About the end of the twelfth century there came a change. The human mind began to awake from its long lethargy; began to writhe and struggle against the dead hand of authority which held it down. The Crusades, as Guizot shows, had much to do with the rise of the new spirit, by causing educative contact with a high Saracenic civilization. Men began to wonder and to think. Heresy inevitably appeared, and became rife. In 1208 Innocent III established the Inquisition, but failed to strangle the infant Hercules. In 1209 began the massacre of the Albigenses, which continued more or less for about fifty years, the deaths being at least scores of thousands; but the blood of the martyrs was the seed of further freedom and enlightenment. Nature began to be studied, in however rudimentary a way, by Roger Bacon and his brother alchemists. The Reformation came, weakening ecclesiastical authority still further by dividing the dogmatic forces into two hostile camps, and thus giving science its chance. Galileo appeared, and did his work, though with many waverings, for Paul V and Urban VIII kept successively a heavy hand on him; he was imprisoned at seventy, when in failing health, and, some think, tortured--though this is uncertain, and his famous _e pur si muove_ is probably mythical. More important still, Francis Bacon, teaching with enthusiasm the method of observation and experiment. The conception of law, of rationality and regularity in nature, emerged; Kepler and Newton laid down the ground plan of the universe, evolving the formulæ which express the facts of molar motion. Uniformity in geology was shown by Lyell, while Darwin and his followers carried law into biological evolution. Then man became swelled-headed; became intoxicated with his successes. It had already been so with Hume, and it became more so with his disciples. Man treated his own limited experience as a criterion, and denied what was not represented by something similar therein. Especially was this the case when alleged facts had any connection with religion. Religion had tried to exterminate science, and it was natural enough that, in revenge, science should be hostile to anything associated with religion. Consequently, the scientific man flatly denied miracles, not only such stories as the rib of Adam and the talking serpent (concerning which even a church father like Origen had made merry in Gnostic days fifteen hundred years before), but also the healing miracles of Jesus, which to us are now beginning to look possible enough.