Version: v1, Published online: 1998
Retrieved October 16, 2021, from https://www.rep.routledge.com/articles/biographical/putnam-hilary-1926-2016/v-1
7. The incoherence of metaphysical realism
In 1976 Putnam’s philosophy underwent a major shift; rejecting what he referred to as ‘metaphysical’ realism, he adopted ’internal’ realism in its stead. The attack on metaphysical realism, first presented in the final chapter of Meaning and the Moral Sciences (1978) is elaborated on in Models and Reality and in Reason, Truth and History (1981).
Just as establishing the objectivity of reference was central to Putnam’s earlier realism, the dispersion of reference into a plurality of possible relations is at the heart of his later criticism. The argument draws on model-theoretic considerations. The Löwenheim–Skolem theorem entails that a first-order theory, rich enough to contain arithmetic, does not determine its models up to isomorphism (see Löwenheim–Skolem theorems and nonstandard models). Putnam extrapolates: even an ideal theory of the world, complying with all empirical and theoretical constraints, will not define a unique model, that is, a unique reference relation. In particular, causality, previously seen as anchoring language in reality, now becomes just another relation, and hence open to interpretation.
Putnam’s point is not to embrace scepticism. His argument is that both the metaphysical realist who purports to have a theory of everything, including the ’correct’ reference relation, and the sceptic who undertakes to refute that theory, are making the same mistake – they are assuming a non-existent vantage point external to any language or description-scheme. From the internal perspective, questions about reference cannot arise, ’chair’ refers to chairs, ’cherry’ to cherries. ‘To speak as if this were my problem, “I know how to use my Language, but, now, how shall I single out an interpretation?” is to speak nonsense. Either the use already fixes the “interpretation” or nothing can’ (1983: 24).
Another argument against scepticism is found in Reason, Truth and History (1981), where considerations of reference and intentionality lead Putnam to conclude that the sceptic’s favourite fantasy – that we are all brains in a vat – is self-refuting (see Scepticism). The repudiation of scepticism is a recurrent theme uniting Putnam’s earlier and later work. The strategy, however, changes; Putnam’s responses to Quine, who has also invoked the Löwenheim–Skolem theorem, illustrate these. Whereas Putnam initially tried to reduce indeterminacy by increasing the number of constraints on an adequate translation, he later came to see the problem itself as a sceptical variation on a misguided metaphysics.
Ben-Menahem, Yemima. The incoherence of metaphysical realism. Putnam, Hilary (1926–2016), 1998, doi:10.4324/9780415249126-Q117-1. Routledge Encyclopedia of Philosophy, Taylor and Francis, https://www.rep.routledge.com/articles/biographical/putnam-hilary-1926-2016/v-1/sections/the-incoherence-of-metaphysical-realism.
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