The development of the human race is often marked by periods of intense change in which profound new ideas or practices emerge, that not only define that era but also the eras to come. There is perhaps no other period more integral to the shaping of civilization into what it is now than the age of the Scientific Revolution. What are historians referring to when they mention this period of time? How did it come about and what legacy did it leave behind? And if it wasn’t strictly a violent conflict, what exactly about it made it a revolution? These are all questions that will be answered shortly. Along the way, it will also become clear how the Scientific Revolution evolved and matured, and what important factors and figures allowed this movement to proliferate.
The period prior to the Scientific Revolution is commonly acknowledged as the Renaissance. During this time, science was the compilation of knowledge based on the bedrock of ancient Greek teachings, and to a lesser extent, medieval scientific discoveries. There was a direct link between traits of practicing Christianity and the subsequent rise of science. As an intellectual figure, Aristotle still loomed large in influence despite having been dead for thousands of years. His most popular ideas, among the last shreds of “science” from classical antiquity that still had a place, would soon be challenged relentlessly. The Aristotelian tradition of pure deduction would be spurned for the new practice of mixing deduction with inductive reasoning. The invention of the printing press and the sponsorship of scientists by patrons of high status were both important factors in the rapid discovery and spread of knowledge (Bramly, 23).
Most historians would agree that the release of Nicolas Copernicus’ work On the Revolutions of the Celestial Spheres in 1543 marked the official beginning of the Scientific Revolution. Copernicus proposed replacing the geocentric model that had Earth at the center of the universe with a heliocentric model, which theorized that Earth was just one of a host of planets rotating the sun. The geocentric model popularized by Aristotle had been widely accepted in the field of astronomy for the last five thousand years. (Ferguson, 44) At the core of that model was the philosophy that Earth was a world rampant with flaws and imperfections, whereas the heavenly bodies were physically perfect in every way. Matter on Earth was formed from the four elements of earth, water, fire, and air; what lay above was thought to be made of a material called “aether”. Copernicus’ new model not only introduced a new way of understanding the way the planets moved, it also upended the idea that there was something divine about them as opposed to the mundaneness of Earth. Upon the release of the work, many high ranking intellectuals within the Church as well as the pope himself were actually intrigued by the new model and wanted to see it more fleshed out. In fact, the Gregorian calendar that is still in use today was based on Copernicus’ model. This one work, however, was not enough to convince the other leading figures in the field of astronomy at the time that Aristotle had been wrong all along. In addition to there not being many copies produced of the first edition, it was also a difficult text to understand, mainly due to a variety of astronomical mathematics techniques that were novel at the time. (Goble, 68)
Johannes Kepler was the first significant astronomer to consider Copernicus’ model to be a scientifically accurate one. He read Copernicus’ research in college and proceeded to make it his life’s work to prove in further detail the validity of the heliocentric model. Much of his work was done under the guidance of the Danish astronomer Tycho Brahe. Brahe was a believer in the traditional geocentric model, but he made numerous key observations that would aid in discrediting Aristotle’s long held ideas. For instance, he found he was unable to determine the parallax of a comet, something that clearly implied that the comet’s trajectory had extended past the Moon. This was in direct contradiction to the Aristotelian concept of a celestial sphere. In November of 1572, he also observed a supernova occur in the Cassiopeia constellation. Kepler himself observed another one in 1604. The existence of these “new stars” meant that the heavens were not perfect and unchanging as previously thought. Kepler used these observations that he and Brahe had made before Brahe’s death in conjunction with Copernicus’ computations to create the Rudolphine Tables in 1627, which was a set of planetary tables that predicted the movements of the planets with great accuracy. More importantly, his analysis of planetary movements led to him developing the three fundamental laws of planetary motion. Kepler was firmly convinced that there was a mathematical connection that singularly explained planetary motion. His three laws stated that 1) planets orbit in ellipses around the Sun, 2) the speed that a planet is moving is inversely related to how far it its center is from the center of the Sun, and 3) a planet’s orbital period is directly related to how far it is from the Sun. This third law would later have a major role in the discovery of the law of gravity by Isaac Newton. (Hatch)
