IT’S HARD TO IMAGINE today’s popular writing about physics without the existence of two books in particular. The first is A Brief History of Time (1988), in which Stephen Hawking crystallized a way of pitching physics in grand terms — the “we will know the mind of God” stuff — that has proved irresistible for writers ever since. Never mind that quantum gravity and black holes have never accounted for more than a tiny fraction of research efforts in physics. Hawking laid out his story so compellingly that it seemed, at least for some young readers (and here I indulge in autobiography), that those legions of misguided scientists not working on such subjects must be wasting their time. This was a function as much of Hawking’s image as of his books. He perfected the role of “celebrity physicist,” although, to be sure, Albert Einstein was there first, and Carl Sagan did much to refine the role. Hawking’s opinions were perpetually news both because he was brilliant, and because they were his. If Stephen Hawking thought quantum cosmology was the most important subject of all, who were we to disagree?

The second book is in some respects a response to Hawking. It is journalist John Horgan’s The End of Science: Facing the Limits of Knowledge in the Twilight of the Scientific Age (1996), which argues that scientists, having inherited answers to most of nature’s big questions, are now constrained either to study increasingly insignificant details or to play with abstractions increasingly unlikely to be tested. Working scientists are bound to reject Horgan’s thesis, almost of necessity. But the book’s value lies less in its science than its style. When Horgan describes Hawking leading a pack of cosmologists into the sanctuary of a church for a concert, he casts Hawking as a prankster priest, a pied piper for a world in which post-empirical science has replaced pre-empirical religion. Horgan plays these earnest cosmologists, muttering about dark matter in the pews, for comedy. Expecting kid gloves, many scientists gave Horgan unguarded interviews, and then were outraged when journalist Horgan printed their words.

The great physicist Philip W. Anderson reviewed The End of Science, and his denunciation expressed an attitude shared by many scientists. Of course, Anderson disagreed with the book’s premise — as a Nobelist with many significant discoveries to his name, he could counter it with numerous personal discoveries. But he also worried that the book, however clever, might give further ammunition to the anti-science crowd:

Insofar as the scientists have eagerly angled for public notice, and in many cases for our own bestseller status, one might feel we have reaped a whirlwind of our own sowing; nonetheless where our remarks are shoehorned into favouring Horgan’s personal agenda, we have a legitimate complaint.

Anderson’s chiding comment expresses how many in the science community feel toward science writing in general. For science to interest the wider public, it must present itself as something other than a source of settled answers. Yet it seems that many scientists would prefer only scientists to have divergent or quirky opinions about it. It’s fine, in this view, for Hawking to posit the end of philosophy, but not for Horgan to posit the end of science. Worthy science writers, in other words, dutifully summarize the positions of the scientists without getting too much in the way. They allow scientists — or, even better, “the science itself” — to eclipse any “personal agenda.”

This may account for why a lot of science writing is boring, but it also makes some sense as a default setting for popular science. After all, it’s hard enough for a scientist immersed in a subject to form a coherent view of it. There’s nothing more embarrassing than a writer who only sticks his toe in knuckle-deep before leveling objections that any expert could rebut.

That said, a few nonscientist science writers have managed to thread the needle, providing unusual opinions without Horgan-esque offense. Consider Jim Holt, whose new essay collection, When Einstein Walked with Gödel: Excursions to the Edge of Thought, renders received opinions in unexpected ways. Holt plays science for laughs, but when he presents abstractions as apparent absurdities, he’ll often double back to suggest all of them might still be correct. His work is intensely idiosyncratic without containing any idiosyncratic doctrine. He performs his observational comedy within the realm of the higher sciences — math, theoretical physics, philosophy — but gives us enough setup that we’re in on the joke. The pieces usually end with a punch line that lands somewhere between corny and profound. (From “On Moral Sainthood”: “If you want to be a saint, forget about being an angel.”) I don’t know of another writer quite like him.

The new book is a sort of career retrospective for Holt, revisiting and deepening the obsessions of his two previous books. The first of these, the pocket-sized Stop Me If You’ve Heard This: A History and Philosophy of Jokes (2008), is a plumped-up New Yorker article. (Its first iteration ran in a comedy issue of the magazine.) Less a history than a literal joke book, Stop Me is an extreme example of Holt’s approach, with each paragraph excerpting the most diverting parts — usually, just the best jokes — from whatever sources he happened to check.

Holt’s second book, Why Does the World Exist? An Existential Detective Story (2012), is more ambitious, but similarly comic, with Holt casting himself as a journeyman gumshoe out to answer the titular question. “The existence of this cosmos,” Holt wrote near the end of the book, in the nearest thing he gives to an answer, “can be fully explained only on the assumption that it is middling in every way — a vast Walpurgisnacht of mediocrity.” Structurally, the book alternates between sit-downs with various eminences and dilations on the ideas that emerged in these discussions. But near the end, when one might have expected Holt to wrap things up with summaries and restatements, he veers toward the personal, recounting his mother’s death and the philosophical flotsam that filled his mind as he worked to distract himself from sorrow. The book ends with Holt flicking away a cigarette, and a boldface aphorism from Ambrose Bierce: “Philosophy, n. A route of many roads leading from nowhere to nothing.”

