pure forms), and man is a composition of form (soul) and matter (body) with progressive actualization.

God. God alone is being (I Am-ness). Everything else has being. God’s essence is identical to his existence, it is of his essence to exist. God is a necessary being. He cannot not exist. Neither can God change, since he is without potentiality to be anything other than he is. Likewise, God is eternal, since time implies a change from a before to an after. But as the I am (Exod. 3:14), God has no befores and afters. God is also simple (indivisible), since he has no potential for division. And he is infinite, since pure act as such is unlimited, having no potentiality to limit it. Besides these metaphysical attributes, God is also morally perfect and infinitely wise.

Analogy. God is known by analogy. Univocal (totally the same) knowledge of God is impossible, since our knowledge is limited and God is unlimited. Equivocal (totally different) knowledge of God is impossible, since creation resembles the Creator (Ps. 19:1; Rom. 1:19–20); the effect resembles its efficient cause. Because there are great differences between God and creatures, the way of negation (via negativa) is necessary. We must take only the perfection signified (goodness, truth, etc.), without the finite mode of signification, when we apply it to God. So the attribute will have the same definition for creatures and Creator, but it will have a different application or extension, since creatures are finitely good, while God is infinitely good. So before we can appropriately apply the term good to God, we must negate the finite mode (how) in which we find good among creatures and apply the meaning (what) to God in an unlimited way.

Creation. God created the world out of nothing (ex nihilo). Although Aquinas believed that an eternal creation was logically possible, since there is no logical reason and eternal cause cannot be causing eternally; nevertheless, he believed that Scripture teaches a beginning of the universe. Time did not exist before God created—only eternity. God did not create in time; rather, with the world there was the creation of time. So there was no time before time began.

Humanity. Humans are a hylomorphic unity of soul and body. Adam was directly created by God at the beginning, and God directly creates each new soul in the womb of its mother. Despite this unity of soul and body, there is no identity between them. The soul survives death and awaits the reunion with the body at the resurrection.

Ethics. Just as there are first principles of thought, so there are first principles of action called laws. Aquinas distinguishes four kinds. Eternal law is the plan by which God governs creation. Natural law is the participation of rational creatures in this eternal law. Human law is a particular application of natural law to a local community. And divine law is the revelation of God’s law through Scripture and the church.

Virtues are in two classes: natural and supernatural. The former include prudence, justice, courage, and temperance. These are part of the natural law. Supernatural virtues are faith, hope, and love.

Neo-Thomism

A philosophical school that in the twentieth century attempted to apply the thought of St. Thomas Aquinas to theological and other intellectual problems.

Thomism, which had experienced failures and successes from the time of Aquinas on, appeared to have triumphed in 1880 when Pope Leo XIII declared it to be the official (though not exclusive) philosophy of Catholic schools.

However, at its very moment of triumph, Thomism was severely questioned by the dominant philosophies based on the thought of Immanuel Kant. Consequently, the movement bifurcated. Transcendental Thomism, represented by Joseph Maréchal, Bernard Lonergan, and Karl Rahner, self-consciously adapted itself to Kantian thought. But another wing, under the leadership of étienne Gilson and Jacques Maritain, sought to recover a pure, Aristotelian version of the teachings of Aquinas himself. Eventually this understanding crossed confessional boundaries to include such Protestants as E. L. Mascall. This article will concentrate on this latter movement.

The metaphysical distinctive of neo-Thomism may be found in its insistence on the maxim that “existence precedes essence.” For that reason Maritain has claimed that Thomism is the original existentialism. Put simply, this means that one has to know that something exists before one knows what it is, and before one knows that something exists, one has to accept that anything exists. This latter conviction is not the result of a rational deduction; it is an immediate awareness. Thus, the act of being, apprehended in a direct intuition, precedes its various modalities.

