Dretske, scepticism and the principle of epistemic closure: towards the theory of relevant alternatives

Scepticism essentially posits that knowledge is impossible, varying depending on the philosopher and context. One type of scepticism presupposes the 'principle of epistemic closure' (PEC), which states that if any epistemic subject knows a proposition P and knows that P implies Q, then that subject knows Q. According to this sceptical argument, one does not know a proposition if she does not know one of its contrasting consequences. Dretske countered this argument by rejecting PEC and proposed the theory of relevant alternatives as an alternative criterion for truth, addressing its absence in his epistemology. This essay aims to analyse Dretske's objection to this sceptical argument and his proposal of a theory of relevant alternatives.