The date and location of his birth unknown, Jean Du Hamel (not to be confused with Jean-Baptiste Du Hamel [1624–1706], the first secretary of the Académie des sciences) is connected to Cartesianism by his critical response to the Cartesian elements of Pierre-Sylvain Régis's Système de philosophie (1690; title changed in later editions to Cours entier de philosophie). In his Réflexions critiques sur le système cartésien de Mr Regis (1692), he attacks the Cartesian method of doubt, charges that the cogito argument begs the question, and argues against the Cartesian conception of the objective being of ideas (see AT VII 92–93, CSM II 66–67 for a similar complaint). Du Hamel also criticizes Régis in particular for his (nonstandard, from a Cartesian perspective) views that our ideas of bodies are sufficient to entail that bodies in fact exist and that matter, once created, cannot be destroyed, even by God. Régis responded to these attacks in his Réponse aux Réflexions critique du M. Du Hamel (1692). Du Hamel's reply to this response came several years later in his brief (sixteen-page) Lettre de Monsieur Du Hamel, ancien professor de philosophie de l'Université de Paris, pour server de replique à Monsieur Régis (1699). He was also the author of a Scholastic, and decidedly anti-Cartesian, course of philosophy, Philosophia universalis (1705). Du Hamel died in Paris in 1705.

See also Being, Formal versus Objective; Cogito Ergo Sum; Doubt; God; Régis, Pierre-Sylvain