Why Does the World Exist? was an international best seller, and Jim Holt seemed briefly to flirt with rebranding himself from magazine writer to public intellectual. The TED talk he gave around this time is painful to watch, with Holt approaching the gig as a sort of intellectual stand-up, and the forum expecting another zippy thought leader. In another post-World appearance, Holt was introduced as “now working on a book about free will, rationality, self-deception, and happiness.” And is When Einstein Walked with Gödel that book? I don’t think so, but what’s clear is that Jim Holt has — thankfully — remained the same old Jim Holt.

For a collection of pieces culled from two decades of work, When Einstein presents a remarkably unified sensibility. Often, this sensibility is that of a writer in awe of his characters’ simultaneous intelligence and naïveté. Holt is the sort of writer who is only too happy to interrupt a discussion of mathematics, say, to drop in the following sort of tragicomic précis:

Owing to his unyielding and sometimes paranoiac sense of integrity, [the mathematician Alexander] Grothendieck ended up alienating himself from the French mathematical establishment. In the early 1990s, he vanished into the Pyrenees — where, it was reported by the handful of admirers who managed to track him down, he spent his remaining years subsisting on dandelion soup and meditating on how a malign metaphysical force was destroying the divine harmony of the world, possibly by slightly altering the speed of light. The local villagers were said to look after him.

This is a summary by a writer who is genuinely glad that Grothendieck existed, even if he disagrees with Grothendieck’s philosophy and is well aware of its tragic personal outcomes.

In the preface, Holt self-consciously notices that many of his subjects have a “tragic arc,” from the story of Georg Cantor, the “creator of the theory of infinity” who “died in an insane asylum,” to David Foster Wallace, whose book on Cantor Holt reviews. But if Holt is a pessimist about people, he does not indulge (aside, perhaps, from a short piece on string theory) in much pessimism about science. His interest in these matters seems to be that of a dilettante aesthete, and there’s an attractively geeky too-close-to-the-glass kind of enthusiasm in many of these essays that all but points and yells — “Hey! You! Have you heard of this?”

At first glance, one might not notice any obvious pattern in the topics Holt has pursued. These include the friendship of Albert Einstein and Kurt Gödel; the nature of time; the rise of statistics; methods of proof in mathematics; computers in the Cold War; how the universe will end; the prehistory of Kripkean reference; distinguishing truth, beauty, and bullshit; and many others.

On second glance, there are context clues. Not one of these essays was originally published for the traditional crowd of popular science readers. Holt aims instead for the literary crowd. (The book is dedicated “To the memory of Bob Silvers,” longtime editor of The New York Review of Books.) For the usual readers of science journalism, the science might be enough, but Holt is writing for readers who demand a reason to care — readers, that is, who expect their science embedded in a philosophical metanarrative. Holt pipes his pastries with a line of technical jam, but this is often just the extra zing, with the main substance in the surrounding frame.

Take, for instance, “The Riemann Zeta Conjecture and the Laughter of the Primes,” the collection’s fourth essay. In a breezy essay of 20-some pages, Holt cannot hope to fully explore the Riemann hypothesis (Prime Obsession, John Derbyshire’s popular treatment, runs up to page 448), so he doesn’t try. Instead, he uses the Riemann hypothesis as a sort of leitmotif: as a subject he can return to every so often while he explores other stuff — the “other stuff,” in this case, being what the world might look like in a million years, the ontological status of mathematical truth, and what makes jokes jokes. These are not, we should pause to acknowledge, subjects that naturally intertwine themselves into a smooth braid. The fact that they appear together is a strong signal of a writer’s “personal agenda,” in the positive sense of the phrase.

“What will civilization be like a million years from now?” Holt attempts to answer this opening question by appealing to a generalized Copernican principle holding that we should be able to estimate the lifespan of various natural or cultural phenomena by considering how long they have been around already. He asserts that in Year Million there will be, to 95 percent certainty, no organized religion, no baseball, no internet — alas, no industrial technology at all. And what will still be here? For that, we need to reach back to very old things, to the parts of culture that predate modern humans. Our evolutionary lineage diverged from that of the chimps some five to seven million years ago, yet we have laughter and a number-sense in common with the chimpanzees. Hence laughter and numbers might survive to Year Million.

Holt asks us to wonder about the contrast between math and humor: “Just as nothing is more timeless than number, the core of mathematics, nothing is more parochial and ephemeral than humor, the core of laughter. So, at least, we imagine.” But Holt wonders if, in Year Million, our successors may see things differently, with laughter seeming profound, and numbers trivial.

It’s in this context that Holt briskly introduces the Riemann zeta hypothesis, an unproven but widely celebrated conjecture posited by Bernhard Riemann in 1859 that — should it turn out to be true — would link the complex numbers to the prime numbers. But instead of getting deep into the math, Holt zooms out to consider how this might look with a million years of hindsight.

