 Wittgenstein’s critique of set theory begins somewhat benignly in the Tractatus, where he denounces Logicism and says (6.031) that “[t]he theory of classes is completely superfluous in mathematics” because, at least in part, “the generality required in mathematics is not accidental generality”. In his middle period, Wittgenstein begins a full-out assault on set theory that never abates. Set theory, he says, is “utter nonsense” (PR §§145, 174; WVC 102; PG 464, 470), ‘wrong’ (PR §174), and ‘laughable’ (PG 464); its “pernicious idioms” (PR §173) mislead us and the crudest possible misinterpretation is the very impetus of its invention (Hintikka 1993: 24, 27).