Full Idea
In mathematics, the most brilliant formalist of all was Hilbert
Gist of Idea
The most brilliant formalist was Hilbert
Source
James Robert Brown (Philosophy of Mathematics [1999], Ch. 5)
Book Reference
Brown,James Robert: 'Philosophy of Mathematics' [Routledge 2002], p.63
A Reaction
He seems to have developed his fully formalist views later in his career. See Mathematics|Basis of Mathematic|Formalism in our thematic section. Kreisel denies that Hilbert was a true formalist.