Time m-1

by Stephen Baxter

  Maura frowned. “The what?”

  Emma took a breath. “Malenfant, listen to me. Everything we’ve built up so far will be destroyed. Unless we start to take action.”

  “Action? Like what? A sellout to NASA?”

  “Maybe. And you have to cut your links with this character.”

  Cornelius Taine smiled coldly.

  Malenfant’s hands, clasped behind his back, showed white knuckles.

  The meeting broke up without agreement on a way forward. And on the way out, Maura whispered to Emma, “Carter? Who the hell is Carter?”

  Emma didn’t get to her apartment until midnight that night. When she walked in the door she told the TV to turn itself on. And there, on every news channel, was Cornelius Taine.

  Cornelius Taine:

  So, Dr. Taine, you’resaying that these people from the future — the ones you call downstreamers — have reached into the past, to us. To send a message.

  Yes. We believe so.

  But if the downstreamers exist — or will exist — they survived this catastrophe of yours. Will survive. Whatever. Right? So why did they need to send a message?

  You’re asking me about causal paradoxes. The downstreamers are saving their grandmothers, us, from drowning. But if she had drowned they wouldn’t even exist, so how can they save her? Right?

  Umm. . . yeah. I guess —

  There’s a lot we don’t understand about time. What happens if you try to change the past is at the top of the list. Let me try to explain. It is a question of transactions, back and forth in time.

  The Feynman radio works on the notion of photons — electromagnetic wave packets — traveling back in time. Fine.

  But photons aren’t the only waves.

  Waves lie at the basis of our best description of reality. I mean, of course, the waves of quantum mechanics. These waves represent flows of — what? Energy? Information? Certainly they crisscross space, spreading out from every quantum event like ripples.

  We have good equations to tell us how they propagate. And if we know the structure of the waves we can tell a great deal about the macroscopic reality they represent. A clumping of the waves here means this is the most likely place to find that traveling electron emitted from over there.

  But, like electromagnetic waves, quantum wave packets emitted from some event travel both forward and backward in time. And these backward waves are vital to the structure of the universe.

  Suppose you have an object of some kind that changes the state of another: a source and a detector, maybe of photons. The source changes state and sends quantum waves off into future and past. The future-traveling wave reaches the detector. In turn this emits waves traveling into both future and past, like echoes.

  Here’s the catch. The quantum echoes cancel out the source waves, both future and past, everywhere — except along the path taken by the ordinary retarded waves. It’s like a standing wave set up between source and receiver. Because no time passes for a wave traveling at light speed, all of this is timeless too, set up in an instant.

  It’s called a transaction, as if source and detector are handshaking. “Hi, I’m here.” “Yes, I can confirm you are.”

  So there really are waves traveling back in time?

  So it seems. But you don’t have to worry about them.

  I don’t?

  No. There are no back-in-time paradoxes, you see, because the backward waves only work to set up the transaction; you can’t detect them otherwise.

  And that’s how our reality works. As the effects of some change propagate through space and time, the universe knits itself into a new form, transaction by transaction, handshake by handshake.

  Umm. And this is quantum mechanics, you say? So what happened to all that quantum funny stuff? The collapsing wave function, and Schrodinger’s cat, and the Many Worlds Interpretation, and —

  Oh, you can forget all that. We study that today the way we study Roman numerals. Now that we know what quantum mechanics is really all about, it’s hard to imagine how people in those days thought like that. Do you follow?

  Umm. . . Madeleine?

  Let me get this straight. If I go back and change the past, I create a new universe that branches off at that point… right? If I kill my grandmother, I get two universes, one where she lived and I was born, one where she dies and I was never born —

  No. Perhaps you haven’t heard me. It just doesn’t work like that.

  There is only one universe at a time. New universes may bud off from others, but they are not “parallel” in the way you say. They are separate and entire, with their own self-consistent causalities.

  So what happens if I go back in time and do something impossible, like kill my granny? Because if she dies, I could never be born, and could never have killed her.

  Each quantum event emerges into reality as the result of a feedback loop between past and future. Handshakes across time. The story of the universe is like a tapestry, stitched together by uncountable trillions of such tiny handshakes. If you create an artificial timelike loop to some point in spacetime within the

  negative light cone of the present—

  Whoa. In English.

  If you were to go back in time and try to change the past, you would nullify all those transactions, the handshakes between future and past. You would damage the universe, erasing a whole series of events within the time loop.

  So the universe starts over, from the first point where the forbidden loop would have begun to exist. The universe, wounded, heals itself with a new set of handshakes, working forward in time, until it is complete and self-consistent once more.

  Then changing the past is possible.

  Oh, yes.

  Tell me this, Dr. Taine. According to this view, even if you do go back and change the past, how do you know you succeeded? Won ‘tyou change along with the past you altered?

  We don’t know. How could we? We’ve never tried this before. But we think it’s possible a conscious mind would know.

  How?

  Because consciousness, like life itself, is structure. And structure persists as the cosmic tapestry changes.

