09. The Scientific Revolution

Copernicus put forth a heliocentric (sun-centered) view of the universe. The sun was at the center of the universe and the planets, in spherical orbits, revolved around it. The moon revolved around the earth. The earth rotated on an axis as it revolved around the sun, thus giving the erroneous impression that the sun and fixed stars revolved around the earth. Today we recognize Copernicus’ heliocentric view as at the heart of the scientific truth of our solar system. His conclusions were not without their flaws nor were they completely original,[1] but he presented them with such assertiveness that they caught scholarly attention.

Scholarly approval of Copernicus’ conclusions came haltingly. The Catholic Church initially remained silent on the matter. Protestant theologians, Luther’s being the loudest voice, railed against the Copernican heresy. It was not until 1616 that the Church assigned Copernicus’ On the Revolution to the Index of Prohibited Books. (It was removed in 1835.) Were it not for two later astronomers, Tycho Brahe and Johannes Kepler, Copernicus might have disappeared from modern learning.

Tycho Brahe (1546 - 1601) was a Danish mathematician and astronomer who rejected Copernicus outright but who inadvertently gave the heliocentric theory greater validity. With the patronage of King Frederick II, Brahe constructed a great observatory (Uraniborg) on an island near Copenhagen. His studies enabled the collection of a large quantity of valid astronomical data, which was altogether remarkable because the telescope had not yet been invented. Rejecting the Aristotelian-Ptolemaic view, Brahe concluded that the planets revolved around the sun, but the sun itself revolved around the earth. On the death of the Danish king, Brahe relocated to Prague, where he continued his astronomical studies under the patronage of the Habsburg Emperor Rudolf II. In 1600, the year before his death, Brahe was joined by a younger assistant named Johannes Kepler.

Johannes Kepler (1571 - 1630) had rejected the study of Lutheran theology to become a mathematician, and, on Brahe’s death, succeeded as court mathematician for Emperor Rudolf II. Kepler sought to reconcile Brahe’s astronomical data with Copernicus’ heliocentric theory. As a mathematician, he sought to discover regular numerical or geometric relations in planetary movement. Through his work, he concluded that Copernicus was wrong – not about heliocentrism - but about the planets moving in spherical orbits. The planets including earth, Kepler proved, moved in elliptical orbits. The sun was one of the foci of each elliptical orbit. This became his first law of planetary motion. Kepler formulated two additional laws based on this concept: that the planets move in their orbits at unequal velocity and that planets with larger orbits move more slowly than those with smaller orbits. Thus, by applying his own mathematical understanding to Brahe’s measurements of planetary motion, Kepler proved Copernicus’s theory correct. Still, it was not correct in ecclesiastical eyes, and both the Protestant and Catholic churches condemned Kepler’s works. It would take the work of an Italian astronomer, Galileo, to give the heliocentric theory effective verification.

Galileo Galilei (1564 - 1642) was born into Pisan nobility. At the University of Pisa he followed his father’s wishes and pursued medicine but would abandon it for his real love, mathematics. He later taught mathematics at the universities of Pisa and Padua. His interests in mathematical theory took him into astronomy and physics. In 1609, taking an idea from a Flemish lens grinder he had read about, Galileo constructed a telescope and turned it to the skies. What he saw amazed him. He could actually see what his predecessors could not. He saw mountains on the moon, spots on the sun, satellites orbiting Jupiter, Saturn’s ring, the phases of Venus, the innumerable stars of the Milky Way. Old beliefs were suddenly proved incorrect. Planets were not ethereal and changeless forms but material substance like the Earth. The heliocentrism of Copernicus and Kepler was correct and now verified through observation. He published his observed findings in The Starry Messenger in 1610. The effect was stunning. Church scholars and cardinals, surprisingly, initially hailed him as a hero. The Medicis named him court mathematician of Florence.

Nonetheless, there was opposition. Dominicans and Jesuits urged the Roman Inquisition to investigate Galileo’s findings as heresy. The Court ruled that his findings were heresy and he was warned by the Pope in 1616 not to teach heliocentrism as truth. He continued his investigations and in 1632 published his most famous work, Dialogue on the Two Great Systems of the World. The “two great systems” were the Ptolemaic and Copernican. Published in Italian rather than Latin, Dialogue was easy to read and popular. It challenged the position of the Church through a dialogue between “experts” in each area of thought. The “voices” of the dialogue were those of “Salviati” (Copernican) and “Simplico” (Ptolemaic). Of course, Salviati won the argument, and the Church was not amused by having its position voiced by one called “Simpleton.”

