Trespassing on Einstein's Lawn (33 page)

“You were really interested in his work, weren't you?” my colleague asked. “Do you want to write the obit?”

I nodded silently. I couldn't help feeling heartbroken. I had spent years imagining that when my dad and I finally did write our book about the nature of reality, Wheeler would read it. In a weird way, I had always assumed that we would be writing it
for him.
In my mind we would personally deliver a freshly printed copy, which he would immediately and eagerly read. As he turned the last page and let the back cover thump closed, he'd look up at us, remembering the cryptic words he had offered us years ago in Princeton, and with a twinkle in his eye say, “I see you've figured it out. Well done.”

As I settled into my desk chair to begin composing the obituary, I texted my dad the bad news:
Wheeler died.

My phone buzzed back right away:
It's a sad day for reality.

It didn't seem fair that time had run out on Wheeler. That the universe had blinked out of existence before he ever had a chance to solve its riddle. That his four questions—
Why the quantum? It from bit? A participatory universe? How come existence?
—still hung in the air like stunned raindrops.

They weren't the only ones hanging there. What about the self-excited circuit and the boundary of a boundary? How would we decipher their meanings now?

As I filed Wheeler's obituary, I thought back to that day in Princeton. To the awe we had felt as we consulted the oracle, and to the aftershocks that ran through us while we stood speechless on Einstein's lawn. That day had been the start of something. Something that had led me here, to Cambridge, to
New Scientist
, to day after day spent masquerading as a journalist.

Masquerading? Was I still a fake after all these years? How long would I have to do this before I'd stop feeling like it was some kind of prank? Maybe everyone feels like a fraud in their own life, I thought. Maybe everyone is.

Or maybe the problem was that I wasn't a fraud anymore. This job was supposed to be a cover for something. Had I gotten so swept up in
the means that I had forgotten the end? Worse, had I forgotten the beginning?

As I mourned Wheeler's death, I realized I was mourning something else. I spun slowly in my desk chair, surveying the lifeless cubicle. Where was my father? Where had he been when I was mulling over horizons in my quantum flat in Notting Hill? Where had he been when I was discussing the multiverse on the Santa Barbara beach or non-Boolean logic at the Tribeca Grand? In Bloomsbury? At the Holiday Inn? Where had he been then? Where was he now?

My plan to score a permanent press pass and gain us access to the inside world of physics was working, but somewhere along the way I had veered off course, started speaking in singular pronouns, trying to create a life for myself. I had to, I knew, but still. Five years earlier, on a spring day just like this one, when I decided to go to the Davis conference without him, I had unknowingly set off a chain of events that had ended here, in an office, in a desk chair, alone. Was that past now written in permanent ink? If I viewed things differently now, would I compute a new wavefunction? Select a new history? Enact some quantum process of top-down regret?

And what did the old history look like through my father's eyes? Was he proudly watching his daughter from afar as she lived out a shared dream, crashing the physics party vicariously through her as life happily carried on in the suburbs? Or was he stuck there, trapped in a life that ran on its own momentum, watching his idea slip away from him, his own invention speeding off into the distance like a missed—or hijacked—train? Maybe in some other universe we had run giddily from Einstein's lawn and just kept on running. Maybe we were still hunting down reality together there. Maybe Wheeler was alive and the rain was falling. It didn't matter, though, because I was stuck in this one.

“It's a shame we never went to talk to him a second time,” my father said.

I nodded my regret, then took a swig of cold soda.

It was the height of summer in Boston, and my parents had come up
from Philadelphia to visit. The three of us were lounging on my balcony, overlooking a sun-drenched Memorial Drive and the Charles River, the Boston skyline rising from the far riverbank and reflecting in the sparkling water. My mother sat happily knitting while my father and I talked physics as usual. It was a perfect simulation of a perfect day.

“Why didn't you?” my mother asked, her eyes on her knitting.

“We couldn't,” I said. “About a year ago I contacted Ken Ford, who worked with him, to see if we could set up an interview, but he told me Wheeler was in a nursing home. He didn't say we couldn't go, but it seemed too disrespectful.”

“Since when are you worried about being disrespectful?” my mother laughed.

“We could have pretended to be doctors and gone into his room,” my father said. “We'd ask him procedural medical questions, but then we'd slip in some questions about the nature of reality.
Are you having difficulty breathing? Are you experiencing any nausea? What does it mean that the boundary of a boundary is zero?
”

“You
are
a doctor!” I said.

He chuckled. “Oh, yeah!”

“Anyway, he was so hard of hearing at that point, it would have been impossible,” I said.

“So now what?” my mother asked.

“I don't know.”

It was depressing. With Wheeler gone, the mystery of his cryptic phrases had grown even deeper and more profound in my mind. Of course, I knew he hadn't come up with
the
answer to the universe—if he had, we would have heard about it by now. Wheeler would be a household name, the Nobel committee might have sat up and taken notice, fundamental physics would be over and done with, and we wouldn't have been on this quest in the first place. And yet somehow, despite all that, I was convinced that those phrases were the keys to reality's riddle.

Maybe I just wanted to believe that, because it was romantic and exciting and it made me feel important, as if I were somehow carrying Wheeler's torch, as if he had intended to hand it to some brilliant
physicist that day back in Princeton but his eyesight was failing and he mistakenly handed it to me. To us. Now, years later, that flame was flickering, threatening to extinguish, and all I could see of it was a wisp of smoke, cutting the air like a rat's tail.

