Cultural relativism is defended by nobody, but it is easy to refute (which by the way is probably why noone ever believes in it) by precisely the kind of stereotyped question that the dogmatic realist drags up from his undergraduate years. Such questions as: How do you distinguish science from voodoo? What would you say to a Mormon on a porch? Would you really help Latour exorcise someone having a grand mal seizure?
A dogmatic realist would have no trouble distinguishing voodoo from science. Without doing the slightest research on voodoo he would just presume it is making the same sort of knowledge claims as natural science, and that it was obviously false. So in terms of content this sort of question is directed at a “cultural relativist”. Cultural relativism is some sort of crazy position that all knowledge claims are of equal value. It is an old stereotype concocted by the analytic tradition of the pre-Popperian pre-Quinean “knowledge is justified true belief” variety, and has no application in the real world.
Feyerabend who has a very interesting take on this question:
“ancient doctrines and ‘primitive’ myths appear strange and nonsensical only because the information they contain is either not known, or is distorted by philologists or anthropologists unfamiliar with the simplest physical, medical or astronomical knowledge. Voodoo … is a case in point. Nobody knows it, everybody uses it as a paradigm of backwardness and confusion. And yet Voodoo has a firm though still not sufficiently understood material basis, and a study of its manifestations can be used to enrich, and perhaps even to revise, our knowledge of physiology” (AGAINST METHOD, 3rd edition, p35-36):