17. The general principle illustrated by the particular example just discussed is here stated: knowledge without practice is imputed to a man as great and presumptuous sin. James reverts to the principle with which he started. Nothing more injures the soul than wasted impressions. Feelings exhaust themselves and evaporate, if not embodied in practice. As we will not act except we feel, so if we will not act out our feelings, we shall soon cease to feel.