Summary |
Putnam attempted to refute metaphysical realism by the use of a model-theoretic argument (or perhaps arguments, in the plural). For the most part, the required model theory was very simple. The easiest model theoretic argument involved the idea of a permutation over the objects of the world, so that (for example) my word "cat" does not apply to all and only cats, but to cats*, where cats* might just be cherries. (Another model theoretic argument involved appeal to the Completeness Theorem of first-order logic, or the Löwenheim-Skolem Theorem.) The aim of these arguments was to threaten the metaphysical realist with radical indeterminacy of reference (which Putnam did not himself embrace, but took to be a reductio of metaphysical realism). In response to the claim that causation (for example) fixes reference, Putnam always responded by maintaining that this was just more theory. Much of the subsequent literature has turned on the acceptability (or otherwise) of Putnam's just more theory manoeuvre. |