David Hume

Hume was born into a family of minor Scottish gentry and entered Edinburgh University at twelve. His family meant him for the law, but he found 'an insurmountable aversion to everything but the pursuits of philosophy and general learning'. At eighteen he discovered 'a new scene of thought' and overworked himself into a nervous collapse. In 1734 he went to France and lived three years near La Flèche, where Descartes had studied, writing the Treatise of Human Nature. Published in 1739, it 'fell dead-born from the press', as he put it.

He twice applied for chairs at Edinburgh and Glasgow and was twice rejected as an atheist. He tutored a mad marquess, served as a general's secretary, and recast the Treatise as the more accessible Enquiry Concerning Human Understanding and Enquiry Concerning the Principles of Morals. In the 1750s he wrote a six-volume History of England, became a best-seller and grew rich on royalties. In 1763 he went to Paris as embassy secretary, was lionised by the salons, brought Rousseau to England, and was then driven to distraction by Rousseau's paranoia.

His philosophy starts from one principle: every idea derives from an impression. We never observe a necessary connection between cause and effect, only constant conjunction; 'necessity' is the expectation that habit produces in the mind. Induction cannot be justified by reason. When I look inward I find no 'self', only perception after perception. Reason can tell us only means; ends are set by passion, and moral judgements come from sentiment, not reason. He faced death with composure; Boswell visited expressly to learn whether an atheist was afraid, and Hume replied that he feared it no more than his non-existence before birth. The Dialogues Concerning Natural Religion, published posthumously, remain the most powerful critique of the argument from design.