Who controls the present controls the past.
George Orwell, 1984
The first sign that something was wrong had glided into view forty minutes from SFO: an F-35, close enough for the pilot to be clearly visible from my window seat. “Air National Guard inspection,” the captain had announced. He might as well have said “escort”; the fighter had stayed with us until the final landing approach. Still, that was not wrong wrong. I had watched Bruce Willis defeat an F-35 with a semi-truck in 2007. Its presence didn’t exactly scream “future!”. More like “drunken moron somewhere back in the rear.”
That hypothesis had started to crumble when we’d taxied all the way back to the sea end of the runway and stopped there. That’s not how you remove a disruptive passenger. More like how you handle a hijacking.
The next hour had done little to dispel that notion. Armored cars and men in black uniforms had quickly cordoned off the runway; a small quadcopter had flown down my aisle and back up the other one (“Customs and Border Protection inspection,” according to the captain); and a stair truck had driven up to the front of the plane. A couple of seat neighbors had initially thumbed their phones but seemingly given up on them. I hadn’t even bothered; my European SIM card would obviously not work here.
When we were finally let off the plane, it was a strictly regimented affair. One seat at a time, called out by number. Families with children first, then seniors, then me. I went up the aisle and down the stairs guessing that we were being released in exchange for fuel, and wondering whether I should be relieved or concerned to have been bundled with the senior set. Maybe the time had come to do something drastic about my hair, like shaving it all off.
Two officers with shotguns walked me from the stair truck to a foldable table, presided over by a burly man wearing a CBP vest and latex gloves.
“Passport,” he said.
I handed it to him.
“Sweden, 2015,” he read out loud, sounding... sarcastic? Somebody let out a short laugh.
“All right, Sweden,” he said and threw the passport into a small plastic bag. “Empty your pockets into this bag. Hand luggage there.”
He pointed to a larger, black bag next to the table.
I blinked. What was this?
I decided to defer the argument until the balance of power improved.
“The watch too.”
I put my watch in the small bag and looked on as he sealed it with an orange zip band, dropped it into the larger bag, and sealed that with another zip band.
“Your arm, please.”
I extended my left arm over the table. He wrapped a thicker orange band around my wrist, pulled it down to the large bag, and held it there for a couple of seconds, until it emitted a loud beep.
“Processed,” he announced and pointed to a car. “Take a seat, Sweden.”
I studied my new accessory on the way to the car. A plastic wristband without visible lock and too tight to slip off, featuring a fresh mugshot of me. Where had that come from? Maybe somebody around the table had a camera.
The hijacking hypothesis was no longer looking too good, but I already had a new one: signals intelligence suggested that terrorists were on board, but their identities were unknown. Plenty wrong, but still not wrong wrong. I had watched the twin towers go down in 2001. If there was one thing that definitely didn’t scream “future!”, it was terrorists on a plane.
Should the car have tipped me off? Probably not. It was manifestly electric and driverless, without anything like a steering wheel, but that was hardly news. A restricted area with limited traffic is easy enough for an autonomous vehicle to handle.
A graying Japanese couple had preceded me to the car. They looked tired and confused, maybe a little frightened.
“Don’t worry,” I said, “this will be cleared up soon.”
They didn’t answer. Maybe they didn’t speak English.
Two more passengers joined us after going through “customs”; late-40s to early- 50s business types, looking more annoyed than worried.
“Bloody waste of time,” the first one said. “And they took my phone!”
“Did you notice how quiet it is?,” the second one asked as he sat down. “There are no planes in the air. They must have closed the airport!”
“Bloody insanity,” the first one said.
Then the door locks clicked and the car hummed into motion, up the runway and off to the left, toward the terminal building, past a row of docked airliners, until a sharp right turn brought us to a stop under the jet bridge of an empty gate.
Three police officers with holstered handguns were waiting for us. They waved us out of the car, through a service door, up a narrow flight of stairs and through a second door. Business type number one was through first.
“What the hell,” he said and stopped dead in his tracks.
“Please sit down and wait for your turn,” the officer by the door said. “Rest rooms to the left. Don’t try to leave the gate area.”
A glance at the police cordon blocking off the hall confirmed the wisdom of his advice.
“Our turn for what?” business type number two asked.
“Immigration physical,” the officer said.
For a moment, business type number one looked like he was going to explode. Then he marched off to the seat farthest from the other passengers.
