Full Idea
A great part, perhaps the greatest part, of the business of our reason consists in analyses of the concepts that we already have of objects.
Gist of Idea
Our reason mostly analyses concepts we already have of objects
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
I am quite happy to think of this as the central and crucial aspect of philosophy, though I am much more sceptical about purely linguistic analysis, as developed by Frege and Russell. It describes much of what Aristotle did.