"All science has one aim, to find a theory of nature. We have theories of races and of functions, but scarcely yet a remote approach to an idea of creation. We are now so far from the road to truth that religious teachers dispute and hate each other, and speculative men are deemed unsound and frivolous. But to a sound judgment, the most abstract truth is the most practical. Whenever a true theory appears, it will be its own evidence. Its test is, that it will explain all phenomena. Now many are thought not only unexplained, but inexplicable--as language, sleep, madness, dreams, beasts, sex." (Vol. i. pp. 5, 6.) These extracts give us the key to Mr. Emerson's thought, which runs through all his writings, whether in prose or poetry; though more fully mastered and better defined in his later productions, essays, and lectures, than it was in his earliest production from which we have quoted. In studying these volumes, we are convinced that what the writer is after is reality, of which this outward, visible universe, both as a whole and in all its parts, symbolizes. He seeks life, not death; the living present, not the corpse of the past. Under this visible world, its various and ever-varying phenomena, lies the real world, one, identical, universal, and immutable, which it copies, mimics, or symbolizes. He agrees with Plato that the real thing is in the methexis, not in the mimesis; that is, in the idea, not in the individual and the sensible, the variable and the perishable. He wants unity and catholicity, and the science that does not attain to them is no real science at all. But as the mimesis, in his language the hieroglyphic, copies or imitates the methexic, we can, by studying it, arrive at the methexic, the reality copied or imitated.