
La nature ne fait jamais des sauts.
Avant-propos to Nouveaux essais sur l'entendement humain (1704).
A later, more famous Latin version — "Natura non facit saltus" — is from the Philosophia Botanica (1751) by Linnaeus.
A variant translation is "natura non saltum facit" (literally, "Nature does not make a jump") ([Ökonomische Theorie und christlicher Glaube, Andrew, Britton, Peter H., Sedgwick, Burghard, Bock, LIT Verlag Münster, 2008, 978-3-8258-0162-5, 289, https://books.google.com/books?id=goW6JsEUz4EC] Extract of page 289 https://books.google.com/books?id=goW6JsEUz4EC&pg=PA289).