At Quanta magazine, IAS director and string theorist Robbert Dijkgraaf has signed up to the multiverse mania bandwagon with an article announcing There are no laws of physics. There’s only the landscape. Dijkgraaf’s version of the string landscape ideology is:
The current point of view can be seen as the polar opposite of Einstein’s dream of a unique cosmos. Modern physicists embrace the vast space of possibilities and try to understand its overarching logic and interconnectedness. From gold diggers they have turned into geographers and geologists, mapping the landscape in detail and studying the forces that have shaped it.
The game changer that led to this switch of perspective has been string theory. At this moment it is the only viable candidate for a theory of nature able to describe all particles and forces, including gravity, while obeying the strict logical rules of quantum mechanics and relativity. The good news is that string theory has no free parameters. It has no dials that can be turned. It doesn’t make sense to ask which string theory describes our universe, because there is only one. The absence of any additional features leads to a radical consequence. All numbers in nature should be determined by physics itself. They are no “constants of nature,” only variables that are fixed by equations (perhaps intractably complicated ones).
While giving the usual 1995 justification for the “M-theory” conjecture of a unique string theory, Dijkgraaf neglects to mention that, 23 years later, no one has a viable proposal for what this unique theory might be. He mentions none of the problems of moduli stabilization, or that the theorists “mapping the landscape in detail” don’t actually know what equations govern this supposed landscape and thus have hit a dead-end, unable to predict anything about anything.
The problem is that what Dijkgraaf is writing about is the situation of Theorists Without a Theory, trying to turn this failure into success by arguing that it is a radical new discovery, the discovery that “There are no laws of physics”. He ends with
A more dramatic conclusion is that all traditional descriptions of fundamental physics have to be thrown out. Particles, fields, forces, symmetries — they are all just artifacts of a simple existence at the outposts in this vast landscape of impenetrable complexity. Thinking of physics in terms of elementary building blocks appears to be wrong, or at least of limited reach. Perhaps there is a radical new framework uniting the fundamental laws of nature that disregards all the familiar concepts. The mathematical intricacies and consistencies of string theory are a strong motivation for this dramatic point of view. But we have to be honest. Very few current ideas about what replaces particles and fields are “crazy enough to be true,” to quote Niels Bohr. Like Alice and Bob, physics is ready to throw out the old recipes and embrace a modern fusion cuisine.
The argument seems to be that we need to throw out our highly successful quantum field theories, replacing them with a “radical new framework” describing “impenetrable complexity”. But what is this “radical new framework”? As best I can tell, what’s now popular at the IAS is the “it from qubit” idea that is the topic of this summer’s PITP program. It seems that Witten has taken up the study of quantum information theory, with a new expository preprint just out. I’ll look forward to seeing what the PITP lecturers present, but so far I haven’t seen the slightest indication that this “radical new framework” can get off the ground as a fundamental unified theory.