Full Idea
Russell's theory of types avoided the paradoxes, but it had the result that features common to different levels of the hierarchy become uncapturable (since any attempt to capture them would involve a predicate which disobeyed the hierarchy restrictions).
Gist of Idea
Type theory means that features shared by different levels cannot be expressed
Source
comment on Bertrand Russell (Mathematical logic and theory of types [1908]) by Michael Morris - Guidebook to Wittgenstein's Tractatus 2H
Book Reference
Morris,Michael: 'Guidebook to Wittgenstein's Tractatus' [Routledge 2008], p.112