On the Concept of Real Use of Reason

Abstract

The subject matter of the article is the concept of “the real use of reason” (usus realis) alluded to by Kant in Critique of Pure Reason A299/B355 and in A305/B362. After comparing it with the “real use of understanding” examined in De mundi sensibilis and in the Critique of Pure Reason, the real use of reason is presented as a legitimate and useful performance that should be distinguished from the deceiving illusion induced by an appearance generated by reason itself. The real use of reason (its production of ideas and principles) proves itself as an unavoidable condition for the regulative use of ideas as well as a condition for the production of a critical metaphysics.

Keywords

• idea
• reason
• illusion
• illusory appearance
• schein
• usus realis
• realer gebrauch
• real use of reason