The other hugely important figure that helped advance the field of astronomy during the Scientific Revolution was Galileo Galilei, who has also been called the first physicist. Galileo was doubly significant not only because of the groundbreaking nature of his discoveries, but also due to the methods he used to make them. Before the 17th century, all areas of knowledge were generally viewed as just different branches of philosophy. The same methods of logic were used to explain phenomena found in nature, religion, and civilization. Galileo was among the first pioneers to not only use reason, but to also use a distinct scientific method along with concrete mathematical calculations to conduct his experiments. Aristotle and his followers throughout the centuries preceding the Scientific Revolution promoted a series of unshakeable “truths” that supposedly described the causes of events on Earth and throughout the universe. Galileo was unimpressed with the reasoning behind these Aristotelian concepts of motion and set out to answer the question of how objects move as opposed to why, from something as small as a feather to the planets. While Galileo’s contemporaries still believed in the notion that heavy objects fall faster than lighter ones, Galileo was inclined to disagree based on what he had seen watching hailstones fall. To him, hailstones of different sixes seemed to hit the ground simultaneously. In one of his most famous experiments, Galileo was said to have tested the speed of falling weights from the top of the Leaning Tower of Pisa. Such a hands on approach was almost unheard of among traditional philosophers. He also proposed a simple thought experiment to definitively prove Aristotle wrong: “For, if we suppose the two blocks equal and close together, all agree they will fall with equal speed. Now, imagine them joining together while falling. Why should they double their speed as Aristotle claimed? Therefore, there is no reason why blocks of the same material but of different weights should fall at unequal rates.” (MacLachlan, 24) Later on Galileo would claim that a heavier density would cause an object to fall faster through air. He applied Archimedes’ principle that water has buoyancy to air, reasoning that air must also have buoyancy in order to support objects of different densities. He even declared that in a vacuum, all objects would have the same rate of falling. This was proved to be true with the invention of vacuum pumps in the mid-17th century, and more dramatically, with the experiment of a feather and a hammer falling next to each other on the moon during the Apollo 15 mission of 1971. Astronaut David R. Scott said, “This proves that Mr. Galileo is correct.”
To further emphasize the do-it-yourself mentality that Galileo had in his research, Galileo was able to publish his iconic Starry Messenger pamphlet only due to the fact that he had created a telescope for himself that magnified distant objects by twenty times. In 1609, Galileo received word that Dutch spyglass makers had managed to produce telescopes that magnified objects by three to four times using a convex lens and a concave lens on opposite ends. Upon discovering the secret to the spyglass, Galileo set out to make an even superior device. After increasing the focal length of the convex lens and shortening the length of the concave eyepiece, Galileo quickly had a telescope to present to the Venetian senate that could magnify objects by nine times. By the end of the year, he had grinded a new set of lens to an optimal magnifying power of twenty. This particular telescope was strong enough for him to make the startling discovery that the surface of the moon was not smooth and perfect as a heavenly object should be according to Aristotle; rather, it was filled with spots, craters, mountains, and valleys, similar to Earth. Even more interestingly, he observed that Jupiter had four moons orbiting it.
This was the first piece of evidence that planted the seed in Galileo’s mind that the Copernican system must be correct. How could Earth be at the center of every universal revolution when Jupiter itself had moons revolving around it? (Hatch) In addition, he noted that none of the planets or moons he had observed through his telescope produced their own light. They “shone” because they were reflecting sunlight. Galileo claimed to have performed an experiment where a stone was held at the top of a masthead of a moving ship. While Aristotelians asserted that a stone falling from the mast of such a ship would end up far from the stern, Galileo argued that what actually happened was the stone ended up at the base of the mast due to the earth’s motion. The tides, too, were attributed to the motion of the earth (and the moon). As a result of these bombastic propositions, the Catholic Church began to take notice and publicly condemned the specific notion that the Sun was at the center, with the Earth moving around it in a daily rotation. Notably, these ideas were judged as such by theologians appointed for the task by the Inquisition, instead of fellow scientists. Galileo was commanded to give up trying to spread acceptance of the Copernican system as fact. When the next pope, Pope Urban, was appointed, he gave Galileo his blessing to produce a scientific dialogue between three characters regarding the earth’s motions, provided that the mention of tides was toned down and that any theory proposed would be seen as no more than fantasy. However, when this second work was published, the pope seemed to have a sudden change of heart, partly due to the belief that Galileo had subtly mocked him by having a simpleton character in his dialogue satirically speak about God’s power. (MacLachlan, 92) Galileo was summarily put on trial by the Inquisition and his dialogue was put on the Index of Prohibited Books. Upon Galileo’s death in 1642, Pope Urban denied him a proper ceremony and monument. His body was placed in the back of a chapel in Florence instead of being laid in the main church (until 1737), an ignominious end for someone who had essentially laid the groundwork for modern physics.
