"Mathematics is independent of logic. ...Where mathematical objects are given by their relations to the ...parts of a mathematical structure, we transform these ...by a sequence of tautologies and thus proceed to the relations of the object to other components of the structure. ...The fact that ...a theorem is ...only understood after a chain of tautologies, proves merely that we build our structures too complicated to be comprehended in one view."
January 1, 1970
https://en.wikiquote.org/wiki/L._E._J._Brouwer