Full Idea
Mathematics seems to be the one and only place where we humans can be absolutely sure that we got it right.
Gist of Idea
Mathematics is the only place where we are sure we are right
Source
James Robert Brown (Philosophy of Mathematics [1999], Ch. 1)
Book Reference
Brown,James Robert: 'Philosophy of Mathematics' [Routledge 2002], p.2
A Reaction
Apart from death and taxes, that is. Personally I am more certain of the keyboard I am typing on than I am of Pythagoras's Theorem, but the experts seem pretty confident about the number stuff.