“What about people who knew him?” my father asked. “Like his former students? They would have some idea what Wheeler had been thinking about.”

I shot up in my chair. “That's true. We could go talk to people who might know what he meant by those phrases. We could say we're writing an article about it.”

“Why would I be writing an article?” my father asked.

Good point. “Okay, so we'll say we're coauthoring a book.”

“You
are
coauthoring a book,” my mother said.

I nodded. “Right.”

That was true—kind of. We had been talking about it for years, the book my father had suggested we ought to write together when we found the answer to the universe, the book I dreamed would someday be represented by John Brockman. Every time I visited my parents' house, my father and I would excuse ourselves to go upstairs to the physics library by telling my mother we had to “work on our book.” Every time I told my friends I couldn't go to a party because I was busy learning physics, I told them I was “working on our book.” “Our book” had become the central character of our lives, and yet it didn't exist as anything more concrete than a distant dream. Working on the book had never included putting a word on paper. Working on the book meant working on the universe. It meant doing research. It meant living my life. And when I really thought about it, I suppose I never actually distinguished between those things: my life, our book, the universe. If I was really honest with myself, I had to admit that although I didn't buy into Bostrom's simulation argument, I had always had the acute sense that I was living
inside
our book, a book that would only become a tangible object when we found the answer to the universe. Writing had always meant searching for the answer, and the answer had always borne the shape of a book destined to sit alone in our empty library.

It all hung together, if barely. We'd tell people we were coauthoring a book in order to ask them about Wheeler's riddles, and in turn solving
Wheeler's riddles might allow us to finally write our book. It was life imitating imaginary art. A self-excited delusion.

The Cahill Center for Astronomy and Astrophysics at Caltech was a strange and fitting feat of modern architecture, a building that looked like it had been built by gauge forces, by the patching together of several mismatched reference frames.

My father and I had come to Pasadena, California, to speak with physicist Kip Thorne, one of Wheeler's former students. I could tell my father was excited to meet the celebrity physicist. “I always think of him as being straight out of
Star Trek
!” he said giddily as we approached the building.

Finding our way from the lobby to Thorne's office took some effort, as my father and I maneuvered the odd and disorienting angles.

Thorne himself was tall and bald, with a pointed goatee, and did bear a slight resemblance to Captain Picard. He kindly invited us to sit down.

“We met John Wheeler very briefly at a conference years ago, and he said two things to us that were rather cryptic,” I explained. “He said that the universe is a self-excited circuit, and then, in response to a question about the universe coming from nothing, he said, ‘The boundary
of a boundary is zero.' Can you tell us anything about what those phrases mean?”

My dad and me with Kip Thorne (center)
Jo Ann Boyd

“Mathematically, the boundary of a boundary is a basic principle from which you can derive certain properties of spacetime curvature. How you use that to explain the birth of the universe, I don't know. I've never found the idea terribly useful. I have the opposite view that Johnny did about how fundamental it is.”

Thorne made it clear that he didn't have any more to say on the matter. From his reference frame, he was looking at two copies of the same disappointed face.

“Okay,” I said. “What about the self-excited circuit?”

“From a certain point of view, which Wheeler adopts, systems can become classical only when observed. They behave quantum mechanically and indeterminately until observed, and the observation collapses the wavefunction. So Wheeler conceives of the universe as having been born and having evolved quantum mechanically until it naturally generates life. Then that life performs the observation that collapses the state of the universe to make it classical. It's self-excited in the sense that the observation comes from within the universe, not from the outside. When I describe it, it sounds fairly simple, but my impression is that it's a lot deeper than it sounds.”

I nodded. “Does it have to be biological life that makes the observation?”

“I think that was his view,” Thorne said. “Intelligent beings that arise naturally as the universe evolves. The person who can give you deeper insight into this is Wojciech Zurek. He worked with Wheeler at Texas when Wheeler was developing these ideas. I spent very little time with Wheeler during those years, but I think it is a deep idea. Zurek is the best living expert on that idea.”

“What are your views on observers?” I asked, hoping Thorne might say more.

“I tend toward the view that they are not important at all,” he said.

Not important
at all
? Without considering their perspectives, how could you ever get at ultimate reality?

“We've come to the conclusion that for something to be ultimately real, it has to be invariant and observer-independent,” I said. “But we
don't think observers have to be conscious or biological or anything like that. Just reference frames.”

“So you don't think space is real? Or that time is real?” Thorne asked, seeming shocked and annoyed.

“Not ultimately real,” I said, surprised at his reaction. Don't get annoyed at me, I thought. Tell it to Einstein! “Do you disagree?”

“As physicists, we have been tremendously successful at building pictures and mathematics that are very predictive, but we have never developed any set of tools or criteria to tell us what is ultimate reality. I think we are less in the position to probe those issues than philosophers are. But the only philosophers who have a prayer of making progress are those that understand the physics. I steer clear of asking what is ultimate reality.”

Fair enough, I thought, though it was hard to imagine that kind of aversion to the big questions coming from a student of Wheeler's. “Did Wheeler influence your thinking on physics?” I asked.