The Scientific Revolution
The term scientific revolution is used to indicate the historical period in which the modern
methods of scientific inquiry were established. Although the "revolution" took place over
hundreds of years, it is usually associated with the great discoveries of the first modern
scientists, including Johannes Kepler, Galileo, and Isaac Newton, in the early-to-late 1600s.
The most remarkable and enduring legacy of that era was the formulation of the scientific
method. Simply put, the scientific method is a strict set of rules that dictate the proper course of
establishing facts. It involves the formulation of a hypothesis, the listing of assumptions, the
isolating of variables in any experiment, and the rational analysis of experimentally observed
data to support a conclusion. The scientists before the scientific revolution did not act within
those guidelines; their conclusions were thus based on confusing arrays of mixed variables and
the acceptance of false assumptions about the world that stemmed from the beliefs of their eras.
Therefore, the scientific revolution had as much to do with a shift away from religious beliefs as it
did with formal scientific and mathematical advances.
1. What is the scientific method? Why was it the most important result of the
scientific revolution?
Science before the 17th Century
The state of science prior to the scientific revolution was a mixture of three unrelated influences:
the scholarly writings of the natural philosophers of ancient Greece, the technological advances
made by the tradespeople of the Middle Ages, and the imposed doctrines of whatever religious
sect was in power at the time. Although work was being done in the fields of biology and
chemistry, the main thrust of the scientific revolution was centered around astronomy and
physics.
The natural philosophers of ancient Greece made great strides in observing and categorizing the
world around them, but their writings were highly speculative and were based on the
assumptions and beliefs of their time. The astronomy of antiquity was equally ill founded by
today's standards. The curious, erratic motions of the planets as viewed from the Earth were well
known and documented by the time Claudius Ptolemy (AD 85–165) put the finishing touches on
the Greeks' version of the solar system. Using geometry, a complex web of over 80 circles was
constructed to explain the paths of the Sun, Moon, and planets. Although this mathematical
construction seemed to work well in predicting the positions of the planets, the system's
complexity was a direct result of the false assumption that the Earth was the center of the
universe. Nonetheless, the main principles of the natural philosophers of ancient Greece were
generally accepted in one form or another for the next 1400 years.
The time between the fall of Greece in the first century AD and the Renaissance was not marked
by any major advances in science as an academic endeavor. There were, however,
improvements in technology, specifically as it pertained to commerce and warfare. Examples
include the discovery of magnetism and the use of the magnetic compass in navigation, as well
as the importation and use of gunpowder from China. Those discoveries, although scientific in
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nature, were made and put to use by a largely uneducated public. Thus, there was little attempt
made to document or understand the new technology. The alchemists of the Middle Ages were
indicative of that trend. They experimented widely in metallurgy but produced no usable results
and were hampered by their belief that different materials were possessed by different "spirits."
This was bad science at its peak, and even the Catholic Church disapproved of the heretical
alchemists.
Indeed, the Catholic Church exerted a great influence over the academic pursuits of the Middle
Ages in Europe. That meant that the philosophies of the era had to conform to the doctrines of
the Church and be consistent with the holy scriptures. The philosophies of the ancient Greeks
were expounded on and used as a basis for the Church to impose its doctrines. For example, the
Church required a hierarchy, or chain of command, to exist between heaven and Earth, which
seemed to be a natural extension of the ideas of Aristotle and Ptolemy. God, it was thought,
existed beyond the sphere of the stars and gave his instructions to angels, who were responsible
for the motions of the planets. The hierarchy extended down to humans and then animals,
plants, and so forth. That conception was accepted as fact, and it is important to note that its
validity depended on the Ptolemic model.
2. Why were there no major European advances in science between the fall of Greece
in the first century AD and the fourteenth century Renaissance?
3. How and why did the Catholic Church limit scientific pursuits?
The Revolution Begins
Arguably, the "first shot fired" in the scientific revolution was by Nicholas Copernicus with the
development of the heliocentric theory at the turn of the 16th century. He realized that the
complexity of Ptolemy's solar system could be improved on by placing the Sun at the center of
the universe and having the Earth and planets revolve around it in circles. His theory was no
better at predicting the motions of the planets than Ptolemy's, but it was mathematically simpler,
and its central idea was to have far reaching consequences. Placing the Sun at the center of the
universe upset the fragile hierarchy between heaven and Earth that was ingrained in the doctrine
of the Catholic Church. Meanwhile, the Church was confronted with the Protestant Reformation,
and the success of Martin Luther and other Protestants, along with the Copernican view of the
universe, dealt the first of many severe blows to the status of the Church in academic circles.
Still, the supporters of Copernicus's ideas were persecuted by the Church until the mid-1600s,
when the idea became widely accepted. (Louis XIV, who ruled during the second half of the 17th
century, was named the "Sun King," the central figure around which France revolved—an
analogy to the Sun's dominant place in the solar system.)
