The need for a solid discipline as a grounding for rationalism is made clear by the aberrations of many of the earlier religious doubters. Bodin, as we have seen, held fanatically by witchcraft; and he likewise accepted astrology, as did many half-developed Italian freethinkers who rejected the ideas of demons and sorcery, and doubted much concerning the Bible. Men reasoned on such matters by the light of their training, of what seemed to be probability, and of scanty evidence, in matters where the traditional hypotheses could be properly checked only by minute and patient scrutiny. Thus the disbelievers in astrology were as a rule bigoted Christians who, like Luther, merely rejected it as unscriptural, while Melanchthon leant to the belief. Of the early English Protestants many theologically rejected it as regards the moral life, while assenting to the theory of astral influence on men's affairs in other regards. Only with new science could come the rational challenge; and even men like Bacon, who consciously strove after scientific method, remained partly prepossessed by the old belief in astral forces. The word "influence," in this sense, constantly appears in all kinds of Tudor and early Stuart literature. It has been said with broad truth that whereas Greece, with her dialectic discipline, exhorted men to make their beliefs agree with one another, and the Christian Church ordered them to make their beliefs agree with her dogma, the modern spirit demands that beliefs should agree with facts. Such a spirit first promoted and then was immensely promoted by the study of natural science. Even in the Middle Ages, as in antiquity, physicians were proverbially given to irreligion; and the study of physics was still more conducive to religious doubt than that of physic. In England the naturalistic spirit, as we may term it, was notably popularized by Bacon in the course of the seventeenth century, but the effectual growth of Protestant fanaticism began in his day, and had to run its course before much energy was available for scientific research; though both Gilbert the electrician and Harvey the discoverer of the circulation of the blood belonged to Bacon's generation. Only a small number of superior minds were capable of the scientific attitude. But even before the Restoration educated Englishmen were weary enough of strife to begin the gatherings which afterwards became the Royal Society, devoted strictly to scientific inquiry, with a positive veto on all theological discussion.