Seven Brief Lessons on Physics by Carlo Rovelli

My rating: 4 of 5 stars

Now I am not going to go so far out of my depth—or so far off-brand—as to write at length about even a popular science book on theoretical physics, especially when this is the first such book I’ve read since I was puzzling over John Gribbin and Paul Davies in my teens. I took advanced physics in high school with the legendary David Spahr, who taught and graded like a college professor, yet in my day rarely had one word said against him, because we knew he was too good for us (I recall that he would recite passages from Milton or FitzGerald’s Rubaiyat to illustrate scientific points or, more remarkably, to use as the bases of word problems). I got terrible grades, of course. Even today, my own students will tell you they are always having to correct my grade breakdowns for my classes because I cannot add to a hundred! Pathologically innumerate, I was even worse in high school: my English and history teachers thought I was a savant, whereas my math and science teachers judged me an idiot. Nevertheless, the more philosophical aspects of physics always fascinated me even though my mathematical comprehension halts at (or long before) the frontier of calculus.

So I took up this brief, lyrical digest of modern physics by the Italian physicist Carlo Rovelli (translated by Simon Carnell and Erica Segre). Written simply enough that it would not make a bad gift even for a middle-schooler, it is also a good book for readers primarily interested in arts and humanities, since Rovelli’s disquisitions on physics are philosophically informed. His commentaries on the implications of relativity theory, quantum mechanics, and the long attempt to reconcile the two bear on far more than technical scientific debate.

To wit: for many us who were reared within the civilizational matrix of print culture and its Enlightenment politics, the infinitude of subjective worlds erupting out of the Internet has been alarming. It is probably not wrong to be worried about some of the extremes of group-level relativism promoted by the identitarian politics of both left and right factions today. But what if group-level relativism is bad because it is not relative enough? What if the law of the universe is, paradoxically, more granularly anarchic than cultural relativism, because every interaction between any two forces is a variable singularity? “Reality,” Rovelli comments, “is only interaction.” He goes on:

A handful of types of elementary particles, which vibrate and fluctuate constantly between existence and nonexistence and swarm in space, even when it seems that there is nothing there, combine together to infinity like the letters of a cosmic alphabet to tell the immense history of galaxies…

Derogating “postmodernism” and preaching a restoration of “objective reality,” some contemporary thinkers call for a return to Gradgrindian fact. These thinkers often seem to be biologists or similar, but I recall learning in school that in the order of knowledge biology depends on chemistry, and chemistry depends in its turn on physics. When castigating the heirs of Nietzsche, our neo-Enlighteners might spare some venom to spit at the heirs of Heisenberg. For the physicist Rovelli, postmodernism errs only in maintaining the Kantian distinction between subjectivity and the truth that is out there, whereas it is the truth perceptible to science that itself renders even the outside or objective world a radically unstable, changeable quantity, continuously altering in interaction with its observers. It is not only the self that is decentered and unstable, but the entire cosmos, which may not even be there if one is not looking at it. What, for instance, are we to make of time as conceptually revised by the theory of loop quantum gravity?

Just as the idea of a continuous space that contains things disappears, so the idea of an elementary and primal “time” flowing regardless of things also vanishes. The equations describing grains of space and matter no longer contain the variable “time.” This doesn’t mean that everything is stationary unchanging. On the contrary, it means that change is ubiquitous—but elementary particles cannot be ordered in a common succession of “instants.” At the minute scale of the grains of space, the dance of nature does not take place to the rhythm of the baton of a single orchestral conductor, at a single tempo: every process dances independently with its neighbors, to its own rhythm. The passage of time is internal to the world, is born in the world itself in the relationship between quantum events that comprise the world and are themselves the source of time.

“The passage of time is internal to the world”: as a literary person, I am happy to know that cutting-edge physics beyond my ken confirms a lesson I learned long ago from Virginia Woolf.

Rovelli concludes his book with philosophical reflections on the nature of humanity and the universe. Rejecting German idealism’s anthropocentrism and its influence (he criticizes Kant, Schelling, and Heidegger by name), he takes his stand with Lucretius and Spinoza: our consciousness and our freedom are identical with the lawful, probabilistic surges of the matter and energy of which we are made, and our ever-shifting and ever-reflexive knowledge may, if we strive for it, as our ancestors strove to track their invisible prey by its visible tracks (Rovelli’s metaphor), come ever nearer to the truth. And the truth is that the universe is a rippling plane of variously interacting quantities, a wave of singular events. Left unexplained is the source of our drive to know; the analogy to paleolithic hunting is a weak reductionism. What does this universe need with our need to understand it, and why is Rovelli so certain that our need does not differentiate us from the placidity of the rocks and stones and trees? But here, admittedly, physics gives way to metaphysics.

In any case, Rovelli’s book, if it cannot provide the final answer to the fundamental questions, is highly useful in reminding this C-student in physics that the universe is almost unspeakably strange, and that appeals to “reality” may be less reassuring, though more poetically exciting, than they seem.

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