Scientific Revolution - Haynes Academy for Advanced Studies

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
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
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
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.

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