Full Idea
Analysis of concepts affords us a multitude of cognitions which are illuminations or clarifications of what is already thought, and yields a priori cognition. Reason also surreptitiously makes a priori assertions, which add something alien to the concept.
Gist of Idea
One sort of a priori knowledge just analyses given concepts, but another ventures further
Source
Immanuel Kant (Critique of Pure Reason [1781], B009/A5)
Book Reference
Kant,Immanuel: 'Critique of Pure Reason', ed/tr. Guyer,P /Wood,A W [CUO 1998], p.140
A Reaction
This is at the heart of Kant's programme, to disentangle these two, and especially to turn a strong critical light on the second one. He does not deny the possibility of a priori knowledge beyond conceptual analysis, but is wary.