...Every truth, every new idea, has to battle against old established notions. If the new idea is persisted in, which is ordinarily the case, a struggle must ensue. The old idea resists, refuses to yield, no matter how false, ridiculous, or pernicious it may be. Yield, however, it must, and does in the course of time. Truth must win in the long run, though it has to fight its way through depths of ignorance, prejudice, and superstition, sustained by hate, bigotry, terrorism, and persecution. As century after century passed in the Dark Ages, apostles of science and truth appeared, here and there, now and then, calm, dignified, patient, persistent and persevering, untiring, self-denying, men of superior intellect, unswayed and undismayed by existing authorities. These men gave us, though not a complete, a very ample revelation of nature, unfolding its mysteries, explaining its phenomena, making known the truth...