Comment on Mixed Reference: The Great Reductionist Project

Sun, 09 Dec 2012 05:49:30 GMT

I think your argument works. But I can't accept GRTm; so I'll have to ditch GRTt. In its place, I'll give analyzing GRT another go; call this new formulation GRTd:

'Every true statement can be deductively derived from the set of purely physical and logical truths combined with statements of the semantics of the non-physical and non-logical terms.'

This is quite unlike (and no longer implies) GRTm, 'Every meaningful statement is expressible in purely physical and logical terms.'

The problem for GRTt was that statements like 'there are no gods' and 'there are no ghosts' seem to be true, but cast in non-physical terms; so either they are reducible to physical terms (in which case both GRTt and GRTm are true), or irreducible (in which case both GRTt and GRTm are false). For GRTd, it's OK if 'there are no ghosts' can't be analyzed into strictly physical terms, provided that 'there are no ghosts' is entailed by a statement of what 'ghost' means plus all the purely physical and logical truths.

For example, if part of what 'ghost' means is 'something non-physical,' then 'there are no ghosts' will be derivable from a complete physical description of the world provided that such a description includes a physical/logical totality fact. You list everything that exists, then add the totality fact 'nothing except the above entities exists;' since the semantic of 'ghost' ensures that 'ghost' is not identical to anything on the physicalism list, we can then derive that there are no ghosts.

Note that the semantic 'bridge laws' are themselves entailed by (and, in all likelihood, analyzable into) purely physical facts about the brains of English language speakers.

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