Department of Philosophy 356 Lecture I Philosophy of Physics PHL 356 S (2017) Department of Philosophy University of Toronto

General information Thursday, 9:30 - 12:00 SS1084 356 Lecture I General information Thursday, 9:30 - 12:00 SS1084 http://www.chass.utoronto.ca/~jrbrown/WeeklyReadings356Physics.htm James Robert Brown 170 St. George St, Room 514 Cell: 519-854-0131 jrbrown@chass.utoronto.ca Office hours: After class or by appointment. Email is often best and fastest.

356 Lecture I Course Outline This course will examine some of the fascinating issues in contemporary physics. The general theme of the course will be: What is objectively real and what is not (in modern physics)? The first part will be devoted to space and time: Does time pass, or is the flow of time an illusion? In the light of special and general relativity, are temporal order and geometrical structure facts about the world or are they conventions? Is space an entity in its own right or just a system of relations among physical bodies? The second part of the course will be devoted to problems in quantum mechanics: Does QM offer a complete description of reality? Do observers discover an already existing reality or do they somehow create it by measuring and observing? The focus will be on the Copenhagen interpretation, the EPR argument, and the Bell results concerning non-locality. Some mathematical background, such as first year calculus is recommended (but it can be rusty).

Texts & Requirements TEXTS: REQUIREMENTS: 356 Lecture I Texts & Requirements TEXTS: Various articles will be assigned. Books (available in Bookstore): Huggett (ed), Space From Zeno to Einstein Rae, Quantum Physics: Illusion or Reality REQUIREMENTS: Two short in-class tests (25% each) Mid-term (50%)

Main themes Space & time 356 Lecture I Main themes Space & time Does time pass, or is passage an illusion of some sort? Does space have a geometry, or is it a (convenient) convention? Do space and time exist independently of other things, or are they some sort of system of relations?

356 Lecture I Quantum Mechanics Do we discover reality or do we somehow create it by measurement? Are there different “realities”, ie, micro-, macro-, physical, mental? If measurement has some effect, does it violate special relativity by sending signals faster than light?

General Theme The unifying theme in the course: How much of current physics is about independent, objective reality, and how much is (in some sense) our creation?

Metaphysics and Epistemology 356 Lecture I Metaphysics and Epistemology Philosophy of physics is largely the metaphysics and epistemology of a special topic, physics. The same could be said for the philosophy of biology, mathematics, and so on. What do these terms mean?

356 Lecture I Metaphysics Metaphysics = the study of the more general features of reality, especially those that are not clearly empirical. (The boundary is fuzzy; there is no sharp line between metaphysics and physics.) For some people, “metaphysics” is a term of abuse. Examples are space and time absolute or relational?  determinism or chance (in physics)? (determinism or freewill (people)? laws of nature – are they just regularities, or a form of causal necessity, or relations among abstract entities?   do chemistry, biology, psychology really reduce to physics (ie, QFT or to strings)? is there any other way to conceptualize reality than in terms of substances with properties? is there a boundary between physics and metaphysics?

356 Lecture I Epistemology Epistemology = the study of knowledge. What is knowledge?, how it is acquired?, what justifies a belief?, and so on. Most scientists and most philosophers are empiricists. Empiricism = all knowledge is based (sometimes indirectly) on sensory experience. Problem: What about non-scientific knowledge: mathematics, ethics, philosophy (eg, the doctrine of empiricism itself), religion?

What about thought experiments? Do bodies fall at different rates? H L H+L Without experiment, I am sure that the effect will happen as I tell you, because it must happen that way. - Galileo

Galileo’s Reasoning Aristotle and common sense claim: H > L. Thus, H+L > H But, H > H+L This is a contradiction. Galileo’s resolution: H = L = H+L. In other words, all bodies fall at the same rate, regardless of their weight.

356 Lecture I What is our job? Physicists are very good at doing physics. (By contrast, astrologers are terrible at doing astrology.) For the most part we will take relativity and quantum mechanics as given. Our job is to make sense out of the best theories going and to try to answer philosophical questions that arise. We might also make a contribution to foundational issues, that is, sort out conceptual confusions. Sometimes we can criticize (philosophers occasionally see conceptual problems that others don’t see), but this will be rare. (Rare in physics, perhaps more common in the social sciences.)

We will meet each week at 9:30 pm and go until noon. 356 Lecture I We will meet each week at 9:30 pm and go until noon. Short break? Normally just a few mins. I will usually hang around for those who want to talk more. Office hours? By appointment, though often around Wednesdays and Thursdays. Check to make sure I’m in. Email is generally fastest. Lectures will be available on-line two or three days in advance. Also posted: required readings and/or links to other papers and possibly interesting things. Each week before class check this site: http://www.chass.utoronto.ca/~jrbrown/WeeklyReadings356Physics.htm

Questions? Math anxiety? Physics background? Philosophy background? 356 Lecture I Questions? Math anxiety? Physics background? Philosophy background? What will tests/exam be like? Other questions?