Realism About What?

Preanalytically, we are all scientific realists. But both philosophers and scientists become uncomfortable when forced into analysis. In the case of scientists, this discomfort often arises from practical difficulties in setting out a carefully described set of objects which adequately account for the phenomena with which they are concerned. This paper offers a set of representative examples of these difficulties for contemporary physicists. These examples challenge the traditional realist vision of mature scientific activity as struggling toward an ontologically well-defined world picture. They challenge antirealist alternatives as well.