Full Idea
In the most important point of the controversy between empiricists and rationalist, the rationalists were right, since logical principles are known to us, but cannot be proved by experience, since all proof presupposes them
Gist of Idea
The rationalists were right, because we know logical principles without experience
Source
Bertrand Russell (Problems of Philosophy [1912], Ch. 7)
Book Reference
Russell,Bertrand: 'The Problems of Philosophy' [OUP 1995], p.41
A Reaction
Russell initially presents this as the answer to 'innate ideas'. I would prefer to say, in the style of Descartes, that logic is self-evident to the natural light of reason. The debate isn't over. A Turing machine may be able to do logic.