 The second component is undermined because there is no type of judgment, and no type of subject matter, with respect to which error is impossible  ((3) above).  In order to have propositional knowledge even about what I am experiencing right now, I must classify it together with other things of the same type. And that requires the exercise of capacities that are inherently fallible: I may not have had enough experiences of things of the same sort to classify this one securely; I may not have attended to what I am experiencing with sufficient care; I may fail adequately to remember similar things that I experienced earlier; and so forth (1946: 90–97; 1962a: 104–131).