van Fraassen's constructivist empiricist account of theories makes an epistemic distinction between entities that can and cannot be observed with the naked eye. A belief about the correctness of a theoretical description of an entity that is observable with the naked eye can be warranted by a theory. In contrast, no theory can warrant a belief about the correctness of a description of an unobservable entity.

I argue that we ought to instead adopt a view that takes account of the fact that some entities that cannot be observed with the naked eye can nevertheless be observed on the basis of the same physical principle as those entities that can be. This suggests that there is a distinction different from van Fraassen's that might do the work van Fraassen intends his to do, but a distinction that is principled. Understanding why this is so suggests that his distinction is grounded merely in human chauvinism.