Physics defends itself
There's not as much math as you'd expect
In philosophy of science, coming up with just the right band-aid that rescues a hypothesis and makes no predictions of its own is considered highly suspicious and the worst kind of what’s called “accommodation.” Ad hominem attacks are an even lesser response. Insults have to rank lower still.
In 2016, a prominent editor and social psychologist Susan Fiske called metascientists “methodological terrorists.” Statistician Andrew Gelman wrote a response on his blog that became a classic. To onlookers, the importance of Dr. Fiske’s post wasn’t just that she was being hostile and ad hominem. It was an admission that psychology didn’t have a better defense against the replication crisis that was having its first empirical confirmations.
It is therefore interesting to try to understand the defense that physics has put up against a major threat to its credibility, the “String Theory Wars.” Works in this genre of critique include Farewell to Reality, The Trouble with Physics, Lost in Math, and recently, The Ant Mill. These are all base-rate books. Their authors doubt certain theories in part because there are trillions of variations on them and, without empirical evidence to promote one variation over another, the probability that a particular variation is true is near zero.
The threat to physics’ credibility is, in other words, Bayesianism, a threat that all of academia has been fighting off since the 1800s. It is unlikely that physics has a good argument against Bayesians because no science has had a good argument. It’s unlikely that physics has been dealing with it internally because no science has.
Bayesianism means being able to publish less. It admits the degree to which results are subjective. It admits the tenuousness of expertise. These are all things that academics don’t like.
Physics is not string theory
There’s a long tradition of debate between physicists who believe string theory and other non-empirical and implausible theories should taint physics as a whole, and physicists who think string theory is alone and on the fringe.
What’s dismaying to onlookers is that a lot of mainstream physics’ defense against critique has been ad hominem. It has not stuck to the truth of string theory, or whether or not more of physics is also untrue. This is the history of the debate, to paraphrase physicist Angela Collier:
Some string theorists wrote popular science books for 30 years.
The great success of string theory these books portrayed was a “lie.”
In the early 2000s through to the present day, other physicists wrote books to counter this lie but they also tainted physics as a whole.
The public stopped wanting to support physics because of this and now “we have to earn their trust back and that sucks.”
After Dr. Collier summarized the debate in this way, her YouTube channel was flooded with commenters she called “physics haters.” She took great umbrage at this, and in September, made an argument that physics should not be put in the same bucket with the lie.
Dr. Collier’s argument was an extreme form of the bad apples defense. When someone loses credibility, science is free to disavow them and claim they were a bad apple, and it often does. The public is left to sort through representatives of science rather than scientific facts.
Dr. Collier makes matters worse by wading in, particularly on the “melon heads” who visited her channel. She calls these alleged physics haters “stupid,” “pathetic,” and listening to opposing physicists like Sabine Hossenfelder “embarrassing” over a dozen times.
The irony is that these commenters don’t represent all of the public either, and just because some used absolutist language like “physics is broken” doesn’t mean there isn’t a more nuanced point to be made. It has been made by physicists for decades. Also, the public generally can’t distinguish her good topics like antimatter from string theory or anything else. For all the vast majority of the public knows, they could be accused of being stupid and pathetic for watching Angela Collier in a few years.
The only solution is to try to debate the probability of whether or not string theory and the rest of physics is true. One way to do that, as the authors above have, is to count the number of possible hypotheses in string theory, a number first published in 2005, and argue that this means that string theory is not true. This is the same argument that was successful in Genome-Wide Association Studies and in Why most published research findings are false. It is an argument the public can understand and the equation is easy to prove.
The question is, if this argument is credible enough for physicists to tell us, why isn’t it credible enough for them to tell each other so we don’t need to get involved?
The answer is simple. Bayesianism is how physicists think. Frequentism is how they publish. Frequentism keeps the lights on.
The insults
Philosopher Robert Crease wrote a review of The Ant Mill last month in Physics World that is quintessentially insulting in a way that would make a youtuber blush. He compares the author, Jesper Grimstrup, to a jilted ex, one you barely remember but has written a whole book about you.
The “ex” part comes from Grimstrup’s departure from academia, what Crease calls a “bad breakup.”
Academia shouldn’t listen to its ex Grimstrup, the review says. Listen to current academic Richard Dawid, a string theory supporter. What would the ex analogy be without a new beau?
String theory opponents have criticized its lack of falsifiability, the domain of perhaps the 20th century’s greatest philosopher of science, Karl Popper. Academia’s new beau doesn’t make elaborate demands like Popper and Grimstrup. He accepts the way things are and simply writes them down:
“Dawid, you see, is making the formalism follow the practice rather than the other way around.”
Dawid himself isn’t as quotable as string theorists may like. He admits string theorists have to “make the best of it” in a “drought” of empirical evidence. Where paradigm shifts were once due to great empirical confirmations, they are now brought on by lack of evidence.
Critiquing Popper is not new. String theorist Leonard Susskind called critics “Popperazzi.”
Going after falsification is also a supremely poor accommodation. If you can overturn the greatest philosopher of science of the 20th century, you should publish it, then go back to physics, not wait until the cards are on the table.
Along with the insults, it’s telling how much these academics describe their own bodies in space, how it felt to read the physics haters. Collier describes how it “feels bad” continually. Crease ends up deciding that The Ant Mill is so “over-the-top” that he finds reading it a “hoot.”
How they felt is not even good evidence for them, let alone for us.
Why use the word “crisis?”
String theory is not all of physics. It is not even a lot percentage-wise. However, the argument for crisis doesn’t solely rest on how much of physics is nonsense because string theory is mixed in. It rests on the fact that all fields have largely rejected Bayesianism.
Bayesian physicist Giulio D’Agostini published a paper in 1998, well before Bayesianism became news in 2005. He describes a recent discovery claim in physics. Although the discovery had a tiny p-value, he couldn’t get any of his colleagues to stake even odds that it was true.
This means that, despite the finding being publishable, experts didn’t think there was even a 50% chance it was true. It was clear to D’Agostini that physicists believed in Bayes’ theorem but didn’t use it when publishing.
Predictions are good evidence. Unfortunately, we can’t go back and make D’Agostini’s paper into a famous prediction. It was certainly predictive, though. “Less than 50%” became the predominant finding for 20 years. In physics, experts being secret Bayesians predicts that the base rate for a prominent theory like string theory might be calculated, which would further confirm to physicists that it’s not true. It predicts that other physicists wouldn’t be able to make a Bayesian argument against the theory because they regularly doubt findings behind the public’s back. Making a Bayesian argument would sink all kinds of ordinary physics papers too.
With no good alternatives, some physicists would spend 20 years writing books for the public instead.
The other reason to use the word “crisis” is self-explanatory. Getting rid of empiricism lets in a lot of things we’d rather keep out of science like religion, mysticism, and quackery. Given physics’ place in science and its obvious ability to inspire the foundations of scientific philosophy, continued empiricism during the drought seems like the least we could ask.