The role of interpretation of existing practice in normative political argument

In political theory concerned with normative evaluations and prescriptions facts can play two roles: 1) Facts can be of importance for the application of general normative principles to particular cases, and 2) facts can be of importance for the justification of normative principles as such. Political realists are critical of the first role, which they take to express a conception of political theory as ‘applied moral philosophy’. The paper investigates how interpretation of existing practices can be part of the second justificatory role, as suggested by proponents of different versions of contextualism and practice-dependence. The paper focuses on Andrea Sangiovanni’s methodological claims about social interpretation to illustrate both how facts can be part of the justification of principles and how interpretation is also faced with a number of problems as a way of justifying normative principles. The paper finally argues that some of these problems can be avoided if one considers the two roles together; what enables interpretation of facts as part of the justification of normative principles precisely is that application and justification are not separate exercises.