At the extremes, Platonists believe that mathematical reality is just “out there,” independent of humans, and constructivists believe that math is merely a bookkeeping structure of our own making. Many mathematicians lean toward Platonism (Holt quotes the French mathematician Alain Connes: “the sequence of prime numbers […] has a reality that is far more permanent than the physical reality surrounding us”), but Holt proposes they might lean the other way in Year Million. The generalized Copernican analysis suggests that a proof of the Riemann hypothesis (if it arrives) should get here in the next few millennia. And what then? Perhaps the problem’s profundity will evaporate into tautology. “My prediction, then,” writes Holt, “is that long before the Year Million, mathematicians will have awakened from their collective Platonist dream.”

Now Holt brings in his final rhetorical flourish, returning to laughter and mathematics. The core of humor — and here, Holt gestures toward evolutionary neuroscience and Schopenhauer — is the discovery of an incongruity, which is “the opposite of boring old tautology.” Holt imagines that the resolution to the Riemann hypothesis will one day look like a sort of joke, worthy of the “higher laughter” that “is called forth when we see an incongruity resolved in some clever way”:

The Riemann zeta hypothesis, when it is finally dispatched in the aeons to come, will provide just such a resolution. Amid peals of laughter, the Platonic otherness of the primes will dissolve into trivial tautology. It is sobering to think that that what is today regarded as the hardest problem ever conceived by the human mind may well be, in the Year Million, a somewhat broad joke, fit for schoolchildren.

I found Holt’s essay on the Riemann hypothesis to be totally charming. In fact, this was my experience for nearly the whole book. In piece after piece, Holt acts as a model host, giving us only the best bits while paring away most difficulties. As he notes in the preface, “My ideal is the cocktail-party chat: getting across a profound idea in a brisk and amusing way to an interested friend by stripping it down to its essence (perhaps with a few swift pencil strokes on a napkin).” When Einstein Walked with Gödel mostly delivers on this goal. It’s a perfect bedtime book, with each essay providing a luminous devotional on weighty topics, delivered with a light touch.

This light touch is almost enough to allow the book to work as daytime reading, although in the bright light some parts can look cloudier than one might wish.

Consider, once again, the “generalized Copernican principle.” Does it make any sense? Can we expect a good estimate for any given thing’s future lifespan simply by considering its age thus far? Clearly not. To estimate the future lifespan of a newborn, for instance, one needs to know something about population statistics, not just the time of birth. Readers interested in a detailed discussion of the implicit assumptions in “Copernican” reasoning can consult the critique by physicist Carlton M. Caves, but this error highlights the dangers of cocktail-party dilettantism. With scientists, as with others, startling claims often turn out to be bullshit.

Holt’s piece on the Riemann hypothesis has so much other good stuff that the bit of accidental BS doesn’t ruin it. But in other pieces, Holt doesn’t so much accidentally stumble on BS as he actively follows his nose toward it, allowing his Horgan-ish impulses to dominate.

Like Horgan, Holt often tells stories drawn from science that undercut the imposing reputations of individual scientists. Ada Lovelace, daughter of Lord Byron, is often credited as the first computer programmer, but here she is presented as a vain incompetent whose familial celebrity was used by Charles Babbage for self-promotion. Francis Galton, a pioneer in population statistics, is depicted as the sort of nascent eugenicist who would walk the streets while filling out covert checklists on the women he passed by for entries in his “beauty map” of Britain. Even the logician Kurt Gödel, whose friendship with Einstein occupies the book’s title essay, is depicted in a second anecdote as nearly derailing his immigration proceedings when he claimed to have discovered an inconsistency in the US Constitution. (Unfortunately for us, the content of Gödel’s complaint is lost to history.) And I won’t even try to describe Holt’s talk with Frank Tipler, the American cosmologist famous for his eschatological ravings.

Reading Why Does the World Exist? back in 2012, I thought it marked a new direction for science writing, a playful turn toward the personal, the digressive, toward jokes. In When Einstein Walked with Gödel, Jim Holt goes further down this path, cementing his reputation as one of the few pop-science practitioners whose primary aim is aesthetic bliss. Beauty and truth are only loosely conjoined, but in “Say Anything,” the new book’s closing essay, Holt gives us his own reason to prefer truth to bullshit: “Most bullshit is ugly.” But when bullshit isn’t ugly — think poetry — Holt is happy to defend that, too. I suppose most people who experience aesthetic bliss in the presence of technical material are siphoned off into scientific professions, not writing for magazines. But Holt is an unusual magazine writer: he reveres abstract ideas but not their human vessels, and part of his originality lies in how he accepts (and amplifies) the distinction.

Holt may be an anti-Platonist, but he seems glad to visit the world of ideal forms. So long as he searches these heights for specimens, I’ll be excited to see what he brings back next.


David Kordahl is a graduate student in physics at Arizona State University.