This paper asserts that contemporary normative theories of justice use the justice-defining function of procedural justice. The justice-defining function can be distinguished from other functions within the broader procedural justice concept. The article exemplifies the use of the justice-defining function by reference to the theories of justice of Rawls and Habermas. The main argument is that relying on the justice-defining function is persuasive only insofar as additional arguments about the three elements of fairness are presented. In this respect, theories of justice tend to be deficient.