The Moral Philosophy of John Stuart Mill Christopher Macleod, Lancaster University The inal version of this paper is forthcoming in The Cambridge History of Moral Philosophy, edited by J. Timmermann and S. Golob. 1 Mill and the Nineteenth Century The spirit of Mill’s philosophy is, irst and foremost, one of naturalism. For the purposes here, we can understand the basic thrust of Mill’s naturalism as a commitment to two connected claims. Firstly, that man is wholly part of nature: humans are objects broadly continuous with other simpler objects which we encounter in experience and which are subject to natural laws. Secondly, all of our knowledge of the world must come through empirical observation: there can, in effect, be no substantial knowledge that is gained a priori. The claims are distinct, but clearly related. The guiding thought is that if man is merely a part of nature, no transmission of information about some part of nature can occur except by causal chains leading from those external events to ourselves – which is to say by way of sense perception. 1 Mill’s commitment to naturalism makes him an invigorating philosophic companion for twenty-irst century readers – but we should not lose sight of the historical context in which he wrote. Mill was the most inluential English language philosopher of the nineteenth century, and his work in epistemology, metaphysics, political theory, and moral philosophy relects characteristically nineteenth century concerns. The period in which Mill’s general outlook was crystallised was one asking searching questions about how to move beyond the legacy of the European Enlightenment, and how to respond to the rise of democratic social structures. Much of Mill’s moral philosophy, which shall be the focus of this chapter, can be seen to engage with these issues. To the generation active in the early nineteenth century, Enlightenment optimism had been signiicantly tempered by the chaos of post-Revolutionary France. The breakdown of traditional modes of authority seemed to usher in an age of individualism and materialism, corrosive of any meaningful ethical life. A ready explanation was offered. The Enlightenment had been committed to the unrestricted use of free critique: no doctrine was sacrosanct, and every principle was asked to justify itself on the basis on evidence. This thoroughgoing commitment to criticism, however, seemed to undermine the possibility of any agreement upon or attachment to substantive moral doctrines, ending in a sceptical reliance of each individual on his own preference. The Enlightenment was, in this sense, seen as a negative moment, in need of supplementation. Mill shares this view: the eighteenth century is characterised by him as an age which is dominated by thinkers who saw “what was not true, not what was”. “To tear away, was indeed all that these philosophers, for the most part, aimed at: they had no conception that anything else was needful”. 2 The problem for the nineteenth century was how to ill the void left by the Enlightenment and overcome scepticisim without reverting to dogmatism. 1 See J. Skorupski “The Fortunes of Liberal Naturalism,” in J. Skorupski, The Cambridge Companion to John Stuart Mill (Cambridge: Cambridge University Press, 1998), pp. 1–34 for discussion of the relation of Mill’s naturalism to the various aspects of his philosophy. 2 Mill, Coleridge, X: 131–2, 139. References to Mill are taken from J.M. Robson (ed.) The Collected Works of John Stuart Mill (London and Toronto: University of Toronto Press and Routledge, 1963–1991), citing volume and page. See also Mill, Bentham, X: 80, Mill, Spirit of the Age, XXII:230–3. 1