USC2170 Doing Science Lecture 1 : Philosophy of Science

1. USC2170 Doing ScienceLecture 1 : Philosophy of Science Wayne M. Lawton Department of Mathematics National University of Singapore 2 Science Drive 2 Singapore 117543 Email matwml@nus.edu.sg http://www.math.nus.edu.sg/~matwml/courses/Undergraduate/SPS_Doing/2006/ Tel (65) 6516-2749 1

2. REFERENCE [1] Samir Okasha, Philosophy of Science – A Very Short Introduction, Oxford University Press, 2002. This book, available in the Science Coop, was recommended to me by Dr Kuldip Singh. It gives a readable description of philosophical problems in contemporary science. The author is a young researcher who specializes in biological issues. http://human-nature.com/nibbs/03/okasha.html 2

3. PLAN FOR WEEK 2 LECTURE Give overview of philosophy & science Analyze reasons for the “Scientific Revolution” Assign reading in 7 topics (1 / tutorial group) - prepare to discuss during your next tutorial 3

4. OVERVIEW • Question : What Do Philosophers Do ? • Get lost in thought • Formulate difficult questions • 4. Derive clear answers • 5. Aggravate people • 6. Conduct methodical experiments 4

5. OVERVIEW • Answers : Philosophers • Get lost in thought • Formulate difficult questions • 4. Derive clear answers • 5. Aggravate people • 6. Conduct methodical experiments 5

6. OVERVIEW • Question : What did Greek Philosophers do ? • Bring their philosophical tradition when • they invaded Greece and Asia Minor (Turkey) • 2. Developed a skeptical method for inquiry • 4. Discovered the Pythagorean Theorem • 5. Invented useful technology and computation • 6. Used empirical methods 6

7. OVERVIEW • Answer : Greek Philosophers • Myceneans and later Dorians did not have a • philosophical tradition when they invaded • Greece, the Myceneans became civilized through • contact with native inhabitants and the Minoans, the • Dorians through contact with Egypt, Persia, and the • Phonecians from whom they got their alphabet. • 2. Developed a skeptical method for inquiry • 3. The Pythagorean Theorem was long known by • Babylonians,Chinese,Egyptians,Indians,Sumerians • 4. Their economy was slave-based and they • had neither interest nor need for technology • 5. Only Aristotle and the physician Hyppocrates 7

8. OVERVIEW This skeptic method included the Socratic Method http://en.wikipedia.org/wiki/Socrates#Socratic_method In this method, a series of questions are posed to help a person or group to determine their underlying beliefs and the extent of their knowledge. The Socratic method is a negative method of hypothesis elimination, in that better hypotheses are found by steadily identifying and eliminating those which lead to contradictions. It was designed to force one to examine his own beliefs and the validity of such beliefs. In fact, Socrates once said, "I know you won't believe me, but the highest form of Human Excellence is to question oneself and others." 8

9. OVERVIEW The mathematical technique “Proof by Contradiction” exemplifies this method Theorem: There does NOT exist a rational number q = N/D such that q x q = 2. Greek Proof. Assume that there does exist such a number. We can assume that the integers N and D are chosen to have no common factors (why). Then N x N = 2 x D x D. Clearly N x N is even. Therefore N is even (why?). Therefore N x N is divisible by 4. Therefore D x D is even (why?). Therefore D is even (why?). This contradicts our assumption that N and D were chosen to have no common factors since if they are both even then they have the factor 2 in common. This contradiction shows that the initial assumption that there does exist a number q that is rational and satisfies q x q = 2 is false. Therefore there does not exist a rational number q = N/D such that q x q = 2. Remark: This means that the square root of 2 is irrational. 9

10. SCIENTIFIC REVOLUTION • Consider the following people : Socrates,Plato, • Aristotle, Alexander, Ptolemy, Avicenna • What were their nationalities and professions ? • What student ‘rebelled’ against their teacher by favoring the empirical approach ? • What factors, other than ‘merit’, promoted the Greek intellectual tradition ? • How did this tradition later impede science ? 10

11. SCIENTIFIC REVOLUTION • Greek: Socrates, Plato, perhaps Ptolemy; • Macedonian: Aristotle, Alexander; Persian: Avicenna • Astronomer: Ptolemy, King: Alexander • 2 Aristotle ‘rebelled’ against Plato by embracing a • thoroughly empirical methodology • 3 Alexander’s military conquests, merging of Plato’s • ‘idealism’ in Christianity,Islamic scholarship and • toleration • 4 In western Europe between ~500-1500 Plato & • Aristotle became the intellectual cornerstone of a • rigid tradition under the control of the authoritative • Roman Catholic Church 11

12. SCIENTIFIC REVOLUTION • from page 3 in [1]: “In 1542 the Polish • astronomer Copernicus (1473-1543) published a book • attacking the geocentric model of the universe, which • placed the stationary earth at the centre of the universe • with the planets and the sun in orbit about it.” “the • Catholic Church who regarded it as contravening the • Scriptures and in 1616 banned books advocating the • earth’s motion” Questions : • where did the geocentric model originate ? • what did Copernicus suggest as an alternative ? • 3. what did authorities in the Church really think about • the Copernican theory and what were they afraid of ? 12

13. SCIENTIFIC REVOLUTION Answers : the geocentric model originated with Ptolemy Copernicus suggested a heliocentric theory Church authorities were extremely intelligent and knowlegeable – some were even amateur astronomers and most probably agreed with Copernicus, but they were afraid of violent social chaos that would occur if “the people that they administered” started to think and thereby undermine their authority; history validates their concern for Dangerous Ideas: 1517 Luther posted Thesis protesting indulgence sales 1525 Peasant’s War : 300K Insurgents, 100K Dead 1618-48 Thirty Years War : 20% central Europe Dead 13

14. SCIENTIFIC REVOLUTION It was also a cultural and social revolution 1542 Copernicus Heliocentric Theory 1609/19 Kepler 1st,2nd / 3rd Laws of Planetary Motion 1609 Galileo demonstrates improved 20X telescope 1610 discovers moons of Jupiter performs mechanical experiments on objects sliding down inclined planes and refutes Aristotle 1632 Dialogue Concerning the Two Chief World Systems Descartes, Huygens, Gassendi, Hooke, Boyle, etc 1687 Newton Principia Mathematica 19-20th Centuries : what are some developments 14

15. SEVEN TOPICS Topic 1. Scientific Reasoning Chapter 2 p18-41 Topic 2. Explanation in Science Chapter 3 p40-57 Topic 3. Realism and Antirealism Chapter 4 p58-76 Topic 4. Scientific Change and Scientific Revolutions Chapter 5 p77-94 Topic 5. Philosophical Problems in Physics, Biology and Psychology Chapter 6 p95-119 Topic 6. Science and its Critics Chapter 7 p120-134 Topic 7. Professional Ethics (supplementary articles) 15