We admire the genius of a Kepler and a Copernicus, we sympathize with their enthusiasm as they observe the movements and develop the laws of the heavenly bodies; we look through the telescope, not without a feeling of awe, as it seems to lift us up, and bear us away into the unknown and the infinite, revealing to us what it would almost seem had never been intended for the human eye to see; but one thing is even more wonderful than the telescope--that is the mind that contrived it. One thing is more awe-inspiring than the stars, and that is the mind that discovers their hidden laws, and unlocks their complicated movements; and when we would observe the most curious and wonderful thing of all, we must leave the tubes and the tables, the calculations and the diagrams with which the man works, and study the man himself, the workman. _Relation of this Science to the practical Arts and Sciences._--But aside from the view now presented, the connection of mental science with other and practical arts and sciences is much more intimate than is usually supposed. Take for example the very noblest of all sciences--theology; we find it, in an important sense, based upon and receiving its shape and character from the views which we entertain, and the philosophy which we adopt of the human mind. Our philosophy underlies our theology, even as the solid strata that lie unseen beneath the surface give shape and contour and direction to the lofty mountain range. _Psychology as related to Theology._--Not to speak of the very idea which we form of the divine Being, borrowed as it must be, in a sense, from our previous conception of the human mind, and our own spiritual existence, not to speak of the arguments by which we seek to establish the existence of the divine Being, involving as they do some of the nicest and most important of the laws of human thought, what problems, we may ask, go deeper into the groundwork of any theological system than those pertaining to human ability, and the freedom of the will--the government of the affections and desires--the power of a man over himself, to be other and better than he is, and to do what God requires. But these are questions purely psychological. You cannot stir a step in the application of theology to practical life, till you have settled in some way these questions, and that view, whatever it be, crude or profound, intelligible or absurd, is, for the time, your science, your philosophy of the mind.