On his day in 1273, something very remarkable, even defining, happened in the life of Thomas Aquinas. He was a Dominican monk and is one of the two biggest hitters in the history of Christian theology, alongside Saint Augustine. His great achievement was the harmonisation of Aristotelian philosophy with Christian medieval theology which he explored at great length in his masterpiece, the Summa Theologiae. He has been called a genius by Anthony Kenny, who is arguably Britain’s most distinguished living philosopher today. He was canonised by the Roman Catholic Church in 1323.

And yet on that morning, in the priory of San Domenico, Naples, just after celebrating the mass of the day, Aquinas fell silent. From that moment on, he did not pen a single further word. The man whose intellect had grappled with the philosophy of nature, logic, metaphysics, morality, mind and theology had apparently reached an impasse.

Biographers have tried to explain this abrupt halt to his work in a number of ways. It might have been caused by a stroke, or a breakdown, or sheer exhaustion, they have speculated. After all, he died only three months later, though that was probably the result of a fall. Others have said he had a mystical experience at the altar. But perhaps the truth of the matter is found in the response he gave to his friend who begged him to continue: ‘Reginald, I cannot, because all I have written seems like straw to me,’ Aquinas replied.

This comment has in turn provoked the spilling of much ink. It has been taken as a rejection of his oeuvre, from the master’s own mouth, as if by ‘straw’ he meant ‘rubbish’. That, though, is to misunderstand the word. Straw was, in fact, a conventional metaphor for a literal reading of the Bible. It expressed the conviction that a straightforward treatment of scripture might provide the believer with comfort, or some basic material upon which to build their faith, but that such a use of the Bible was at best a first step. The implication of Aquinas calling his work ‘straw’ is therefore positive, not negative. His goal had been to understand God. He had made many attempts at the summit. But whilst they had produced wonderful insights, he had reached the point at which he was able to appreciate the most profound truth of all. The peak lies behind the clouds. God is unknown. Not in spite of, but because of all his efforts – with its theological sophistication, subtlety and seriousness – the best interpretation of what happened to Aquinas on St Nicholas’ Day 1273, is that he had reached as profound an appreciation of the divine mystery as was possible. His new silence was not a rejection but the culmination of his life’s work.