And they ain't outside the head either

According to a classical view in the philosophy of language, the reference of a term is determined by a property of the term which supervenes on the history of its use. A contrasting view is that a term's reference is determined by how it is properly interpreted, in accordance with certain constraints or conditions of adequacy on interpretations. Causal theories of reference of the sort associated with Hilary Putnam, Saul Kripke and Michael Devitt are versions of the first view, while defenders of determination by interpretation theories include Donald Davidson, Daniel Dennett and John Haugeland. I use a variant of Putnam's Twin Earth thought experiment to argue against the first view generally, and causal theories of reference in particular, then go on to argue that a properly-formulated version of the principle of charity can account for the intuitions that seem to support causal theories. Finally, I apply my version of interpretationism to the problem of reference to abstract objects and compare it with some of Wittgenstein's and Quine's views about language.