The Scientific Revolution is generally viewed as a 17th-century phenomenon. Most historians consider it to have started with the astronomical discoveries of individuals like Kepler and Galileo and ended with the publication of Newton’s major works. Science involves using reason, observation, testing, and systematic thought to uncover truths about the world and about people, animals, and things in the world. “Science” didn’t really exist before the Scientific Revolution. Scientists in ancient and medieval times were really philosophers who drew conclusions based on deductive reasoning; they rarely conducted practical experiments. In medieval times “science” had very little basis in fact and drew more from superstition and religious belief. Chemistry, alchemy aimed to develop potions that would do things such as change iron into gold, cure all disease, or bestow immortality. Astrology was based on the concept that the positions and conditions of celestial bodies could influence human existence, both positively and negatively. Practitioners of astrology would often claim that human suffering (including sickness) could be explained by the position of the stars. Factors Leading to the Scientific Revolution The first universities appeared during the Middle Ages. Universities initially focused law and philosophy, Gradually expanded their subject offerings and established professorships in areas such as mathematics, astronomy, medicine, and other science-related disciplines. The Crusades and trade networks brought Europeans into greater contact with Muslim societies. Cultural and intellectual exchanges occurred; this helped improve Europeans’ understanding of mathematical principles and science. The Renaissance inspired advances in art and literature. Europeans looked beyond the church and the Bible for knowledge and truth. Wealthy families such as the Medici in Italy also supported scientific research. The Age of Exploration was a factor as well. Navigating across the Atlantic Ocean and around Africa motivated advances in mathematics, astronomy, and cartography. European monarchs provided funding and/or support for scientific research. The philosophy of rationalism: all knowledge comes from reason. René Descartes a philosopher and mathematician is regarded as the father of modern rationalism. In Discourse on Method and The Meditations, he reasoned that all of his prior knowledge was subject to doubt because it was based on traditional beliefs rather than on reason. He pondered what he could honestly say he knew to be true, going so far as to doubt whether he was awake or dreaming—or if he even existed. He rethought his world view: his thoughts existed, which then suggested the existence of a thinking being—himself. He then came to his famous conclusion, “Cogito ergo sum,” which means “I think, therefore, I am.” The philosophy of empiricism: the only real way to acquire knowledge is through experience; observation. Empiricism is the opposite of rationalism experience vs. reason. Some of the first writings on empiricism came in the 13th century from Roger Bacon, an English scholar. In Opus Maius, “There are two modes of knowledge, through argument and experience. ‘Argument’ brings conclusions and compels us to concede them, but it does not cause certainty nor remove doubt in order that the mind may remain at rest in truth, unless this is provided by experience.” Empiricism also helped lead to the development of the scientific method. English philosopher Sir Francis Bacon laid the theoretical groundwork for what became known as the scientific method. Inductive reasoning, using concrete facts to reach conclusions. He believed that all scientific research should rely on careful observation and experimentation rather than thought and reasoning. He believed the data obtained should then be recorded and analyzed according to logic and reason, then used to produce a testable hypothesis. The Scientific Method Observe -> Develop a theory -> Test the theory How wrong was Aristotle? Aristotle wrote many works concerning biology, zoology, and physics. He relied on reason rather than empirical evidence and did not conduct experiments; many of his conclusions were incorrect. He hypothesized that gravity occurred because objects were attracted to the Earth’s core, and theorized that heavier objects would fall to earth more quickly than lighter ones. He also came up with a theory of astronomy which hypothesized that a motionless Earth lay at the center of the universe surrounded by concentric crystal spheres. One sphere held the moon, another the sun, others held each of the five known planets and the last held what the ancient Greeks referred to as the “fixed stars.” Ptolemy, another ancient Greek, was an influential mathematician, astronomer, and geographer who lived in the 2nd century CE. He wrote Syntaxis, he gave a comprehensive overview of mathematical astronomy