In 1633 Galileo was again summoned before the Inquisition and condemned as a heretic. His trial became symbolic of the legacy of learning: the clash between the truth of faith and the truth of science. Terrified by the prospect of eternal damnation, he recanted, affirming that the earth was the stationary center of the universe. Legend has it that as he left the court, he muttered “E pur se muove” (“Yet it does move.”) (Durant 611). His Dialogue was consigned to the Index of Prohibited Books. (It would remain there until 1835. He would not be absolved of his heresy until 1983!) Under arrest, Galileo spent the last eight years of his life confined to his house and gardens in Florence. There he continued his study of that branch of physics called mechanics, the science of motion.

While not as dramatic as his work on astronomy, Galileo’s work on mechanics was just as remarkable and significant. In short, Galileo formulated “generalizations of enormous importance: the laws of the pendulum; the law of falling bodies, or acceleration; the plotting of the parabolic curve of a projectile fired by a cannon. These phenomena could be expressed in mathematical terms” (Knapton 175). The stories that he dropped a melon and a grape from the Leaning Tower of Pisa to measure their respective rates of fall and that he discovered the principle of the pendulum while staring at the hanging lamps in the Pisa cathedral are, like Newton’s apple, apocryphal. In his last years he gradually lost his sight and was assisted in his work by his daughter, a nun. His later works were smuggled out of Italy and published in the Netherlands.

The Prophets of Science: Bacon and Descartes

Francis Bacon (1561 - 1626)

Born the son of a royal official, Bacon grew up in the heady world of Elizabeth’s court in which he would eventually serve as an officer. He studied law and, through his political connections, managed to build a considerable personal fortune. He eventually rose to the rank of Lord Chancellor (prime minister) in the court of King James I and served as regent for England when James was in Scotland. Angered over James’ pretensions to absolutism, Parliament impeached Bacon for corruption in 1621, forcing him to retire from government. He turned his full attention to what previously had been an active avocation: philosophy and science.

In an unfinished work called The Great Renewal, Bacon called for humanity to abandon its preconceived and traditional approach to learning and start anew. In his Novum Organum (1620) he formalized the inductive approach to understanding. From this comes what we call the Scientific Method. Rather than begin with an assumption from which logical conclusions might be deduced, Bacon urged scientists to move from the particular to the general, from the concrete to the abstract (Spielvogel 591). Through experimentation and observation, correct generalizations would result. This founding of knowledge on experimentation and observation is called empiricism.

Bacon saw science as a means to an end: continued human progress. Heretofore the prevailing thinking about science had been that it was a form of philosophy, an intellectual exercise through which truth might be discovered. Bacon saw science as having a practical purpose. “I am laboring to lay the foundation,” he wrote, “… of human utility and power.” This human power should be used, he stated, to “conquer nature in action” (Spielvogel 591).

Thus, it is with Bacon that science first acquired the justification for its accomplishments in all areas of its application – anatomy, biology, chemistry, physics, to name a few. The legacy is mixed. Science has provided humanity with great benefits as well as great dilemmas. Think of the search for a cure to cancer in a world that likewise has developed nuclear weapons and anthrax.

What else?

It is from Bacon’s Advancement of Learning (1623) that we get the expression “Knowledge is power.”

In his The New Atlantis (published posthumously in 1627) Bacon described a scientific utopia in which humanity enjoys a perfect society through knowledge and command of nature.

Rene Descartes (1596 - 1650)

Of French aristocratic background and with a Jesuit education, Descartes studied law but found mathematics to be his primary interest. At the University of Paris he was profoundly influenced by the writings of Montaigne and became fascinated with skepticism. While on military duty during the Thirty Years War, Descartes believed he had a “revelation” that directed him to seek an undeniable means of understanding truth.

In a world that he saw full of confusing intellectual uncertainties, he sought to find order. He would begin with doubt. He would set aside all that he had learned and seek a new way of understanding. In his most famous work, Discourse on Method (1637), he explained the foundation of his purpose: “Cogito ergo sum” (“I think, therefore I am.”). He could not, after all, doubt his own existence. As a rational man, he would accept only those things his reason showed to be true. Moving from this principle, he deduced two others: the existence of God and the separation of mind and matter. We are here concerned with the latter.

The philosophical separation of mind and matter has come to be known as “Cartesian Dualism.” God, Descartes stated, created two fundamental realities: 1) the “thinking substance” being the reality of mind, senses, spirit, consciousness, and subjective experience; and 2) the “extended substance,” the reality of matter, that which is objective. In the material world (that of “extended substance”) there are two primary characteristics: extension (meaning all matter occupies space) and motion. Through the use of reason and mathematics, the material world can be understood as it is: “pure mechanism, a machine that is governed by its own physical laws” (Spielvogel 590). The foundation of those physical laws was mathematics.

Descartes was the founder of coordinate geometry. By use of coordinates any algebraic formula could be plotted as a curve in space and contrariwise, any curve in space could be converted into algebraic terms and thus dealt with by methods of calculation. As a result, the world of nature could be reduced to mathematical form.

Descartes’ approach was deductive. One should begin one’s understanding with a general principle or problem, which should then be separated into “as many parts as may be necessary for its adequate solution” the way a mathematical proof is formulated.

