The Scientific Revolution
mid 1500’s-mid 1700’s
A new way of looking at
the world.
1. Definition
Scientific Revolution : a period during which
there was a radical change in how people
looked at the natural world, based on critical
observation and a willingness to question
accepted beliefs
2. Pre-modern Ways of Thinking
• “Scientific”
• Magical
• Philosophic
• Religious
“Scientific Thinking”
• Aristotelian
– Motion: rest is natural; motion requires a mover
– heaven and earth:
• the heavens are light, airy, and perfect
• perfect spheres in perfectly round orbits
– Matter: Earth, Air, Fire, Water
– Cosmology: a motionless earth at the fixed center of
the universe
• Aristotle and the Church:
– his ideas fit well with Scripture and doctrine.
“Scientific Thinking”
• Ptolemaic System
– Earth at center of the universe
– All other objects on “Heavenly Spheres”
– Motion of heavenly objects explained by cycles
and epicycles
– perfect spheres and perfect circles
Magical Thinking
• Alchemy
– contribution: mutability of matter
• Astrology
• Witchcraft
• *** many of these ideas would continue
long after the Scientific Revolution
Philosophy
• Logic and Epistemology
– how we know and what we know
• Metaphysics
– what exists, why it exists, whether there is God,
and what is the nature of God
• Ethics and Politics
– morality; what is right and wrong for
individuals and society
• *** Science as a separate field of study
arises from Philosophy
Religious Thought
• Reformers (Luther, Calvin, etc)
– emphasis on salvation, and living in a manner
that glorifies God
• Catholic/Counter Reformation
– made harder to express new opinions
• Most new ideas arose in Protestant
countries or France
Causes of the Scientific
Revolution
• Medieval Universities
• the Renaissance
• Overseas Trade
• Improved methods
• The Reformation
Medieval Universities
• Preservation of ancient texts
• Emphasis on finding the simplest
explanation (“Ockham’s Razor”)
• The Rise of philosophy as a field
independent of theology.
The Renaissance
• Rediscovery of advanced mathematics
• The tradition of patronage
• Classical values of order and simplicity
• Humanism – emphasis on the limitlessness of
human accomplishment
Overseas Trade
• Need for better navigational tools
• Gresham College
– Courses on navigation
– Created a tie between practical concerns and
scientists
• New navigational tools led to new and more
accurate knowledge
Improved Methods
• Improved instruments
• Francis Bacon (1561-1625)
– Novum Organium
– Empiricism (inductive experimentalism)
• form hypothesis (model) and see if it fits the
evidence
• Rene Descartes (1596-1650)
– linked algebra and geometry
– Discourse on Method (1637)
• Deductive mathematical rationalism
The Reformation
• In most Protestant nations – an openness to
new ideas developed
– Because of the absence of a central religious
authority
• In Catholic nations (except France) – the
counter Reformation limited new ideas.
3. Development of the Scientific
Revolution
• Nicolaus Copernicus (1473 – 1543)
– A clergyman and astronomer
– On the Revolutions of the Heavenly Orbs (1543)
– A mental breakthrough based on simple math
– A heliocentric universe was simpler
– Still committed to a series of crystal spheres and
the perfection of circular motion
• Tycho Brahe (1546 – 1601)
– Contributed a mass of data from 20 years
of observation
– His perception of the universe:
• Planets revolved around
the sun
• Planets and sun revolved
around the earth-moon system
Johannes Kepler (1571 – 1630)
• An assistant to Brahe
• Tried multiple hypotheses using Brahe’s
data.
• Developed 3 Laws of Planetary Motion
The First Law of Planetary Motion
The orbits of the planets are ellipses, with the Sun
at one focus of the ellipse.
The Second Law of Planetary Motion
The line joining the planet to the Sun sweeps out
equal areas in equal times as the planet travels
around the ellipse
The Third Law of Planetary Motion
The ratio of the squares of the revolutionary
periods for two planets is equal to the ratio of the
cubes of their semimajor axes.
The Significance of Kepler
• Destroyed the Aristotelian/Ptolemaic
system
• Established a precise mathematical
relationship between all the elements of the
solar system.
Galileo Galilei ( 1564-1642)
• Two New Sciences
– utilized controlled experiments
– showed uniform acceleration of falling objects
– formulated the law of inertia
• Starry Messenger
– observed the four moons of Jupiter
– observed the “imperfect” surface of the moon
The Newtonian Synthesis
• Isaac Newton (1642 -1727)
– united the experimental and mathematical
sides of modern science
– Mathematical Principles of Natural
Philosophy (1687)
• provided an explanation for heavenly motion
based on the observed properties of motion
on earth.
• Three laws of motion
Consequences of the Scientific
Revolution
• A new attitude
– skepticism; willingness to question old beliefs
– confidence in the power of reason
– emphasis on natural law at work in the universe
• New methods of obtaining knowledge
• A competitive scientific community
• Some practical effects
– navigation; weaponry
The long axis of the ellipse is called the major axis,
while the short axis is called the minor axis. Half of
the major axis is termed a semimajor axis. It can be
shown that the average separation of a planet from
the Sun as it goes around its elliptical orbit is equal to
the length of the semimajor axis. Thus, by the
"radius" of a planet's orbit, one usually means the
length of the semimajor axis.