Full Idea
In order to be sure that new expression can be translated into expressions not containing them, it is necessary to have a survey of all possible expressions, and this can be furnished only by syntactical considerations.
Gist of Idea
A logical system needs a syntactical survey of all possible expressions
Source
Kurt Gödel (Russell's Mathematical Logic [1944], p.448)
Book Reference
'Philosophy of Mathematics: readings (2nd)', ed/tr. Benacerraf/Putnam [CUP 1983], p.448
A Reaction
[compressed]