Together with Rousseau, John Stuart Mill (1806–73) supplied nearly all of the arguments and most of the emotional weather – the texture of sentiment – that have gone into defining the Left-liberal vision of the world.

Mill’s peculiar brand of utilitarianism – a cake of Benthamite hedonism glazed with Wordsworthian sentimentality – accounts for part of his appeal: it provides a perfect recipe for embellishing programmatic shallowness with a cosmetic patina of spirituality. It is a recipe that has proven irresistible to those infatuated with the spectacle of their own virtue.

Another large part of Mill’s appeal rests on his “feminism” – his conviction, put forward in The Subjection of Women, that differences between the sexes were accidental and that, as Leslie Stephen put it, “women could be turned into men by trifling changes in the law”. Both are indispensable elements in the intoxicating potion that constitutes Mill’s appeal and makes much of his thinking seem so contemporary.

Mill’s arguments and pronouncements about man as a “progressive being”, the extent of individual autonomy, the limits of acceptable moral and legal censure, the importance of innovation and (perhaps his most famous phrase) “experiments in living” are all familiar to the point of invisibility. Likewise his corollary insistence on the poverty of custom, prejudice and tradition. Mill’s contentions on these subjects are nowadays less objects of debate than of reverence.