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Guest Post: A conversation with Lee Smolin about his new book "Einstein’s Unfinished Revolution"
http://backreaction.blogspot.com/2019/06...about.html

INTRO (Hossenfelder): Tam Hunt sent me another lengthy interview, this time with Lee Smolin. Smolin is a faculty member at the Perimeter Institute for Theoretical Physics in Canada and adjunct professor at the University of Waterloo. He is one of the founders of loop quantum gravity. In the past decades, Smolin’s interests have drifted to the role of time in the laws of nature and the foundations of quantum mechanics.

TH: You make some engaging and bold claims in your new book, Einstein’s Unfinished Revolution, continuing a line of argument that you’ve been making over the course of the last couple of decades and a number of books. In your latest book, you argue essentially that we need to start from scratch in the foundations of physics, and this means coming up with new first principles as our starting point for re-building. Why do you think we need to start from first principles and then build a new system? What has brought us to this crisis point?

LS: The claim that there is a crisis, which I first made in my book, Life of the Cosmos (1997), comes from the fact that it has been decades since a new theoretical hypothesis was put forward that was later confirmed by experiment. In particle physics, the last such advance was the standard model in the early 1970s; in cosmology, inflation in the early 1980s. Nor has there been a completely successful approach to quantum gravity or the problem of completing quantum mechanics.

I propose finding new fundamental principles that go deeper than the principles of general relativity and quantum mechanics. In some recent papers and the book, I make specific proposals for new principles.

[...] TH: You part ways with a number of other physicists in recent years who have railed against philosophy and philosophers of physics as being largely unhelpful for actual physics. You argue instead that philosophers have a lot to contribute to the foundations of physics problems that are your focus. Have you found philosophy helpful in pursuing your physics for most of your career or is this a more recent finding in your own work? Which philosophers, in particular, do you think can be helpful in this area of physics?

LS: I would first of all suggest we revive the old idea of a natural philosopher [related], which is a working scientist who is inspired and guided by the tradition of philosophy. An education and immersion in the philosophical tradition gives them access to the storehouse of ideas, positions and arguments that have been developed over the centuries to address the deepest questions, such as the nature of space and time.

Physicists who are natural philosophers have the advantage of being able to situate their work, and its successes and failures, within the long tradition of thought about the basic questions. Most of the key figures who transformed physics through its history have been natural philosophers: Galileo, Newton, Leibniz, Descartes, Maxwell, Mach, Einstein, Bohr, Heisenberg, etc. In more recent years, David Finkelstein is an excellent example of a theoretical physicist who made important advances, such as being the first to untangle the geometry of a black hole, and recognize the concept of an event horizon, who was strongly influenced by the philosophical tradition. Like a number of us, he identified as a follower of Leibniz, who introduced the concepts of relational space and time. (MORE)



Physicist Lee Smolin On Einstein's Unfinished Revolution in Quantum Physics: Author Q&A
https://www.space.com/einsteins-unfinish...rview.html

Space.com: What's the difference between realistic and anti-realistic approaches to quantum mechanics?

Lee Smolin: To me, the difference between somebody who is a realist about quantum phenomena versus somebody who is not a realist is, as a realist, you believe there is a complete story, and there's a complete description, that we can attain of any atomic process, of any nuclear process, of anything going on in the subatomic world. Quantum mechanics doesn't give such a complete description of each and every process individually, and so it can't be complete. We have to find a deeper theory beyond it. Quantum mechanics is a step towards the comprehension of subatomic physics, but it's not the final step. So the job is to go more deeply and invent or discover a better theory that does give a complete description.

If you're what we call an anti-realist, then you think that quantum mechanics as it was written down in the 1920s is possibly the final theory, and there's no motivation to look deeper.

Space.com: You refer to people who are searching for the completion of quantum theory as "naive realists" because their views don't need convoluted justifications. Can you elaborate on this term?

Smolin: Naive really means sophisticated. Naive means you've heard all the basic objections to the idea that we can give a complete description of the world as it is and reject those and hold it as our goal to understand nature completely and as if we weren't here. Science is a description of nature that's supposed to be objective, not imposed upon by our experiments or by our ideas or our beliefs.

Space.com: Does "naive" mean being completely open to new ideas and beliefs?

Smolin: Completely open? No. People forget that physics, like any science, has a history and a tradition. Take a simple idea like momentum, which should be understood in the context of all the discussion since the 16th and 17th century about the principle of inertia, the principle of relativity, and so forth. You can't explain a concept like momentum without being immersed in the whole history of the concept.

[...] Space.com: Your book details the history of quantum physics in the early 20th century. Why did the anti-realist quantum revolution sparked by Niels Bohr become the dominant view — in seemingly the blink of an eye?

Smolin: There were two things that acted simultaneously. One of them, and the most important, was the astounding experimental success. [...] So, the experimental success was astounding, and it was quick. Measured against that, the dissent even of people like Einstein, Schrödinger and de Broglie who said, "Wait a minute! The foundations are a mess!" All of that could be swept under the rug.

That was the first thing. The second thing is the prestige and charisma of Niels Bohr [...] His very hypnotic, charismatic personality could influence the thoughts of a generation of people coming out of a terrible war [World War I]. So it's a bunch of different things at a time.

Space.com: And other theories couldn't make headway.

It is astounding that the pilot wave theory of de Broglie — even if it could be championed by Einstein, by de Broglie and in a way by Schrödinger — had no impact, in spite of the fact that these were not nobodies. These were world famous people with Nobel Prizes, who had done great science, but their dissent could nonetheless be ignored for several generations.

[Pilot wave theory, which Louis de Broglie developed in the 1920s and David Bohm expanded in the 1950s, asserts that electrons encompass both particles and waves and that particles move in the direction that waves guide them. It is deterministic, not probabilistic.]

I think ultimately scientists are human beings, and we are influenced by all kinds of things, from unconscious bias to ambition to social forces. The history of quantum mechanics becomes a story worth contemplating, but it's not an unusual story.

[...] Space.com: Please describe your current work.

Smolin: The most important thing I'm doing in my new work is taking seriously the role of nonlocality. [...] So, I take that seriously, and try to make a theory in which these quantum entanglements are fundamental and the notion of space is emergent. Space doesn't exist; we can make an emergent, approximate description of space in the same way that we use pressure and temperature to describe a gas.

I'm not by any means the only person trying to develop this theory. The idea that space may be emergent from entanglement is an old idea that's getting new traction from people like Roger Penrose. My theory is that space may be emergent, but that time is fundamental and that causality is fundamental. That's a view that a number of people would agree with, and a lot of people would disagree with. (MORE - details)
Smolin does a lot of talking/writing and not much actual physics results.