Science and Enlightenment

Theme: The changes in scientific thought, religion, social order, and attitudes toward

government wrought by the Scientific Revolution and the Enlightenment

Lesson 4

Agenda

• Science– Copernicus– Kepler– Galileo– Newton

• Enlightenment– Philosophes– Voltaire– Montesquieu– Smith– Locke

Science

GalileoPtolemaic Universe

New Ideas

• During the Middle Ages, scientific ideas were largely based on religious traditions rather than direct observation and mathematical reasoning

• During the 17th and 18th Centuries, scholars began relying on observation and mathematics to transform the natural sciences– The “scientific revolution”

• The result impacted well beyond the scientific community, affecting moral, social, and political thought

• The change weakened the influence of churches and encouraged the development of secular thinking

The Ptolemaic Universe

• 2nd Century A.D. Greek scholar Claudius Ptolemy envisioned a motionless earth surrounded by a series of nine hollow, concentric shapes that revolved around it

The Ptolemaic Universe

• Ptolemy’s first seven spheres held the moon, Mercury, Venus, the sun, Mars, Jupiter, and Saturn

• The eighth sphere held stars• The ninth sphere was empty,

surrounded the whole cosmos, and provided the spin that kept the other spheres moving

• Beyond the spheres, Christian astronomers placed Heaven

Claudius Ptolemy

The Ptolemaic Universe

• Heavenly bodies were thought to be composed of a pure substance that did not experience change or corruption

• They were not subject to the physical laws that governed the Earth

• Each made a perfect circular path in revolving around the Earth

The Ptolemaic Universe

• This cosmology did not account for observations of erratic movements on the part of the planets

• These were explained by an elaborate and difficult system of adjustments known as epicycles

• As astronomers gathered more data on planetary movements, they sought to reconcile their observations with Ptolemaic theory by adding more epicenters

The eccentric, epicycle and equant combined. The

planet (P) revolves around the center of the epicycle

(D) which moves around the center of circle (C) but

moves uniformly around the center of motion (M). The

earth (E) is not at the center of motion or the center of

the eccentric.

Nicolaus Copernicus

• In 1543,Copernicus published On the Revolutions of the Heavenly Spheres which argued that the sun, rather than the Earth, stood at the center of the universe and that the planets revolved around the sun

Nicolaus Copernicus

• Copernicus’s idea harmonized much better with observed data than did Ptolemy’s, but it was not warmly received

• If Copernicus was right, then the Earth was just another planet and human beings were not the center of the universe

• At the time, this had serious religious ramifications

Impact beyond Science

• “Of all discoveries and opinions, none may have exerted a greater effect on the human spirit than the doctrine of Copernicus. The world had scarcely become known as round and complete in itself when it was asked to waive the tremendous privilege of being the center of the universe. Never, perhaps, was a greater demand made on mankind - for by this admission so many things vanished in mist and smoke! What became of our Eden, our world of innocence, piety and poetry; the testimony of the senses; the conviction of a poetic - religious faith? No wonder his contemporaries did not wish to let all this go and offered every possible resistance to a doctrine which in its converts authorized and demanded a freedom of view and greatness of thought so far unknown, indeed not even dreamed of.” – Johann Wolfgang von Goethe

Scientific Revolution

• Copernicus’s work inspired astronomers to examine the heavens in new ways

• Increasingly they based their theories on observed data and used mathematical reasoning to organize the data

• Gradually Copernicus’s model replaced Ptolemy’s

• This reliance on observation and mathematics ushered in the “Scientific Revolution”

Johannes Kepler (1571-1630)

• Johannes Kepler used mathematics to demonstrate that planetary orbits are elliptical, not circular as in the Ptolemaic theory

Kepler’s First Law

• The orbits of the planets are ellipses, with the sun at one focus of the ellipse.

Kepler’s Second Law

• The line joining the planet to the sun sweeps out equal areas in equal times as the planet travels around the ellipse.

