There’s a really confusing passage in p. 42 of Mathias Frisch’s book on inconsistency in classical electrodynamics. He suggests, in response to the “problem” of inconsistency in classical electrodynamics, that we modify our account of theory acceptance:
this problem disappears if in accepting a theory, we are committed to something weaker than the truth of the theory’s empirical consequences. I want to suggest that in accepting a theory, our commitment is only that the theory allows us to construct successful models of the phenomena in its domain, where part of what it is for a model to be successful is that it represents the phenomenon at issue to whatever degree of accuracy is appropriate in the case at issue. That is, in accepting a theory we are committed to the claim that the theory is reliable, but we are not committed to its literal truth or even just of its empirical consequences. This does not mean that we have to be instrumentalists. Our commitment might also extend to the ontology or the ‘mechanisms’ postulated by the theory. Thus, a scientific realist might be committed to the reality of electrons and of the electromagnetic field, yet demand only that electromagnetic models represent the behavior of these ‘unobservables’ reliably, while an empiricist could be content with the fact that the models are reliable as far as the theory’s observable consequences are concerned.
If acceptance involves only a commitment to the reliability of a theory, then accepting an inconsistent theory can be compatible with our standards of rationality, as long as inconsistent consequences of the theory agree approximately and to the appropriate degree of accuracy… our commitment can extend to mutually inconsistent subsets of a theory as long as predictions based on mutually inconsistent subsets agree approximately.*
What confuses me about this is that I do not know what Frisch could mean by a theory being reliable apart from its consistently producing predictions that agree with experiment. Frisch wants to avoid instrumentalism by claiming that in accepting a theory, all we are committed not just to the observable consequences of the theory, but also possibly to the reality of the ontology and mechanisms of the theory. That is, in accepting the theory of electrodynamics, we might also be committed to the claim that electromagnetic models represent the behavior of ‘unobservables’ like ontology and mechanisms reliably. But what does it mean to represent reliably, apart from being a representation that reliably leads to predictions that agree with experiment? What does Frisch mean in the excerpt above by “represents the phenomenon at issue to whatever degree of accuracy is appropriate”? How can degrees of accuracy be attributed to representations over and above the accuracy of their experimental predictions?
Incidentally, I’m appalled at how expensive Frisch’s book is now. I bought it for $9 on Amazon when OUP slashed prices after having decided to stop printing it. Now it costs $60. The Kindle Edition costs $53.72!
* Frisch, M. (2005). Inconsistency, Asymmetry, and Non-Locality: A Philosophical Investigation of ClassicalElectrodynamics. Oxford University Press, USA.