His much longer book, Reality Is Not What It Seems: The Journey to Quantum Gravity (2014), covers the same territory in greater detail (and greater length: 288 pages). After I finished what amounted to an appetizer, I tucked into the main course. I’m about 30% through it and am enjoying it quite a bit more than I have his work so far.
Both books, but especially the longer one, explore the theory of Loop Quantum Gravity (LQG), of which Rovelli is a co-founder.
Note that the publication dates listed are the Italian publication dates. The English publications were 2105 for Seven Brief Lessons On Physics and 2016 for Reality Is Not What It Seems.
I’ll also mention that much of the text in the brief one appears in the longer one. If one plans to read the long one, it’s possible to skip the short one, but it does make a nice appetizer.
I read his book The Order of Time (2017) and struggled somewhat with it on both style and argument. I’m not taken by his theory that time is emergent. In my view that’s cart before the horse. [See Time and Two Doors for details.]
My previous post was about a book by Paul Halpern, and there I mentioned how much I enjoyed his clean efficient writing style compared to the ornate style of other authors I’ve waded through. (What’s embarrassing is recognizing my own tendency to be baroque. Might be why I’m sensitive to it.)
To my eye, Rovelli is one of those baroque authors. I struggled with that, along with what I saw as a tendency to hand-wave, all though The Order of Time.
Seven Brief Lessons On Physics also felt ornate to me as well as overly casual in the brevity of some topics. (Not inaccurate, but far from the approximation I would have chosen.)
A lot of people really like Seven Brief Lessons On Physics — it gets a lot of what I’m sure are well-deserved rave reviews — but the best I can give it an Eh! rating. (Granted, I’m not at all the audience for the book.)
I know very little about LQG and don’t have an opinion there, but I believe time to be fundamental whereas Rovelli believes it’s emergent. I also am not sympathetic to views that place relations as a primary unit of reality. I think that’s another cart-horse confusion.
The post on his book about time explores why I think time can’t be emergent, I won’t get into it here. My problem with relationship-based views is that, by definition, a relationship is between two things. Without the things, there is no relationship.
I should mention that my rejecting a view doesn’t necessarily mean eliminating it from any consideration. It means putting it on the bottom of my stack of likely answers. It means I’d have to be satisfied it wasn’t any of those answers first. (Hard, repeatable, experimental evidence is always persuasive.)
Our understanding of reality is contingent on new knowledge. Nearly every physics book written touches on how our view of reality has evolved.
Speaking of which, Rovelli goes into that in detail in Reality Is Not What It Seems. He goes back to the earliest Greek thinkers in exploring how scientific thinking itself came to be.
I did find that kind of interesting (although I’m not much of a history buff, especially ancient history).
Somehow, at least so far, his writing seems cleaner and more engaging to me. I frequently became absorbed in Halpern’s narrative — that didn’t happen in the first two Rovelli books I read, but it’s happening here in the third.
It may be that his telling a history story doesn’t give me a case of the Yeah, Buts, whereas some of his physical speculations and stories do.
One thing I credit Rovelli on is being clear on what we know (very little, really), what we think we know (a fair bit), and what he’s speculating on. More importantly to me, there is no sense of evangelism.
Since I’m only a third through, and we’re still on history, I won’t go into it too much. (Unless I run into something especially striking, I don’t plan to review it once I finish.)
Here are some of the bits I noted so far (mostly from the brief book)…
¶ One of Rovelli’s key arguments about time not being fundamental involves Special Relativity: “the theory that elucidates how time does not pass identically for everyone.” (Something that’s even more true under General Relativity.)
As stated, it’s false. Time does indeed pass exactly the same for everyone. However observers in one frame may see time in another frame passing differently (but the people in that frame don’t). That’s why it’s call Relativity.
My view is that the rock-solid consistent ticking of proper time, if anything, is an indication of time’s fundamental nature. The clock for every particle in the universe ticks the same for that particle.
So when Rovelli asserts that (and he does often), it grates. What he means is there’s no universal clock — a Newtonian idea. Which is true.
