The radical craving is for life,--for the power to feel, to think, to love, to enjoy. And as it is impossible to reach a state in which we are not conscious that this power may be increased, we can find happiness only in continuous progress, in ceaseless self-development. This craving for fulness of life is essentially intellectual and moral, and its proper sphere of action is the world of thought and conduct. He who has a healthy appetite does not long for greater power to eat and drink. A sensible man who has sufficient wealth for independence and comfort does not wish for more money; but he who thinks and loves and acts in obedience to conscience feels that he is never able to do so well enough, and hence an inner impulse urges him to strive for greater power of life, for perfection. He is akin to all that is intelligible and good, and is drawn to bring himself into ever-increasing harmony with this high world. Hence attention is for him like a second nature, for attention springs from interest; and since he feels an affinity with all things, all things interest him. And what is thus impressed upon his mind and heart he is impelled to utter in deed or speech or gesture or song, or in whatever way thought and sentiment may manifest themselves. Attention and expression are thus the fundamental forms of self-activity, the primary and essential means of education, of developing intellectual and moral power. Interest is aroused and held by need, which creates desire. If we are hungry, whatever may help us to food interests us. Our first and indispensable interests relate to the things we need for self-preservation and the perpetuation of the race; and to awaken desire and stimulate effort to obtain them, instinct is sufficient, as we may see in the case of mere animals. But as progress is made, higher and more subtle wants are developed. We crave for more than food and wife and children. The social organism evolves itself; and as its complexity increases, the relations of the individual to the body of which he is a member are multiplied, and become more intricate. As we pass from the savage to the barbarous, and from the barbarous to the civilized state, intellect and conscience are brought more and more into play. Mental power gains the mastery over brute force, and little by little subdues the energies of inorganic nature, and makes them serve human ends. Iron is forced to become soft and malleable, and to assume every shape; the winds bear man across the seas; the sweet and gentle water is imprisoned and tortured until with its fierce breath it does work in comparison with which the mythical exploits of gods and demi-gods are as the play of children. Strength of mind and character takes precedence of strength of body. Hercules and Samson are but helpless infants in the presence of the thinker who reads Nature's secret and can compel her to do his bidding. If we bend our thoughts