Structural Empiricism, Again1

As is well known, there are two crucial arguments in the realism debate. According to the no-miracles argument, it would be a miracle if our best scientific theories – namely, those which successfully predict novel phenomena – were not true (or approximately true). So, we should take theories that yield novel predictions as being true or, at least, approximately so. Clearly, considerations of this sort are raised to support realism. On the other hand, according to the pessimist metainduction, many of our best-confirmed theories have turned out to be false. So, how can we guarantee that current theories are true? Considerations such as these, in turn, are meant to provide support for anti-realism. Since these arguments pull in opposite directions, the question arises as to whether there is some way of accommodating the intuitions underlying both arguments. A positive answer is provided by structural realism. According to the latter, scientific theories capture the “structure of the world”, and that is why they are so successful in predicting novel phenomena. However, capturing the “structure of the world” is compatible with introducing radically different ontologies, since the same structure can be instantiated in different ways. So, our theories may well be false, as far as their ontological commitments are concerned, but this doesn’t preclude them from correctly capturing the relevant overall structure.