Young Galileo, with all the energy and imprudence of youth--what a blessing that youth has a little imprudence and disregard of consequences in pursuing a high ideal!--as soon as he perceived that his instructors were wrong on the subject of falling bodies, instantly informed them of the fact. Whether he expected them to be pleased or not is a question. Anyhow, they were not pleased, but were much annoyed by his impertinent arrogance. It is, perhaps, difficult for us now to appreciate precisely their position. These doctrines of antiquity, which had come down hoary with age, and the discovery of which had reawakened learning and quickened intellectual life, were accepted less as a science or a philosophy than as a religion. Had they regarded Aristotle as a verbally inspired writer, they could not have received his statements with more unhesitating conviction. In any dispute as to a question of fact, such as the one before us concerning the laws of falling bodies, their method was not to make an experiment, but to turn over the pages of Aristotle; and he who could quote chapter and verse of this great writer was held to settle the question and raise it above the reach of controversy. It is very necessary for us to realize this state of things clearly, because otherwise the attitude of the learned of those days toward every new discovery seems stupid and almost insane. They had a crystallized system of truth, perfect, symmetrical; it wanted no novelty, no additions; every addition or growth was an imperfection, an excrescence, a deformity. Progress was unnecessary and undesired. The Church had a rigid system of dogma which must be accepted in its entirety on pain of being treated as a heretic. Philosophers had a cast-iron system of truth to match--a system founded upon Aristotle--and so interwoven with the great theological dogmas that to question one was almost equivalent to casting doubt upon the other. In such an atmosphere true science was impossible. The life-blood of science is growth, expansion, freedom, development. Before it could appear it must throw off these old shackles of centuries. It must burst its old skin, and emerge, worn with the struggle, weakly and unprotected, but free and able to grow and to expand. The conflict was inevitable, and it was severe. Is it over yet? I fear not quite, though so nearly as to disturb science hardly at all. Then it was different: it was terrible. Honor to the men who bore the first shock of the battle!