His writings made Descartes the “father of modern rationalism.” The separation of mind and matter allowed scientists to understand the material world through reason unencumbered by the subjectivity of the mind. The sensory mind tells us that the sun revolves around the earth. Reality, however, demonstrated through a rational understanding, shows differently.

Most textbooks consider Bacon and Descartes in the same breath … well, certainly in the same context: as pioneers of modern thought. Palmer states that:

Both addressed themselves to the problem of knowledge …. attacked earlier methods of seeking knowledge …. The medieval (or Aristotelian) methods were backward. They held that truth is not something that we postulate at the beginning and then explore in all its ramifications, but that it is something which we find at the end, after a long process of investigation, experiment, or intermediate thought …. They both became heralds or philosophers of a scientific view. They maintained that there was a true and reliable method of knowledge …. Bacon and Descartes thus announced the advent of a scientific civilization. (Palmer et al., 268)

What else?

Descartes published his Discourse in French, not Latin, to symbolize his break with the scholastic tradition.

Descartes’ books were placed on the Index of Prohibited Books by the Catholic Church.

The Messiah of Science: Sir Isaac Newton (1642 - 1727)

Were it not for the plague that ravaged England in 1666, Newton might be remembered only as a Cambridge scholar who showed promise in mathematics. The University closed and Newton returned to his home village for a period of 18 months during which he invented calculus and began his work on the law of universal gravity. In 1669 he returned to Cambridge and was later appointed a professor of mathematics. In time he also became a noted scholar in both astronomy and physics. In 1687 he published his monumental work, Philosophae Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy) – the Principia. In 1703 he became president of the prestigious Royal Society (for scientific investigation) and was knighted by Queen Anne in 1705, the first time a knighthood had been awarded for scientific research. In 1727 he was buried in London’s Westminster Abbey, the only scientist so honored in British history.

So what makes Newton so significant? He became the first great modern authority on scientific investigation and understanding, becoming, in effect, to modern civilization what Aristotle had been to classical and medieval civilization. How so? Through his work on mechanics.

In the Principia Newton put forth the idea that all in the universe is governed by principles of natural law that science can discover and verify. His research led him to conclude that there were three fundamental laws governing motion: “every object continues in a state of rest or uniform motion unless deflected by a force; the rate of change of motion of an object is proportional to the force acting upon it; and to every action there is always an equal and opposite reaction” (Spielvogel 582). Applying his theories of mechanics to astronomy, Newton was able to show that the planets – as well as all objects on earth - were governed by these laws of motion. In formulating his law of universal gravity, he concluded that every particle of matter attracts every other with a force (gravity) proportional to the product of their masses and inversely proportional to the square of the distance between them.

Gravity = mass × mass¹

distance²

Thus it was mathematically proven how the planets were kept in their elliptical orbits around the sun, rather than flying off into space in straight lines. The same principle explains an apple falling from a tree or the trajectory of a projectile fired from a cannon.

Newton’s Principia would have great impact on future scientific and philosophic thought (as we shall later see when studying the Enlightenment). Through investigation and reasoned conclusion, the human mind could discover all laws governing the natural world. The implications were limitless. The contemporary English poet Alexander Pope perhaps best stated Newton’s significance.

Nature and nature’s laws lay hid in night;

God said, “Let Newton be,” and all was light.

(Merriman 343)

The Newtonian system was both empiric and rational. Through induction (Bacon) one should examine the known facts and frame a hypothesis to reduce them to order. Through deduction (Descartes) one would then draw logical consequences from the hypothesis by mathematics or other means. The consequences should then be compared with observation or experiment. If the consequences agree, the hypothesis may be called a theory.

Newton is said to have “created a new cosmology in which the world was seen largely in mechanistic terms” (Spielvogel 583). The world was one huge machine that he believed was created by God that operated through a system of uniform and absolute natural laws. This understanding (with its spiritual component dropped by later scientists) formed the basis of scientific thought through the end of the 19^th century.

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The images in this section are from Wikipedia sources.

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Sources for the Scientific Revolution

Durant, Will and Ariel. The Age of Reason Begins. Simon and Schuster, 1961.

Knapton, Ernest. Europe 1450 – 1815. New York: Scribners, 1958.

Merriman, John. A History of Modern Europe. New York: Norton, 1996.

Palmer, Robert R. et al. A History of the Modern World. Boston: McGraw Hill, 2002.

Spielvogel, Jackson. Western Civilization. Minneapolis: West, 1997.

[1] The third century Hellenist astronomer Aristarchus of Samos presented a heliocentric theory that was later rejected by the Church. Nicholas of Cusa, a 15^th century German bishop and theologian, suspected a sun-centered universe but never pursued mathematical proof as was also the case with the great scholar-artist Leonardo da Vinci (Merriman 332).