The great achievements of philosophers are usually a matter of intellectual technology – the tools for thinking that they devise rather than the use to which they personally put them. In these terms Bacon was an exemplary judge of ideas, yet his work failed to ignite a scientific revolution, partly because he was neither a great mathematician nor an especially diligent ­experimenter.

But he was not the only philosopher in history who failed to be the finest exponent of his own precepts. William of Ockham, after all, used his famous razor to infer that there was no such thing as motion.

Bacon’s ideas were of the kind useful beyond the waxing and waning of theories, the kind immune to the errors and fancies of their creators. He did enough to have secured a reputation as a scientific genius if only his empiricist heart had been coupled with Italian descent and the ability to draw and paint. If he had had his way, the new translations of Aristotle would have brought an age of discovery rather than one of dogmatism and pedantry.

The recent denigration of Bacon’s achievements has less to do with their limitations than with a concern to rehabilitate his milieu. It is fashionable to argue that the medievals, unjustly vilified by 19th-century histor­ians, were in fact paragons of open-minded reason. This would have been news to poor Bacon, who found himself imprisoned for several years for unorthodoxy.

He was one of many thinkers – Descartes and Luther among them – who by innovating attempted to strengthen the Christian faith. But as reformers such men were not fooling any­one. In each case, the Church was quite right to see that its enemies would ultimately reap the bene­fits of their insight.