In recent years it has become common for some philosophers interested in the problems of ordinary and scientific knowing to identify themselves as “naturalistic” epistemologists. At minimum, this characterization indicates that the bearers consider themselves to be taking science, and particularly the science of psychology, very seriously – to be using empirical observations as an integral part of their attempt to fulfill epistemology's traditional ambition to explain what knowledge is, how we come by it, and how it can be distinguished from its pretenders. Major difficulties attend any attempt to give a more detailed and general account than this, as to what distinguishes naturalistic epistemologists from their fellow, nonnaturalistic, philosophers of knowledge. Nelson (1984) expresses the problem:

In begging philosophical questions, a general definition of naturalism would also run roughshod over differences of opinion among naturalistic epistemologists regarding the distinguishing features of their scholarship.