Full Idea
The understanding is not capable of intuiting anything, and the senses are not capable of thinking anything. Only from their unification can cognition arise.
Gist of Idea
Understanding has no intuitions, and senses no thought, so knowledge needs their unity
Source
Immanuel Kant (Critique of Pure Reason [1781], B075/A51)
Book Reference
Kant,Immanuel: 'Critique of Pure Reason', ed/tr. Guyer,P /Wood,A W [CUO 1998], p.194
A Reaction
At first glance this seems to settle the rationalist-empiricist debate at a stroke, by rejecting the rationalist dream of knowledge arising from pure intuitions, and the empiricist dream of knowledge from pure sensation. It can't be that simple, though…