Lecture 2: The Scientific Revolution
The Scientific Revolution
• 1550 - 1700
◦ a fast change in 150 years
◦ before this: religion had all the answers > though all major questions had been answered
Astronomy
• what was believed:
◦ we were one planet among many
‣ earth was the center of the universe
‣ earth was surrounded by crystal spheres (fixed stars)
• Copernican revolution: the sun is the center of the universe
◦ by Copernicus
◦ he assumed this to calculate the movements of planets
◦ worked so well people figured it was true
• Newton introduced gravity
◦ to explain why the stars don't fall and why we orbit the sun
‣ the sun is so massive so it influences the other planets
◦ took away the crystal sphere theory
• Galileo discovered telescope
◦ found mountains and craters on the moon
‣ moon was thought to be a perfect sphere
◦ prosecuted because of moon and believing Copernican theory
‣ forced to say sun is not center
Chemistry
• what was believed:
◦ everything in the universe is made of earth,
fire, wind and water (4 elements) FIRE
not dry
◦ humans are made of the four elements in a
AIR EARTH
different composition than a plant
wet cold
• gradually realized there are elements and what
WATER
they are made of
◦ molecules are made of atoms
• medicine:
◦ people left their body to science
◦ started cutting people up after they died
◦ figured out how the heart works
,Psychology
• what was believed:
◦ the combination of elements also decides health and who we are (psychology)
◦ religion forbade cutting into people so no understanding of human body
result: clash between church and science
◦ church had the monopoly on science
◦ it was thought that everything can be found in the bible
◦ emphasis on not questioning gods word
◦ some were prosecuted
• the clash of so many different world views lead to the question: what is knowledge?
◦ everyone's beliefs were at stake
The rise of skepticism
(Montaigne was skepticist)
plato: there are three conditions that are individually necessary and jointly sufficient
- belief: you must believe x to know x
- truth: x must be true
- justification: your belief must be justified
justified true beliefs = knowledge
Skepticism : we do not have any knowledge
• we may believe something
• and they may be true
• but there is no way to justify
◦ your senses are not reliable (think optical illusions)
◦ your brain decides what you see or hear etc
knowledge based on observation - but observation not reliable
Two historically influential answers
a. rationalism
b. empiricism
Rationalism
• we can be certain about things
Descartes: "I doubt therefore I think, I think therefore I am"
cogito argument
◦ i doubt about everything, but the fact that i doubt means i exist - in order to be able to doubt
◦ start with what you know for sure then deduce
mathematical beliefs
• 1+1=2
distinct
clear t ideas
use deduction to infer
knowledge
, deduction: if you know the premises are true,
you are absolutely certain that the conclusion
is also true
explanation ^:
P1: men are mortal
P2: socrates is a man
C: socrates is mortal
Empiricism
• sensory experience is the source of all knowledge
• tabula rasa: there is no innate knowledge
• empirical knowledge: knowledge based on observation
• typically pro-science: best way to investigate our world
Bacon:
• nihilist
• there is nothing in our mind that was not first in our senses
• use induction to obtain knowledge
◦ induction: if you are certain that the premises are true, it becomes more likely that the
conclusion is true
Two problems for empiricists
1. Skepticism: how do we know what we see is true
◦ we only see an interpretation of the world
◦ everything is subject to how your senses perceive something
‣ how do we know what the original actual, "thing" is?
2. problem of induction
• how do we know induction is a reliable source for reasoning
◦ how do i know that a plus b is c
• answer: because it has worked well in the past
◦ problem with answer: you use induction to justify induction
‣ when hand in assignment: "don't use wiki" "you use wiki to prove wiki is reliable"
How would empiricists respond to rationalists?
Everything that you know comes from your senses
The Scientific Revolution
• 1550 - 1700
◦ a fast change in 150 years
◦ before this: religion had all the answers > though all major questions had been answered
Astronomy
• what was believed:
◦ we were one planet among many
‣ earth was the center of the universe
‣ earth was surrounded by crystal spheres (fixed stars)
• Copernican revolution: the sun is the center of the universe
◦ by Copernicus
◦ he assumed this to calculate the movements of planets
◦ worked so well people figured it was true
• Newton introduced gravity
◦ to explain why the stars don't fall and why we orbit the sun
‣ the sun is so massive so it influences the other planets
◦ took away the crystal sphere theory
• Galileo discovered telescope
◦ found mountains and craters on the moon
‣ moon was thought to be a perfect sphere
◦ prosecuted because of moon and believing Copernican theory
‣ forced to say sun is not center
Chemistry
• what was believed:
◦ everything in the universe is made of earth,
fire, wind and water (4 elements) FIRE
not dry
◦ humans are made of the four elements in a
AIR EARTH
different composition than a plant
wet cold
• gradually realized there are elements and what
WATER
they are made of
◦ molecules are made of atoms
• medicine:
◦ people left their body to science
◦ started cutting people up after they died
◦ figured out how the heart works
,Psychology
• what was believed:
◦ the combination of elements also decides health and who we are (psychology)
◦ religion forbade cutting into people so no understanding of human body
result: clash between church and science
◦ church had the monopoly on science
◦ it was thought that everything can be found in the bible
◦ emphasis on not questioning gods word
◦ some were prosecuted
• the clash of so many different world views lead to the question: what is knowledge?
◦ everyone's beliefs were at stake
The rise of skepticism
(Montaigne was skepticist)
plato: there are three conditions that are individually necessary and jointly sufficient
- belief: you must believe x to know x
- truth: x must be true
- justification: your belief must be justified
justified true beliefs = knowledge
Skepticism : we do not have any knowledge
• we may believe something
• and they may be true
• but there is no way to justify
◦ your senses are not reliable (think optical illusions)
◦ your brain decides what you see or hear etc
knowledge based on observation - but observation not reliable
Two historically influential answers
a. rationalism
b. empiricism
Rationalism
• we can be certain about things
Descartes: "I doubt therefore I think, I think therefore I am"
cogito argument
◦ i doubt about everything, but the fact that i doubt means i exist - in order to be able to doubt
◦ start with what you know for sure then deduce
mathematical beliefs
• 1+1=2
distinct
clear t ideas
use deduction to infer
knowledge
, deduction: if you know the premises are true,
you are absolutely certain that the conclusion
is also true
explanation ^:
P1: men are mortal
P2: socrates is a man
C: socrates is mortal
Empiricism
• sensory experience is the source of all knowledge
• tabula rasa: there is no innate knowledge
• empirical knowledge: knowledge based on observation
• typically pro-science: best way to investigate our world
Bacon:
• nihilist
• there is nothing in our mind that was not first in our senses
• use induction to obtain knowledge
◦ induction: if you are certain that the premises are true, it becomes more likely that the
conclusion is true
Two problems for empiricists
1. Skepticism: how do we know what we see is true
◦ we only see an interpretation of the world
◦ everything is subject to how your senses perceive something
‣ how do we know what the original actual, "thing" is?
2. problem of induction
• how do we know induction is a reliable source for reasoning
◦ how do i know that a plus b is c
• answer: because it has worked well in the past
◦ problem with answer: you use induction to justify induction
‣ when hand in assignment: "don't use wiki" "you use wiki to prove wiki is reliable"
How would empiricists respond to rationalists?
Everything that you know comes from your senses