¶ One bit that appears in both books crystallized something for me: “But general relativity is a compact gem: conceived by a single mind, that of Albert Einstein, it’s a simple and coherent vision of gravity, space, and time. Quantum mechanics, or “quantum theory,” on the other hand, […] more than a century after its birth it remains shrouded in mystery and incomprehensibility.”
Elsewhere he explicitly mentions what’s implied here, that quantum mechanics is the work of many minds and something of a patchwork in embodying electromagnetism, the weak force, and the strong force.
What crystallized was why I’ve long favored GR as likely the more correct theory over QM. The former is a singular coherent physical vision that makes sense. The latter is, as Richard Feynman famously said, something no one comprehends.
¶ Writing about the “quantum leaps” of the electron: “Its as if God had not designed reality with a line that was heavily scored but just dotted it with a faint outline.” For a theoretical physicist Rovelli invokes God quite a bit (not that I’m complaining; far from it).
Another one: “The beautiful theory, SU(5), despite its considerable elegance, was not to the good Lord’s liking.” (Apparently, late in life, Einstein’s belief in Spinoza’s god gained an anthropomorphic aspect. Einstein would refer to bad theories as “sins” against god.)
Rovelli also writes about stars in the “heavens” which I found rather poetic, but you see what I mean about baroque?
¶ Speaking of which, here’s another example: “Here, in the vanguard, beyond the borders of knowledge, science becomes even more beautiful — incandescent in the forge of nascent ideas, of intuitions, of attempts. Of roads taken and then abandoned, of enthusiasms. In the effort to imagine what has not yet been imagined.”
Incandescent forge, wow! Again, I’m not really objecting. It’s just slightly bemusing language to run into in a physics book. It may be that Latin culture is so much more supportive of expressive comportment. Part of me thinks it’s kinda cool, but style is also a distraction.
¶ It’s funny how I don’t agree with Rovelli at all when it comes to time or the idea that reality is mainly relationships, but I do quite agree with him on other points.
For instance: “I believe that our species will not last long. It does not seem to be made of the stuff that has allowed the turtle, for example, to continue to exist more or less unchanged for hundreds of millions of years, for hundreds of times longer, that is, than we have even been in existence.”
I have expressed similar sentiments on this blog.
¶ Lastly, a footnote in the longer book caught my eye:
“This cloud is described by a mathematical object called “wave function.” The Austrian physicist Erwin Schrödinger has written an equation describing its evolution in time. Quantum mechanics is often mistakenly identified with this equation. Schrödinger had hopes that the “wave” could be used to explain the oddities of quantum theory: from those of the sea to electromagnetic ones, waves are something we understand well. Even today some physicists try to understand quantum mechanics by thinking that reality is the Schrödinger’s wave. But Heisenberg and Dirac understood at once that this would not do. To view Schrödinger’s wave as something real is to give it too much weight — it doesn’t help us to understand the theory; on the contrary, it leads to greater confusion. Except for special cases, the Schrödinger’s wave is not in physical space, and this divests it of all its intuitive character. But the main reason why Schrödinger’s wave is a bad image of reality is the fact that when a particle collides with something else, it is always at a point: it is never spread out in space like a wave. If we conceive an electron as a wave, we get in trouble explaining how this wave instantly concentrates to a point at each collision. Schrödinger’s wave is not a useful representation of reality: it is an aid to calculation that permits us to predict with some degree of precision where the electron will reappear. The reality of the electron is not a wave: it is how it manifests itself in interactions, like the man who appeared in the pools of lamplight, while the young Heisenberg wandered pensively in the Copenhagen night.”
That’s how I see it as well. Rovelli doesn’t seem down with MWI. Other than this footnote, it’s not mentioned at all. (He doesn’t talk much about Schrödinger, either. I believe this footnote is the only time he’s mentioned.)
The other thing I found kind of charming in the longer book is how much Rovelli brings in various Italians in history, often awarding them high credit as scientific thinkers.
Stay safe, my friends! Go forth and spread beauty and light.