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Back to Physics 190, 2015: Freshman Seminar: Where do laws of nature come from?

We will talk about what we mean by such different terms as laws of nature, theories, principles, and models. We will discuss why we believe that there should be laws describing how nature works, whether traditional inanimate nature, or biological and even social systems. We will investigate why and how such laws would emerge, and why they will be written always in the language of mathematics.

We will address these questions from the perspective of many different fields: physics, biology, philosophy, etc. Nonetheless, this is a physics class, a science class, and not a philosophy class (I am quite ill-equipped to teach philosophy). Thus we will deal with philosophy in general, and philosophy of science in particular, only tangentially. We will not argue much about whether the reality is fundamentally mentally-constructed, immaterial, and subjective, or objective, and exists independently of us talking about it. Instead, we will focus on how science describes this reality, largely leaving the nature of the reality undiscussed, and taking approaches that a practicing scientist would use.

  • What are scientific laws?
  • Why does Nature allow itself to be confined by laws?
  • How do we discover these laws?

Additionally, we will be attending a handful of science seminars across campus, trying to reconcile what we learn during the seminar with what real scientists are doing.


  • We had to reschedule the second replacement class again. The two extra classes now are Mar 20, 11:30-12:45 and Mar 24, 8:45-10:00.
  • Replacement classes have been scheduled for Mar 20, 11:30-12:45 and Mar 27, 11:30-12:45.
  • Two classes are being rescheduled. Please pay particular attention to assignment due dates and new class times. I will be updating the schedule as it becomes clearer, after you submit your availability. Ilya 15:34, 25 February 2015 (EST)
  • A discussion board has been setup for the class on Blackboard. Please use it to share and discuss your ideas.Ilya 21:14, 25 January 2015 (EST)
  • Welcome to the class!


  • Syllabus -- we will deviate from it in the course of the class
  • Discussion Leaders -- what you are expected to do
  • Weekly office hours: Monday, 2:00-3:00.