The modern view of the solar system was developed by the work of Tycho Brahe and his disciple
Johannes Kepler at the turn of the 17th century. Copernicus's model represented a large step
forward in the understanding of the universe, but inconsistencies remained. The supporters of
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Copernicus believed that the planets were imbedded in perfectly transparent crystalline spheres,
whose rotations around the sun accounted for their circular motions. That belief was overturned
by Brahe when he observed a comet that passed through the solar system without "shattering"
the supposed spheres. Brahe was unsurpassed in his observations and measurements of the
night sky, and they were so accurate that they pointed to inconsistencies in the calculations of
Copernicus's model. Brahe's work led Kepler to drop the assumption of perfect circular paths and
propose that the planets moved in elliptical paths around the Sun. From that idea, he derived his
three laws of planetary motion, which replaced the complicated geometrical schemes of Ptolemy
and Copernicus with three simple algebraic equations.
The importance of Kepler's work is twofold. First, it was based on the very accurate observations
of Brahe, and second, he was able to derive simple and elegant mathematical equations to
explain those observations. The principles of the ancient Greeks and the beliefs of the Church
were being replaced with immutable laws of nature and mathematical and observational proof of
their validity.
4. What did Copernicus, Brahe and Kepler prove? How did they do it?
Galileo And The Limits Of Scientific Enquiry
At around the same time, the Italian Galileo was performing experiments that had to do with the
motion of objects. Galileo's genius lay in his ability to isolate the variables of his experiments,
which created "idealized" conditions from which he deduced mathematical constructs. For
example, in his experiments with balls rolling down inclined planes, he made sure that all the
surfaces were polished smooth so that the motion of the ball itself could be studied. The effects
of air resistance and friction on moving objects were well known at the time, but Galileo
attempted to ignore them by reducing their influence. By doing so, he was able to collect data
and formulate a set of simple equations that governed the motions of projectiles. By timing his
experiments, he was able to deduce the acceleration of objects due to gravity, and in doing so,
he laid down the fundamental principles of the modern study of mechanics. Once again,
mathematics and observation through experiments took precedence in the formulation of
scientific facts.
Galileo found Copernicus' heliocentric theory believable, but he lacked the necessary device to
test it. This dilemma was ended in 1609, when on a visit to Venice, he learned of a new "eyeglass" used to see things very distant. With this as his inspiration, Galileo returned to Padua to
design and build what is now known as the telescope. With his new device, Galileo discovered
many new things: that the Moon was not smooth, but had many craters and mountains; that
Jupiter had four moons, thus disproving the theory that only Earth was orbited by a natural
satellite; and that the phases of Venus could not be explained correctly within the traditional
Earth-centered model of the universe. However, many theologians scorned the heliocentric
theory of Copernicus because it conflicted with the Bible and Church doctrine concerning the role
of Earth in God's created order. These critics now turned their attention to Galileo, who was soon
warned that he ought to teach and discuss the heliocentric theory as only speculative. Galileo
persisted with a new work arguing for Heliocentrism and the book caused the Office of the
Inquisition to summon Galileo to stand trial for heresy. The main question at hand was whether
he had defied the pope, who had made it against the faith "to hold, defend, and teach the
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Copernican doctrine." After a five-month trial, Galileo was convicted for holding and believing
"false doctrine, contrary to the Holy and Divine Scriptures." His punishment was prohibition of his
book Dialogue and a prison sentence. Given the alternative option of recanting his scientific
positions, however, Galileo accepted, swearing, "I will never again say or assert . . . anything that
might furnish occasion for a further suspicion."
5. How did Galileo confirm Copernicus’ theory?
6. Why did Galileo’s work get him in trouble with the Church?
Newton and Gravity
Duing the 17th century, the centers of scientific activity shifted from Italy and Germany to the
more prosperous regions of France, the Netherlands, and England. The shift was good news for
science, in that those countries were under the influence of the Protestants, who were much
kinder to the development of new ideas than the Catholics had been.
The Englishman Isaac Newton is credited as the most significant scientist of his time. Aside from
developing the calculus, he is known for establishing the universal law of gravity, thus putting to
rest the speculations and misconceptions of his predecessors. Newton did not "discover" gravity
per se, but he did make the important connection between Galileo's work on falling objects and
Kepler's laws of planetary motion. Using rigorous mathematical proofs, Newton showed that
falling objects move under the same influence as the planets. That influence, of course, is
gravity. Newton's laws of motion were accepted as uncontested laws of nature for 200 years until
Albert Einstein proved him wrong with his special and general theories of relativity.
While the scientific revolution represented an overall break with superstition and religious
hegemony, it is important to note that beliefs still play a part in science. What scientists of one
era believe to be fact may be disproven by scientists of the next. Einstein himself did not believe
in the validity of quantum mechanics, a field in which he made significant contributions.
7. What was the critical connection that Newton made between Galileo and Kepler’s
work?
8. From your own perspective, do you think that there should be any limits placed on
scientific enquiry?
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