It would be no great exaggeration to state that seventeenth-century philosophy came to be dominated by René Descartes (1596–1650) and the Cartesians. The century opened with a generally dominant scholasticism, in many flavours, encountering some opposition from various humanists. Although there were scholastics and humanists throughout the era, the ascendancy of Cartesian philosophy in mid-century changed the equation, and the battle became defined as Cartesians versus anti-Cartesians, or perhaps rather more broadly as Moderns versus Ancients. Even the neo-Epicurean humanist Pierre Gassendi (1592–1655) and the theologically minded Augustinians from Port-Royal came to be characterised in relation to Cartesianism.

Renaissance humanism used history and the study of languages to revive and rediscover much of Classical antiquity: its science, philosophy, art, and poetry. When we think of its accomplishments, we remember the works of Rabelais, Montaigne, and Charron, among others. Although one does not find the term ‘humanist’ used by the circle around Descartes, Descartes's principal correspondent Marin Mersenne (1588–1648), in his L'Impiété des Deistes (1624), refers to a distinct set of opponents in which we can find several scholars we would consider as such. After having discussed such ‘despicable authors’ as Charron, Cardano, Machiavelli, Bruno, the ‘accursed’ Vanini, ‘and similar rogues’, Mersenne talks about the work he is writing against them: ‘I do not want to spend much time on this subject, since I expect to refute everything these authors stated so inappropriately in the Encyclopaedia I am preparing in the defence of all truths and against all sorts of lies, in which I will examine more diligently what has been advanced by Gorlaeus, Charpentier, Basso, Hill, Campanella, Bruno, Vanini, and a few others.’