Among critics of EC, at least three such purported explanations have emerged.[20] Since each is intended to preserve the thought that we do ordinarily know many things, the granting of knowledge in the relevant ‘low standards’ case is taken to express a truth. What needs explaining, then, is why denying knowledge to the same subject can seem correct once the standards are raised, even though none of what would normally be regarded as epistemically relevant features have changed. Though they are not obviously competing, each attempt to explain this in non-contextualist terms focuses on different factors. Framed in terms of the airport example described in Section 3.4 above, and in broad outline only, these sample non-contextualist proposals are as follows: