Bernard le Bovier de Fontenelle (1657-1757), French writer. Fontenelle wrote extensively on the history and philosophy of mathematics and science. His most famous work was Entretiens sur la pluralite des mondes (Conversations on the Plurality of Worlds, 1686). His novelistic style made complex topics widely accessible. He was a particular advocate of the philosophical and mathematical theories of Rene Descartes (1596- 1650).