Another in my book review series, this is philosophy of science in the capable hands of a physicist. As usual, I have a commentary in which I offer something of an alternative that could break the philosophical logjam that is Dr. Hossenfelder’s primary concern. It is presented here in this separate essay.
In my book review (below) I mention Dr. Hossenfelder’s “secondary concern”, that being the politics and economics of doing physics in a university research environment. I made only cursory reference to this part of her book, but it deserves a little more attention as it is, in part, the result of the lack of break-through empirical discoveries on which university physicists could hang their hats. The doctor spends a good chapter on this subject and hits on all the players. Too many post docs chasing university jobs, too many tenured professors in major physics department not making room for new players, too much emphasis on volume publishing and citation in a limited number of journals.
It is thanks in great part to this publish-and-be-cited cycle, and the money being chased by it, that novel approaches to existing problems are not more prevalent. In the absence of data, new approaches are mostly ignored until (thanks to success if it comes) they cannot be ignored any longer. But that can take years, even decades. Meanwhile, their proponents are left out in the cold. Speaking of cold, Dr. Hossenfelder briefly addresses the dark matter mystery and mentions Fritz Zwicky (who passed away in 1974). Zwicky proposed dark matter as a solution to the galactic gravitational mystery back in the 1930s. A crack pot idea then, but no more.
Sabine Hossenfelder is a physicist with a social media following, a much beloved blog, an attitude, and now a book to go along with it all. This is not a physics book, it is a philosophy book. Its subject matter falls squarely into “philosophy of science”. It is not a book about philosophy of science, but a book that does philosophy of science. Specifically, She mounts a strong critique of present attitudes and assumptions underlying approaches to today’s work in theoretical physics and cosmology. Particle physics, string theory, quantum gravity, quantum mechanics and field theory, black holes, and the origins of the universe all come within her scope. In Dr. Hossenfelder’s view all of them suffer from a similar bias towards the idea that mathematical consistency alone is a truth criterion. Nowhere is this made more plain than in her delightful demonstration that the present predilections of every single one of the above fields can be turned into a multiverse hypothesis!
Hossenfelder knows that data is important. She also knows that modern experimentation in the physical and cosmological sciences is expensive and sometimes takes years to produce data and sometimes not even then. The physicists know this too. It used to be that theories explained existing data and then made new predictions subsequently confirmed or ruled out by further experiments. But the easy experiments have been done. The problem is that there are too many physicists, too many people chasing the next grant, the next tenured position, and not enough money, or new data, to go around. This is a part of the problem, the economics, sociology, and politics of the field. She addresses these, but they are a secondary concern. Her primary concern is squarely philosophical.
At the present level of exploration of physical foundations there are darned few predictions to be confirmed or denied either because doing so is too expensive, experiments have resulted negative outcomes, or the predicted phenomena lie beyond any conceivable experiment. What then are the legions of theoreticians to do? Noticing that many of the successful physical theories of the past have a certain elegance and simplicity about them, intrepid physicists turn to beauty and the notion of naturalness. Neither of these ideas is bad, but they are not, by themselves, good arbiters of truth and this is exactly Dr. Hossenfelder’s point and the primary subject of the book.
Of the twin notions, naturalness is the easier to quantify as it comes down to there being no, or few, “arbitrary numbers” needed to make the theory match the data. The number “1” (or numbers very close to it) is “natural” because it doesn’t change what it multiplies. Un-natural parameters (outside of science known as “fudge factors”) detract from a theory unless they can be satisfactorily explained. The demand for explanation of the fudge factors drives further theory building and she notes that as one is explained, others seem inevitably to appear. Beauty is a more vague idea still as are associated ideas of simplicity (related to naturalness) and elegance. Beauty is, after all, in they eye of the beholder and this is no less characteristic of physicists and their foundational theories as it is in art.
Dr. Hossenfelder traveled from Stockholm to Hawaii and points in between interviewing famous physicists to garner their opinions on this subject. These interviews form a goodly part of the book. Some of her interviewees work firmly in the mainstream of modern physics. Others occupy peripheral positions but have enough street credit to be read by their peers, at least for a while. Her interviews are brilliant and funny. She asks good questions, philosophical questions, and all her interviewees agree with her! The present tendency in physics she so well illuminates is a problem! But there is also consternation. “What else can we do?” is an oft repeated refrain.
Through the process of relating all of this to us, Dr. Hossenfelder expresses her own insecurities about her choice of specialty, and even physics altogether! Has she wasted her time she wonders? Perhaps. But if I had the power I would hire this woman instantly; not in physics, but in philosophy! This theoretical physicist has a lot to contribute to the philosophy of science. Not that the physicists will care much of course. As is often the case in philosophy, insights go unrecognized until after problems that might have been avoided have fully broken upon us.
Dr. Hossenfelder is not absolutely alone crying in the wilderness here. There are a few of her peers in the physics community who see the same problems and have written about them; Lee Smolin comes immediately to mind and there are, perhaps, a few others. She should not despair however. Her credentials are impeccable. She has a lot more to contribute, if not to physics directly, then to philosophy of science. She should embrace her new community!