Critique of practical reason

The second of Kant’s three critiques, Critique of Practical Reason forms the center of Kantian philosophy. Kant establishes his role as a vindicator of the truth of Christianity in this work, published in 1788, and he approaches his proof by presenting positive affirmations of the immortality of the soul and the existence of God. The philosopher offers an argument concerning the summum bonum of life: people should not simply search after happiness, but follow the moral law and seek to become worthy of the happiness that God can bestow. This seminal text in the history of moral philosophy offers the most complete statement of Kant’s theory of free will and a full development of his practical metaphysics.