Direct realism and the brain-in-a-vat argument (Skepticism, preference principle)

The brain-in-a-vat argument for skepticism is best formulated, not using th e closure principle, but using the "Preference Principle," which states tha t in order to be justified in believing H on the basis of E, one must have grounds for preferring H over each alternative explanation of E. When the a rgument is formulated this way, Dretske's and Klein's responses to it fail. However, the strengthened argument can be refuted using a direct realist a ccount of perception. For the direct realist, refuting the BIV scenario is not a precondition on knowledge of the external world, and only the direct realist can give a non-circular account of how we know we're not brains in vats.