A philosopher, a physicist, and a writer walk into a bar . . .

That could have been the opening to William Egginton’s The Rigor of Angels, a wonderfully thoughtful exploration of the intersection of thought that connects the seemingly disparate trio of Immanuel Kant, Werner Heisenberg, and Jorge Luis Borges. What binds these three men across time and discipline is their willingness to set aside the most basic premise we humans operate daily on and accept that what we consider “reality” is only, can only ever be, our experience/perception of it and not “reality itself.” If a reality exists “out there,” it is beyond our ability to know it. Egginton doesn’t claim these three were the first to consider the idea; in fact, one of the pleasures of the book is his historical overview of how the concept, as well as alternative ones, rose again and again from different sources and dressed in different language/forms.

The book focuses on the paradoxes or “antinomies” that arise when we assume our view of reality and reality itself are one and the same, paradoxes of morality, of free will, or more concrete scientific observations, such as the quantum “weirdness” that pops up in experiments showing entanglement (“spooky action at a distance”) or interference in the famed double slit experiment.

Egginton grounds the abstract philosophical questions by detailing the lives of the men, who as they wrestle with the big thoughts also deal with mundane issues like teaching undergraduates, working odd jobs while struggling to publish, or trying to impress one’s idols. What could have been a lot of airy discussion that leaves the human behind instead becomes a more personalized exploration. The three come fully alive, so one, for instance, one is deeply moved by Kant’s eventual slide in physical and mental infirmity in his old age or compelled to dive in Heisenberg’s mind to know the truth of his time working under the Nazi regime (though appropriately enough for the book’s subject, we have to accept we will never know what he was truly thinking).

Egginton can sometimes get a bit repetitive in the points he’s making; I’m not sure the book needed all of its length. But the repetition also serves to reinforce concepts that can be difficult to wrap one’s mind around. After all, Kant’s work is notoriously dense (I confess to bouncing hard off it myself), so much so that during his time “a rumor quickly spread that his famously difficult writing had driven at least one student insane and a popular psychologist inveighed against” studying him.

Luckily, Egginton himself is far from difficult to read. He writes with a welcome and informing clarity, whether detailing Kant’s philosophical works, performing an exegesis of Borge’s short fiction, or explaining the development of quantum physics from the standard model to Heisenberg’s Uncertainty Principle to Everett’s Multiverse theory. But Egginton is better than simply clear and informative; his writing can wax surprisingly, delightfully lyrical at times. As when he argues that Borges saw that:

to be human is to straddle the impossible border between ephemerality and eternity, loss and permanence. From the vantage of a sifting, vanishing time we project an eternity hopelessly out of reach. Like the exile who ‘with a melting heart’ reclass ‘expectations of happiness,’ we ‘gather up all the delights of a given past in a single image.’ Eternity is nostalgia, the inextinguishable desire for what we’ve lost.

The Rigor of Angels delves into deep questions and matter of import in a clear and thoughtful fashion but does not sacrifice beauty of language of thought on the altar of clarity. Nor does it ever lose sight that these questions did not spring out of the ether but came from the lived experiences of real people moving through daily experience and interacting with other people. Highly recommended.

The Rigor of Angels is a deep-dive into some of the most intense philosophical questions through the avenues of three historical figures, the physicist Werner Heisenberg, the philosopher Immanuel Kant, and the writer Jorge Luis Borges. The core of the book is the fact that, as Kant says, space and time, which we take as facts of reality, are the conditions of the possibility of experience, rather than things-in-themselves that exist outside of us. Egginton takes the reader through various paradoxes that seem utterly unsolveable which arise from the issue of taking space and time to be universal things, or from misapplication of a kind of 'God's-eye view' of the universe. One of the great beauties of the book is seeing the way philosophical ideas return again and again in different forms, and how some of the greatest problems that Borges, Heisenberg, and Kant faced were different faces of the same issues. Egginton's writing is clear and concise through even some extraordinarily complicated topics, and his willingness to use analogy and to refresh the reader at various points is very helpful. The book is dense but I found it very rewarding.