Aquinas, Thomas

(c. 1224–1274) the most important Christian theologian of the European Middle Ages Thomas was the son of an Italian count. He became a Dominican friar (see DOMINICANS) and devoted his life to teaching and writing THEOLOGY. His greatest book was the Summa Theologica (1266–73), "the summary of all theology." In Thomas's day western Europeans were just discovering the ideas of the Greek philosopher Aristotle (384–322 B.C.E.). Thomas found these ideas very attractive. He insisted that truth was one, because GOD was one. Therefore, he argued, what human reason said was true could not be opposed to what God's revelation said was true. The two were compatible. But human reason could not discover everything. Therefore, God fi nished what reason began by revealing the fullness of truth. Thomas included God's existence among the truths that reason could discover. In fact, he provided several classic proofs for the existence of God (see GOD, THE EXISTENCE OF). He also felt that although all human beings had a natural sense of right and wrong, reason alone could not discover truths such as the INCARNATION of God in JESUS and the triune character of God (see TRINITY). Eventu-ally Thomas's teachings became more or less the offi cial teachings of the Roman Catholic Church.