This apprehension of being leads the Thomist to posit the existence of God via the cosmological argument. For even though the reality of being is an inescapable fact, it is not a logically necessary truth. Being exists but need not exist. Thus, being is inherently contingent, and its contingency makes it finite. If it exists in view of having no inherent necessity to do so, it must be caused to exist. Also, the very forms that being assumes are due to the interplay of various causes; and the fact of change, so characteristic of being, must be the result of causal actions as well. Therefore, being is bounded by causes wherever it appears. However, since it is a logical absurdity for anything to cause itself, there must be an external cause of being. Now if that cause is also finite, we have not grounded finite being yet, and it still should not exist. A chain of finite causes would carry the same problem with it. Hence, the Thomist posits an original uncaused cause of all being, viz. God.

The understanding of God as unconditioned necessary existence goes far in providing the basis for Thomistic natural theology. For if God is uncaused, he is unlimited. Then he contains all perfections infinitely; e.g., he is all-good, omnipresent, omniscient, all-loving, perfect person, etc. There can be only one such God, since a God who possesses all perfections cannot differ from any other God who would also possess all the identical possessions. Thus, Thomists feel confident that their philosophical arguments concern the same God they worship in church.

Thomism understands the relationship between God the Creator and the created order to be analogical. God is the source of all being, and finitude participates in his being, but only with limitations. In the matter of applying language to God, predication proceeds analogically as well. Language is derived from the finite world. But then it is applied to God with the understanding that he is the source of all named properties and that he possesses all those properties without limitation. For example, one may apply the word love to God even though it is a word learned within human finite relationships, because God is pure love and the originator of all human love.

The insistence on being over essence also makes itself felt in Thomism’s understanding of the human person. Thomism avoids both a Platonic mind-body dualism and a reductive materialism. With the understanding of the soul as the form of the body, the human is seen as a unit, composed of soul and body in mutual dependence. Thus, for instance, cognition combines both the physical/empirical (sensation) and the spiritual (abstraction). Thomistic writings have consistently defended the dignity and integrity of human personhood, particularly against totalitarian ideologies.

In theology Thomism has usually been linked to conservative expressions of orthodox doctrines, partially due to the close dependence on Aquinas’s own formulations. Since the Second Vatican Council it has lost much ground in Catholic circles to philosophies of more recent origin, e.g., phenomenology or process thought, due to a certain impatience with Thomism’s supposedly outmoded Aristotelianism. At the same time there has been some movement in evangelical Protestantism to adopt Thomistic philosophical principles for purposes of apologetics and theological enhancement, e.g., by Norman L. Geisler.

By Norman L. Geisler and W. Corduan

Bibliography[1]

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[1] V. J. Bourke, Aquinas’ Search for Wisdom and Thomistic Bibliography: 1920–1940; M. D. Chenu, Toward Understanding St. Thomas; G. K. Chesterton, St. Thomas Aquinas; R. J. Deferrari, Complete Index of the Summa Theologica of St. Thomas Aquinas; Latin-English Dictionary of Thomas Aquinas, etc.; Lexicon of St. Thomas Aquinas Based on Summa Theologica and Select Passages of His Other Work; K. Foster, Life of St. Thomas Aquinas; É. Gilson, Christian Philosophy of St. Thomas Aquinas; M. Grabmann, Interior Life of St. Thomas Aquinas; J. Maritain, St. Thomas Aquinas, Angel of the Schools; A. Vos, Aquinas, Calvin and Contemporary Protestant Thought; A. Walz, Saint Thomas Aquinas: A Biographical Study. Walter A. Elwell, Evangelical Dictionary of Theology: Second Edition (Grand Rapids, MI: Baker Academic, 2001), 822-823, 1197–1198. N. L. Geisler and W. Corduan, Philosophy of Religion; é. Gilson, Christian Philosophy of St. Thomas Aquinas; H. J. John, ed., Thomist Spectrum; B. J. F. Lonergan, Insight: A Study of Human Understanding; J. Maritain, Degrees of Knowledge; Scholasticism and Politics; E. L. Mascall, Existence and Analogy.