This display of fickleness by the pope prompted other scientists of the time to be increasingly wary of aligning themselves with Church figures or royalty. To secure their autonomy, scientists established two significant scientific societies in the 1660s: the Royal Society of London and the Academy of Sciences (in France). These societies were operated more as self-governing corporations rather than collective clients of patrons, as they had previously been. More generally, Galileo’s career of upholding scientifically researched conclusions in the face of such adamant opposition from authority undoubtedly endowed future scientists with the spirit of challenging tradition. In the coming centuries, Galileo came to symbolize “the fight for freedom in science against the arrayed forces of philosophy and religion…” (MacLachlan, 109)
Due to the efforts of Kepler and Galileo, the heliocentric model neared widespread acceptance by the end of the 17th century. The last major piece of the puzzle was of course Sir Isaac Newton. Most historians refer to the period of his discoveries as the closing chapter of the Scientific Revolution. (Burns, 21) Newton was enamored with the idea that “Creation…unfolds from simple rules, patterns iterated over unlimited distances. So we seek mathematical laws for economic cycles and human behavior. We deem the universe solvable.” He sought to define and standardize the concepts of time, space, place, and motion.
Newton was born in the year that Galileo had died, and he was undeniably influenced by Galileo’s works. He immediately identified with Galileo’s open defiance of Aristotelian principles; in particular, with the idea that all objects are made of the same heavy material, and descend at a uniform rate. This did not mean, however, that the speed of descent was the same. Although Galileo at the time had not conceived the exact concept of inertia, the essence of his reasoning was that motion was not a process but rather a state of being, and objects are either in motion or are motionless. (Gleick, 25) This notion would be the foundation of Newton’s subsequent research on what causes objects to move the way they do.
The other great influence on Newton’s thinking was the French mathematician and philosopher Rene Descartes. While Euclid’s theorems proved useful to him when learning geometry as a college student, it was Descartes’ Geometrie that allowed Newton to bridge the two worlds of geometry and algebra. Through this introduction to analytical geometry Newton was given the tools to describe the rate of change of quantities, or what we now know as calculus. In 1666, Newton used calculus to help him draw a connection between the acceleration of an apple towards Earth and that of the moon towards Earth. He theorized that there must be some kind of force coming from the earth that was responsible.
After further studying motion, Newton turned his attentions to the movement of heavenly bodies. His new mathematical tools allowed him to improve Galileo’s original calculations and apply them to Kepler’s concept of elliptical orbits. Newton reasoned that the planets revolved in an elliptical orbit around the sun because there was a force between them that was inversely related to the square of the distance between them. This force was the same force governing the acceleration of the apple to Earth and the Moon to Earth, Newton declared. Thus came into existence officially the idea of a universal gravitational force. In 1686 he put these ideas onto a manuscript that would change science forever: the Principia. In it, Newton formally stated his three laws of motion: 1) Every object is either in motion or at rest, and both states are due to outside forces, 2) An output of force causes motion, and both can be quantified, and 3) Every action has an opposite and equal reaction. In Book III of the Principia, titled The System of the World, Newton took his concept of universal gravitation and used it to explain why gravity was attracting objects towards the center of bodies: “The force points towards the center of bodies, not because of anything special in the centers, but as a mathematical consequence of this final claim: that every particle of matter in the universe attracts every other particle. From this generalization the rest followed. Gravity is universal.” (Gleick, 135) In a poetic about circle, Newton answered the question of the tides that had plagued Galileo, explaining that the gravity of the sun and the moon on opposite sides of the planet was to blame for them.
The Scientific Revolution was more than just a series of discoveries; it was a shift in attitudes from a deductive method of reasoning to an inductive method. It was the acceptance of a standard scientific method that necessitated external observation and tangible calculations. It was not until the Scientific Revolution that science itself could be called a discipline of its own, independent from philosophy and with its goal being constant improvement on what already existed. The Revolution also spawned a multitude of modern branches of science, including calculus, astronomy, and physics. It is important to note that the growing prominence of science in this time went hand in hand with the lessening influence of Church and royalty on how scientists went about their research. In fact, these powers would eventually become subject to the inescapable and ever widening reach of science. To this day, the ideas and methods pioneered during the Scientific Revolution are still used and are still relevant. We have this period of time to thank for current innovations like computers, smartphones, and feats of modern engineering. In the 17th century, history was altered forever.
