The Model-Theoretic Argument Unlocked

Abstract

In the Preface to Realism with a Human Face, Hilary Putnam remarks that “the difference between the present volume and my work prior to The Many Faces of Realism is a shift in emphasis: a shift from emphasizing model-theoretic arguments against metaphysical realism to emphasizing conceptual relativity” (Putnam, 1990, pp. x–xi). One might be tempted to view this as at least partially vindicating those defenders of metaphysical realism (henceforth ‘Realism’) who have been urging all along that the so-called ‘model-theoretic argument’ (MTA) is flawed. I argue, however, that Putnam’s remark should not be thought to provide such succour to the Realist, and that, quite the contrary, appeals to ‘conceptual relativity’ help to clarify why Putnam takes certain standard Realist responses to the MTA to be inadequate. In so doing, I also attempt to clarify another aspect of Putnam’s ‘internalist turn’ stressed in his most recent writings, namely, the sense in which this turn is ‘Kantian’ in nature. I argue, against those who hold that central features of our scientific picture of the world are threatened by Putnam’s assault on Realism, and overlooked in the formulation of the MTA, that Putnam’s ‘internal realism’, like Kant’s ‘empirical realism’, preserves the relevant features of that picture while challenging a particular metaphysical interpretation of it.