The 'Brains in a Vat' - hypothesis and the internal realism

This paper investigates Hilary Putnam's famous 'Brains in a vat' hypothesis. In the literature of the problem, it is mostly discussed as an antisceptic hypothesis. It was introduced firstly in 1981 in the book 'Reason, Truth and History'. No doubt it is not self evident at first sight that the real point of the argument is not the refutation of scepticism, but the grounding of the author's own epistemological view. In part he launched an attack on the view he termed 'metaphysical realism', in another part he wanted to ground his own internal realism. The author claims Putnam's argument is imperfect either if we think of his thinking experiment as an antisceptic hypothesis or if in correspondence to the previous approach we investigate it as a review of metaphysical realism. And the last but no less important thing is that it fails to sufficiently support Putnam's own epistemology.