Kant classifies the uses of reason as public and private. The public use of reason is discourse in the public sphere, such as political discourse (argument and analysis); the private use of reason is rational argument, such as that used by a person entrusted with a duty, either official or organizational. Skillfully praising King Frederick II of Prussia (r. 1740–86) for his intellectual receptiveness to the political, social, and cultural ideas of the Enlightenment, the philosopher Kant proposes that an enlightened prince is one who instructs his subjects to: "Argue as much as you will, and about what you will, only obey!"