Trespassing on Einstein's Lawn (16 page)

“Even so,” she said, “I think it's time you consider a more sustainable plan.”

She was right, of course. I couldn't learn physics in the coat room forever. Luckily, I
did
have a plan. “I'm thinking about going back to school,” I announced. “There's a program in the philosophy of science at the London School of Economics. Nick Bostrom went there. He says we're probably living in a computer simulation, and he hangs out on John Brockman's website. Not that Brockman's website is the simulation.
This
is.” I waved my arms in the air to indicate our kitchen. “At first I was thinking, if everything is a simulation, what's the point of grad school? But I don't see how simulated learning can be anything other than actual learning, right? Anyway, I suspect the whole thing is an invalid argument because it presupposes a view from outside reality.”

“You're moving to London?” my mother asked.

“
Simulated
London,” my father corrected her.

“But we'll miss you,” she said. “And our phone bill is going to be outrageous.”

Ever since I had moved to New York my father and I had replaced our nightly kitchen-table cosmology talks with phone calls that ran on for hours.

“We'll switch to email,” my father said.

“What about Cassidy?” she asked.

I gave her a sheepish grin.

“Oh, no,” my mother said. “I told you when you got that dog that we were not going to end up taking care of it. I am
not
going to have dog hair all over my furniture. I am
not
going to be picking up poop.”

“
Simulated
poop,” my father said.

“There must be philosophy of science programs in the U.S.,” said my mother.

“Sure,” I said. “But there's no evidence that they lead to Brockman.”

“And you need him because …?”

“So he can be our agent.”

“For?”

“For the book we're going to write when we find the answer to the universe.”

“Can't you just call him when the time comes?”

I laughed at her adorable naïveté. “Um, no. You can't just
call
John Brockman. Do you know what you get if you go to the website for his literary agency? A blank page that says ‘Brockman, Inc.' That's it. There's nothing to click on! It's so badass.”

“So you're going to move to London so you can go to school in the hopes that for some inexplicable reason it will lead you to an agent for a book you haven't written about an answer you haven't found.”

I nodded. “Exactly!”

I looked over at my father. He grinned.

My mother threw up her hands. “Well, at least you have a plan.”

Later that night, having trouble sleeping, I wandered into our physics library. It felt good to be back in that room, warm and homey with its broken-in leather couch and the spines of countless books painting brightly colored stripes across the walls. It was comforting, being surrounded by all that wisdom. I noticed that my father had added a new bookcase, and I wondered, as I always did, when he found time to read so many books. I knew his job didn't afford him many spare moments, and it was dawning on me that he was using all of them to pursue our strange mission. That this wasn't just a hobby for him. Despite his mellow, Zen-like demeanor, the appearance of that bookcase betrayed an urgency. A hunger. This thing
meant
something to him. Of course I had always known that, but there was something about seeing it rendered in rich mahogany that gave it weight—not only the weight of the wood or the tomes on its shelves, but the weight of his ambition, an ambition
that was now my inheritance. I wanted it to add up to something. I wanted to earn his words, the ones he had leaned in to tell me all those years ago in the Chinese restaurant, to prove to him that he had chosen well when he chose me to be the heiress of his secrets, the beneficiary of everything and of nothing.

Scanning the shelves, a single book caught my eye:
At Home in the Universe
, Wheeler's essays on physics. I hadn't looked at it since our mystifying conversation with Wheeler in Princeton, so I curled up on the couch with a blanket and began to read.

Wheeler was searching for reality's building blocks, the most basic units from which life, the universe, and everything emerge.
“No search has ever disclosed any ultimate underpinning, either of physics or of mathematics, that shows the slightest prospect of providing the rationale for the many-storied tower of physical law,” he wrote. “One therefore suspects it is wrong to think that as one penetrates deeper and deeper into the structure of physics he will find it terminating at some
n
th level. One fears it is also wrong to think of the structure going on and on, layer after layer, ad infinitum. One finds himself in desperation asking if the structure, rather than terminating in some smallest object or in some most basic field, or going on and on, does not lead back in the end to the observer himself, in some kind of closed circuit of interdependences.… Is the universe a ‘self-excited circuit'? Does the universe bring into being the observership, and the observership give useful meaning (substance, reality) to the universe?”

I adored Wheeler's writing: poetic, prophetic, and raw. A superposition of science and art, fact and dream. In his quest for ultimate reality, he viewed every inexplicable mystery as a clue. Wheeler was never going to shut up and calculate. He wanted answers, and he wasn't going to rest until he found them.

In the book, Wheeler had drawn a diagram: a capital letter
U
for “universe.” The top of the right-hand side was the big bang, the swooping curve the history of the universe, time marching right to left and culminating at the top left of the letter, where a giant eye, a present-day observer, was perched, the product of billions of years of cosmic evolution. In turn, the eye looks back across the abyss to the far tip of the letter, present to past, its gaze, presumably, giving meaning (substance, reality) to the universe. A self-excited
U
.

John Wheeler's drawing of the universe looking back to its birth and creating itself in the process
Betsy Wilson

The universe creates us so that we can create it? Reality, for Wheeler, was a kind of Möbius strip, like Escher's hands drawing themselves. Was it just circular logic, or was it the only explanation that stood a chance of satisfying? The alternatives sure weren't. Either you've got some infinite regression of turtles atop turtles, and you're left wondering where the hell all the turtles came from, or reality comes to a screeching halt at some particle or field, and again you're stuck wondering, why
that
? Where did
that
come from? There was something distinctly more palatable about a causal loop, but I couldn't help thinking that the most satisfying thing of all, the thing that would stop all the but-how-did-that-get-there's in their tracks, would be a loop made of nothing at all.

