Full Idea
Understanding and sensibility can determine an object only in combination; if we separate them, then we have intuitions without concepts, or concepts without intuitions, but in either case representations that we cannot relate to any determinate objects.
Clarification
'Intuitions' are provided by our 'sensibility'
Gist of Idea
We cannot represent objects unless we combine concepts with intuitions
Source
Immanuel Kant (Critique of Pure Reason [1781], B314/A258)
Book Reference
Kant,Immanuel: 'Critique of Pure Reason', ed/tr. Guyer,P /Wood,A W [CUO 1998], p.364
A Reaction
Although Kant seems to be rejecting the rationalist v empiricist debate, I take this to be evidence that Kant was a rationalist, because he thinks understanding cannot arise just from sensibility.