_Relation to other Sciences._--The _importance_ of mental science appears from its relation to other sciences. We find in nature a gradually ascending series. As we pass from the observation and study of the mineral to the forms of vegetable life, from the plant to the insect--and thence to the animal, and from the animal, in his various orders and classes, to man, the highest type of animated existence on the earth, we are conscious of a progression in the rank and dignity of that which we contemplate. But it is only when we turn our attention from all these to the intelligence that dwells within the man, and makes him master and lord of this lower world, that we stand upon the summit of elevation and overlook the wide field of previous inquiry. Toward this all other sciences lead, as paths along the mountain side, starting from different points, and running in different directions, converge toward a common terminus at the summit. As the mineral, the plant, the insect, the animal, in all their curious and wonderful organizations, are necessarily inferior to man, so is the science of them, however important and useful, subordinate to the science of man himself; and as the human body, curious and wonderful in its organism and its laws, is nevertheless inferior in dignity and worth to the spirit that dwells within, and is the true lord of this fair castle and this wide and beautiful domain, so is the science of the body, its mechanism, its chemistry, its anatomy, its laws, inferior to the science of the mind, the divinity within. _Other Sciences Creations of the Mind._--Many of the sciences justly regarded as the most noble, are themselves the creations of the mind. Such, for example, is the science of number and quantity--a science leading to the most sublime results, as in the calculations of the astronomer, yet a pure product of the human intellect. Indeed what is all science but the work of mind? The creations of art are wonderful, but the mind that can conceive and execute those creations is still more to be admired. Language is wonderful, but chiefly as a production and expression of mind. The richness, the affluence, the eloquence, the exactness, the beauty, for example, of the Greek tongue, of what are these the qualities, and where did they dwell--in the Greek language, or in the Greek mind? Which is really the more noble and wonderful then, the language itself, or the mind that called into being such a language, and employed it as an instrument of expression; and of which is the science most noble and worthy of regard?