Aquinas, Thomas, St

Aquinas, Thomas, St (c.1225–74). Dominican philosopher and theologian, recognized as one of the greatest thinkers of the Catholic Church. He was canonized in 1323 and declared a Doctor of the Church in 1567. Feast day, 28 Jan. Aquinas's major works include commentaries on Aristotle and the Bible, general treatises (Summae) on Christian doctrine, and discussions of particular topics such as Truth and Evil. Central to his outlook is the notion of God as Creator ex nihilo (out of nothing). On Aquinas's account, God is the cause of there being anything apart from himself. In the light of this view, Aquinas further argued that God is not one of a class of spiritual beings; he is sui generis, not an individual, omniscient, omnipotent, changeless (meaning ‘timeless’), perfect, incomprehensible, and the cause of all that comes to pass, including the choices of his creatures. Aquinas rejected determinism and believed in free will, but he also insisted that the free actions of creatures are directly caused by God as Creator of everything.

In the areas of ethics and psychology Aquinas resembles Aristotle. He rejected a sharp mind-body dualism, and he held that criteria of human goodness are discovered by a study of human nature which is essentially bodily and social. But according to Aquinas, human beings can be transformed by grace to a level not anticipated by philosophy. He also held that by faith one can have access to truths about God not themselves demonstrable philosophically. These truths include doctrines like the Trinity and the Incarnation, which Aquinas believed to be revealed by God. See also THOMISM; QUINQUE VIAE.