This paper uses Durkheim’s distinction between cause and function to explore the aims and implications of Forrester’s critique of liberal egalitarianism in In the Shadow of Justice. I suggest that there is an interesting tension in Forrester’s argument between the portrayal of Rawlsian justice theory as a vestigial institution—a ‘survival’—left over from 1950s liberalism, and its continuing presence in political theory as a doctrine that has a strong function in policing the bounds of permissible philosophical discourse on politics. I then suggest that liberals are, in their nature, functionalists about politics, and that this may mean that they cannot easily countenance the kind of realism for which Forrester advocates at the end of her book.