Aquinas, St Thomas (1225–1274)

Italian philosopher and theologian, the greatest figure of the school of scholasticism. He was a Dominican monk, known as the ‘Angelic Doctor’. In 1879 his works were recognized as the basis of Catholic theology. His Summa contra Gentiles/Against the Errors of the Infidels (1259–64) argues that reason and faith are compatible. He assimilated the philosophy of Aristotle into Christian doctrine. He was canonized in 1323.

His unfinished Summa Theologica, begun 1265, deals with the nature of God, morality, and the work of Jesus.

His works embodied the world view taught in universities until the mid-17th century, and include scientific ideas derived from Aristotle. The philosophy of Aquinas is known as Thomism.

He was born at the castle of Roccasecca, the property of his father, the count of Aquino, in the territory of Naples. He studied at the university of Naples where he first came under the influence of the Dominican order of mendicant friars, and, in spite of family opposition, entered their ranks 1244. He then studied under German scholar Albertus Magnus in both Cologne and Paris, and taught in Paris 1256–72.

Working from fresh translations of Aristotle into Latin by his fellow Dominican William of Moerbeke (1215–1286), Aquinas created a subtle philosophy often described as Christian Aristotelianism. He also drew on the works of St Augustine, Avicenna, Averroës, and the neo-Platonists. In metaphysics, he contrasts a thing's essence (that is, what makes it what it is) with its existence, though in God they coincide. He argued that the soul is immortal but cannot be permanently disembodied; therefore, physical resurrection is required. He developed five ways of demonstrating the existence of God. His theory of meaning relies on analogy; for example, the term ‘God's wisdom’ is to be understood by analogy with human wisdom.

A great defendant of the attitude of the Dominican order during the controversy of the 1240s–50s between the university of Paris and the mendicant orders, he was held in high esteem by popes Urban IV and Clement III, who were beholden to him for advice. The greater part of his later life was taken up in visits to various potentates and in the duties of his state. He was called again 1272 to his professorial chair at Naples, and two years later was summoned by Pope Gregory X to the General Council of Lyons. He set out despite illness, but died at the Cistercian monastery of Fossanuova on 7 March 1274.