In a remarkable article entitled Contemplating the End of Physics posted today at Quanta magazine, Robbert Dijkgraaf (the director of the IAS) more or less announces the arrival of the scenario that John Horgan predicted for physics back in 1996. Horgan argued that physics was reaching the end of its ability to progress by finding new fundamental laws. Research trying to find new fundamental constituents of the universe and new laws governing them was destined to reach an endpoint where no more progress was possible. This is pretty much how Dijkgraaf now sees the field going forward:
Confronted with the endless number of physical systems we could fabricate out of the currently known fundamental pieces of the universe, I begin to imagine an upside-down view of physics. Instead of studying a natural phenomenon, and subsequently discovering a law of nature, one could first design a new law and then reverse engineer a system that actually displays the phenomena described by the law. For example, physics has moved far beyond the simple phases of matter of high school courses — solid, liquid, gas. Many potential “exotic” phases, made possible by the bizarre consequences of quantum mechanics, have been cataloged in theoretical explorations, and we can now start realizing these possibilities in the lab with specially designed materials.
All of this is part of a much larger shift in the very scope of science, from studying what is to what could be. In the 20th century, scientists sought out the building blocks of reality: the molecules, atoms and elementary particles out of which all matter is made; the cells, proteins and genes that make life possible; the bits, algorithms and networks that form the foundation of information and intelligence, both human and artificial. This century, instead, we will begin to explore all there is to be made with these building blocks.
In brief, as far as physics goes, elementary particle physics is over, from now on it’s pretty much just going to be condensed matter physics, where there at least is an infinity of potential effective field theory models to play with.
Dijkgraaf ends with an argument indicating that human intelligence is outmoded, artificial intelligence is our future:
Science concerns all phenomena, including the ones created in our laboratories and in our heads. Once we are fully aware of this grander scope, a different image of the research enterprise emerges. Now, finally, the ship of science is leaving the safe inland waterways carved by nature, and is heading for the open ocean, exploring a brave new world with “artificial” materials, organisms, brains and perhaps even a better version of ourselves.
Along the same lines, today also brings an article in the New York Times by Dennis Overbye, Can a Computer Devise a Theory of Everything? The article discusses the new MIT Institute for Artificial Intelligence and Fundamental Interactions and Max Tegmark’s hopes that AI will “discover all kinds of new laws of physics”. My guess is that this will work just fine if you give up on the 20th century understanding of what a “law of physics” is and follow Dijkgraaf’s lead. The problem then may be not so much “will we understand the new laws of physics found by AI?”, but rather that of them not being interesting enough to be worth understanding…
Update: To clarify the point I was trying to make about the Dijkgraaf piece arguing against the “end of physics”, compare it to the similar 1996 piece Gross and Witten published in the Wall Street Journal (a summary is here, an extract here). Gross and Witten were strongly disagreeing with Horgan, whereas it seems to me that Dijkgraaf implicitly agrees with Horgan that fundamental physics has hit a wall and theorists are moving on to do something else.