Nicolas Malebranche

Malebranche was born in Paris with a malformed spine and, sickly, was educated at home. He entered the Oratory and studied scholastic theology and church history without interest. In 1664 he came across Descartes' Treatise on Man at a bookstall and was so excited, it is said, that his heart raced and he had to stop to catch his breath. He spent the next decade on Descartes and in 1674 published The Search after Truth.

Descartes had left the problem of how mind and matter interact. Malebranche's answer: they do not. Created things have no real causal power; only God does. When I will to raise my hand, my volition is merely an 'occasion', and God, according to the general laws he has established, raises the hand. This is occasionalism. Likewise our ideas do not come from bodies; we see them directly in God, whose mind is the common place of all intellects.

He fought a fierce controversy over the nature of ideas with the Jansenist Arnauld for more than a decade and corresponded with Leibniz. The Treatise on Nature and Grace tries to explain by general laws why God permits evil: God acts by the simplest means rather than intervening case by case. His works were placed on the Index, yet they influenced Berkeley and Hume, whose scepticism about causation borrows directly from his denial of created causal power.