On Seven Brief Lessons on Physics

This little book was, with some caveats, a pleasure to read. Rovelli’s prose is beautiful, and he covers a great deal of physics in quick succession: relativity, quantum mechanics, the cosmos, subatomic particles, gravity, time, consciousness. The first four chapters are breezy, and I have little quarrel with them. The last three are the Wild West, where the topics are genuinely contentious, and a reader shouldn’t go in assuming this is settled science — the fact is we have little idea what gravity, time, or consciousness actually are; we barely have a starting point. With that in mind, I can’t really evaluate Rovelli’s claims, since I don’t know the competing arguments, but I can lay out his.

Gravity is the hard one, the point where quantum mechanics and general relativity become irreconcilable and physicists have to fudge the numbers. Rovelli favors loop quantum gravity as a reconciliation, which, if I understand it, suggests that neither space nor time is “out there” — that, like subatomic particles, they are quanta distributed unevenly through the universe. That surely has its limitations, though I haven’t the faintest idea what they are. He likewise finds that time as we experience it isn’t out there: our best understanding ties it to heat, so that time happens when heat passes from one set of atoms to another. Maybe, maybe not — we may be wired to understand time because it’s an evolutionary advantage, which wouldn’t make it something “out there.” I found his commentary on consciousness wholly unconvincing. As with everything else, he looks not at what things are but at the relationships between them, since that’s all we can do after quantum mechanics — fair enough — but then he falls back on the idea that consciousness is merely an emergent property of neurons interacting. It could be true, but there is no evidence whatsoever for how we get from electrical signals to complex thought, and until there is, the claim that consciousness arises from neural interaction is untenable. So what is consciousness? I haven’t the slightest damned idea, but my intuition pushes me away from physicalist arguments until some evidence turns up. I’d happily change my mind when confronted with it; for now, the case for consciousness-as-neural-mechanism is exactly as strong as the case for the soul — which is to say there’s none either way, and we have to run on vibes. Still, Rovelli’s writing is charming, and it was a delight to read.