and formalized the concept of a geocentric (meaning “earth-centered”) model of the universe. He also offered detailed mathematical rules describing the motion of each of the planets. Models of the Universe: Geocentric Geocentric: the Earth is at the center of the universe; all heavenly bodies move around the Earth Models of the Universe: Heliocentric Heliocentric: the Sun is at the center of the universe; all heavenly bodies move around the Sun—including the Earth In 1514, Copernicus wrote Commentariolus, a short, handwritten notebook of observations in which he laid out the foundations of his heliocentric theories. He did not sign his name to Commentariolus and distributed it only to a few friends, feared it might anger of the Catholic Church. He then wrote Concerning the Revolutions of the Celestial Spheres, in which he expanded on the heliocentric model he had proposed in Commentariolus. It was published just before his death. Tycho Brahe is important largely because he gathered a huge amount of astronomical data with unprecedented accuracy. He also came up with a theory of the heavens that offered an alternative to both the Ptolemaic and Copernican models, arguing that the Sun and the Moon revolved around Earth while other planets in the solar system revolved around the Sun. The latter assertion helped answer observationbased criticisms about earlier conceptions of the Universe without requiring a heliocentric model of the universe. Johannes Kepler originally studied theology but ended up as a professor of mathematics. As a student of Tycho, he studied both his teacher’s works as well as the writings of Copernicus. Kepler claimed that while Tycho’s data was correct, his interpretations of the data were incorrect; he further argued that Tycho’s data actually proved Copernicus correct. Kepler also took issue with Copernicus’ claim that astronomical bodies moved in circles, asserting instead that they moved in elliptical patterns— an assertion that later proved correct. Kepler used Tycho’s data and his own observations to develop three laws of planetary motion and proved the core of heliocentric theory. Galileo Galilei is considered the father of modern physics, astronomy, and the “Father of Science.” He created several different telescopes and used them to record extraordinary amounts of data. His interpretations of the data yielded some remarkable discoveries. •Stars were farther away than planets •Mountains on the Moon •Jupiter has four moons •Saturn has rings He eventually compiled and published his observations in a 1610 work titled The Starry Messenger. Galileo’s work, combined with the previous discoveries of Copernicus and Kepler, proved Ptolemaic model of the universe was incorrect. He also conducted a famous experiment in which he showed Aristotle had been mistaken in his assumption that objects of different weights falling at different rates of speed. He establish an explanation of speed and motion. Galileo also created a thermometer, which permitted more accurate data collection. The Catholic Church perceived heliocentric theories as questioning long-held doctrinal teachings about the nature of the heavens. The Church ultimately found it easier to condemn the heliocentric view of the universe as “foolish” and “formally heretical” rather than figure out how it could fit into a religious framework. In 1630, Galileo had received permission from the Vatican to publish the Dialogue. Months after its first printing in 1632, Pope Urban VIII ordered a halt to distribution of the book and created a special commission to investigate whether the work was heretical. The commission recommended that Galileo’s case be referred to the Roman Inquisition, which ruled on cases of suspected heresy. The tribunal threatened Galileo with torture, imprisonment, and even burning at the stake if he refused to recant his views; eventually, he did. He was sentenced to house arrest. Galileo was forced to recite prayers every day and wasn’t supposed to be allowed visitors. The trial had a chilling effect on scientists practicing in Italy and pushed the focus of mainstream science north to places like England and France. It also highlighted the tensions between religion and science. Sir Isaac Newton He synthesized the works of Copernicus, Kepler, and Galileo in formulating his theories on gravity and motion. In the Principia, perhaps the most influential science book ever written. he presented a new view of the world, expressed in mechanical terms. Newton portrayed the universe as a large clock that operated by a consistent set of rules. The book was well received by the academic community of Europe at the time and his new world view became the accepted paradigm until the atomic age. Legend holds that Newton “discovered” gravity when an apple fell on his head from a nearby tree, although many believed Newton—who loved to tell stories—made the whole thing up.