Today in class we tried to get clear on what exactly distinguishes the scientific realist from the constructive empiricist (who accepts a form of anti-realism).  It became clear that these are competing philosophical views concerning 1) the real aim of scientific theories and 2) what one commits oneself to in adopting or accepting a scientific theory.  According to both views, the aims of science require that our theories be empirically adequate, and accepting a scientific theory will involve the belief that the theory is empirically adequate.  The divisive issues concern 1) whether or not empirical adequacy is ALL we should expect from a scientific theory, and 2) whether or not the belief that a theory is empirically adequate is ALL that is involved in accepting that theory.

The realist thinks that we are right to expect more from scientific theories, and that we are committed to more when we accept them–we are right to expect that our scientific theories should provide true statements about the world (and not just about its observable aspects), and scientists are committed to the existence of the entities that are postulated within the theories they accept.

The constructive empiricist thinks that empirical adequacy is all we should expect and that it is all that scientists are committed to when they accept a theory. 

By the end of class, it seemed that some of us were fairly convinced that the constructive empiricist is right.  Realism appears to move us beyond properly scientific considerations and into the realm of metaphysics; perhaps even leading to a kind of dogmatism that conflicts with the proper scientific attitude.  At the same time, however, constructive empiricism seems to leave the success of science entirely unexplained–realism at least tries to offer an explanation for the empirical adequacy of certain theories; i.e., they ‘save the appearances’ because the entities they postulate actually do exist and actually do explain the characteristics of observable objects.  If the anti-realist is right, there are empirically adequate theories and there are theories that are not empirically adequate–the former tend to survive and the latter tend to die off.  This Darwinian account of the success of science is not very satisfying to those who are interested in understanding what it is about certain theories that explains their empirical adequacy.

If Musgrave is right, the constructive empiricist recommends a kind of philosophical schizophrenia and, as if this weren’t bad enough, his or her position may well be incoherent.  It is only if we artificially disassociate the ‘scientific world picture’ from our everyday beliefs and attitudes that we can make the fine distinction between accepting that a theory is empirically adequate and accepting that the theory is true.  In the case of ordinary empirical objects, there is no difference between the two views–they both agree that scientific theories make true claims about these objects.  The whole case, then, rests on the observable/unobservable distinction, which is one that the constructive empiricist has difficulty accounting for on his or her own terms:

Is the statement that there are unobservable objects true? 

If so, then we appear to be able to make true claims about unobservable objects.
If not, then why are we placing so much emphasis on this distinction in making a big deal about the difference between realism and constructive empiricism?

For next time, I would like us to focus on Section II (Realism and Explanation) and on the concluding paragraphs (p 1110) of Musgrave’s essay “Realism versus Constructive Empiricism”.  Is Musgrave effective in salvaging a commitment to realism?  Why or why not?