 At first glance, one might think that Hypoxia is simply a case of undercutting defeat, and Aisha’s justification for believing G is defeated just as one’s perceptual beliefs might be defeated by, for instance, evidence of tricky lighting. But as Feldman (2005) argues, higher-order defeat and undercutting defeat are importantly different. Compare Hypoxia to a case in which you find out that a certain wall, which appears to be red, is illuminated by a red light. In the latter case, you might recognize that your experience as of a red wall generally supports the belief that the wall is red, and also recognize that you responded appropriately to that evidence before finding out about the tricky lighting. But in Hypoxia it seems that Aisha is not in a position to recognize either of these things. If she takes her higher-order evidence seriously, she will come to doubt whether her first-order evidence ever supported G in the first place. And she will also doubt whether she evaluated it correctly. (See Coates 2012 and Christensen 2010a for similar discussion.) So higher-order defeat is not simply undercutting defeat.