  Peter van Inwagen has long defended a form of "modal skepticism," that is, skepticism concerning our knowledge of what states of affairs are possible (see his “Ontological Arguments,” 1977/1995). He applies it in a reply to the argument from evil (1991/1995, 1996, 2006). This is a vigorous application of items 3 and 4 from Alston's inventory. The idea here is that there is no reason to think that our modal intuitions about matters not related to ordinary life are reliable. It is plausible that the moral skepticism involved is just a sub-class of the modal skepticism involved, and even if it is not a subclass, all the issues are quite parallel. Thus for the sake of brevity the focus will be primarily on the “pure” modal skepticism here, though there will be a bit more to say about potential moral skepticism in Section 5.