Critique of Practical Reason
Immanuel Kant's theory of the will consists of the will being guided subjectively by maxims and objectively via laws. The former, maxims, are precepts of what is considered pleasurable, displeasurable, or neither. On the other hand, laws are objective, apprehended "a priori"—prior to experience. In other words, Kant's belief in the "a priori" proposes that the will is subject to a before-experience practical law—this is, according to Kant in the "Critique of Practical Reason", when the law is seen as "valid for the will of every rational being", which is also termed as "universal laws"