If a man born blind were to gain his sight in later life would he be able to identify the objects he saw around him? Would he recognise a cube and a globe on the basis of his earlier tactile experiences alone? This was William Molyneux's famous question to John Locke and it was much discussed by English and French empiricists in the eighteenth century as part of the controversy over innatism and abstract ideas. Dr Morgan examines the whole history of this debate: Locke's own (negative) answer to the question, the contributions of Berkeley, Condillac, Diderot and Voltaire and the factual...