The Order of Time by Carlo Rovelli

Like all the posts in my 2023 reads list, this comes at a lag, meaning I read this a while back—though in this case, a while back is just last week. 

Carlo Rovelli’s The Order of Time is a book that I’ve noticed on the shelf at the local library a few times. Because that particularly library jumbles together all of its English language books in a single room—kids’ books, comics, YA novels, and adult fiction and nonfiction—it’s always seemed a little out of place, and caught my eye each time I’ve been there. 

Having finally signed out a copy, I don’t think it took me more than a couple of days to read it, and not just because it’s a slender volume. It is less than 200 pages, but some of those pages are quite mentally challenging and I would credit Rovelli’s lyricism and readability for the swiftness of my reading.

Now, lucidity is something I value in a science popularization, but lyricism, that’s a different thing… usually. I tend to be leery about science popularizations that include quotations from Nietzsche, Horace, Proust, and the like, in part because so often scientists are not the best science communicators and the literary materials can end up unwittingly inviting wildly incorrect interpretations of the material. That isn’t the case with Rovelli, though: he is careful with his literary and cultural allusions, always using them in ways that seem to clarify his points rather than distorting them. 

He’s also appropriately and openly uncertain of his conclusions: he seems convinced, for himself, but also owns the facts when it comes to what is or isn’t known for certain. What he argues is essentially that time isn’t a distinct property of the universe, but a property that exists subjectively in our perceptions, in relation to the interactions between objects. We perceive interactions by which entropy seems inevitably to increase in the long run, but Rovelli argues that it could just as easily be that this perception is just that: a mistaken perception rooted in our naïve (hardwired), limited sensorium. Perhaps, he argues, entropy doesn’t increase over time in aggregate, but it only looks that way because we only interact with (and perceive) a limited subset of all matter in the universe. (We cannot see on the quantum level, for example.) That isn’t so much to say—as New Agers insist—that time is “merely an illusion,” but rather to say that the way time seems to work according to our perceptions probably is only a small part of the big picture, limited enough to qualify as a sort of misleading illusion, comparable to the way that the Earth’s rotation creates the illusion that the sun orbits the Earth. Science has thrown aside the barriers to realizing this about other perceptual illusions among humans many times in the past, so perhaps he’s right. Perhaps not. He admits it could go either way, but gives his best try at explaining what is known and what seems to be true to the best of his understanding. 

I didn’t walk away from the book understanding very much about how this ties into loop quantum gravity (which is Rovelli’s specialty), but that may be because I read the last part rather quickly, alongside a sick child who sometimes needed my attention. (Everything happens in a context, and at least subjectively, our time is limited.) I did notice that Rovelli is a proponent of loop quantum gravity, meaning that he’s also somewhat partisan in his claims. I used to wish science popularizers would avoid partisan claims and stick to the controversies—presenting them as such without taking a side—but as I’ve aged I’ve gotten used to the fact that this is an ideal many will not live up to fully. That said, Rovelli does at least admit where his biases lay, at least from what I could tell as an interested layperson. 

In any case, while the book is really light on equations, it’s heavy on ideas and even heavier on its ruminations about those ideas, and it is supremely literate. (No “Two Cultures” mutual illiteracy here: Rovelli has read his Horace, Proust, Shakespeare, and more, and thoughtfully engaged with them all.) The Order of Time manages to be a beautiful book in a lot of ways, while also being an occasionally challenging science popularization. I haven’t yet looked up the book’s critics, but I feel certain some must exist out there… and I feel certain most of them also would argue it’s worth reading, even if they’re less than completely comfortable with Rovelli’s conclusions.