Scientific Revolution Notes

Introduction

The Scientific Revolution is the term given to a gradual development of a way of investigating and knowing the natural world. Although it has roots that stretch back earlier, the Scientific Revolution is considered by most historians to be a seventeenth-century phenomenon, beginning with Galileo's challenge to the old Aristotelian view of the cosmos and the authority of the Catholic Church in 1610, and culminating in the creation by Isaac Newton of the concept of a "universe" held together by the single force of universal gravitation in 1687 (Newtonian Physics-or the basic principles of motion)

The Traditional View of the Cosmos

The traditional view of the cosmos in European civilization was one that it had inherited from the ancient Greek philosopher Aristotle. The Aristotelian cosmos was based on observation and common sense. Because the Earth appeared, to all of one's senses, to stand still, Aristotle made the Earth the unmoving center point of the cosmos. The moon, the planets, and the stars were conceived of as "fixed" because they do not move relative to each other, and they were also understood to move in concentric circular orbits around the Earth because that is what they appeared to do.

The Aristotelian cosmos was divided into two realms:

  • the terrestrial realm, which contained the Earth and all matter inside the orbit of the moon
  • the celestial realm, or the realm of the heavens that existed beyond the orbit of the moon

In the Aristotelian cosmos, there were five basic elements, each of which was defined by its qualities:

  • earth, which was heavy and tended to sink towards the center of the cosmos
  • water, which was slightly lighter and accumulated on top of solid earth
  • air, which was lighter still
  • fire, which was the lightest of all and tended to try to rise above all the others
  • the ether,perfect matter that existed only in the celestial realm and which moved in uniform circular motion

The qualities of the five types of matter served as the basis of Aristotelian physics. The motion of terrestrial matter was understood to be the result of its composition. For example, if you threw a rock, its motion described a parabola because the force of the throw gave its motion a horizontal component, while its heaviness gave it a vertical component towards the Earth. If you filled an airtight bag with air and submerged it in water, it would float to the top because the air was lighter than earth or water. The planets and stars of the celestial realm moved at a uniform rate in perfect circles around the Earth because they were composed purely of ether.

To the medieval church scholars who rediscovered and translated the writings of Aristotle, this Earth-centered, or geocentric, model of the cosmos not only made logical sense, it confirmed the Christian theological doctrine that the perfect kingdom of God awaited in the heavens for those humans who could transcend the corruption of the world.

Alternative Traditions of Knowledge Before the Scientific Revolution

Although the dominant tradition of knowledge in European civilization prior to the Scientific Revolution was scholasticism, which derived its knowledge from ancient texts like those of Aristotle, there were other alternative traditions upon which the Scientific Revolution drew.

Hermeticism

One of these was the tradition of natural magic and alchemy, which understood the natural world to be alive with latent power, just waiting to be tapped by those who could learn its secrets. One strain of magical thought drew inspiration from a corpus of texts erroneously attributed to a supposed ancient Egyptian priest, Hermes Trismegistus. Hermeticism taught that the world was infused with a single spirit that could be explored through mathematics as well as through magic.

Neoplatonism

The most powerful and potent of the alternative traditions was developed by Renaissance humanists who rediscovered and revered the work of the ancient Greek Philosopher Plato. Neoplatonism located reality in a changeless world of spirit, or forms, rather than in the physical world we experience. To the neoplatonists, mathematics was the language with which one could discover and describe the world of forms. Like the Hermetic tradition, neoplatonism taught that mathematics described the essential nature and the soul of the cosmos, a soul that was God itself.

The Platonic–Pythagorean Tradition

By the advent of the seventeenth century, these alternative traditions had fused into an approach to gaining knowledge of the natural world that has come to be known as the Platonic–Pythagorean tradition (after Plato and the ancient mathematically oriented school of Pythagoras), which had as its goal the identification of the fundamental mathematical laws of nature.

Development of New Institutions

Because the curricula of traditional universities were devoted to the teaching of Aristotle and other authorities in the scholastic tradition, new institutions were required for the alternative traditions to flourish. New institutions that emerged to fill that role included:

  • royal courts, where kings, dukes, and other ruling nobles were determined to show off both their wealth and their virtue by patronizing not only great artists and musicians but also natural philosophers
  • Royal Societies and Academies, like the Royal Society of London and the Royal Academy of Sciences in Paris, both established in the 1660s, where organized groups of natural philosophers sought and received the patronage of the crown by emphasizing both the prestige and the practical applications of their discoveries
  • smaller academies under the patronage of individual nobles, like the AccademiadeiLincei, which formed in 1657 under the patronage of Marquess of Monticelli in Italy
  • new universities, particularly in Italy, that were funded by the civic-minded merchants in the Renaissance tradition and that were outside the control of the Church

