 Since Wittgenstein did not adopt this expedient, it seems likely that he would have regarded the predicate “x is a complex consisting of a and b, combined so that aRb” as meaningless in virtue of — among other things — its containing ineliminable occurrences of the pseudo-concepts “complex,” “combination,” and “constitution.” Only the first of these notions figures on his list of pseudo-concepts in the Tractatus (4.1272), but there is no indication that that list is supposed to be exhaustive. 