String Theory has been the dominant candidate for a ‘theory of everything’ for decades. But Eric Weinstein thinks its dominance is unjustified and has resulted in a culture that has stifled critique, alternative views, and ultimately has damaged theoretical physics at a catastrophic level. In this exclusive interview, Weinstein defends String Theory against some of its critics, but ultimately argues the need for a fundamental cultural shift to save the vitality of the field from certain death.
These days almost all of theoretical physics is conducted by professional academics working in universities. Leaving aside the droves of amateurs bombarding high profile physicists with their pet theories that supposedly prove Einstein wrong or solve the measurement problem of quantum mechanics once and for all, there are very few, but notable exceptions. Eric Weinstein is perhaps the most famous among them.
There is something alluring about the image of the lone genius, hacking away at some of the hardest theoretical physics problems, aiming to uncover the secret language of the universe armed with just pen, paper, and their intellect. We owe this image of the physics maverick to Albert Einstein who singlehandedly triggered one of the two major revolutions in physics while working as a patent clerk. Weinstein’s day job has been a bit more glamorous than that, being the managing director of Thiel Capital for a number of years, though these days he is working with Thiel in a different capacity and describes himself as an entertainer, being the host of a podcast, The Portal.
What if, Weinstein continues, the very idea of spacetime is doomed? ‘Spacetime’ is just a model, and one that might be deeply problematic.
I reached out to Weinstein because I wanted to talk to him about String Theory. A recent exchange he had with Brian Greene, one of the most influential string theorists alive today, has been ringing in the back of my mind and I wanted to find out more about Weinstein’s views on the matter. In his exchange with Greene, he accused string theory, or rather string theory culture, as being the main obstacle for the development of theoretical physics in the past 50 years or so. Weinstein repeated some of these claims in a recent podcast with Brian Keating and Dan Greene. So why is it that despite some of the most distinguished theoretical physicists seeing String Theory as the most promising candidate for a so-called theory of everything, does Weinstein hold it responsible for the discipline’s stagnation?
“Before we attempt a theory of everything, we need to understand our two fundamental models for physical reality”, Weinstein begins. You see, ever since Einstein, physicists have been assuming that a theory of everything is the next logical step for physics, when in fact we probably still don’t fully understand the two theories we are trying to merge: Quantum Field Theory and General Relativity.
“People assume the standard model is fine as it is. But some of the things blocking us [merging gravity with the standard model] are things we think we know, but are in fact wrong and misleading.” So, in a way, jumping ahead to a theory of everything is the wrong approach. We first need to untangle the various hidden assumptions that we have sneaked in, both in General Relativity as well as Quantum Mechanics, that have become blind spots propagated from one generation of physicists to another. And while physicists often recognise that this might be the case, Weinstein isn’t sure they appreciate just how big of a problem it is, and how difficult it will be to unto. “Once our minds are grooved in certain ways, it’s very hard to have any new thoughts.”
“I have nothing against String Theory per se, as String Theory doesn’t hurt anyone. But I am absolutely committed to the idea that if we do not purge String Theory culture and Quantum Gravity culture, and get back to collegiality, self-critique, that this field will die.”
Finding a way of merging our understanding of all the different forces of nature into one theory isn’t exactly motivated by mundane practical concerns, Weinstein admits, as there aren’t many daily problems of real life for which we appear to need a theory of everything.The goal is to find a way to make General Relativity compatible with Quantum Theory. But, again Weinstein insists, that might happen in a way that most physicists don’t expect. What theoretical physicists have been focussing on is quantizing gravity. Their guiding intuition is that we need to find a way for quantum mechanics to work not just on the small scale, but on the large scale, on objects with enough mass to put a dent into spacetime. At the moment, Einstein’s field equations don’t seem to allow for that. But what if, Weinstein continues, the very idea of spacetime is doomed, as theoretical physicist Nima Arkani-Hamed suggests? ‘Spacetime’ is just a model, and one that might be deeply problematic. There are plenty of different structures, according to Weinstein, that could replace spacetime and from which it could be recovered. If that is the case, gravity might not need to be quantized in the first place.
We’re back at the idea that we still don’t understand General Relativity well enough, or that we haven’t yet sufficiently interrogated one of its key concepts, in this case spacetime. This reminds me of Sabine Hossenfelder’s claim that we still don’t understand one of the key issues of quantum mechanics: the measurement problem.
So why, instead of interrogating the fundamentals of Quantum Mechanics and Relativity, have theoretical physicists been focussing on attempts to merge the two in the form of String Theory? This is where Weinstein and his critique about the state of physics comes alive. The project of Quantum Gravity, of which String theory is one version, became toxic in the mid 1980s, according to Weinstein, silencing anyone who dared challenge the direction of travel, and suppressing any alternative proposal for a way forward. Theorists who expressed any dissent from the orthodoxy of Quantum Gravity “simply didn’t get grants and jobs”, Weinstein argues, “their careers ended”. Once the Quantum Gravity community took hold and began to weaponize the standards for new ideas, the bar for publishing anything in the foundations of physics that that challenged that project became prohibitively high, while at the same time the standards for publishing anything that was part of the Quantum Gravity project were lowered. This had nothing to do with the fact that the people working on Quantum Gravity, and String Theory in particular, weren’t capable. In fact, Weinstein thinks the physicists that ended up going into String Theory were generally the most intellectually able. But they became the status quo, the establishment, and as with every establishment, it became tempting to solidify its hold on power by pushing forward double standards for itself and its competitors.
