Pre-analytically, 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 quite practical difficulties in setting out a carefully described set of objects and their properties which adequately account at least for the phenomena with which they and those in their research specialty are concerned. I offer 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 a clear and ontologically well-defined world picture. (shrink)