Thomas Aquinas (1224–1274) was a theologian, philosopher, and the consummate apologist of the medieval church. Born in Italy, he joined the Dominican order. He was canonized by the Roman church in 1326. Aquinas wrote De anima (On the Soul), De Ente et Essentia (On Being and Essence), De veritate (On Truth), On the Power of God, Summa contra Gentiles, and The Unity of the Intellect Against the Averoeists. By far his most important and influential writing went into his magnum opus systematic theology, Summa Theologica, which was still unfinished at his death.

The thought of Aquinas is rich and varied. He wrote on many topics, including faith and reason, revelation, knowledge, reality, God creation human beings, government, and ethics. His mind was intensely analytical, making his arguments difficult for the modern reader to follow. His writing style is sometimes dialectical and highly complex, especially in Summa Theologica. This is less…