The invention of printing also fostered the scientific revival by making it easy to spread knowledge abroad in every land. The pioneers of Renaissance science were Italians, but students in France, England, Germany, and other countries soon took up the work of enlightenment.
The names of some Renaissance scientists stand as landmarks in the history of thought. The first place must be given to Copernicus, the founder of modern astronomy. He was a Pole, but lived many years in Italy. Patient study and calculation led him to the conclusion that the earth turns upon its own axis, and, together with the planets, revolves around the sun. The book in which he announced this conclusion did not appear until the very end of his life. A copy of it reached him on his deathbed.
THE COPERNICAN THEORY
Medieval astronomers had generally accepted the Ptolemaic system. Some students before Copernicus had indeed suggested that the earth and planets might rotate about a central sun, but he first gave reasons for such a belief. The new theory met much opposition, not only in the universities, which clung to the time-honored Ptolemaic system, but also among theologians, who thought that it contradicted many statements in the Bible. Moreover, people could not easily reconcile themselves to the idea that the earth, instead of being the center of the universe, is only one member of the solar system, that it is, in fact, only a mere speck of cosmic dust.
An Italian scientist, Galileo, made one of the first telescopes--it was about as powerful as an opera glass--and turned it on the heavenly bodies with wonderful results. He found the sun moving unmistakably on its axis, Venus showing phases according to her position in relation to the sun, Jupiter accompanied by revolving moons, or satellites, and the Milky Way composed of a multitude of separate stars. Galileo rightly believed that these discoveries confirmed the theory of Copernicus.
Another man of genius, the German Kepler, worked out the mathematical laws which govern the movements of the planets. He made it clear that the planets revolve around sun in elliptical instead of circular orbits. Kepler's investigations afterwards led to the discovery of the principle of gravitation.
VESALIUS, 1514-1564 AND HARVEY, 1578-1657
Two other scientists did epochal work in a field far removed from astronomy. Vesalius, a Fleming, who studied in Italian medical schools, gave to the world the first careful description of the human body based on actual dissection. He was thus the founder of human anatomy. Harvey, an Englishman, after observing living animals, announced the discovery of the circulation of the blood. He thereby founded human physiology.
THE SCIENTIFIC METHOD
Copernicus, Galileo, Kepler, Vesalius, Harvey, and their fellow workers built up the scientific method. In the Middle Ages students had mostly been satisfied to accept what Aristotle and other philosophers had said, without trying to prove their statements. Kepler, for instance, was the first to disprove the Aristotelian idea that, as all perfect motion is circular, therefore the heavenly bodies must move in circular orbits. Similarly, the world had to wait many centuries before Harvey showed Aristotle's error in supposing that the blood arose in the liver, went thence to the heart, and by the veins was conducted over the body. The new scientific method rested on observation and experiment. Students learned at length to take nothing for granted, to set aside all authority, and to go straight to nature for their facts. As Lord Bacon, one of Shakespeare's contemporaries and a severe critic of the old scholasticism, declared, "All depends on keeping the eye steadily fixed upon the facts of nature, and so receiving their images simply as they are, for God forbid that we should give out a dream of our own imagination for a pattern of the world." Modern science, to which we owe so much, is a product of the Renaissance.