Henri de Boulainvilliers

The education at Juilly had great impact on Boulainvilliers: a special accent on critical history had been introduced into the Oratory by Caesar Baronius and Richard Simon, and through the science classes he became familiar with the works of Jean Baptist van Helmont, Robert Boyle and Edme Mariotte.

By 1715-1720, he wrote his Traité d'astronomie physique using the Cartesian method, commenting on the nature of gravity and the movement of planets and drawing on sources such as Jean-Baptiste du Hamel and Huygens.

He described his method as experimental philosophy and closely preceded the Dutch experimentalists led by Anthony Leeuwenhoek (Nieuwentijt, Boerhave, Volder) He retained affection for astrology, for which he was famous in Court gossip.

He stressed in his writings the corruption absolutism played in the fall of France when he contrasts the role English and French historians were able to investigate history.

Boulainvilliers's study of Spinoza, as captured in the collected treatises published by Renée Simon (1973), shows an exceptional development from a basic criticism to an enlightened understanding marked by the incredibly generous way in which he let his opponent use his own voice.

The comte Boulainvilliers was no blind follower of Descartes; he knew how to make use of his method, but he could equally well criticise him on metaphysical points.

Yet in his persistent criticism of Spinoza's monism (through the concept of the "unity of substance"), in writings inaccessible to the multitude, his independent judgement remained unspoilt.