Information closure and the sceptical objection

Abstract

In this article, I define and then defend the principle of information closure (pic) against a sceptical objection similar to the one discussed by Dretske in relation to the principle of epistemic closure. If I am successful, given that pic is equivalent to the axiom of distribution and that the latter is one of the conditions that discriminate between normal and non-normal modal logics, a main result of such a defence is that one potentially good reason to look for a formalization of the logic of " {Mathematical expression} is informed that {Mathematical expression}" among the non-normal modal logics, which reject the axiom, is also removed. This is not to argue that the logic of " {Mathematical expression} is informed that {Mathematical expression}" should be a normal modal logic, but that it could still be insofar as the objection that it could not be, based on the sceptical objection against pic, has been removed. In other word, I shall argue that the sceptical objection against pic fails, so such an objection provides no ground to abandon the normal modal logic B (also known as KTB) as a formalization of " {Mathematical expression} is informed that {Mathematical expression}", which remains plausible insofar as this specific obstacle is concerned.