When a professor of rhetoric at the University of Utrecht, one Johan Georg Graevius, wrote to Leibniz, castigating the Tractatus Theologico-Politicus as a “most pestilential book,” whose author “is said to be a Jew named Spinoza, but who was cast out of the synagogue because of his monstrous opinions,”² Leibniz prudently chimed in with his own diplomatic calumny: “I have read the book by Spinoza. I am saddened by the fact that such a learned man has, as it seems, sunk so low.”

A letter from Spinoza to Leibniz. Note his watchword, caute, in the lower right-hand corner.

Spinoza remained throughout his life, and well into the eighteenth century, a thinker whom one could admire only in secret, hiding one’s sympathy just as his Marrano antecedents had concealed their wayward Jewishness. Open admiration could destroy even the most established of reputations, well into the eighteenth century’s so-called Age of Reason. In the 1780s, for example, Friedrich Heinrich Jacobi launched a generalized attack on Enlightenment thought by claiming that the late poet Lessing had been a closet Spinozist, a charge sufficient to compromise the entire movement for which Lessing had been a leading spokesman³ Jacobi even went after Immanuel Kant and his successors, arguing that “consistent philosophy is Spinozist, hence pantheist, fatalist, and atheist.”

The holy furor aroused by the name Spinoza is in contrast to the man’s predilection for peace and quiet. He confessed himself to have a horror of controversy. “I absolutely dread quarrels,” he wrote an acquaintance, explaining why he had declined to publish a work that contains some of the main themes of The Ethics, titled Short Treatise on God, Man, and His Well-Being.⁴ The signet ring he wore throughout his life was inscribed with the word caute, Latin for “cautiously,” and it was engraved with the image of a thorny rose, so that he signed his name sub rosa.