But though admiration and respect may excite to inquiry, they cannot supply the want of it. What, then, is to be done in order to enter on this in a useful manner and one adapted to the loftiness of the subject? Examples may serve in this as a warning and also for imitation. The contemplation of the world began from the noblest spectacle that the human senses present to us, and that our understanding can bear to follow in their vast reach; and it ended- in astrology. Morality began with the noblest attribute of human nature, the development and cultivation of which give a prospect of infinite utility; and ended- in fanaticism or superstition. So it is with all crude attempts where the principal part of the business depends on the use of reason, a use which does not come of itself, like the use of the feet, by frequent exercise, especially when attributes are in question which cannot be directly exhibited in common experience. But after the maxim had come into vogue, though late, to examine carefully beforehand all the steps that reason purposes to take, and not to let it proceed otherwise than in the track of a previously well considered method, then the study of the structure of the universe took quite a different direction, and thereby attained an incomparably happier result. The fall of a stone, the motion of a sling, resolved into their elements and the forces that are manifested in them, and treated mathematically, produced at last that clear and henceforward unchangeable insight into the system of the world which, as observation is continued, may hope always to extend itself, but need never fear to be compelled to retreat.