"Science is not a hypothesis that you then go out into the world to test. That’s what we tell religious fundamentalists, so they don’t invade our subject."
This has been going on for several decades now, according to Weinstein, and the theoretical physics community is suffering from something akin to the sunk-cost fallacy. “Too many PhDs, conferences, dollars, jobs later, we are effectively looking at something that’s too big to fail.”
When I press Weinstein on whether his critique of String Theory goes beyond this sociological account of how one project - a project that despite all the talent it attracted, has essentially stalled - came to dominate the field at the expense of all other projects, I get less of a response than I was expecting: “I have nothing against String Theory per se, as String Theory doesn’t hurt anyone. But I am absolutely committed to the idea that if we do not purge String Theory culture and Quantum Gravity culture, and get back to collegiality, self-critique, that this field will die.”
Weinstein, for example, has little time for one of the standard objections against String Theory: that it’s unfalsifiable, and hence it’s not really science. “Science is not a hypothesis that you then go out into the world to test. That’s what we tell religious fundamentalists, so they don’t invade our subject. We have oversimplified the scientific method into a fairy tale we tell slow children because we have bad actors, if we didn’t, then we could say what science really is.” The problem, according to Weinstein, is that the scientific community itself has internalised some of these “fairy tales” and uses them to discredit their opponents.
"Science requires the middle finger. In the absence of a middle finger, it doesn’t work. When you impoverish people, you dismantle the scientific method.”
What then I asked, is science, given that, none of the definitions philosophers of science have come up with over the years seem to fit the bill. “Everything that results in reliable knowledge is science” retorted Weinstein. “Science includes the hypothetico-deductive model, but it also includes Kary Mullis getting stoned out of his mind and coming up with the polymerase chain reaction, or Kekulé dreaming of snakes swallowing their own tail, and coming to understand the structure of benzenes.”
But for Weinstein, even if science is not as neatly structured in its methodology as we might like to think, it does require a certain amount of freedom, financial freedom in particular, in order to function properly. “Science requires the middle finger. In the absence of a middle finger, it doesn’t work. When you impoverish people, you dismantle the scientific method.” What Weinstein is referring to will be all too familiar to junior academics, not only in theoretical physics, but across all academia: job insecurity, and financial precarity. When your career depends on pleasing more powerful and established academics, then the questioning, doubting, and interrogating suffers – science suffers.
So what’s the way forward? Weinstein thinks two things need to happen. First, it would help “if some of the people most responsible for the popularity of String Theory behaved like scientists rather than bullies and stepped up to the plate and addressed the need to get rid of this culture or were to at least enter serious debates in open forums about the utter 70 year fiasco of Quantum gravity, the spell would be broken” “I can’t even begin to say how bad the culture is. It’s destructive of healthy inquiry, and it has always been deliberately bullying and destructive of healthy inquiry, as the only way it survives is that people are afraid to question the lack of successes or progress in the field, despite all the talent and resources that have gone into it.”
Weinstein hopes that this clearing of the air shouldn’t be hard for people at the end of their careers, with no need for any further recognition and accolades. When I ask Weinstein who he has in mind, two names come up: Edward Witted and David Gross. Weinstein describes Witten “as the Michael Jordan of theoretical physics, if only Michael Jordan was a better basketball player”, and credits him for having directed everyone towards String Theory, after he himself became convinced that was the way forward. David Gross, on the other hand, was one of the only String Theorists who brought with him a Nobel-prize-winning contact with experiment from a previous era, and so lent his support to String Theory as ‘real physics’
The other thing Weinstein recommends is securing enough resources for the future generation of theoretical physicists. “If you wanted to see how the oldest two generations of theoretical physicists welcomed the young, I highly recommend Goya’s painting of Cronos eating his children.” Despite his thorough critique of the String Theory and Quantum Gravity community, Weinstein’s last words on the matter is that we need to give more money, not less. The financial insecurity that people feel about their future is part of what fuels the bad behaviour, according to Weinstein.
“If people don’t have the ability to speak back to their advisors, to talk back against their institutions, the problem will continue. It’s time to for theoretical physicist to stop worrying where their next pay cheque will come from in a world of prosperity built on the back of 19th-20th century physics discoveries, or to be worried they will be defamed as a crank or a crackpot or charlatan by people who have failed at their jobs for 50 years and projecting their fears of inadequacy, self-hatred and wasted lives. If you want to get science you can rely on, you have to get rid of science you can control. Please give my competitors and detractors more money so they can go back to being colleagues rather than trolls with PhDs.”