 A willingness to allow ‘natural’ to play these multifarious syntactic roles is a central development in Sider  (2011).  (Sider signals this by using the word ‘structural’ instead of ‘perfectly natural’.) As well as defending the intelligibility and importance of questions posed in such terms, Sider defends certain specific claims of the relevant sort: e.g. that either Structural(and) or Structural(or); that either Structural(∃) or Structural(∀); that Structural(Structural); and that it is not the case that Structural(necessarily).