Malebranche and Occasionalism

Nicolas Malebranche (1638–1715), a French Oratorian priest ordained in 1664, developed the most systematic and influential version of occasionalism, the doctrine that no finite created substance — whether mind or body — possesses genuine causal power, and that God alone is the true and only efficient cause of every event in the created universe, in his major work The Search after Truth (De la recherche de la vérité), first published in 1674–1675 and substantially revised across several subsequent editions through 1712. Malebranche's starting point was broadly Cartesian — he was profoundly influenced by his 1664 reading of Descartes's Treatise on Man, an encounter he later described as having produced heart palpitations severe enough to force him to set the book down repeatedly — yet he pushed Cartesian metaphysics toward a conclusion Descartes himself had not drawn: that the radical difference in kind between mind and body, which had already generated the interaction problem discussed above, in fact rules out any real causal power in creatures altogether, of any kind, mental or physical, and not merely across the mind-body divide.