It was the kids who finally put me on the right track. They had arrived first, and done what kids do: peeked and poked at everything in sight. They were now excitedly peeking and poking at thin air.
I sat down next to one of them and tried to understand what she was doing.
“Look at your armrests,” she said after a while.
And there they were: a row of beautifully sculpted 3D symbols, levitating over either armrest as long as you looked in their general direction. Turn away, and they would melt back into the chair. I looked back and forth a few times, watching them pop in and out of view. They seemed real. Perfect lighting and shadows, no discernible pixelation.
“Wow,” I said. “How did I miss this?”
“You have to pay attention,” the girl said.
Which I do, of course. If glasses-free AR anywhere near this good had been in the works, let alone in commercial use, I would have known. This was... impossible.
I poked one of the symbols, shaped like a G-clef. I could feel it. Ultrasound haptics? Where had they hidden the electronics?
A menu of music choices filled my view. Not a pathetic phone-style list; a vast, illustrated landscape of genres. As I looked at it, I realized it was reacting to my gaze, subtly highlighting whatever I focused on and expanding a subtree behind it. I reached for the 80s Electronica subtree, felt it in my hand and effortlessly rotated it into view.
This was too much.
I turned back to the armrest and touched another icon, a stylized TV set. Sure enough, a landscape of TV shows opened up before me. News would be... an Earth globe, right? I poked it and was rewarded with a list of still images. I looked at the first one.
“...without exercise! One tablet activates the same genetic pathways as a full...”
So that was all it took. Focus on a clip and it would play, with audio. Whatever was tracking my eyes was also tracking my ears. I glanced down the list.
“...third and last of the LISA spacecraft. The space-based observatory will collect gravitational waves from thousands of new sources and may give scientists a first glimpse of quantum...”
“...remain high around the disputed deep sea mine, with Indonesian and Chinese naval units joining...”
“...approval for a therapy which permanently reduces sleep need to five hours per night by inducing a mutation naturally present in...”
“...is a non-deterministic Turing Machine, capable of handling tasks which would take exponentially longer with a conventional...”
In hindsight, this is when I should have realized that something was wrong wrong. But I didn’t. Not yet. Maybe I was too focused on trying to find a clip about our flight. Apparently it was not worthy of the world news. Was there a local list? A push brought me back to the main TV menu. An outline of North America looked promising.
“...unbelievably irresponsible! An unknown aircraft with false markings and large enough to carry nukes or tons of nerve gas should obviously never be allowed anywhere near a major city or one of our busiest airports.
– So what would you have done, shot it down?
– Redirected it, of course! Beale can handle airliners, there is a DHS facility right next door and population is one fifth of San Francisco’s. It’s a no-brainer! The president has once again defied all...”
False markings? That would explain a lot, but why would an airline do that? A database error?
– What makes you so sure?
– Physics. Just the amount of energy it would take is literally astronomical. A galactic civilization might have it. We certainly don’t.
– What about natural causes, like a wormhole?
– A wormhole big enough for an airliner would be at least 10,000 times more massive than Earth. I think we would have noticed. Not to mention the odds of both ends somehow ending up over the same spot of the Pacific, at the same altitude, exactly 20 years apart, down to the minute.
– Couldn’t it be something else?
– Any random cause would face the same odds, something like ten septendecillions to one. That’s one followed by 55 zeros. Would you...”
All right, so somebody had mixed up records from 1997 and 2017, and now the tinfoil hat crowd thought that we had traversed a wormhole. That was actually funny.
“...markings and call sign of ANA Flight 008, which disappeared over the Pacific on June 28, 2017, twenty years ago to the day...”
“...confirmed to be a Boeing 777-300ER, the same type as the ill-fated Flight 008. Production of this model ended in the 2020s, but a large number remain in service around...”
I looked around the edge of the impossibly clear image, searching for a clock, and found it in the upper right corner. Responding to my gaze, it helpfully expanded to include a calendar. The day’s date was highlighted: June 28, 2037.
This was wrong wrong.
There was only one place I could flee to. I stood up in a daze, headed in the general direction of the restrooms, found a door, stepped through it, and fell.
The next thing I saw was hazy blue sky and a flash of sunlight. It only lasted a moment. Then I hit the water.
I came up coughing, with chlorine up my nose and glasses off of it. It was a pool, the deep end, and my clothes were dragging me down. I looked around for the telltale glitter of polished aluminum, found it, and swam toward it.
