  The understanding of principled consistency used in this conception of interpretivism corresponds to one understanding of Dworkin’s famous distinction between fit and justification as dimensions of interpretation (Dworkin 1986). Dworkin said that correct interpretation must both fit and justify its object. On the understanding in discussion, fit operates as a threshold constraint on eligibility of interpretations. Independent moral appeal governs the choice among alternatives that pass the threshold (cf. Raz 1994: 223). Fit, on this conception, is meant to ensure that a candidate interpretation is indeed an interpretation of some object rather than an invention. It is a nonmoral constraint, in two ways. First, it is meant to secure consistency with a set of norms that are grounded in nonmoral considerations—in the action and psychology of agents and institutions. Second, the relevant notion of consistency itself is meant to be nonmoral, a constraint of formal consistency between norms and principles. (See Greenberg 2004 on fit as a matter of formal consistency with practice. Greenberg argues that a constraint of formal consistency is empty.) The thought is that the original set of norms could not really constrain interpretation if substantive, moral considerations played some role in determining what it is to fit the norms. If the notion of fit were tainted by the very kind of consideration that defines the ideals against which the actual norms are to be measured, the distinction between interpreting the actual practice of institutions and inventing a new, better practice would be erased.