This chapter describes how philosophical theorizing about justice can be connected with empirical research in the social sciences. We begin by drawing on some received distinctions between ideal and non-ideal approaches to theorizing justice along several different dimensions, showing how non-ideal approaches are needed to address normative aspects of real-world problems and to provide practical guidance. We argue that there are advantages to a transitional approach to justice focusing on manifest injustices, including the fact that it enables us to set aside some reasonable disagreements about justice. The ‘bottom-up’ approach we advocate, for which we borrow Wolff’s term ‘real-world political philosophy’, is an empirically-informed normat...