But although all our knowledge begins with experience, it does not follow that it arises from experience.

Kant makes this remark at the very opening of his critical philosophy, in the Introduction to the first edition of the Critique of Pure Reason (1781). He is setting up the central problem that motivates the work: how synthetic a priori knowledge is possible. Against both rationalists who treat knowledge as derivable from pure reason alone and empiricists who reduce it to sensory impressions, Kant argues that experience is the occasion that “awakens” cognition, but the mind contributes necessary forms and concepts that structure what can be experienced at all. The line introduces his “Copernican” turn: objects of experience must conform to our mode of cognition.

The sentence distinguishes the starting point of knowledge from its ultimate sources. Kant grants empiricism its key insight—without sensory input, cognition never gets underway—yet denies that experience can explain the necessity and universality found in mathematics, basic principles of natural science, and the very framework of objective experience. For Kant, the mind supplies a priori forms (notably space and time) and fundamental concepts (the categories) that organize sensations into coherent objects and lawful relations. Thus experience is not a raw given that simply imprints itself on us; it is already shaped by conditions of possible experience. The quote signals Kant’s attempt to reconcile empiricism and rationalism by showing how both receptivity and spontaneity are required for knowledge.