There are lots of things I don’t understand – say, the latest debates over whether neutrinos have mass or the way that Fermat’s last theorem was (apparently) proven recently. But from 50 years in this game, I have learned two things: (1) I can ask friends who work in these areas to explain it to me at a level that I can understand, and they can do so, without particular difficulty; (2) if I’m interested, I can proceed to learn more so that I will come to understand it. Now Derrida, Lacan, Lyotard, Kristeva, etc. — even Foucault, whom I knew and liked, and who was somewhat different from the rest — write things that I also don’t understand, but (1) and (2) don’t hold: no one who says they do understand can explain it to me and I haven’t a clue as to how to proceed to overcome my failures. That leaves one of two possibilities: (a) some new advance in intellectual life has been made, perhaps some sudden genetic mutation, which has created a form of “theory” that is beyond quantum theory, topology, etc., in depth and profundity; or (b) … I won’t spell it out.