Per Tristan’s suggestions, I took out stacks of books from Widener Library (Harvard had not figured out yet that I’d quit—I suppose Blevins wanted to hide the fact lest it reflect poorly on him). These included tomes on everything from heliography to Queen Victoria’s private life to Baruch Spinoza’s sexual proclivities to Frederick Bakewell to the Tempest Prognosticator to Strouhal numbers. I would bring these to Tristan, and we would divide our time between perusing them and Internet searches.
We soon knew more about the Great Exhibition and its thirteen-thousand-odd exhibits than Prince Albert ever did. We knew more about its showcase, the Crystal Palace, than even Joseph Paxton, the gardener who’d designed the fucking blessed thing. We learned little that was helpful. However, one evening in March, as I sat on the consignment-store couch I’d insisted on bringing in to spruce up the place, and Tristan lolled on the rug (provenance ditto) beside a low table with a beer, each of us bleary-eyed from reading, I encountered a passage in an obscure booklet entitled Arresting and Alluring Astronomical Anecdotes, published in 1897. Here I learned that while the Great Exhibition of 1851 was in process (it lasted for several months), an event of relative interest occurred elsewhere in Europe, to be precise, in K?nigsberg, Prussia: for the first time in history, a solar eclipse was successfully photographed.
I read this statement aloud. It set Tristan on fire with excitement. He had already suspected that photography in particular, of all technological developments, was the likeliest to have somehow impeded magic. Now, somehow, he was certain. It took me a while to calm him down to the point where he could explain himself.
“I’ll be honest with you: as a physicist, I am a hack,” he admitted. “I majored in it, yes, but I was never employed in that capacity. But if you cut me I still bleed physicist blood. I’ll go to my grave believing that, if magic existed, there’s a scientific explanation for it.”
“That sounds like a contradiction to me,” I said, “since our whole working hypothesis is that science broke it somehow.”
He held up a hand. “Work with me here. Have you ever heard of the many-worlds interpretation of quantum mechanics?”
“Only in cocktail party discourse that would make you roll your eyes and heave deep sighs.”
“Well, there are certain experiments where the results only make sense if the system that’s being observed actually exists in more than one state until the moment when the scientist makes the observation.”
“Is this Schr?dinger’s cat? Because even I have heard of that.”
“That’s the classic example. It’s just a thought experiment, by the way. No one ever actually did it.”
“That’s good. PETA would be all over them.”
“Do you know what it is?” Without waiting for me to answer, Tristan went on: “You put a cat in a sealed box. There’s a device inside of the box that is capable of killing the cat, by breaking open a vial of poison gas or something. That device is triggered by some random event generator, like a sample of some radioactive material that either decays—producing a bit of radiation—or doesn’t. You close the lid. The cat and the poison gas and the radioactive sample become a sealed system—you cannot predict or know what has happened.”
“You don’t know if the cat is alive or dead,” I said.
“It’s not just that you don’t. You can’t. There is literally no way of knowing,” Tristan said. “Now, in a classical physics way of thinking, it’s either one or the other. The cat is either alive or dead for real. You just don’t happen to know which. But in a quantum physics way of thinking, the cat really is both alive and dead. It exists in two mutually incompatible states at the same time. Not until you open the lid and look inside does the wave function collapse.”
“Whoa, whoa, you had me until the very end!” I protested. “When did we start talking about—what did you call it? A wave function? And how does that—whatever it is—collapse?”
“My bad,” he said. “It’s just physicist lingo for what I was saying. If you were to express the Schr?dinger’s cat experiment mathematically, you’d write down an equation that is called a wave function. That function has multiple terms that are superimposed—it’s not just one thing.”
“Multiple terms,” I repeated bleakly.
“Yeah. A term here means a fragment of math—it is to an equation what a phrase is to a sentence.”
“So you’re saying there is one term for ‘cat is alive’ and another for ‘cat is dead’? Is that what you mean in this usage?”
“Yes, O linguist.”
“And when you say they are superimposed—”
“Mathematically it just means that they are sort of added to each other to make a combined picture of the system.”
“Until it ‘collapses’ or whatever.”
He nodded. “Multiple terms superimposed is a quantum thing. It is the essence of quantum mechanics. But there is this interesting fact, which is that that kind of math only works—it only provides an accurate description of the system—until you open the lid and look inside. At that point, you see a live cat or a dead cat. Period. It has become a classical system.”
“Department of . . . Deadly Observations?” I asked.
He rolled his eyes.
“Anyway, that’s what you mean by the collapse of the wave function.”
“Yes, it’s just physicist-speak for the thing that happens when all of the superimposed terms—the descriptions of different possible realities—resolve into a single, classical outcome that our brains can understand.”
“Our scientific, rational brains, you mean,” I corrected him.
A look of mild satisfaction came onto his face. “Exactly.”
“But now we’ve circled back to my theory!” I complained.
He looked mildly confused. “Which theory is that?”
“The one that belongs more to children’s literature than to reality—remember?”
“Oh, yeah. People have to believe in magic.”
“Yes!”
“That’s not exactly what I’m saying,” he said. “Yes, human consciousness is in the loop. But hear me out. If you buy the many-worlds interpretation of quantum mechanics, it means that all possible outcomes are really happening somewhere.”
“There’s one world with a live cat and another with a dead cat.”
“Exactly. No kidding. Complete, fully independent realities that are the same except that in one of them, the cat’s dead, and in the other, it’s alive. And the quantum superposition? That just means that the scientist standing there with his hand on the lid of the box is at a fork in the road. Both paths—both worlds—are open to him. He could shunt into one, or the other. And when he hauls the lid open, the decision gets made. He is now in one world or the other and there’s no going back.”
“Okay,” I said. Not in the sense of I agree with you but of I am paying attention.
“The scientist can’t control which path he or she takes,” Tristan continued.
I saw that he was trolling me—waiting for me to pick up the bait.
No, it was more than that. He wanted me to mention a possibility that he could think about, but never say out loud—because he was all Mr. Science.
So I did. “Let’s switch it up a little, then,” I said. “And swap out the white lab coat and the clipboard for, I don’t know, a pointy black hat and a broom. And lose a pronoun. If she did somehow have the ability to choose which world she was going to be shunted to when she opened the lid—if she could control the outcome—”