‘Be a philosopher; but, amidst all your philosophy, be still a man,’ wrote the great philosopher of the Scottish Enlightenment David Hume. Julian Baggini’s The Great Guide appropriately intersperses exegesis of Hume’s philosophy with biography, character analysis and maxims on how to live that are extracted or derived from his writings. It is also an account of Baggini’s own travels in Hume’s footsteps to Chirnside (his childhood home in Berwickshire), to the college of La Flèche in the Loire, where he wrote A Treatise of Human Nature, to Paris, where he was feted by philosophes and salonnières, and to Edinburgh, where he lived and died. Hume was, briefly in each case, a merchant’s clerk in Bristol, tutor to a mad marquess, secretary to a lieutenant general on a military expedition to Brittany, a librarian, private secretary to the British ambassador to France and an undersecretary of state in London. He was also a scholar, a wit, a bon viveur, a gourmet, possibly (Baggini surmises) a great cook and a bachelor who loved women’s company. Above all, of course, he was a man of letters. Baggini emphasises that Hume’s six-volume history of England and his essays on science, economics, psychology, political theory and art were not, as many commentators have said, abnegations of his philosophy but essential to it (indeed, psychology was not a discipline distinct from philosophy until the 1870s).

‘The cornerstone of his entire philosophical project,’ says Baggini, was a lesson he learned from a breakdown he suffered at the age of eighteen: that ‘philosophy must be rooted in an accurate understanding of human nature’. Having left Edinburgh University, he had been philosophising exuberantly for six months when (he