Cajetan original name, Tommaso de Vio (c.1469– 1534), Italian prelate and theologian. Born in Gaeta (from which he took his name), he entered the Dominican order in 1484 and studied philosophy and theology at Naples, Bologna, and Padua. He became a cardinal in 1517; during the following two years he traveled to Germany, where he engaged in a theological controversy with Luther. His major work is a Commentary on St. Thomas’ Summa of Theology (1508), which promoted a renewal of interest in Scholastic and Thomistic philosophy during the sixteenth century. In agreement with Aquinas, Cajetan places the origin of human knowledge in sense perception. In contrast with Aquinas, he denies that the immortality of the soul and the existence of God as our creator can be proved. Cajetan’s work in logic was based on traditional Aristotelian syllogistic logic but is original in its discussion of the notion of analogy. Cajetan distinguishes three types: analogy of inequality, analogy of attribution, and analogy of proportion. Whereas he rejected the first two types as improper, he regarded the last as the basic type of analogy and appealed to it in explaining how humans come to know God and how analogical reasoning applied to God and God’s creatures avoids being equivocal. See also THOMIS. P.Gar.