 Karttunen, a proponent of the second option, takes wh-complements to denote sets of true propositions, so that ‘what John reads’ denotes (Karttunen 1977, 20) “a set which contains, for each thing that John reads, the proposition that he reads it.” On Groenendijk and Stokhof’s account, by contrast, ‘what John reads’ denotes the proposition that is true in a possible world if and only if the set of things that John reads in that world equals the set of things John in fact reads. That is, ‘what John reads’ denotes a proposition that entails for each thing John reads that he reads it and for each thing John does not read that he does not read it. Thus if one knows what John reads, it follows on Groenendijk and Stokhof’s account (but not on Karttunen’s) that one knows what John does not read. Also, on Groenendijk and Stokhof’s account, the difference between knowing-that and knowing-wh amounts to a difference in what we might call the rigidity of the complement. Consider the claim that I know that John reads Moby Dick and the claim that I know what John reads. The term ‘that John reads Moby Dick ’ refers to the same proposition at every possible world; the term ‘what John reads’ refers to different propositions at worlds at which John reads different things (and refers to the proposition that John reads Moby Dick at those worlds at which Moby Dick is the one and only thing that John reads). 