With this critick of the ideas of the reason there is still another question. If these ideas have no objective significance, why are they found within us? Since they are necessary, they will doubtless have some good purpose to subserve. What this purpose is, has already been indicated in speaking of the theological idea. Though not constitutive, yet are they regulative principles. We cannot better order the faculties of our soul, than by acting “_as if_” there were a soul. The cosmological idea leads us to consider the world “_as if_” the series of causes were infinite, without, however, excluding an intelligent cause. The theological idea enables us to look upon the world in all its complexity, as a regulated unity. Thus, while these ideas of the reason are not constitutive principles, by means of which our knowledge could be widened beyond experience, they are regulative principles, by means of which our experience may be ordered, and brought under certain hypothetical unities. These three ideas, therefore, the psychological, the cosmological, and the theological, do not form an organon for the discovery of truth, but only a canon for the simplification and systematizing of our experiences. Besides their regulative significance, these ideas of the reason have also a practical importance. There is a sufficient certainty, not objective, but subjective, which is especially of a practical nature, and is called belief or confidence. If the freedom of the will, the immortality of the soul, and the existence of a God, are three cardinal principles, which, though not in any way contributing to our knowledge, are yet pressed continually upon us by the reason, this difficulty is removed in the practical field where these ideas have their peculiar significance for the moral confidence. This confidence is not logical, but moral certainty. Since it rests wholly upon subjective grounds, upon the moral character, I cannot say it is morally certain that there is a God, but only I am morally certain, &c. That is, the belief in a God and in another world is so interwoven with my moral character, that I am in just as much danger of losing this character as of being deprived of this belief. We are thus brought to the basis of the PRACTICAL REASON.