Abstract

If one compares various skeptical arguments about our perceptual beliefs with arguments against scientific realism one immediately notices important similarities. Skeptical arguments about perceptual beliefs are often based on the premise that all of our perceptual beliefs could be wrong. Our experience is consistent with many different states of affairs; some familiar examples are hallucination, an evil demon, and brains in a vat. Thus it is claimed we have no reason to believe that the perceptual beliefs we normally form are true and alternative beliefs are false.One of the most powerful arguments against scientific realism is based on the claim that our data underdetermines our theory. There exist empirically equivalent theories, which means that there is no observation that could lead us to accept one and reject the other. Each member of a class of empirically equivalent theories will be equally supported by the evidence.