  1. January 14. Introduction.
    No reading assignment.
    Attending seminar: Tatyana Sharpee, Maximally Informative Behaviors Implemented by Simple Neural Circuits
  2. January 19. Holiday, no class.
  3. January 21. Laws of nature, scientific principles, scientific theories, models in sciences, hypotheses.
    Assignment: Research, make, and submit your written definition of the five concepts above, and be ready to discuss them. It may help you to start from the encyclopedia articles below, and then maybe to follow citations to primary sources.
    Additional topics: We will discuss the past seminar by Sharpee part of the class.
  4. January 26. Doing science: Falsifiability and Integrity.
    Assignment: Summarize the essays Cargo Cult Science by Feynman, and Science: Conjectures and Refutations by Popper, and Ellis and Silk, 2014. I would expect you to identify 1-2 main points in each of the essays (at least three total), and list 1-2 questions about each essay (at least three total) that you would like to discuss. As always, if you found something surprising or hard to believe, or that you don’t agree with, please note that in your summaries. You should bring a copy of your summary to class to help you participate in discussions.
  5. January 28. How do we update our beliefs? Probability and Bayes theorem.
    Assignment: Khan Academy lectures on Probability and Statistics, pay particular attention to the Monty Hall problem/Bayes theorem. You may also want to read Feynman's lecture on Probability. Summarize your understanding of the Bayes theorem. What would you like me to explain? As always, three points and three questions.
    Lecture: I will give a lecture on basic probability theory and Bayes theorem, and how it is used to verify the laws of nature.
  6. February 2. How do we update our beliefs? Probability and Bayes theorem. Part II
    Assignment: No new reading assignment. I suggest you read/listen the previous class assignment again, and see if you understand things now that you didn't understand before.
    Lecture: I will give a lecture on basic probability theory and Bayes theorem, and how it is used to verify the laws of nature.
  7. February 4. How do we update our beliefs? Probability and Bayes theorem. Part III
    Assignment: Wigner's essay on unreasonable effectiveness of math. Snow's essay on the asymmetry in math/science and humanities in the general culture. Please provide an itemized list of your own understanding of why "the book of nature is written in the language of mathematics" (this is a quote from Galileo).
  8. February 9: Why math? and Matters arising: Do we use Bayesian inference in everyday life?
    Assignment: Kording and Wolpert article on Bayesian integration.
  9. February 11: The structure of scientific revolution
    Assignment: Kuhn's book (or its wiki summary) on The structure of scientific revolution. In addition to the usual three points/three questions, think of a few examples of scientific revolutions and examples of continuous progress. Can you think of contradictions to Kuhn's ideas?
  10. February 16:
    Reading: papers for the upcoming seminar by de Polavieja. Read Perez-Escudero and de Polavijea, 2011.
    Assignment: questions about the paper above.
  11. February 18: Attending seminar: Gonzalo de Polavieja, http://www.quantitative.emory.edu/events/speakerseries1.html . Do
    Do not come to the classroom, but go directly to the seminar room in the Modern Languages Building.
    No written assignment.
  12. February 23: Character of Physical Law, Lecture 1. Law of Gravitation.
    Assignment: Summary and questions about the Lecture 1.
    Assignment: Summary of the lecture by Gonzalo Polavieja; feel free to post questions if you have them as well, but this is not required.
  13. February 25: Snow day, no class.
  14. March 2 and March 4 -- classes rescheduled, no classes.
  15. March 9 and March 11 -- spring break, no classes.
  16. March 16: Character of Physical Law, Lecture 2. The Relation of Mathematics to Physics.
    Discussion Lead: Alex Lin
    Assignment: Summary and questions about the Lecture 2. Assignment Due: March 2, 9:30 am.
  17. March 18: Character of Physical Law, Lecture 3. The Great Conservation Principles.
    Discussion Lead: Scott Weitzner
    Assignment: Summary and questions about the Lecture 3. Assignment Due: March 4, 9:30 am.
  18. March 20, 11:30 am: Character of Physical Law, Lecture 4. Symmetry in Physical Law.
    Discussion Lead: James Martin
    Assignment: Summary and questions about the Lecture 4. Assignment Due: March 16, 9:30 am.
  19. March 23: Character of Physical Law, Lecture 5. The Distinction of Past and Future
    Discussion Lead: Jonathan Kaminski
    Assignment: Summary and questions about the Lecture 5. Assignment Due: March 18, 9:30 am.
  20. March 24, 8:45 am: Character of Physical Law, Lecture 6. Probability and Uncertainty.
    Discussion Lead: Zheng Qiao
    Assignment: Summary and questions about the Lecture 6. Assignment Due: Mar 23, 9:30 am.
  21. March 25: Character of Physical Law, Lecture 7. Seeking New Laws.
    Discussion Lead: Dorcas Adedoja, Assignment Due: Mar 25, 9:30 am
    Assignment: Summary and questions about the Lecture 7.
  22. March 30
    Reading: papers for the upcoming seminar by Murthy. Coen et al., 2014, Nature.
    Assignment: Summary and questions about the Coen et al. paper above.
  23. April 1
    Attending seminar
    Mala Murthy, http://www.quantitative.emory.edu/events/speakerseries1.html
  24. April 6: How much detail is too much?
    Assignment: Questions and summary of the following pieces: Rosenblueth and Wiener, L Carroll, JL Borges
    Discussion Lead: Jin Rim
  25. April 8: More is different! -- This is how new theories emerge
    Assignment: Questions and summary of Weisskopf and Anderson articles. Compare and contrast their ideas.
    Discussion Lead: Daniel Rodriguez
  26. April 13: How do new theories emerge at longer scales?
    Assignment: Questions and summary of the Wilson article.
    Discussion Lead: Kyle Spitzer
  27. April 15: How do we describe emergent theories?
    Assignment: Questions and summary of Goldenfeld/Kadanoff article and Lazebnik article. Are they talking about the same thing? Why yes or why no?
    Discussion Lead: Cherisse Wilkins
  28. April 20: How do we find which laws of nature to discover?
    Assignment: Questions and summary about Hamming's lecture.
    Discussion Lead: TBA
  29. April 22. Project presentations.
  30. April 27. Project presentations.


In (roughly) chronological order. Notice that not all of these pieces will be assigned for you in class. Some are for your enjoyment only.

  • L Carroll, Sylvie and Bruno Concluded. Chapter 11: The Man in The Moon (see passage about the pocket map), 1893.
  • A Rosenblueth and N Wiener, The Role of Models in Science, Philosophy of Science 12:316, 1945. PDF.
  • JL Borges, Of Exactitude in Science, translated by NT di Giovanni, 1946.
  • K Popper, Science: Conjectures and Refutations, Lecture at Peterhouse, Cambridge, 1953. PDF.
  • CP Snow, The Two Cultures and The Scientific Revolution, Cambridge UP, 1959. PDF.
  • EP Wigner, The Unreasonable Effectiveness of Mathematics in the Natural Sciences, Communications on Pure and Applied Mathematics 13:1, 1960. PDF.
  • TS Kuhn, The Structure of Scientific Revolutions, U Chicago Press, 1962. PDF. See also this Wikipedia article.
  • RP Feynman, The Relation of Physics to Other Sciences, in The Feynman Lectures on Physics, 1963.
  • RP Feynman, Probability, in The Feynman Lectures on Physics, 1963.
  • RP Feynman, What is Force?, in The Feynman Lectures on Physics, 1963.
  • V Weisskopf, In Defence of High Energy Physics, Nature of Matter: Purposes of High Energy Physics, 1965. PDF.
  • RP Feynman, The Character of Physical Law, Modern Library, New York, 1994. PDF. Also available as annotated videos of Feynman's 1964 Messenger Lectures from Microsoft Research. Videos and the book are equivalent, you either need to read or to watch. I would watch the lectures -- there's magic in how Feynman delivers them, which gets lost in the transcribed version:
  • PW Anderson. More is different, Science 177:393, 1972. PDF.
  • RP Feynman, Cargo Cult Science, 1974.
  • KG Wilson, Problems in Physics with Many Scales of Length, Scientific American 241:140, 1979. PDF.
  • RP Feynman, The pleasure of finding things out, BBC/PBS Interview, 1981.
  • R Hamming, You And Your Research, Bell Communications Research Colloquium Seminar, 1986.
  • N Goldenfeld and LP Kadanoff, Simple lessons from complexity, Science 284:87, 1999. PDF.
  • Y Lazebnik, Can a Biologist Fix a Radio? —or, What I Learned while Studying Apoptosis. Biochemistry (Moscow) 69(12):1403, 2002. PDF.
  • K Kording and D Wolpert, Bayesian integration in sensorimotor learning. Nature 427:244, 2004. PDF.
  • F Wilczek, Whence the force of F= ma? I: Culture shock, Physics Today 57(10):11, 2004. PDF.
  • F Wilczek, Whence the force of F= ma? II: Rationalizations, Physics Today 57(12):10, 2004. PDF.
  • F Wilczek, Whence the force of F= ma? III: Cultural diversity, Physics Today 58(7):10, 2005. PDF.
  • D Deutsch, TED: A new way to explain explanation, 2009.
  • A Pérez-Escudero and G de Polavieja G. Collective Animal Behavior from Bayesian Estimation and Probability Matching. PLoS Comput Biol 7(11): e1002282, 2011. PDF.
  • S Arganda, A Pérez-Escudero, and G de Polavieja, A common rule for decision making in animal collectives across species, PNAS 109:20508, 2012. PDF.
  • P Steinhardt, Big Bang blunder bursts the multiverse bubble, Nature 510:9, 2014. PDF.
  • P Coen, J Clemens, A Weinstein, D Pacheco, Y Deng, and M Murthy. Dynamic sensory cues shape song structure in Drosophila, Nature 507:233, 2014. PDF.
  • G Ellis and J Silk, Scientific method: Defend the integrity of physics, Nature 516:321, 2014. PDF.

And some additional reading for those who want to venture farther.

And some encyclopedia articles:

Online classes: