To get rid of errors meant originally to lose gods and heaven. The ideal world was the cause of metaphysics. Metaphysics which drew the investigation of the supernatural into the circle of its activity, did so for the purpose of enlightening the human mind. Thus its problem was from the outset of a twofold nature. It desires to throw light on the natural process of thought, which was temporarily unbalanced by a bent for the supernatural, and for this reason it first loses itself in the clouds. While human reason has now become soberer, the meaning of the term "metaphysics" has also been sobered down. Our contemporaneous metaphysicians speak no longer of such transcendental things as the ancients did. Present day metaphysics occupies itself with such abstract ideas as the thing and nothing, being and coming into being, matter and force, truth and error. Particularly the investigation of doubtful, erroneous, and evident or true understanding, which we here discuss, is a part of metaphysics. The term metaphysics, then, has a double meaning, one of them transcendental and extravagant, the other natural and within sober limits. Our sober task of demonstrating the positive outcome of philosophy that acquired sober methods in dealing with understanding also compels us to face transcendental metaphysics, which sobers down in the course of time and develops into its opposite, into pure, bare, naked physics. The divine has become human, the transcendental sober, and so understanding grows ever more unequivocal and evident in the progress of history. In order to become clear on the problem of understanding, we must cease to turn our eyes to any one individual opinion, thought, knowledge, or perception. We must rather consider the process of understanding in its entirety. We then notice the development from doubt to evidence, from errors to true understanding. At the same time we become aware how unwise it was to entertain such an exaggerated idea of the contrast between truth and error. Whoever searches for true and evident understanding will not find it in Jerusalem, nor in Jericho, nor in the spirit; not in any single thing, but in the universe. There the known emerges from the unknown so gradually that no beginning can be traced. Understanding comes into being and grows, is partly erroneous and partly accurate, becomes more and more evident. But there is never an absolutely true understanding any more than there can be an absolutely faulty one. Only the universe, but not any single thing, is absolute, imperishable, and impregnable.