The Critique of Practical Reason

The second of the three critiques, The Critique of Practical Reason, takes up the subject of moral philosophy. Kant argues that the fundamental rule of morality is that it holds universally. He criticizes previous ethicists for saying that the moral person is working toward the greatest good rather than that the greatest good is the thing the moral person is aiming for. Morality determines the greatest good, not the other way around. Kant concludes the work with a plan for moral education.