  The fact that we can clearly and distinctly conceive of the body existing without the mind and vice versa entails that the body is really distinct from the mind. Ontological relationships are reflected in human thought when we are thinking clearly and distinctly, and if a modal abstraction is present, we can be certain that the items under consideration are the modes of a substance. On the other hand, when one thing can be thought while considering the other as not existing, the things are not modes after all, but really distinct substances. Otherwise, there is no criterion of intelligibility, and for Norris “all Truth is intelligible” (30). If we do not accept the standard of clarity and distinctness, no standard for human judgment remains.