Catholic Dictionary




A principle or fact that is assumed to be true and that is a basis for action or argumentation. In the philosophy of Immanuel Kant, it is one of the assumptions of practical reason. The existence of God is assumed to assure a moral order in the world, and the immortality of the soul is assumed so that moral perfection might continue beyond a person's mortal life on earth. But in the Kantian system these are mere postulates; they are said to be beyond rational proof.