“The machine,” I said, “must subvert free will.”
I handed the box containing my prediction to my friend Neil and sucked on my still-bleeding finger. The machine applied an analgesic after taking a blood sample, but didn’t supply bandages. What sense did that make?
I missed a question from Neil while internally complaining. “Sorry, what?”
“What makes you say that?” Neil repeated.
“It’s obvious. Your life will be totally different depending on whether or not you read the prediction,” I said. “Remember my mother? She wouldn’t leave the house after she got her prediction of RUN OVER; she was too scared of cars.”
“Yeah, but then she—”
“Yes, yes, she got run over by a vacuum cleaner. We all had a good laugh, then a good cry, then another good laugh.” I cleared my throat. “I’m over it now. But it got me thinking.”
I ignored the editorial remark. “It got me thinking about how the machine could work.”
“You mean, internally?”
“In a more general sense. If my mother hadn’t become a shut-in, I can only presume that she would have been run over by a car, as we all expected. But that would have changed the lives of hundreds of people. Everyone in her extended family, the person driving the car, witnesses to the incident… the whole ensemble. So they would do different things and be in different places and mental states than they are now. This can’t not affect how they die, right?”
“I guess.” Neil’s tone was noncommittal.
“But some people would have already gotten their readings before my mother was killed. Which means that their deaths were preordained by those methods. My mother’s decision to read her prediction, her reaction by becoming a shut-in… None of those were actual decisions, on a universal level. For the predictions of the people who would have witnessed her being run over by a car to come true, she must have not been run over by a car. It looks as though none of our actions can be the product of free will. We have to do certain things and behave in certain ways so that the machine’s predictions have consistent histories. Meaning, that they’re true.”
“So?” Neil asked.
“So the only way to check is to look or not look… randomly.”
“What are you going to do, flip a coin to see if you should read your prediction?” He scoffed. “Plenty of people have done that already.”
“No, it’s a feature of the universe itself,” I breathlessly explained. “You see, there’s this thing in quantum mechanics called the Copenhagen interpretation. It explains how particles and waves are the same thing, really, only under differing circumstances. Everything that we classically consider to be a particle—photons, electrons, and the like—are only so when they’re being observed. Otherwise, they are waveforms. And they’re not just masquerading; they are actual waves, with all the properties of classically-considered waves. Now, here’s the important part: those properties include indefinite location.
“When a particle is… sort of ‘spread out’ to become a wave by not being observed, subsequent observation will collapse the waveform back into a particle at any point in space which the waveform could have previously occupied. But there’s no way to tell beforehand; it’s entirely probabilistic.
“So what I have set up here is a photon emitter, a photon detector, and a half-silvered mirror. I’ve set the emitter up to emit only a single photon, which may or may not pass through the mirror into the detector. If it doesn’t, then the photon bounces off into the universe, never to be distinguished from its brethren again. If it does, however, then the detector will turn the filter on this box transparent, and I’ll be able to read my prediction for the first time. Isn’t it genius?!”
Neil sighed. “That or insane. Where’d you get all this equipment, anyway?”
“Of course.” He mounted the box into the frame next to the photon detector, then had a thought. “I just don’t see how the universe can be purely probabilistic. Couldn’t it be deterministic, but just in a way that we can’t—”
“No,” I said, “no hidden variables. This has all been proven pretty conclusively. But it’s another long story; I’ll explain after we finish this.”
I flipped the switch and the emitter powered on.
There is some universe, among the many worlds, where the filter stayed opaque. I opened the box and read of some mundane death to strike me down the line. I made some money, raised a family, and lived a reasonably long life no different than anyone else’s. I like to think that when the time came, I was ready for it.
There is also some universe where the filter turned transparent. I became a celebrated public figure, as the only person ever to get a reading and have a good chance of it not coming true. The results were confirmed after I died in some other way, and I was buried under a lavish grave that read He taught us how to escape Fate.
But in this universe… In this universe, there is only a doctor performing an autopsy. One who is surprised to find a small piece of paper embedded in the right temporal lobe of my brain. On which is printed—in crisp, black letters—the words QUANTUM TUNNELING ACCIDENT.