Looking back on John Stuart Mill, we see him as the most important English philosopher of his century. For us, he fits naturally into what we think of as a British empiricist tradition between Hume in the previous century and Russell in the next. Yet this is not how Mill himself would have thought of his work. ‘Empiricism’ was something he criticised and wished to avoid. Nor did he look back to Hume. Instead, he looked back to his father, James Mill. His father, he thought, provided the most advanced analysis of the human mind, which for Mill was the central key to all philosophy. And, again following his father, he looked back before him to the account of the mind in David Hartley, building on Locke.