  It is at this point that theories of  vagueness  can play a role in the debate. Two of the leading theories of vagueness, epistemicism and supervaluationism, provide principled reasons to reject M2. The epistemicist says that there are semantic facts that are beyond our possible knowledge. Arguably we can only know where a semantic boundary lies if that boundary was fixed by our use or by the fact that one particular property is a natural kind. But, say the epistemicists, there are many other boundaries that are not like this, such as the boundary between the heaps and the non-heaps. Here we have a similar kind of situation. It is vague just which of the oi is a cloud. What that means is that there is a fact about which of them is a cloud, but we cannot possibly know it. It might be thought that this is not so much a response to the argument above as a straight-out denial of one of its premises. And since we have to appeal to the most contentious feature of epistemicism, that there are these brute semantic facts that are beyond our epistemic access, some may doubt its plausibility. Weatherson 2003a argues that this problem becomes more pressing when one applies epistemicism to the Problem of the Many than when one merely wields epistemicism to solve the  Sorites Paradox.  However, epistemicism is a well developed research program that provides a coherent framework for thinking about vagueness. If, on the balance of considerations, epistemicism is thought to be the right theory of vagueness, then it is fair to simply deny M2, and say it could be a brute semantic fact that oj satisfies ‘cloud’ and ok does not.