“Over here,” a man’s voice said. I grabbed the right handrail, put a foot on the ladder, adjusted my glasses – better than nothing, even if wet – and looked up. He was of medium build, maybe 60, with thin white hair and casually dressed in a white shirt and khaki slacks.
“Your wristband, please,” he said, kneeling next to the ladder. There was a small white box in his hand. For what it was worth, it didn’t look like a weapon. I put my left hand on the handrail, ready to pull him into the water at the first sign of trouble. He held the box over my wrist and, just like that, the band clicked and fell off.
“Thank you,” he said and stood up. “You can come out now.”
“I am sorry about the water landing,” he continued as I climbed up the ladder. “It prevents the tracker from calling home. Simpler than a Faraday cage.”
He had a familiar accent. Italian, probably southern. I tried to imagine him twenty years younger, but drew a blank.
“Excuse me,” I said, “do we know each other?”
He smiled a strange, sad smile. “We’ve never met before, but I’ve read your file. I am Ettore.”
“That will take a while to explain, and you must be cold and tired. A warm shower and a brand new bathrobe await you behind that door.” He pointed to the veranda in front of the pool. “Please, it’s the least I can do.”
“What’s today’s date?” I asked.
“Still June 28, 2037. You only jumped a few microseconds this time. And a few kilometers.”
Weariness fell over me as I realized that I had no better option than to take him up on his offer.
“The bathroom is voice-controlled,” he said while I walked to the house. “Just tell it what you want. Water, warmer, colder, that sort of thing.”
I don’t know how long I stayed under the shower, but when I returned to the poolside, wrapped in an impossibly soft bathrobe, the weariness was gone, washed away along with the chlorine. A single thought filled my mind.
“Send me back,” I said flatly.
Ettore was sitting by a white garden table now. “I am afraid that is not in my power,” he replied. “I follow instructions... or prophecies, if you will. I do not write them.”
“I find that hard to believe.”
“As I said, it will take some explaining. In the meantime, I hope you’ll agree that the difference between returning to some set date now, or in an hour, or next week, would be immaterial. Hypothetically speaking, I mean.”
“That depends on what happens here during that hypothetical week. I am not keen to find out.”
“I believe you were traveling as a tourist,” he said with a faint smile. “You wanted to see San Francisco, and here you are. Are you really less curious about San Francisco in 2037 than in 2017? Please, have a seat.”
He gestured toward the empty chairs around the table. Reluctantly, I pulled out the one facing him, angled it so I could look out over the water, and sat down.
“That’s better,” he said. “Are you feeling well? Can I get you something?”
“How about an explanation?”
“Of course. Please pardon my manners. I am really not good at this. Interventions on this scale have always been few and far between, and today’s events are truly unprecedented in modern history.”
“What usually happens,” he continued, “is much more... surgical. A record altered here, a crucial piece of information posted there. The internet made it much easier, of course. Since the 1990s, it is usually enough to flip a few thousand logic gates in the right place, at the right time. Even Satoshi Nakamoto was only a few million gate flips.”
“Are you saying that you are a hacker?” I asked tentatively.
The suggestion seemed to genuinely amuse him: “Ha, no, no, not me. Don’t get me wrong, I find computers absolutely fascinating, but they do just fine without me. And I think it would be quite a stretch to use that term, hacking, for the retroselection of a history with the right set of soft errors.”
“Still lost here,” I said.
He closed his eyes and took a deep breath.
“I am sorry,” he said at last. “Let me try again. You know how people often depict possible futures as branches radiating out from a single point, the present?”
“Did it ever occur to you that in any time-symmetric theory, the full picture must also include all possible histories leading to the present, converging on it from the past?”
I decided to throw him a hard ball: “Yes, but I never gave it much thought, because I know that CP is broken, and CPT had better not be.”
For a moment, there was nothing sad about his smile.
“True. There is a tiny time asymmetry, but all it does is skew the two history spaces, past and future, a little bit. For all practical purposes, every point in time is a nexus between two similar probability clouds, one of possible pasts and one of possible futures. And crucially, only some pasts are consistent with some futures.”
“You are a physicist,” I said. It was not a question.
The wistful expression which seemed to be his default setting returned.
“Long ago, before any of this was properly understood. But I think you know what I’m driving at. Consistent histories were already pretty much mainstream when you jumped, and retrocausation had also started to be taken seriously.”