  Think about a DNA molecule. Some of the genes are important for the body’s structure; some are just junk. If you could perturb reality, consider possible alternate destinies for that molecule, you could see a lot of variation in the junk without affecting the operation of the molecule in any significant way. But if there’s a change in the key structural components, those that contain information, the molecule may be rendered useless. Therefore, the key structure must be stable in the face of small reality changes.

  So if in some way our minds span reality changes…

  Then maybe we’ll be able to perceive a change, an adjustment of the past. Of course this is speculative.

  And what about free will, Dr. Taine? Where does that fit into your grand plan ?

  Free will is a second-order effect. Even life is a second-order effect. Light dancing from the rippled surface of time’s river. It is not the cause even of the ripples, let alone the great majestic flow itself.

  That’s onegosh-darnedgloomy view.

  Realistic, however.

  You know, our time is just a bubble far upstream that must seem utterly insignificant compared to the great enterprises of the future. But it isn’t insignificant, because it’s the first bubble. And if we don’t survive the Carter catastrophe, we lose everything — eternity itself.

  Emma Stoney:

  The media types had it all: the Carter prediction, the message from the future, the real reason for the redirection of the Nautilus. All of it.

  Emma was convinced it was Cornelius himself who had leaked the Carter stuff. It increased the pressure on Bootstrap hugely, but that only seemed to reinforce Malenfant’s determination to fight his way through this: to maintain his links with Cornelius, continue on to Cruithne, and launch again.

  Which, of course, was exactly what Cornelius wanted. She had been outflanked.<
br />
  She spent a sleepless night trying to figure out what to do next.

  Michael:

  At first the School seemed a good place to Michael. Better than

  the village, in fact.

  The clothes were clean and fresh. The food was new and sometimes tasted strange, but there was always-a lot of it. In fact there were refrigerators that lit up and had food and drink inside, food the children could help themselves to whenever they wanted. Michael found he missed baobab fruit, though.

  There were lots of children here, from very small to young teenagers. They lived in dormitories, which were bright and clean.

  At first the children had been wary of each other. They had no common language, and children who could speak to each other tended to gather in groups. There was nobody who spoke

  Michael’s language, however. But he was used to being alone.

  This was a place called Australia. It was a big empty land. He saw maps and globes, but he had no real understanding of how far he had come from the village.

  Except that it was a long way.

  There were lessons. The teachers were men and women called Brothers and Sisters.

  Sometimes the children would be gathered in a room, ten or fifteen of them, while a teacher would stand before them and talk to them or have them do work, with paper and pen or softscreen.

  Michael, like some of the other children, had a special softscreen that could speak to him in his own tongue. It was comforting to hear the little mechanical voice whisper to him, like a remote echo from home.

  The best times of all were when he was allowed to go explore, as if the softscreen were a window to another world, a world of pictures and ideas.

  He had no interest in languages or music or history. But mathematics held his attention from the start.

  He drank in the symbols, tapping them onto his softscreen or scratching them on paper, even drawing in the dust as he had at home. Most of the symbols and their formalism were better than the ones he had made up for himself, and he discarded his own without sentiment; but sometimes he found his own inventions were superior, and so he kept them.

  He loved the strict rigor of a mathematical proof — a string of equations, statements of truth, which nevertheless, if manipulated correctly, led to a deeper, richer truth. He felt as if his own view of the world were crystallizing, freezing out like the frost patterns he watched inside the refrigerators, and his thinking accelerated.

  Soon, in math class, he was growing impatient to be forced to work at the same pace as the other children.

  Once, he grew restive.

  That was the first time he was punished, by a Sister who yelled at him and shook him.

  He knew that that was a warning: that this place was not as friendly as it seemed, that there were rules to learn, and that the sooner he learned them the less harm would come to him.

  So he learned.

  He learned to sit quietly if he was ahead of the rest. He could do his work almost as effectively that way anyhow.

  Michael seemed to be the one who enjoyed mathematics the most. But most of the children had one or two subjects in which they excelled. And then it was Michael’s turn to sit and struggle, and the others’ turn to race ahead, risking the wrath of the teachers.

  Any children who showed no such talent were soon taken out of the School. Michael didn’t know what happened to them.

  It was a paradox. If you weren’t smart enough you were taken out of the School. If you were too smart you were punished for impatience. Michael tried to learn this rule too, to show just enough ability but not too much.

  It didn’t matter anyhow. Most of his real work he did in his head, in the dark, and he never told anybody about it.

  There were many visitors: adults, tall and dressed smartly, who walked around the classes and the dormitories. Sometimes they brought people with cameras who smiled as if the children were doing something of great importance. Once a woman even took away Michael’s softscreen, looking at the work he had recorded there with exclamations of surprise. He was given another softscreen, but of course it was empty, containing none of the work he had completed. But that didn’t matter. Most of it was in his head anyhow.

