In setting up his influential "constructive empiricist" project, Bas van Fraassen (1980, 12) characterizes realism about scientific theories by the following three claims: (i) Scientific theories should be interpreted "at face value". If the theory includes the sentence "there are quarks", it should be understood as making the same kind of claim we make when we say "there are cans of beer in the refrigerator": there is no reinterpretation. (ii) Scientific theories purport to be true (iii). We may in principle have good reasons for believing that a scientific theory is true.