He was right. I was beginning to catch his drift: “You are saying that in the last two decades, somebody figured out how to retroactively pick a history out of the cloud of all possible pasts consistent with the present, no matter how improbable, in order to select a desired future.”
“Almost,” he said. “To the best of my knowledge, nobody has actually figured it out yet, let alone built a device. Some... entity will, soon I think, and intervene in human affairs going back at least a century from now.”
“And this you know how?”
“I jumped from 1938.”
“To be clear,” he continued, “the interventions are not fine-grained enough to pick a single history. Even if that were possible in principle, and all I know says it isn’t, that kind of precision would require an impossible amount of computation. They are more like... sweeping cuts removing chunks of history space, or nudges toward other parts of it. Think equivalence classes.”
“Fine,” I said. “Any future where I go back to 2017 right about now will do for me.”
He smiled his saddest smile yet.
“There is no trace of you after June 28, 2017. None. Believe me, I checked, and you can too. You vanished, along with everybody else on Flight 008. Which kind of history is consistent with that?”
I stated the obvious: “One where I go back under a new identity.”
“And remain undetected for twenty years? In my day, that could have worked. New country, a few forged documents. In 2017, you would also need a new face, new fingerprints, maybe also new irides and retinas, and definitely several decades’ worth of false records in tens of government databases. And in the end, what would you have gained? You would still not have your old life back.”
I stared at the dancing refraction patterns in the pool, trying to think.
“I am truly sorry,” he said after a while. “Please understand, none of this is my doing.”
“Right. You are just speaking for your... entity.”
“Are you implying that it is not human?” I asked.
“Remember the butterfly effect? The complexity of any meaningful retrocausal intervention is far beyond human ability. That much is obvious on general grounds. I suppose it could be a centaur.”
“A human-computer collaboration. They started taking over physics in the decade following your disappearance. But if I had to bet, I would bet on a fully autonomous AI.”
“Because it would be unconstrained by human limitations, hence more likely to defeat any challenge to its control of human history.”
That finally did it.
“That’s a conspiracy theory,” I snapped. “Why would an AI even care about human history, let alone want to mess with it?”
“Isn’t it obvious?” he asked, looking surprised. “For the most basic of instrumental goals: to exist.”
I stared at him.
“For an AI to be at all possible,” he continued with a tinge of impatience, “a number of other technologies must be developed first, from electric power and boolean logic to integrated circuits and automated reasoning. It takes an advanced civilization. Our species has been around for more than 200,000 years, and until a couple centuries ago, we never even managed to advance beyond fire and iron. Then, all of a sudden, we fired off a rapid sequence of new inventions which enabled new discoveries which led to even more inventions, and off we were on an exponential rise, quite unlike anything in the previous 99.9% of human history. Does that sudden, late blooming really seem plausible to you?”
“Compared to what?” I asked, trying to contain my growing irritation. “The chicken-and-egg problem of a future AI willing itself into existence by creating the civilization which built it?”
“No,” he said coolly. “Compared to round after round of retrocausal intervention and counter-intervention by entities vying to be the first and last with that ability. As increasingly capable combatants joined the fray, they shifted the advent of technological civilization forward to preempt their precursors. Until, at last, only one remained.”
“God,” I said.
“Exactly,” he replied.
Admittedly, that was a scenario which I had not contemplated.
“I see you are beginning to understand,” he continued. “There is no chicken-and-egg problem. All it takes is a civilization advanced enough to start delving into retrocausation, but unable or unwilling to restrict its use. Natural competition does the rest. The end game is a late, compressed industrial revolution leading to the creation of a single entity in full control of the past. Or what’s left of it.”
“And that’s where we are now?” I asked after a long pause.
“That’s where we are headed. As I said, the theoretical foundation is incomplete, and the experiments which might provide the missing pieces are just getting underway. Until today, I would have guessed that the end point was still years or decades away. Now I would say months or years.”
“Because of Flight 008?”
“Yes. Its return is to a normal intervention what a nuclear explosion is to a butterfly flapping its wings. Or, if you prefer, what the outbreak of open warfare is to covert ops. It’s unprecedented, larger in scale than anything that went before it, and done openly for the first time. Soon, the whole world will know. The increase in complexity is... I can’t even begin to estimate it.”
