The reception of Descartes in the second half of the seventeenth century took very different forms, which have been the subject of numerous and documented studies. On this subject, we cannot limit ourselves to categories that are too simplistic. Descartes had faithful disciples and resolute adversaries; he also had critical readers, combining admiration and the conviction that his philosophy, as revolutionary as it is, had to be both followed and reformed. The Oratorian Nicolas Malebranche (1638–1715), who passes for one of the greatest French Cartesians, surely counts among the number of readers who wants to be Cartesian, without however being understood as a disciple of Descartes. Malebranche himself has perfectly expressed the nature of his Cartesianism in declaring, at the end of his first work, the Search after Truth (Recherche de la vérité; 1674–5): “I admit however that I owe to Descartes or to his manner of doing philosophy the opinions that I oppose to his, and the boldness to criticize him.” In this chapter I attempt to clarify the sense of this remarkably ambivalent affirmation with some examples.