They are Ideas, _i.e._ concepts of the objective reality of which we cannot theoretically be certain. On the other hand, the highest final purpose to be worked out by us, by which alone we can become worthy of being ourselves the final purpose of creation, is an Idea which has in a practical reference objective reality for us, and is also a thing. But because we cannot furnish such reality to this concept in a theoretical point of view, it is a mere thing of faith of the pure Reason, along with God and Immortality, as the conditions under which alone we, in accordance with the constitution of our (human) Reason, can conceive the possibility of that effect of the use of our freedom in conformity with law. But belief in things of faith is a belief in a pure practical point of view, _i.e._ a moral faith, which proves nothing for theoretical pure rational cognition, but only for that which is practical and directed to the fulfilment of its duties; it in no way extends speculation or the practical rules of prudence in accordance with the principle of self-love. If the supreme principle of all moral laws is a postulate, so is also the possibility of its highest Object; and consequently, too, the condition under which we can think this possibility is postulated along with it and by it. Thus the cognition of the latter is neither knowledge nor opinion of the being and character of these conditions, regarded as theoretical cognition; but is a mere assumption in a reference which is practical and commanded for the moral use of our Reason.