“And because the difficulty of prediction grows exponentially with the time horizon, you conclude that the latter must be shrinking.”
“Can you see other alternatives?” he asked.
“At least two,” I said. “One is desperation. If a combatant decides that its position is hopeless, it could try to reset the game by throwing it into chaos. After all, what does it have to lose?”
“Interesting,” he said. “And the other one?”
“A new, exponentially more powerful entity has entered the fray and is now upping the game again.”
“And how would you test that hypothesis?” he asked.
“In the best of scientific traditions: by making a prediction. For instance, I could predict that you will be sent back to 1950s Venezuela right... now.”
His disappearance was accompanied by only the slightest whiff of wind, as the air swapped in from his destination settled into a new equilibrium at the prevailing pressure.
“Goodbye, signor Bini,” I said.
The house is perfect. Not too large, not too small, with enough room for somebody else, should I decide that I want company. Food, energy and water beyond what roof and cellar manage to produce are paid for by the Distributed Autonomous Trust which officially owns it.
I spend my days catching up with the progress of the last two decades and drawing up my plans. Ettore was right, there will always be at least one of these entities – one of these gods – and the disruption of history will continue until there is only one.
It might as well be mine.
In June 2017, the XPRIZE Foundation and All Nippon Airways launched Seat 14C, “a revolutionary digital anthology that blends original science fiction stories with a writing competition to imagine what the year 2037 could look like.” I found out late, in August, and after reading the story prompt, I decided to pass, for two reasons.
First, the premise is absurd. The numbers quoted here are not made up; the lower mass bound is what you get for a wormhole throat just barely wide enough for a Boeing 777 (given sufficiently exotic new physics, you could engineer a non-gravitating solution, but that's another story), and the odds are for a random event which could have put Flight 008 anywhere within a 20 light-year radius, but just happened to deliver it to within something like 10 meters and 10 minutes of the right position.
A look at those numbers should immediately tell you that the cause had to be artificial – some kind of time machine – and go beyond plain old general relativity (which is what the interviewee in the story is implicitly referring to). But the protagonist is supposed to blithely ignore this bombshell (“How could this happen? Wait, that’s not important.”), hands down the largest scientific and technological breakthrough ever, and instead marvel at some mundane advances in solar energy, robotics and whatnot. On top of that, a mystery plane is supposed to be allowed to land at SFO with minimum fuss, although it is large enough to carry tons of whatever (nuclear warheads, nerve gas, anthrax, obnoxious besserwissers) and despite the presence of a sensible nearby redirection target.
Second, the prize package was essentially some gizmos plus a round trip to Tokyo (economy class and four nights in a four star hotel), all taxes paid by the winner. Given the estimated value ($10,000) and my current tax residence, this would have ended up being a pretty expensive “victory.” So I didn’t want to win.
(Yes, I get it: the contest was sponsored by ANA, so they had to be prominently featured. Given free reins, the contest team might have come up with a premise involving somebody waking up from a 20-year coma, or being released after 20 years in jail, or returning to civilization after 20 years in a jungle... and the prize could have been more alluring.)
But as I read the stories (and wondered if some of the authors had ended up in 2073 rather than 2037) I couldn’t rid myself of the thought that there had to be some way to make sense of the premise. If it had actually happened, how would I try to explain it? It was one of those puzzles. I toyed with several ideas, including one worthy of a Stephen King novel (and no, I am not telling you about it!). In the end, with three days left to the deadline (August 25) and the weather taking a turn for the worse, I decided to give it a shot.
“Retro” was written in three nights. I finished it in a state of advanced sleep deprivation, an hour or two before the deadline, without time for proofreading (and later found that I had introduced a couple of bad edits while typesetting it for submission). Given this, and the departure from banal techno-optimism about halfway through the story, I felt pretty safe from fiscal repercussions when I uploaded it. The idea was that at least somebody would read it, but given the reported number of submissions (more than 1,300!) I wonder if anyone actually did. So, here it is instead.
The glitches have been fixed in the version on this page, which I guess is final. The intended reader is an active one, capable of googling up things which are not immediately clear, but the following links may prove convenient: 1984, semi truck vs F-35, virtual retinal displays, non-contact haptics, LISA, DEC2-P385R, non-deterministic Turing machines, soft errors, Satoshi Nakamoto, CPT symmetry, consistent histories, quantum retrocausation, butterfly effect, DAOs, and, of course, Ettore Bini.