  There was a girl here called Anna, a little older and taller than the rest, who seemed to learn the rules more quickly than the others. She had big gray eyes, Michael noticed: gray and watchful. She would speak to the others — including Michael, through his softscreen — trying to help them understand what was wanted of them.

  It meant she was in line for punishment more often than most of the others, but she did it anyway.

  Many of the children drew blue circles on their books or their softscreens or their skin or the walls of the dormitories. As did Michael, as he had for a long time. He didn’t know what that meant.

  Those days — in retrospect, strange, bright days — didn’t last long.

  * * *

  Michael couldn’t know it, but it was the publicizing of the

  Carter prophecies — the end-of-the-world news — that forced

  the change in the Schools, including his own.

  Because suddenly people grew afraid: of the future, of their

  own children.

  Leslie Candolfo

  Frankly our biggest problem, since this damn end-of-the-world Carter bullshit broke, has been absenteeism. We’re up over 100 percent nationally. Not only that but productivity is right down, and our quality metric program shows a massive decline in all functions — except Accounting, for some reason. We’ve also had a number of incidents of violence, immoral behavior, and so forth in the workplace, some but not all related to alcohol and/or drugs.

  It’s as if they all believe this pseudoscience bullshit about there being no tomorrow. But of course the clock punchers expect us to keep on providing salaries and bonuses and medical benefits, presumably right up until doomsday itself, with maybe an advance or two.

  I know our competitors are suffering, too. But we can’t go on like this, ladies and gentlemen; our costs are skyrocketing, our profits hemorrhaging.

  I’m pleased to see the federal government is finally taking some positive action. Gray-suited spokesmen denouncing Carter and Eschatology as moonshine were all very well. What they are doing now — pumping out free twenty-four-hour sports, comedy, softsoaps, and synth-rock on TV — is a somewhat more practical

  response.

  We’ve already installed giant video walls in our workplaces in Tulsa and Palm Beach. Productivity took a hit, of course, but happily nowhere near as bad as in other sites without the wall-to-wall pap. We’ve also provided free e-therapy up to four hours a week per permanent employee. For now I agree with the government analysis that an anesthetized workforce is preferable to a workforce plunged into existential gloom.

  But this is just a palliative. We have to find a long-term way to handle this. The end of the world may or may not be inevitable.

  Our stockholder meeting is inevitable, however. I’m open to further suggestions.

  “The Voice of Reason”

  ›Mail this on to ten people you know, and tell them to send it to ten people they known and so on. We have to inoculate the species against the contagion of madness that is plaguing humankindi or this damn Carter hypothesis is going to become a self-fulfilling prophecy. HOW TO DEBUNK CARTER

  › 1) First of all, don’t dismiss it as nonsense. The hypothesis may be wrong-headed, but it’s not irrational and it’s not illogical. We aren’t dealing with the usual airhead crap here. It’s more potent than that.

  › 2) Don’t insult your opponent. Start with the premise that people aren’t stupid, whether they know science and math or not. If you insult them you’ll be seen as arroganti and you’ll lose the argument.

  › 3) The best attack on Carter is the notion that the cosmos is radically indeterministic. You can argue from quantum physics to justify thisi if you can keep your audience with youi or from’ free will if not. There is no way, even
in principle, to say how many humans might exist in the future. So the Carter analogy between humankind and balls in an urn breaks down.

  › 4) If your audience is sophisticated enoughn remind them that the whole argument is based on Bayesian statistics, which is a technique to refine probabilities of an event given a knowledge of prior probabilities. But in this case we have no prior probabilities to work with (we can only guess about the long-term future of humankind). So the Bayesian technique can’t be valid.

  › 5) Reduce the argument to the trivial. It’s trivially obvious that people discussing Carter’s argument find themselves alive today, not hundreds of years in the future. But nothing nontrivial follows from a triviality. Since no humans of the future are yet alive, it isn’t in the least surprising that we aren’t among them

  › 6) You could try a reductio ad absurdum. On any scale an exponential curve looks the same. You always seem to be at the beginning, minuscule compared to what is to come. So the catastrophe will always be just over the horizon. (Of course this argument falls down unless the exponential curve of the human population really does extend to infinity. Any finitude and something like Carter comes into play- But you don’t have to mention that unless challenged.)

  › 7) Appeal to common sense. Look back in time. A human of, say, A.D. 1000 would likewise have been sitting on top of an exponential curve reaching back to the Paleolithic. Would she have been correct to deduce she was in the last generations? Of course not, as we can see with retrospect. (You may find Carter proponents countering this one by saying this is a false analogy, humanity today faces far graver extinction threats than in A.D. 1000 because of our technological advancement! the way we have filled up the Earth, etc.

  And it took our modern-day sophistication to come up with the Carter argument in the first place. So we have formulated the Carter prophecy at precisely the moment it is most applicable to us. But then you can argue that they are appealing beyond the statistics.)

  ‹continuing list snipped›

  › Rememberi though! None of the counterarguments are definitive. You may find yourself up against somebody with as much or more understanding of statistics than you. In that case, escalate the argument until you blind the general audience with science.