Abominable Conjunctions and Gricean Conversation

On Fred Dretske’s account of knowledge, the Epistemic Closure Principle for knowledge is not valid. Dretske takes this to be a virtue since the account is thus able to saves ordinary knowledge from skepticism. On it, you may know that you have hands, although you do not know that you are not a handless brain in a vat. As a correlate, the account also has to countenance the existence of what has come to be known as ‘abominable conjunctions’ – conjunctions of the form ‘I know I have hands but I do not know that I am not a handless brain in a vat’. These conjunctions are abominable in that they look false or in some way incoherent. Dretske suggests that the abomination is merely pragmatic and can be explain in terms of conversational features, more precisely, in terms of the Gricean Conversation Principles and its associated Maxims of Conversation. I argue that no such Gricean explanation is forthcoming, and that the abomination cannot be thought of as a merely pragmatic or conversational phenomenon. As I show, the abomination goes deeper, into the semantics.