I read on as Wheeler trekked through several thorny and seemingly disconnected issues in physics before I realized that he was carefully piecing them together into a grand, if unfinished, vision of reality—one so mind-boggling that it would have seemed insane had it come from anyone but him.

At its heart was the central mystery: the quantum. By freely choosing what to measure—particle or wave, position or momentum—an observer brings a bit of information into existence, transforming a
smoky haze of possibility into a single unit of reality. Such bits, Wheeler said, were the building blocks of the universe. Physical reality, at bottom, was made not of electrons or quarks or strings, not of space or time, but of information—and information, at bottom, was made of observation.

But what exactly did Wheeler mean by an observer? Without careful clarification,
observer
was a dirty word. Fotini Markopoulou had made it clear that by observers she meant reference frames, possible points of view. That was their meaning in relativity, too—reference frames centered on rods and clocks. But in quantum mechanics things always got murkier, especially in interpretations that sought to give observers a privileged role, like the ability to create reality. Wheeler himself acknowledged the problem.
“Any exploration of the concept of ‘observer' and the closely associated notion of ‘consciousness' is destined to come to a bad end in an infinite mystical morass,” he wrote. And yet at times he teetered dangerously on the banks of the morass, his view of observers skewed far more toward minds than toward rods or clocks.

“Unless the blind dice of mutation and natural selection lead to life and consciousness and observership at some point down the road,” he wrote, “the universe could not have come into being in the first place … there would be nothing rather than something.” And later, “There are many to whom the idea of a world without any purpose—except what we and our fellow men agree upon—comes at first as a dreadful shock. Later comes the feeling of challenge; and then at last an inspiration: a feeling that we who felt ourselves so small amidst it all are, in the end, the carriers of the central jewel, the flashing purpose that lights up the whole dark universe.”

I smiled at the poetry but cringed at the thought. As much as I would have liked to imagine myself carrying around some purposeful, radioactive jewel, I couldn't see how bringing consciousness into the mix could possibly help—not least of all because scientists don't know what consciousness is. Whatever it is, it's governed by the same laws of physics and composed of the same particles, fields, or information-theoretic bits as everything else. Of course, Wheeler agreed with that—in the first arc of his loop, the universe gives rise to observers
through the blind dice of mutation and natural selection. Nothing mystical or supernatural happening there. But if that was the case, what could privilege certain physical objects (brains) and not others (rocks) as the “observers” capable of turning around and, with a long gaze to the past, creating the universe? I was confused, but I decided to accept Wheeler's premise and see where it led. I read on.

The
O
-word notwithstanding, Wheeler's view of a universe built bit by bit through observation and measurement suffered an obvious flaw: how could one observer possibly make enough measurements to create everything we see around us? Barring the hallucinatory deceptions of evil demons, the universe appears to be composed of far more bits than could possibly have been born through the handful of observations that a single observer—or even a planetful of observers—could ever muster.
“Mice and men and all on Earth who may ever come to rank as intercommunicating meaning-establishing observer-participants will never mount a bit count sufficient to bear so great a burden,” Wheeler wrote.

He offered a two-pronged solution. First, the total number of bits in the universe must be finite. I knew that general relativity ruled out this possibility—its spacetime manifold was continuous, with an infinite number of points between any two points, the kind of continuum that made my teenage brain reel with Zenoesque rebellion. You'd need an infinite number of bits just to specify the gravitational field, let alone the rest of the universe. But I also knew that general relativity didn't have the last word on spacetime; my foray into loop quantum gravity had taught me that. Zoom in on spacetime to a millionth of a billionth of a billionth of a billionth of a centimeter, and thanks to quantum mechanics the continuum dissolves. Zoom further and the notion of a point loses meaning as the fabric of reality is torn to shreds, threadbare as the dark center of a black hole or the singular breakdown at the beginning of time.

“Spacetime,” Wheeler wrote, “often considered to be the ultimate continuum of physics, evidences nowhere more strikingly than at big bang and collapse that it cannot be a continuum.” What's more, he said, “quantum fluctuations of geometry and quantum jumps of topology are estimated and calculated to pervade all space at the Planck scale of distances to give it a foam-like structure.”

Second, count the contributions of all observers, not merely those living today but all who ever have been and ever will be. That was a bold move, considering its flagrant disregard for the usual rules of time, like that one that says the future comes
after
the past. But quantum mechanics already violated that rule, and no one knew that better than Wheeler.

In the late seventies, he had proposed a thought experiment known as the delayed choice, a twisted take on the classic double-slit experiment that was even more of a mindfuck than the original. In the classic version, the observer has a choice: either he can measure the interference pattern produced on a photographic screen after the photon passes simultaneously through both slits or he can place detectors at each slit to find out which path the photon travels, destroying any interference in the process. In Wheeler's updated version, the observer makes that choice
after
the photon has already passed through the slits. At the very last second, he can remove the photographic screen, revealing two small telescopes: one pointed at the left slit, the other at the right. The telescopes can tell which slit the photon has passed through, and they will always show that the photon took only one path. But if the observer decides to leave the screen in place, interference bands will form, showing that the photon has traveled through both slits. The observer's delayed choice determines whether the photon took one route or two … 
after
it has presumably done one or the other.