This section makes clear that a capability theory of justice is theoretically much more demanding than the basic presupposition of the capability approach that ‘functionings’ and ‘capabilities’ are the best metric for most kinds of interpersonal evaluations. While much has been written on the capability approach in recent years, by an increasing number of scholars, including philosophers, much of the philosophical work needed for turning the open-ended capability approach into a specific theory of justice remains to be done.