  It was the Franciscan John Duns Scotus, more than anyone else, who put an end to the theory of divine illumination. As Steven Marrone (2001) has shown in detail, there were various authors at the end of the thirteenth century who were ready to reject illumination. Indeed, Ghent himself gave illumination less and less attention in his later years. Still, it was Scotus who provided the most impressive and extensive philosophical alternative to illumination theory. (As John Boler remarked in correspondence, “as with Nixon’s trip to China, it probably could only be done by a Franciscan.”) Scotus criticizes Ghent’s argument in detail (Ordinatio I.3.1.4), arguing against Ghent’s own arguments, against the skeptical consequences that would allegedly come from giving up divine illumination, and against the viability of such illumination in its own right. With respect to the last point, Scotus argues that if human cognition were fallible in the way Ghent argues, then outside illumination could not, even in principle, ensure “certain and pure knowledge.” On Ghent’s account, the human mind cooperates with the divine light in achieving such knowledge. Scotus replies: 