What is Philosophy of Physics?
To start with the obvious: philosophy of physics is the part of philosophy of science that deals with the physical sciences. While this is a highly specialized area in philosophy, it is a very broad and diverse field in and of itself. Works in philosophy of physics can be more or less technical, more or less historical, more or less metaphysical. Some use results from physics to address philosophical questions. Others use philosophical expertise to address problems that originate in physics. Some focus on a particular area of physics, such as quantum mechanics, statistical mechanics, or general relativity.
While the physical sciences themselves can be the subject of investigation, many philosophers regard physics as our best guide to the nature of reality. This doesn’t mean that philosophy has nothing to contribute, but that questions about the world should be informed by our best scientific theories. In the latter sense, philosophy of physics stands less in the tradition of
My personal belief is that philosophy, physics, and even mathematics are but different paths to the same goal: understanding the world on the most fundamental level. Philosophy of physics is just a continuation of physics by different means. Many of the questions that I’m dealing with in my research — What is quantum mechanics actually about? What is the origin of the arrow of time in our universe? — used to be part of physics. That they have been largely “outsourced” to the philosophy department is partly the result of our hyper-specialized era in science, partly due to a changed culture in physics (that I find unfortunate). Philosophers, in general, bring a different skillset to the table than scientists trained in solving mathematical equations or conducting experiments, but this doesn’t mean that the problems they are working on are somehow less serious, less substantial, or less scientific.
What to study
Most people working in philosophy of physics today have an education in philosophy, but there is an increasing number of researchers who have transitioned from physics or mathematics or hold a double-degree.
In my experience, it is hard to make a career in philosophy of physics without a Ph.D. in philosophy. On the other hand, you should obviously know some physics if you want to philosophize about it. Good technical (i.e. mathematical) knowledge doesn’t make you a good philosopher of physics, but a lack of relevant technical understanding usually makes you a bad one. You don’t have to be able to solve huge integrals — actually, this will rarely help at all — but you should feel comfortable enough around a mathematical equation to appreciate its content and eventually be able to read a physical research paper. For a professional philosopher of physics, it’s not enough to engage with physics on the level of popular science books (although there are some great popular science books out there, see below).
Maybe you are talented enough to learn all the physics and mathematics you need in self-study, but taking some good classes in university is usually worthwhile if you have the chance. If your education so far has focussed on more traditional areas of philosophy — logic, epistemology, metaphysics, even ancient Greek philosophy — you can put this to good use in the philosophy of physics. In my experience, however, it’s easier to read up on the philosophical background than on physics and mathematics.
Should I change from physics/mathematics to philosophy?
I have transitioned from mathematical physics into
Do not change into philosophy because you think it’s better for your career. Making a career in academia is always hard, and there is usually more money (meaning more positions) in fields that are closer to practical applications. And outside of academia, a degree in physics or mathematics is generally worth more on the job market than a philosophy
Do not change into philosophy because you think it’s easier. Bad philosophy is easy, good philosophy is hard. Philosophy of physics is not a hobby but a serious field of research with professional standards. In particular, doing good work in foundations of physics requires just as much specialized skill and expertise as any other discipline in physics. Don’t think you’ll be a good philosopher just because you’ve been a decent physicist. Don’t even think you’ll be a decent philosopher just because you’ve been a great physicist. Go into the field because you respect it, not because you don’t.
Where to study
Some universities offer graduate programs that specialize in philosophy of science or even philosophy of physics. This is by no means the only path into the field, but certainly a good one.
If you want to do a Ph.D. in
The newly-founded John Bell Institute for the Foundations of Physics is dedicated to creating an international research community for the foundations of physics. Check the website to find leading experts in the field.
Research groups and graduate programs
Here is a selection of universities with a specialized program or research focus in
- University of Lausanne (Prof. Esfeld). This is where I’m currently doing my
- University of Geneva (Geneva Symmetry Group, Prof. Wüthrich). R
esearchproject on the philosophy of spacetime and quantum gravity.
- MCMP (Munich Center for Mathematical Philosophy) at the LMU. Offers
a MAprogram in Logic and Philosophy of Science.
- Oxford. Offers a graduate course on Philosophy of Physics.
- Cambridge. Has a department of History and Philosophy of Science.
- University of Bristol. Has an MA program in Philosophy and History of Science
- Columbia University. Has an MA program “Philosophical Foundations of Physics and regular philosophy of physics courses on the graduate and undergraduate level.
Universityof Pittsburgh. Has one of the top-rated philosophy faculties in the world and a department dedicated to the History and Philosophy of Science.
- UC San Diego. Has a Science Studies program and
a strongresearch focus on philosophyof science and philosophy of physics.
- UC Irvine. Has a department of Logic and Philosophy of Science and a strong research group for the
- Rutgers. Has one of the top-rated philosophy departments in the world with many leading experts in
philosophyof science and philosophy of physics.
- NYU (Prof. Maudlin). Has one of the top-rated philosophy departments in the world with one of the leading experts in foundations of physics.
What to read
The following is not a complete reading list for future students, but a very short (and subjective) selection of my favorite books on foundations of physics that should be accessible to non-experts and give a taste of the discipline at its best. (Links to amazon.com)
Foundations of Quantum Mechanics
- John S. Bell.
Speakableand Unspeakable in Quantum Mechanics. Cambridge Univ. Press, 2nd Ed. (2004).
- Travis Norsen. Foundations of Quantum Mechanics. Springer(2017).
- Detlef Dürr and Dustin Lazarovici. Understanding Quantum Mechanics – The World According to Modern Quantum Foundations. Springer (2020).
Philosophy of Space and Time / Statistical Mechanics
- Tim Maudlin. Philosophy of Physics: Space and Time. Princeton Univ. Press (2015).
- David Z Albert. Time and Chance. Harvard Univ. Press (2000).
- Adam Becker. What is real? TheUnfinishedQuestfortheMeaningofQuantumPhysics. Basic Books (2018).
- Sean Carroll. From Eternity to Here. Dutton (2010).