Semantic Argument to Reject Skepticism

The hypothesis of "brain in vat" is a skeptic one which, like other skeptic hypotheses such as Cartesian Demon, challenges or claims to have knowledge of our everyday beliefs. Providing an argument based on semantic premises, Putnam maintains that he is able to show that skeptic's claim that we cannot know that we are not brains in vat, is false; and thus his argument that all our usual beliefs concerning the world are unjustifiable is inefficient. Premises of Putnam's argument against skepticism are based on his positive approach towards semantic externalism; and presenting various thought experiments, he tries to show that it is the acceptable approach to semantics of referential words of language. Having described two premises about the structure of skeptic arguments and semantic externalism, the author will proceed to describe Putnam's semantic argument against skeptic ones. Then, through a more accurate analysis of the premises of the latter's argument and presenting some critiques, the author will show that, despite what Putnam thinks, his argument is not in itself efficient to reject skeptic hypothesis; and his conclusion is inconsistent with the principles of semantic externalism. In conclusion, taking into account his critiques against the semantic argument, the author will find what conclusions concerning skepticism may be derived from this argument in particular and semantic externalism in general.