The nineteenth century is often thought – with justice – to be the age of individualism. Yet it was also the great age of projects to reintegrate the individual and society. In metaphysics and methodology various schools of philosophy claimed that the thoughts and actions of individuals are constituted, or at least can only be explained, as elements of a historically evolving social whole. Meanwhile the main streams of ethics, though diverse in many other respects, advanced a social conception of human flourishing as the keystone of ethical life. Indeed the whole preoccupation with the relation between individual and social life was at root ethical – grounded in a reaction against what was widely regarded as the shallow and one-sided individualism and rationalism of the Enlightenment.

Not all moral philosophers of the century shared this preoccupation; one thinks of nonconforming figures as diverse as Kierkegaard, Schopenhauer, Nietzsche, or Spencer. Existentialism has roots in the ethically fertile soil of the nineteenth century, as does libertarianism. However, in the present chapter we are concerned with those who did. They can be seen as falling into four broad traditions: German, especially Hegelian, idealism; Marxism (which in some ways continued it); utilitarianism; and positivism. All four of these traditions, in their various ways, take it that the social good is something of fundamental ethical importance, and all are concerned with the social dimensions of individuals’ good.