The Courtier And The Heretic by Matthew Stewart

Mad, bad and dangerous to know - it can only be a philosopher

Bertrand Russell wrote that, of all the great philosophers, Baruch Spinoza was "the noblest and most lovable", and that "as a consequence, he was considered... a man of appalling wickedness". A French theologian declared Spinoza "the most dangerous man of the century"; a knifeman even tried to murder him. For the most part, all philosophers have to worry about today is boring their audience. This is certainly not a problem for Matthew Stewart's book.

Most philosophers tend towards atheism, a tradition that sprang from doubts not over God's existence, but His function. The prospect that this function could retreat as scientific understanding progressed was allayed by Spinoza's ingenious move in regarding God and Nature as identical. To find out more about the laws of nature was to uncover more of God.

Whether this deified nature or abolished God is a question Stewart turns into a compelling adventure. The story of Spinoza and Leibniz is a tale of two conceptions of God and two responses to modernity. To one, God was the world; to the other, He was outside it, creating and guiding.

There is no doubt which position was more acceptable in 17th-century Europe. As Spinoza was part of the Jewish community of Amsterdam, it was thought an abuse of hospitality to impugn the belief-system of his adopted homeland. The synagogue excommunicated the philosopher, after he refused a large bribe to recant. One suspects that Leibniz would have found it harder to turn down the money: Stewart finds him vain, grasping and "metaphysically incapable" of telling the truth.

When Spinoza's Tractatus Theologico-Politicus was finally published in 1670, it destroyed the authority of the Bible and set the liberationist agenda that would lead to a secular society. For Stewart, to attempt this as a Jew amid a Christian theocracy demonstrates that a liberal can be a hero. Leibniz carried on a clandestine correspondence with Spinoza, whom he also visited. Stewart contends that the German's assertions concerning God, mind and the universe make sense only as an attempt to avoid Spinoza's conclusions.

In a sense, Leibniz need not have worried. A new pantheistic religion along Spinoza's lines did not take Europe by storm. It was Leibniz's more traditional God that survived. But history has shown that, if the German won the battle of ghosts, Spinoza had victory over the living.