Full Idea
It is necessary to study the essence of mathematical proof itself if one wishes to answer such questions as the one about decidability in a finite number of operations.
Gist of Idea
To decide some questions, we must study the essence of mathematical proof itself
Source
David Hilbert (Axiomatic Thought [1918], [53])
Book Reference
'From Kant to Hilbert: sourcebook Vol. 2', ed/tr. Ewald,William [OUP 1996], p.1115