Swiss theologian, philosopher, and controversialist whose greatest importance lies in his letters to a wide range of correspondents revealing the intellectual climate of his time.

He was professor in Lausanne from 1700 to 1724 (being twice rector of the university) and again from 1738 to 1749. In the interval, having left Switzerland as a result of a theological disagreement, he held a chair at Groningen, Neth., for two years and was tutor to Prince Frederick of Hesse-Kassel (1726–32). Crousaz wrote numerous mathematical and philosophical works. His Traité du beau (1714; “Treatise on Beauty”) was an attempt to explain subjective differences in aesthetic outlooks. With the encouragement of Cardinal Fleury, he sought to refute the doctrines of the French philosopher Pierre Bayle and the German philosopher Gottfried Wilhelm Leibniz. His critique of Alexander Pope's Essay on Man was translated into English by Samuel Johnson (1742). His correspondence was unpublished, although about 2,000 letters had been located.