Monday, September 12, 2011

What Realism is Not

I just stumbled upon this;  and wondered, My gosh, might anyone imagine that, by Realism, I meant that?

Richard Rorty, Philosophy and the Mirror of Nature (1979), p. 334:

In just what sense were there physical features of reality  capable of being represented accurately only by differential equations, or tensors, before people thought of so representing them?

No mathematical physicist in his senses holds this delusion;  Rorty is tilting at a straw man.  The example of the discovery of the equivalence of wave mechanics vs. matrix mechanics, discussed previously, is well-known.   And one historian of physics opined that, if the seat of his pants told him anything, it was that the tensor formalism for General Relativity would eventually be replaced by something better.

Nor need two very different-looking approaches to the same thing  be mere historical contingencies, as was the case with wave mechanics vs. matrix mechanics, or the Chomskyan Extended Standard Theory vs. Generative Semantics (in Chomsky’s classic phrase, “notational variants”).  Rather, both views may be built into the very subject itself -- provably two sides of the same coin.  This is the vast and fascinating mathematical principle of Duality, which deserves an essay of its own.  In string theory, it is called Maldacena duality, and is a deep idea.

We could call the straw-man, overreaching philosophy “methodological Realism”, except that the phrase sounds too respectable, too much like an aspect  rather than an exaggeration  of  Realism.   Accordingly we shall dub it Tinkertoy Realism.

At all events -- to answer Professor Rorty's initial question:  planetary orbits existed prior to Kepler and Galileo,  and the electron prior to Millikan, in much the same sense that the nightingale antedates Keats.

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