But SELF-knowledge is, of all its other kinds, both the most useful and promotive of personal and universal happiness and success. "Know thyself" was written, in golden capitals, upon the splendid temple of Delphos, as the most important maxim the wise men of Greece could transmit to unborn generations; and the Scriptures wisely command us to "search our own hearts." Since all happiness flows from obeying, and all pain from violating, the LAWS OF OUR BEING, to know our own selves is to know these laws, and becomes the first step in the road of their obedience, which is life. Self-knowledge, by teaching the laws and conditions of life and health, becomes the most efficacious means of prolonging the former and increasing the latter--both of which are _paramount_ conditions of enjoying and accomplishing. It also shows us our natural talents, capabilities, virtues, vices, strong and weak points, liabilities to err, etc., and thereby points out, unmistakably, those occupations and spheres in which we can and cannot succeed and shine; and develops the laws and conditions of human and personal virtue and moral perfection, as well as of vice, and how to avoid it. It is, therefore, the quintessence of all knowledge; places its possessor upon the very acme of enjoyment and perfection; and bestows the highest powers and richest treasures mortals can possess. In short, to know ourselves perfectly, is to know every law of our being, every condition of happiness, and every cause of suffering; and to _practice_ such knowledge, is to render ourselves as perfectly happy, throughout every department of our being, as we can possibly be and live. And since nothing in nature stands alone, but each is reciprocally related to all, and all, collectively, form one magnificent whole--since all stars and worlds mutually act and react upon each other, to cause day and night, summer and winter, sun and rain, blossom and fruit; since every genus, species, and individual throughout nature is second or sixteenth cousin to every other; and since man is the epitome of universal nature, the embodiment of all her functions, the focus of all her light, and representative of all her perfections--of course to understand _him_ thoroughly is to know _all_ things. Nor can nature be studied advantageously without him for a text-book, nor he without her.