Kepler’s Third Law

• The ratio of the squares of the revolutionary periods for two planets is equal to the ratio of the cubes of their semimajor axes:

Kepler’s Third Law

61,500.61,600.248.39.5Pluto

27,200.27,300.165.30.1Neptune

7,060.7,080.84.019.2Uranus

870.868.29.59.54Saturn

142.141.11.95.20Jupiter

3.533.511.88 1.52Mars

1.001.00 1.001.00Earth

0.378 0.3780.6150.723 Venus

0.0580.0580.2410.387Mercury

P**2a**3P (year)a (AU)Object

Galileo Galilei (1564-1642)

• Galileo used the telescope to observe spots on the sun and moon– Discredited the

Ptolemaic notion that the heavenly bodies are smooth, immaculate, unchanging and perfectly spherical

Galileo’s drawing of the moon showing craters

Galileo Galilei

• Other achievements:– Noticed four of the moons

that orbit Jupiter– Observed previously

unknown distant stars– Meant universe is much

larger than previously suspected

– Showed that the velocity of falling bodies depends not on their weight but on the height from which they fall

Galileo’s telescope

Galileo Galilei

• In 1632, he published his Dialogue Concerning the Two Chief World Systems which compares the Copernican and Ptolemaic systems– Found guilty of heresy

by the Spanish Inquisition and spent the rest of his life under house arrest

Galileo’s Dialogue

Isaac Newton (1642-1727)

• Newton used observation and mathematical reasoning to synthesize astronomy and mechanics (the branch of physics that deals with the motion of bodies)

• Culminating figure of the Scientific Revolution– “If I have been able to see

further, it was only because I stood on the shoulders of giants.”

Isaac Newton

• Wrote the Mathematical Principles of Natural Philosophy in 1687

• United the heavens and Earth in a vast, cosmic system• A law of universal gravitation regulates the motion of

bodies throughout the universe• Newton’s laws allowed him to explain seemingly

unrelated phenomena using gravitation– The ebb and flow of the tides and the gravitational pull

of the moon– The eccentric orbits of planets and comets and the

gravitational influence of the sun, the Earth, and other heavenly bodies

Isaac Newton

• Newton put Galileo’s observations about the relations between the forces acting on a body and the motion of the body into useable form

• Three laws of motion:

– An object at rest tends to remain at rest and an object in motion tends to remain in motion unless acted upon by an outside force. (inertia)

– The speed and direction in which an object moves depends on the mass of the object and the amount of force that is applied to it and the direction of the force. (F=ma)

– For every action, there is an equal and opposite reaction.

Tides• Gravity and inertia are opposing forces acting on the Earth’s

oceans, creating tidal bulges on opposite sides of the planet. • On the “near” side of the Earth (the side facing the moon), the

gravitational force of the moon pulls the ocean’s waters toward it, creating one bulge.

• On the far side of the Earth, inertial forces dominate, creating a second bulge.

Enlightenment

Abbé Delille recites a poem in the salon of

Madame Geoffrin, site of many gatherings of the

Enlightenment philosophes

Impact of the Scientific Revolution

• Suggested that rational analysis of behavior and institutions could have meaning in the human as well as the natural world

• Increasingly, thinkers challenged recognized authorities such as Aristotelian philosophy and Christian religion and sought to explain the world in purely rational terms

• The result was a movement known as the “Enlightenment”

Philosophes

• Enlightenment thinkers sought to discover natural laws that governed human society in the same way Newton’s laws regulated the universe

• Collectively, these thinkers were called the philosophes (“philosophers”)

Philosophes

• Believed that natural science would lead to greater human control over the world

and• Rational science of human affairs would lead to

individual freedom and the construction of a prosperous, just, and equitable society

• Their central ideas included– Progress– Deism– Tolerance

Absolutism

• King Louis XIV (1643-1715) of France is credited with having said “L’etat c’est moi!” or “I am the state.”

