 This definition of self-evidence may not be entirely satisfactory. One seeking a positive, informative account of how S could be justified in believing P simply in virtue of the fact that S understands P should not be satisfied when told that P is a special, self-evident proposition, when all this means is that P is justified to a high degree for everyone who understands it. Nevertheless, the lack of an explanation of the mechanism that brings something about is not a decisive reason for thinking it could not come about. We shall assume that (SE) correctly defines self-evidence.