Is space really “the final illusion”? Rob Sheldon comments

Perimeter Institute cosmologist Lee Smolin tells us that “The intuitive idea that objects influence each other because they’re in physical proximity is soon to become another of those beliefs that turn out to be wrong when we look deeper.: From his Conclusion:

The details are unimportant, especially at this early stage. But the takeaway lesson is that the intuitive idea that objects influence each other because they are close in space is soon to become another of those easy beliefs that turn out to be wrong when we look deeper. The smoothness of space is soon to become an illusion that hides a tiny and complex world of causal interactions, which do not live in space—but which rather define and create space as they create the future from the present. Lee Smolin, “Space: The Final Illusion” at Scientific American

We asked Rob Sheldon to comment:

Lee Smolin is head of the Perimeter Institute in Toronto.

He is a staunch opponent of String Theory, and published a memorable book, The Trouble With Physics: The Rise of String Theory, The Fall of a Science, and What Comes Next (2007).

He proposes that “quantum loop gravity” is the best replacement for String Theory, which will unite General Relativity with the Standard Model. Needless to say, the two groups are not on speaking terms. Along the way, Lee has become very skeptical of the Newtonian concepts of time and causality. Like Sabine, he thinks that progress in physics has stalled, but unlike Sabine he thinks it is the Newtonian metaphysics that caused it.

To explain his concerns, here’s a brief introduction to Newtonian metaphysics and Einstein’s Special Relativity that replaced it:

In Newton’s universe, the two things that exist a priori are space & time. Einstein’s Special Relativity (SR) theory characterized the universe as a lattice of meter sticks with clocks at every intersection. But then Einstein showed how it was possible to “squash” space by going very fast at nearly the speed-of-light, which simultaneously “stretched” time.

Taylor & Wheeler, in a very popular SR textbook, argue that space = speed-of-light * time, and the clocks are really just a fourth spatial dimension. T&W used an analogy of kingdom where maps used kilometers for North-South directions and miles for East-West directions, and no one realized that kilometers and miles could be inter-converted. Then all these squash-stretch transformations (known as Lorentz transforms) are really nothing more than rotations in 4-dimensions of space-time. Special Relativity just turned into a map-reading exercise.

But this Einstein view made it seem that time “just exists” the way a meter stick “just exists”. What happens tomorrow is already there, along with what happened yesterday. This is also known as “the block universe” and seemingly removes all causality. Nothing in the past determines the future.

But if there is no causality, then time doesn’t flow, ethics doesn’t have choices, and quantum wave functions don’t collapse. In short, there doesn’t seem to be a way to reconcile Einstein’s view of space-time & gravity with either quantum mechanics/dynamics or ethics or any observational science. This is the nub of the greatest mystery of modern physics: the incompatibility of gravity with the other four forces.

Smolin’s view is to treat time as fundamental, and space as an epiphenomenon. He gets back causality and gravity, but seems to lose science. He argues that he can recover science but at the cost of modifying our Newtonian metaphysics to remove space. He tries to explain this more fully in his two last books: Time Reborn: From the Crisis in Physics to the Future of the Universe (2013) and The Singular Universe and the Reality of Time: A Proposal in Natural Philosophy (2014),

Peter Woit, who—along with Sabine Hossenfelder—is my go-to-guy for no-BS theoretical physics analysis—reviewed the book that explains his “no-space” hypothesis back in 2015. He finds Singular Universe less than compelling.

What Smolin seems to have in mind here is the hypothesis that physical laws are not “timeless”, but can evolve in time, with an example the ideas about “Cosmological Natural Selection” he has worked on. One problem with this is that the question then becomes “what law describes the evolution of physical laws?”, with an answer re-introducing “timeless” laws. Smolin refer to this as the “meta-law dilemma” and devotes a chapter to it, but I don’t think he has a convincing solution…

In his essay, Smolin gives a discussion of mathematics itself which I think few mathematicians would recognize, defining it as “the study of systems of evoked relationships inspired by observations of nature”, and consisting in bulk just of elaborations of the concepts of number, geometry, algebra and logic. I started my career in physics departments, and I’m well aware of how mathematics looks from that perspective (even if you have a lot of interest in math, like I did). My experience of moving to work in math departments made clear to me that the typical ideas of physicists about what mathematics is and what mathematicians do are highly naive, with Smolin’s a good example. Peter Woit, “The Singular Universe and the Reality of Time” at Not Even Wrong

As far as I can tell, Smolin sees this as a Darwinian solution to The Multiverse Problem. I think I’d call it “The Multiphysics Solution”. I suppose this falls under the dictum, “Fight fire with fire.” My own estimation is “garbage in, garbage out.” Which is about as far as I got with his book as well as his SA essay.

Rob Sheldon is the author of Genesis: The Long Ascent

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See also: Quadrillion possible ways to rescue string theory. Rob Sheldon comments.