John Stuart Mill

The [/Essay/] can claim a place amongst those which have had great influence on the progress of thought. It is profoundly in the English tradition of humane science—in that tradition of Scotch and English thought, in which there has been, I think, an extraordinary continuity of feeling, if I may so express it, from the eighteenth century to the present time—the tradition which is suggested by the names of Locke, Hume, Adam Smith, Paley, Bentham, Darwin, and Mill, a tradition marked by a love of truth and a most noble lucidity, by a prosaic sanity free from sentiment or metaphysic, and by an immense disinterestedness and public spirit.

John Maynard Keynes, Essays in biography, 1933, p. 120

Mill’s sex life is important in terms of understanding him as a man, of course, but there are some philosophical implications too. Mill was his century’s pre-eminent thinker on the content of a good life—of which sex must surely form a part. More specifically, in his version of utilitarianism, Mill insisted that it was not only the quantity of pleasure that counted but its intrinsic quality. He distinguished between lower pleasures, defined as ‘animal appetites’ consisting of ‘mere sensation’ and ‘higher’ pleasures ‘of the intellect, of the feelings and imagination, and of the moral sentiments’. Mill suggested sampling, to see which was preferable: ‘Of two pleasures, if there be one to which all or almost all who have experience of both give a decided preference, irrespective of any feeling of moral obligation to prefer it, that is the more desirable pleasure.’ Mill’s view was that the majority of people who had experienced the pleasure of, say, having sex and reading poetry, would find the latter a more intrinsically valuable pleasure; but according to his own philosophical rules he would have been prohibited form making any such judgement unless he had himself experienced both.

Richard Reeves, John Stuart Mill: Victorian firebrand, London, 2007, p. 154