In A Theory of Justice (1971), John Rawls introduces the concept of “reflective equilibrium.” Although there are innumerable references to and discussions of this concept in the literature, there is, to the present author's knowledge, no discussion of the most important question: Why reflective equilibrium? In particular, the question arises: Is the method of reflective equilibrium applicable to the choice of this method itself? Rawls's drawing of parallels between Kant's moral theory and his own suggests that his concept of “reflective equilibrium” is on a par with Kant's concept of “transcendental deduction.” Treating these two approaches to justification as paradigmatic, I consider their respective merits in meeting the reflexive challenge, i.e., in offering a justification for choice of mode of justification. My enquiry into this topic comprises three parts. In this first part, I raise the issue of the reflexivity of justification and question whether the reflexive challenge can be met within the framework of A Theory of Justice.