• Louis’ statement is consistent with the idea of absolutism– the theory that ultimate power in the early centuries of modern Europe was vested in a hereditary monarch who claimed a God-given right to rule

• Louis went so far as to call himself the “Sun King,” claiming that like the sun, everything revolved around him

• Catholicism was the national religion of France– “One faith, one law, one king.”– In 1685 Louis revoked the Edict of Nantes and insisted that

Huguenots convert to Catholicism

Central Ideas of the Philosophe Movement: Progress

• Most philosophes were optimistic about the future because they believed in the inevitability of progress

• Saw human history largely as a history of the improvement of humanity in three respects: – Developing a rational knowledge of the natural world

and the ability to manipulate the world through technology

– Overcoming ignorance bred of superstitions and religions

– Overcoming human cruelty and violence through social improvements and government structures

Central Ideas of the Philosophe Movement: Deism

• Not all, but most philosophes, were Deists– Believed in the existence of a god, but denied

the supernatural teachings of Christianity such as Jesus’ virgin birth, miracles, and the resurrection

– Deists believed in a powerful god who set the universe in motion and established natural laws to govern it, but then took no personal interest in the universe and did not intervene in its affairs (“The Watchmaker”)

Central Ideas of the Philosophe Movement: Deism

• Deists believe– Religion should be reasonable and should

result in the highest moral behavior of its adherents

and– The knowledge of the natural world and the

human world has nothing to do whatsoever with religion and should be approached completely free from religious ideas or convictions.

Thomas Paine (1737-1809)on Deism

• “Here it is that the religion of Deism is superior to the Christian Religion. It is free from all those invented and torturing articles that shock our reason or injure our humanity, and with which the Christian religion abounds. Its creed is pure, and sublimely simple. It believes in God, and there it rests.”

Central Ideas of the Philosophe Movement: Tolerance

• The philosophes hated the crimes they felt had been perpetrated in the name of religion and the name of God

• They felt a fair, just, and productive society absolutely depended on religious tolerance Torture during the Spanish Inquisition

Francis-Marie Arouet (1694-1778) (Voltaire)

• Was especially critical of the Roman Catholic Church which he held responsible for fanaticism, intolerance, and incalculable human suffering

• Wrote Candide in 1759 in which he analyzes the problem of evil in the world and depicts the woes heaped upon the world in the name of religion

• His battle cry against the Roman Catholic Church was ecrasez l’infame (“crush the damned thing”)

Baron de Montesquieu (1689-1755)

• Sought to establish a science of politics and discover principles that would foster political liberty in a prosperous and stable state

• Instrumental in developing the idea of separation of powers (executive, legislative, judicial)

John Locke (1632-1704)

• Studied the relationship between the individual and the state

• Wrote An Essay Concerning Human Understanding in 1689

• Largely anti-authoritarian– Opposition is both on

the level of the individual person and on the level of institutions such as government and church

John Locke

• Individuals should use reason to search after truth rather than simply accepting the opinion of authorities or being subject to superstition – Proportion assent to propositions to the evidence for

them • There must be a distinction between the legitimate and

illegitimate functions of institutions – Based on those distinctions, there is a corresponding

distinction for the uses of force by those institutions. • By using reason to try to grasp the truth and by

determining the legitimate functions of institutions, the individual and society will flourish materially and spiritually

John Locke

• Thomas Hobbes (1588-1679) had described a social contract in which people in a state of nature ceded their individual rights to a strong sovereign in return for his protection

• Locke offered a new social contract theory in which people contracted with one another for a particular kind of government, and that they could modify or even abolish the government– Great influence on Thomas Jefferson and the

Declaration of Independence

Adam Smith (1723-1790)

• Focused on economics and held that laws of supply and demand determine what happens in the marketplace

• Wrote An Inquiry into the Nature and Causes of the Wealth of Nations in 1776 which argued the virtues of a free market economy

Adam Smith

• Free enterprise system• The role of self-interest and laissez-

faire– Through an “invisible hand” self-interest

guides the most efficient use of resources in a nation’s economy, with public welfare coming as a by-product

– State and personal efforts to promote social good are ineffectual compared to unbridled market forces

• Provides the intellectual rationale for free trade and capitalism– (We’ll discuss capitalism in Lsn 6)

Change Wrought by Enlightenment

• Weakened the influence of organized religion, but certainly did not destroy institutional churches

• Encouraged the replacement of Christian values (which had guided European thought on religious and moral affairs for over a thousand years) with a new set of secular values

Legacy of the Enlightenment

• Debate on whether evolution or creationism should be taught in schools

• Debate on Judeo-Christian values and secular humanism

• Debate on free trade and protective tariffs

• Debate on what the role and authority of government should be

Next

• Atlantic Slave Trade