Replies to Discussion on the Empirical Stance

These three commentaries challenge me to confront some new issues as well as to clarify some main points. I want to thank James Ladyman, Peter Lipton, and Paul Teller especially for leavening their critique with so much constructive exploration of how one might go about meeting those challenges. Before replying directly I want to touch on something that has also come up elsewhere. Several reviewers linked The Empirical Stance to The Scientific Image and to the issue of scientific realism in general, while noting with some surprise that this hardly comes up at all in the new book. But scientific realism is not a metaphysical theory. The answer it gives to ‘‘What is science?’’ is a claim which does not invoke any item in the metaphysicians’ cornucopia. The realist claim that science aims to produce literally true theories has as relevant contrary the constructive empiricist claim that the aim is empirical adequacy. Neither is a metaphysical theory. Statements about unobservable entities, implied by our scientific theories, are not ipso facto pieces of metaphysics. ‘‘Atoms are real’’ has a metaphysical past, but need not have today the status of a metaphysical statement. Acceptance of a scientific theory is compatible with agnosticism about the reality of such entities and processes, but agnosticism is by no means an extreme form of rejection. The empiricist critique of metaphysics is nevertheless relevant there simply because scientific realism tends to be embedded in and/or supported by a good deal of metaphysics. The Scientific Image’s last chapter parodies the parallels with largely discredited forms of natural theology, but since then I have seen the need for more direct arguments.