Putnam, Koethe, and Metaphysical Realism

In a discussion note titled "Putnam's Argument Against Realism" 1 John Koethe attempts to refute Putnam's main argument against a view which Putnam calls 'Metaphysical Realism'. (This argument was first put forward by Putnam in Realism and Reason", 2 and in the philosophical literature has come to be called the model-theoretic or modelling argument against Metaphysical Realism). While I am not at all convinced by Putnam's argument, I find Koethe's refutation of the argument even less convincing. In this note I attempt to show where Koethe has gone wrong. According to Putnam, Metaphysical Realism (hereafter abbreviated as M.R.)is more a picture or a model than a theory. It purports to be "a model of the relation of any correct theory to all or part of THE WORLD." 3 According to this model, "there has to be a determinate relation of reference between terms in L and pieces (or sets of pieces) of THE WORLD." 4 The most important consequence of M. R. is that truth becomes radically non-epistemic; that is to say, according to M. R., even a theory that is ideal in every way might turn out to be false. This consequence of M. R. Putnam finds to be unintelligible, and the modelling argument is designed to show just that, viz. that this consequence of M. R. lacks intelligibility. Let T| be an ideal theory by our lights. Now, the argument against the intelligibility of the claim that T, might be false runs thus: