Friday, June 15, 2018

Is Theoretical Physics Wasting Our Best Minds?

Before you continue reading this, let me be very clear right off the bat that there are TWO separate issues here that I will be discussing, and they are thinly connected simply by the over-general reference of "theoretical physics" made by the author of the article that I will be citing.

In this Forbes article, Ethan Siegel highlights the main point made by Sabine Hossenfelder in her book "Lost In Math". Siegel not only pointed this out, but also did an in-depth description leading up to the "naturalness" philosophy that is prevalent in the esoteric fields of physics such as string, etc.

If you are a theoretical particle physicist, a string theorist, or a phenomenologist — particularly if you suffer from cognitive dissonance — you will not like this book. If you are a true believer in naturalness as the guiding light of theoretical physics, this book will irritate you tremendously. But if you're someone who isn't afraid to ask that big question of "are we doing it all wrong," the answer might be a big, uncomfortable "yes." Those of us who are intellectually honest physicists have been living with this discomfort for many decades now. In Sabine's book, Lost In Math, this discomfort is now made accessible to the rest of us.

Certainly this is thought-provoking, and it isn't something I disagree about. For science to give up on empirical evidence, and simply pursue something that looks "natural" or "beautiful" is dangerous and verging on being a religion. So my feelings are consistent with what has been said in the article.

Now comes the other part of the issue. It has always been my pet peeve when someone over-generalize physics as being predominantly being "high-energy physics, astrophysics, string theory, etc...", i.e. the esoteric fields of study. In this case, "theoretical physics" certainly is NOT dominated by those fields. There are theoretical studies in condensed matter physics, atomic/molecular physics, medical physics, accelerator physics, etc... etc., i.e. fields of studies that are certainly not esoteric, have lots of practical applications, etc.

In fact, I would argue that the esoteric fields of physics represents the MINORITY in terms of the number of practicing physicists that we have around the world. As a zeroth-order approximation of this claim, I decided to look at the members of the APS. The APS Divisions correspond to the number of members who declared themselves to be in a certain field within physics. Note that not all members made the declaration, and it is also not uncommon for a member to declare more than one division.

First of all, 79% of APS members are accounted for in this chart for the 2018 membership. Now, what is the percentage of members within the so-called esoteric fields of Astrophysics, Gravitation, and Particles and Fields? 14.9%. Even if you include Nuclear Physics into this, it will come up to 19.8%

Now, forget about theoretical or experimental. Can 19.8% represents ALL of physics? The fields of studies that a lot of people associate physics with are done by ONLY 19.8% of physicists! Using them, one will get a severely inaccurate representation of physics and physicists.

In fact, if you look at the fields more commonly associated with the physics of materials (condensed matter physics and Materials Physics), we get 18.2%, almost as big as Astrophysics, Gravitation, Particles and Fields, and Nuclear Physics combined! Condensed matter physics alone dwarfs other fields, being almost twice as big as the next division, which is Particles and Fields.

But what is more important here is that outside of the 19.8% of physicists in these esoteric fields, an overwhelming percentage of physicists (59.2%) are in fields of studies that are associated with practical applications of physics. So if you were to bump randomly into a physicist, chances are, you will find someone who works in a field related to something of practical importance and NOT a high-energy physicist, a nuclear physicist, etc.

This is my round-about way of complaining that Ethan Siegel article should not be a damnation of "theoretical physics" in general, because the overwhelming percentage of theoretical physics is NOT about these esoteric topics that have been mentioned in his article. Rather, theories in other parts of physics rely very heavily on empirical observations and verification, i.e. the good and tested way of doing science. In those areas, we are definitely NOT wasting our best minds!

A while back, I said that physics is not just the LHC. It is also your iPhone. Even that requires modification. We should say that physics is predominantly your iPhone, with only a smidgen of LHC added as garnishing. That is a more accurate representation of the field as a whole.


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