The Rise of Copernicanism

The central challenge to the traditional view of the cosmos was made in the context of the Church's own effort to reform the calendar and, therefore, the science of astronomy. The annual changes in the position of the Sun, the moon, and the planets with respect to the constellations of stars are the means by which human beings construct calendars that keep track of time and predict seasonal climate patterns. In keeping with the philosophy of scholasticism, European Church scholars constructed calendars based on ancient astronomical tables that dated back to the ancient Greek astronomer Claudius Ptolemy. Though amazingly accurate, the multiplication over thousands of years of small errors in the Ptolemaic astronomical tables led to a situation in the early sixteenth century where the calendars were dramatically out of sync with the actual seasons.

In 1515, a church council appointed to consider calendar reform summoned the Polish churchman and astronomer Nicolas Copernicus to remedy the situation. Educated in a neoplatonic academy and a proponent of the Platonic–Pythagorean tradition, Copernicus proposed to reconcile the calendar and the actual movements of the heavens by introducing a new Sun-centered, or heliocentric, astronomical model of the cosmos.

Copernicus's proposal alarmed Church authorities for several reasons:

  • It questioned the authority of the Aristotelian tradition on which scholasticism relied.
  • It contradicted the physical principles that served as the foundation of physics.
  • It destroyed the theological coherence of the cosmos.
  • It required the Church to admit it had been in error.

Shortly before Copernicus's death in 1543, the Church allowed his theory to be published in a work titled De RevolutionibusOrbiumCaelestum (On the Revolutions of the Heavenly Spheres), provided that it be accompanied by a preface that stated that the theory was only being presented as a useful hypothetical model, and not as a true account of the physical nature of the cosmos. Because Copernicus's great work was written in Latin (which was the language of educated scholars) and because it was a highly technical work, its publication created no great stir. But slowly, over the course of the next 70 years, Copernicanism (as the theory came to be known) spread in circles of men educated both within the Church and in newer academies and societies.

Kepler's Laws

By the seventeenth century, a loose network of Copernicans championed the new world view as part of a new empirical and mathematical approach to the study of the natural world. One was a German mathematician working in the hermetic and neoplatonic traditions, Johannes Kepler, who devoted his life to finding the mathematical harmonies of the cosmos. Between 1609 and 1619, he developed three laws of planetary motion that would come to be known as Kepler's laws.

  1. The first law broke with the tradition of conceiving of the planets as moving in uniform circles, suggesting that the planetary orbits took the form of an ellipse, with the Sun as one of their foci.
  2. The second law abandoned the notion that planetary motion was uniform and asserted that a planet's velocity varied according to its distance from the Sun, sweeping out equal areas in equal times.
  3. The third law gave a mathematical description for the physical relationship between the planets and the Sun, asserting that the squares of the orbital period of a planet are in the same ratio as the cubes of their average distance from the Sun.

Galileo and the Value of Empirical Knowledge

Although Kepler worked in obscurity, Galileo Galilei was an ambitious self-promoter. Dubbing himself a "mathematical philosopher," Galileo championed an approach to knowing the natural world that emphasized the need to apply reason to observational and mathematical data. Also, following the English philosopher Francis Bacon, Galileo combined his approach with an appeal to the practical and pragmatic value of such knowledge.

Having dismantled and analyzed a spyglass he bought from Dutch merchants, Galileo drew up schematics for a larger, more powerful version. The result was the world's first telescope and Galileo immediately turned his new invention on the heavens. In 1610, Galileo published his findings in a pamphlet titled The Starry Messenger. There, he announced several discoveries which, although they did not explicitly promote the Copernican theory, did implicitly call into question the veracity of the Aristotelian model. These discoveries included the following:

  1. the existence of countless stars previously unseen, suggesting that there was much about the cosmos that was not known
  2. the rugged, crater-filled surface of the moon, suggesting that it was not created of perfect celestial matter
  3. four moons orbiting the planet Jupiter, suggesting that it would not be so strange for the Earth to have a moon as well

Unfortunately, Galileo mistakenly believed that both his growing fame and his value to his powerful patron (the Grand Duke of Tuscany, Cosimo de Medici) would protect him from the wrath of the Catholic Church. Because of this mistaken belief, Galileo began to promote more boldly both the Copernican theory and his method of knowing nature through the application of reason to empirical observations. In 1615, he was summoned to Rome, where he narrowly escaped being branded a heretic only because he had a powerful friend, Cardinal MaffeoBarberini, who interceded on Galileo's behalf and managed to get the Church to brand the Copernican theory "erroneous" rather than "heretical." Galileo was set free with a stern warning. In 1623, Barberini became Pope Urban VIII. The following year, Galileo returned to Rome for a series of discussions with the Pope. He left having been given permission to teach Copernicanism as a theory, but not as a true account of the cosmos.

Over the next decade and a half, Galileo continued to promote his particular brand of natural philosophy. In 1632, chafing against the constrictions put upon him, Galileo effectively took his case to the public by abandoning the Latin prose of the scholarly elite for the vernacular Italian of the masses and publishing a thinly veiled attack on what he considered to be the absurdity of the Church's defense of the Aristotelian model. The book, Dialogue on the Two Chief Systems of the World, dismantled the arguments in favor of the traditional, Aristotelian view of the cosmos, and it presented the Copernican system as the only alternative for reasonable people. Early the following year, Galileo was summoned before the Inquisition and forced to recant. He was sentenced to spend the rest of his life under house arrest and forbidden to ever publish again. The long-term effect of Galileo's condemnation was to shift the locus of the Scientific Revolution to the Protestant countries of Europe.

Cartesian Skepticism and Deductive Reasoning

Although many of those who took the lead in the Scientific Revolution in the second half of the seventeenth century were born in Protestant countries, Rene Descartes had been a citizen of Catholic France. But upon hearing of Galileo's condemnation, Descartes relocated to the Netherlands, where he published (in 1637) a challenge to both the authority of scholasticism and to the validity of the Galilean approach. In Discourse on Method, Descartes began by sweeping away all previous claims to knowledge by skeptically asserting that "received knowledge"—i.e., information that you do not learn for yourself—amounted to nothing more than "opinion." But rather than proceed from observation, Descartes extended his skepticism to the senses, which he asserted could easily be fooled; instead, he sought the "clear and distinct idea"—i.e., one that could not reasonably be doubted.

The first idea that Descartes could not doubt was that he was thinking, and that if he was thinking, then he must really exist. From that famous formulation—"I think, therefore I am"— Descartes proceeded to deduce a variety of truths, including the existence of God and a cosmos made up of only two things: matter and motion. Putting the Sun in the center (as Copernicus had done), Descartes described a solar system in which the planets were simply large chunks of matter that were caught in swirling vortices of smaller matter. This cartesian approach of deducing the details of nature from a set of clearly defined general propositions appealed to those who sought an intelligible explanation of the cosmos, rather than the mathematical calculations of the Platonic–Pythagorean tradition.

Newton and Universal Gravitation

It was Isaac Newton who supplied an explanation of the cosmos that was consistent with and conducive to precise mathematical calculation. Newton was an Englishmen who was educated at Cambridge University at a time when its faculty was committed to the advancement of neoplatonism and to the rejection of Cartesianism, which they feared would become the new scholasticism. As a fellow of Trinity College, Cambridge, Newton lived a solitary life and was driven by the notion that God had left clues to his true nature in the laws that governed the natural world. Newton was, therefore, intensely focused on solving the mystery of planetary motion. Using a mathematical system of his own creation, which he called "fluxions" (and which we now refer to as calculus), and following Kepler's suggestion that the path of planetary orbits was elliptical, Newton was able to calculate the orbits of the planets precisely by assuming that each particle of matter, no matter how large or small, was drawn to every other piece of matter by a force which he called universal gravitation.

Newton published his results in 1687 in his great work the Principia Mathematica (or The Mathematical Principles of Natural Knowledge), where he stated: "Every particle of matter in the universe attracts every other particle with a force varying inversely as the square of the distance between them and directly proportional to the product of their masses." The Principia not only provided the correct calculations for planetary motion, it set out "definitions" and "laws of motion" that demonstrated how, henceforth, mathematical philosophy was to be done.

For the rest of the seventeenth century, the methods of Newton and Descartes served as competing models, with Newtonianism reigning in Great Britain and Cartesianism dominating in Continental Europe. But by the dawn of the eighteenth century, Newtonianism had won out and served as a model not just for natural philosophy but for an approach to the understanding of human society that would come to be known as the Enlightenment.

Rapid Review

By the mid-sixteenth century, the spirit of Renaissance humanism fused with other reviving traditions, such as hermeticism and neoplatonism, to create a Platonic–Pythagorean tradition that sought to identify the fundamental mathematical laws of nature. Nicolas Copernicus was the first to challenge the traditional scholastic view of the cosmos by suggesting that the Sun—and not the Earth—was at the center of the system. But it was in the seventeenth century that Copernicus's successors, taking advantage of new spaces for natural philosophy, promoted new ways of knowing about nature.