The Latin vocabulary he used for them still underpins much of European philosophy and culture. The Church continues to hold its ‘Doctor Angelicus’ in the highest regard. His Summa Theologica is the bedrock of Catholic teaching, while for non-Catholic philosophers, his mammoth compilation, Summa contra Gentiles, concerning the principles of natural religion, is the key text.

Dante awarded St Thomas a pinnacle in paradise, a little higher than Aristotle, and called him a flame of heavenly wisdom. Certainly, the influence of Thomas, and his promotion of Aristotle, on all aspects of Western civilisation is profound. However, Bertrand RUSSELL considered his work to be flawed, saying his conclusions were determined by Christian dogma rather than the disinterested detachment of SOCRATES or PLATO.

Thomas was born into the landowning elite and chose the religious life against vicious family opposition. He was a student at the Benedictine monastery at Monte Cassino and at Naples University before joining the Dominican Order in 1244, less than 30 years after its foundation. However, his family were opposed to his plan. His brothers kidnapped him and held him prisoner in Castello Roccasecca, where they tried, unsuccessfully, to arouse him sexually. Thomas, unlike the young St AUGUSTINE, cherished purity. After a year, Thomas finally escaped and went to study Aristotelian philosophy at Cologne, renowned because of the teaching of a fellow Dominican, Albert Graf von Bollstadt, later known as Albertus Magnus, who was canonised and named Doctor Universalis in 1931 by Pius XI. Albertus Magnus is regarded as the father of SCHOLASTICISM, the union of Christian theology and Aristotelian philosophy. He laid the foundations for the work of Aquinas, his star pupil.

Thomas moved to the School of Paris in 1252 and taught there until 1258, when in obedience to the Pope he moved back to Italy and taught at Amagni, Orvieto, Rome and finally at Viterbo, from where he was summoned to the Council of Lyons. Both his great works were written in Italy: Summa contra Gentiles between 1259 and 1264; Summa Theologica between 1266 and 1273. Although unfit and grossly overweight, the result of an enforced sedentary existence, he insisted on his vow of poverty and set off for Lyons on foot. He died on the journey in 1274 and was canonised in 1323.

By the time of Albertus Magnus, enough translations from Arabic were available for Siger of Brabant to be causing chaos in the School of Paris. According to Siger, Aristotle had taught that the world was eternally in existence and eternally self-sustaining. There was no need for a GOD. All mankind shared but one intellect. There was no question of IMMORTALITY of the individual. Corruptions of these kinds were called Averroisms, from Averroës, the Latin name for the great Muslim philosopher Abu’l Walid Ibn Rushd of Cordoba, whose teaching was being corrupted in translation as much as was Aristotle’s.

None of Aristotle’s works are, or were then, extant. They had survived in Greek as copies of notes and texts of a succession of students. Many had been translated into Arabic and Hebrew and used to provide a philosophical basis for Islam by Ibn Rushd, FARABI and Ibn Sina, and for Judaism by Rabbi Moses ben Maimon, usually known by his Latin name MAIMONIDES. Albertus Magnus was fluent in Arabic and Hebrew and able not only to translate Aristotle’s works from these sources, but also to convey the profound exposition and development of his thinking in Islamic and Hebrew tradition.

In addition, Aquinas benefited from translations directly from the Greek produced for him by his fellow Dominican, William of Moerbeck. By these means Aquinas furnished himself with Latin translations of all the available texts of Aristotle and proceeded to standardise a vocabulary that achieved internal consistency. This was in keeping with Aristotle’s principle demands for agreed definitions of words and statements of problems. Indeed, Aquinas achieved a greater internal consistency than Aristotle ever had and defended some of Aristotle’s conclusions with a subtlety they did not merit.

Aquinas made common ground with St Augustine and Plato to achieve the fundamental principle of his teaching, namely that faith and REASON cannot contradict each other because God is the source of both. Aquinas held with Aristotle that nihil est in intellectu quod prius non fuerit in sensu (roughly, nothing is known to the mind that was not first known by the senses), for which reason the existence of God is known to man because God can be sensed in all things. Here he far exceeded Aristotle’s notion of God as disinterested architect.

To expound on this he produced his five proofs of the existence of God, which are a set of metaphysical statements that depend on sensing God in all things. If nowadays PERCEPTION is recognised to be an unreliable tool, neither Aristotle nor Aquinas would have had any truck with such doubts. It is sometimes difficult for the modern mind to think back into the certainty of the mindset of MEDIEVAL PHILOSOPHY, although metaphysical, logical, scientific and mathematical method are utterly dependent on it. Aquinas treated ethics, as Aristotle had done, by reference to purpose and its fulfilment. However, whereas Aristotle’s model seeks to achieve the egocentric development of the individual, Aquinas’s model seeks to achieve supernatural enjoyment of God. Aquinas appears to vacillate between a legalistic model and a MYSTICAL one. This may have been because he was undergoing a spiritual awakening, which overtook his rigorously logical thinking towards the end of his short life. Tolerance is incompatible with divinely inspired truth expressed in terms of Aristotelian logic. For Saint Thomas and his followers, such as the Dominican monks of the Inquisition, the saints in heaven do look down with pleasure on the eternal sufferings of the damned in hell, not least because they denied the self-evident and perverted others.