Reason, Truth and History

A book in which Putnam sets out his 'internal realism' and tries to find a path between a copy theory of truth and cultural relativism. Chapter 1 opens with an ant whose track in the sand happens to look like a caricature of Winston Churchill, asking what makes a mark or thought represent anything. It then presents the brains-in-a-vat argument: if we were brains in a vat, our word 'vat' could not refer to real vats, so the claim 'we are brains in a vat' undermines itself. Putnam rejects metaphysical realism, the view that there is one true description of a world of mind-independent objects seen from a 'God's Eye point of view', using a model-theoretic argument that reference cannot be fixed in the way it requires. Truth instead is idealised rational acceptability. Later chapters argue that rationality cannot be reduced to an algorithm or to cultural norms, criticise Kuhn and Feyerabend, and attack the dichotomy between fact and value.

It contains the most famous philosophical treatment of the brain-in-a-vat scenario and a clear statement of a middle way between realism and relativism.