There’s a German chocolate brand that comes in a neat square and is sold under the tagline: “Quadratisch. Praktisch. Gut.” It’s unintentionally hilarious — I would have loved to be a fly on the wall when the ad agency decided to appeal to consumers’ rational instincts first, as if flavour were just a nice bonus.
I come to think of this as I’m reading Lee Smolin’s The Trouble with Physics : The Rise of String Theory, The Fall of a Science and What Comes Next, in which the author takes aim at the paradigm that has dominated theoretical physics since the ’70s.
According to Smolin, string theorists have fallen in love with what they see as an almost divinely elegant mathematical interpretation of particle theory. The fact that they can neither prove nor disprove their conjecture experimentally is treated as a footnote — the theory is considered too beautiful to be wrong.
If you’re new to string theory, it’s essentially a framework where everything is composed of unimaginably tiny strings. Their different vibrational modes supposedly give rise to all known particles and forces—including gravity. If validated, it could unite quantum mechanics and general relativity into a single, all-encompassing theory of everything. As stated, however, validation remains elusive.
What’s odd about the whole situation is that string theory somehow gets away with it. For two centuries, theoretical physics was revolutionised roughly once a decade — until it hit a brick wall with the advent of string theory in the late ’70s. By the usual standards of science, a paradigm unable to produce empirical evidence should have collapsed under its own weight. But that hasn’t happened. Fifty years on, string theory — now often called M-theory — still dictates the direction theoretical physics is moving — or rather, isn’t moving.
I’m transfixed by Smolin, but his argument also sets off a quiet alarm. If things really are as hollow as he suggests, then entire generations of our most brilliant minds have busied themselves feverishly rearranging deck chairs on the Titanic. That wouldn’t just be an intra-scientific problem — it would be a profound crisis of meaning. It’s almost too bleak to believe. And besides: if it were true, wouldn’t there be more of a ruckus?
In an effort to find out, I turn to one of the most eloquent proponents of string theory: Brian Greene. If he understands the subject half as well as he handles the English language, then he’s a man I can trust.
My copy of The Elegant Universe is filled with scribbles and underlinings, but when I return to my notes a few months after reading it, one passage stands out above the rest:
Since Veneziano’s insightful guess in 1968, the theory has been pieced together, discovery by discovery, revolution by revolution. But a central organising principle that embraces these discoveries and all other features of the theory within one overarching and systematic framework—a framework that makes the existence of each individual ingredient absolutely inevitable—is still missing. The discovery of this principle would mark a pivotal moment in the development of string theory, as it would likely expose the theory’s inner workings with unforeseen clarity. There is, of course, no guarantee that such a fundamental principle exists, but the evolution of physics during the last hundred years encourages string theorists to have high hopes that it does.
The quote stays with me because, despite Greene’s hopeful tone, he seems to be conceding the critics’ central point. And not a minor one, either, but a challenge that cuts to the heart of the project: the foundation is still missing. String theorists may have high hopes that it will one day appear — but hopes, no matter how fervently held, do little to strengthen a scientific case.
And what’s more, since Greene wrote those lines 26 years ago, the Large Hadron Collider has come online, the Higgs boson has been unveiled, and gravitational waves have been detected — a stunning confirmation of general relativity. Meanwhile, string theory is still waiting for its first real-world vindication.
Greene and others tend to explain this away by pointing to the limitations of current experimental equipment. And it’s true: to even stand a hypothetical chance of testing string theory, we’d need particle colliders around 15 orders of magnitude more powerful than anything we can build today — which means it would have to be the size of the entire Milky Way.
Defending a theoretical house of cards by blaming the hardware doesn’t fly with Lee Smolin. If experimental validation is out of reach for any foreseeable technological future, then the theory isn’t just untested — it’s untestable. Which means it’s metaphysics rather than science.
As entertaining as Smolin is on the science, his deeper critique is sociological: postwar academia rewards technical skill and citation metrics over bold thinking – the system favours craftsmen over dreamers. If someone like Einstein had a hard time getting tenure a hundred years ago, then today he wouldn’t stand a chance.
This structure worked well during the long period when theoretical physics was mostly about ironing out the wrinkles in the Standard Model. But it’s a machine optimised for precision, not for noticing when it’s grinding away in the wrong direction.
Hence, the real reason we’re stuck in the infertile paradigm of string theory might not be — as string theorists would have it — that we’ve run out of low-hanging fruit. The real reason might be that we’ve pruned the tree in such a way that no new branches can grow.
It’s a rich paradox: the very field that once embraced the most unorthodox, counter-intuitive ideas in human history now finds itself stalled — precisely because it’s become captive to orthodoxy.
And before you dismiss all this ‘trouble with physics’ as arcane — not necessarily unimportant, but best left to the experts — let me leave you with one final thought from Lee Smolin:
If our generation of theorists has failed to make a revolution, it is because we have organised the academy in such a way that we have few revolutionaries, and most of us don’t listen to the few we have.
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It may seem strange to be discussing academic politics in a book for the general public, but you, the public, individually and collectively, are our patrons. If the science you pay for is not getting done, it is up to you to hold our feet to the fire and make us do our job.