 What does this theorem tell us with respect to the principles of knowledge, then? In one direction it tells us that if one accepts the indistinguishability interpretation, then one has implicitly accepted the principles K, T, B and 4 as reasonable for knowledge. In the other direction, it tells us that if one finds that S5 is the appropriate logic of knowledge and one finds that pointed Kripke models are the right way to semantically represent knowledge, then one must use an equivalence relation. Whether one should interpret this relation in terms of indistinguishability, though, is a matter on which logic is silent.