Rationalism is more than a movement of thought which realized itself at the end of the eighteenth and the beginning of the nineteenth centuries. It is a necessary phenomenon in all normal spiritual life. All real progress in the world is in the last analysis produced by rationalism. The principle, which was then established, of basing our views of the universe on thought and thought alone is valid for all time.^^

Rationalism is \"a necessary phenomenon in all normal spiritual life.\"

So proud men have thought, in all walks of life, since Giordano Bruno was burned alive for his cosmology on the Campo de\' Fiori in 1600. They have gone about their work simply enough. The scientists among them did not set out to be moralists or revolutionaries. William Harvey and Huygens, Euler and Avogadro, Darwin and Willard Gibbs and Marie Curie, Planck and Pavlov, practised their crafts modestly and steadfastly. Yet the values they seldom spoke of shone out of their work and entered their ages, and slowly re-made the minds of men. Slavery ceased to be a matter of course. The princelings of Europe fled from the gaming table. The empires of the Bourbons and the Hapsburgs crumbled. Men asked for the rights of man and for government by consent. By the beginning of the nineteenth century. Napoleon did not find a scientist to elevate tyranny into a system; that was done by the philosopher Hegel. Hegel had written his university dissertation to prove philosophially that there could be no more than the seven planets he new. It was unfortunate, and characteristic, that even as e wrote, on i January 1801, a working astronomer observed the eighth planet Ceres.^^

Scientists prove their virtue in their actions.