Einstein for Everyone
JOHN D. NORTON
Nullarbor Press
2007
revisions 2008, 2010, 2011, 2012, 2013,
2015, 2016, 2017, 2018, 2020
This book is a continuing
work in progress. When I have time, I edit, expand and add to the
chapters. For the convenience of readers who need a stable version that
will not change, there is an archived version, which is a snapshot of
the state of the book at the date indicated:
July 18, 2020.
Preface
For over two decades I have taught an introductory, undergraduate class, "Einstein for Everyone," at the University of Pittsburgh to anyone interested enough to walk through door. The course is aimed at people who have a strong sense that what Einstein did changed everything. However they do not know enough physics to understand what he did and why it was so important. The course presents just enough of Einstein's physics to give students an independent sense of what he achieved and what he did not achieve. The latter is almost as important as the former. For almost everyone with some foundational axe to grind finds a way to argue that what Einstein did vindicates their view. They certainly cannot all be right. Some independent understanding of Einstein's physics is needed to separate the real insights from the neverending hogwash that seems to rain down on us all.
With each new offering of the course, I had the chance to find out what content worked and which of my ever so clever pedagogical inventions were failures. By this slow process of trial and error, indulging the indefinitely elastic patience of the students at the University of Pittsburgh, the course has grown to be something that works pretty wellor so it seems from my side of the lectern.
At the same time, my lecture notes have evolved. They began as chaotic pencil jottings. Over time they solidified into neater pencil script and overhead transparencies; and then into summaries that I posted on my website; and then finally those summaries were expanded into a full text that can be read independently. That text is presented here.
Its content reflects the fact that my interest lies in history and philosophy of science and that I teach in a Department of History and Philosophy of Science. There is a lot of straight exposition of Einstein's physics and the physics it inspired. However there is also a serious interest in the history of Einstein's science. A great deal of my professional life has been spent poring over Einstein's manuscripts, trying to discern how he found what he found. The results of those studies have crept in. In other places I try to show how a professional philosopher approaches deeply intractable foundational issues. The temptation in such cases is to let one's standard of rigor drop, since otherwise it seems impossible to arrive at any decision. That is exactly the wrong reaction. When the problems are intractable, we must redouble our commitment to rigor in thought; and I have tried to show how we can do this.
This
text
owes a lot to many. It came about because, years ago, the chair of the
Department of HPS, urged a meandering junior professor to teach a course
that "did" Einstein and black holes and all that stuff. The text is
indebted to the University of Pittsburgh, which has the real wisdom to
see that it gets the most from its faculty by letting them do what
fascinates them, for they will surely do that best. It owes the greatest
debt to the infinite patience of the students who have taken this class,
told me what works and what does not, and each year allowed me, at least
indirectly, to experience anew that inescapable sense of wonder when one
first grasps the beauty of what Einstein did.
i i i
Contents
Preface  iii 
1. Introduction  read 
Special Relativity  
2. Special Relativity: The Principles  read 
3. Special Relativity: Clocks and Rods  read 
4. Special Relativity: Adding Velocities  read 
5. Special Relativity: Relativity of Simultaneity  read 
6. Is Special Relativity Paradoxical?  read 
7. E=mc^{2}  read 
8. Origins of Special Relativity  read 
9. Einstein's Pathway to Special Relativity  read 
Spacetime  
10. Spacetime  read 
11. Spacetime and the Relativity of Simultaneity  read 
12. Spacetime, Tachyons, Twins and Clocks  read 
13. What is a Four Dimensional Space Like?  read 
Philosophical Significance of the Special Theory of Relativity 

14. Skeptical Morals  read 
15. Morals About Theory and Evidence  read 
16. Morals about Time  read 
17. The Conventionality of Simultaneity  read 
NonEuclidean Geometry  
18. Euclidean Geometry: The First Great Science  read 
19. Euclid's Fifth Postulate  read 
20. NonEuclidean Geometry: A Sample Construction  read 
21.NonEuclidean Geometry and Curved Spaces  read 
22. Spaces of Constant Curvature  read 
23. Spaces of Variable Curvature  read 
General Relativity  
24. General Relativity  read 
25. Gravity Near a Massive Body  read 
26. Einstein's Pathway to General Relativity  read 
Cosmology and Black Holes  
27. Relativistic Cosmology  read 
28. Time Travel Universes  read 
29. Our Universe: What We See  read 
30. Big Bang Cosmology  read 
31. Must There Have Been a Big Bang?  read 
32. Black Holes  read 
33. A Better Picture of Black Holes  read 
Philosophical Significance of the General Theory of Relativity 

34. Geometric Morals  read 
35. The Ontology of Space and Time: The Relativity of Accelerated Motion  read 
36. The Ontology of Space and Time: The Hole Argument  read 
37. Theory and Evidence  read 
38. Cosmos and Infinity  read 
Quantum Theory  
39. Atoms and the Quanta  read 
40. Origins of Quantum Theory  read 
41. Quantum Theory of Waves and Particles  read 
42. A Complex Wave  read 
43. The Measurement Problem  read 
44. Time Travels with Schrödinger's Cat  read 
45. Einstein on the Completeness of Quantum Theory  read 
Retrospect  
46. Einstein as the Greatest of the Nineteenth Century Physicists  read 
i v