Thrice upon a Time

by James P. Hogan

  Charles took a sip from his wine glass and nodded at once as if he had been waiting for the question. The others watched him and waited expectantly.

  "We must conclude that past and present versions of the universe in which we live exist and are equally real," Charles told them. "We thus have a continuum of some kind. I think we're all agreed that it can't be of the popular infinitely branching, parallel variety; that would introduce too many impossible complications. In any case, it isn't supported by the data we've seen." He looked around to invite comment, but the others just nodded silently. "Neither can it be of the simple serial variety that we considered initially; in such a model it would be impossible to affect the present by manipulating a past, and again our results seem to indicate that this is not the case. The only model I can think of that could be consistent with what we've seen is a more complex serial one in which altering the events in a past universe does affect not only the future of that particular universe as it evolves in time, but also the presents of all the other universes that lie ahead of it. In other words there is some mechanism of causal connection through the continuum that the simple serial model doesn't take account of."

  "You mean like with the jar," Lee said. "That one message changed what happened in all the universes involved, not just in the one universe where the message was received."

  "Precisely that," Charles confirmed. "To be anywhere near the reality at all, the model will have to possess a mechanism that explains such evident facts." Those at the table became quiet.

  After a while Cartland asked, "Any ideas?"

  "I think maybe I have," Charles replied. The others looked at him with suddenly renewed interest. "Everything we have discovered so far," he continued, "seems to add up to two things: First, the universe that we see around us and form part of is simply one of many, equally real universes that appear to be strung sequentially along a single timeline; second, events that happen in this universe affect not only its future, but the situations in all the other universes that lie ahead of it. That, of course, suggests a continuity throughout the system; the future universes ahead of us form a progression of states that are evolving from the present state. We need to ask ourselves what the mechanism is that provides that continuity. That same mechanism will turn out to be, unless I'm very much mistaken, the same mechanism that enables events in one universe to alter what happens in another. Obviously we're talking about a causal influence that must be propagated by some means."

  "Agreed, but I don't think you'll find you have to look very far," Cartland said with a shrug. "The continuity follows from the fact that objects don't suddenly just appear and vanish; they endure in time. So a universe an hour, say, ahead of this one will contain the same objects. They provide the continuity."

  "Objects?" Charles repeated in a mildly challenging tone. "A candle, such as the one on the table there? A mayfly? A cigarette? They'll endure in time?"

  "Oh, all right," Cartland conceded. "I used the wrong word. Molecules then. Atoms, if you like."

  "The candle, the mayfly, and the cigarette are breaking down molecules all the time," Charles pointed out. "And they all contain carbon fourteen; atoms come apart too."

  "Oh, you know what I mean, Charles," Cartland said, sounding a little surprised. "Protons, neutrons, and electrons if you like. Or quarks and photons—whatever you'll accept as the basic mass-energy quanta. They don't change."

  "They don't," Charles agreed at last. "But they do rearrange. Bundles of them may come together and remain attached for a while to form a tree, and then fall apart again and disperse when the tree dies and decays. But as you say, Ted, the basic entities endure. They rearrange into different patterns to produce the changes that we call time, and they provide the continuity that enables one universe to evolve from another."

  "But you said all the universes were equally real," Elizabeth said, looking slightly puzzled. "How can the same quarks and things be in all of them at once?" She thought for a moment, and her expression changed suddenly. "Oh, wait a minute. I think I can see what you're getting at. You're saying that the continuity between universes in the time dimension is just as physically real as the spatial continuity inside a universe. Every particle has a real extension in time, just as tangible as its extension in space. Right?"

  "Exactly!" Charles declared. "So if you alter the arrangement of particles in one universe, you alter the arrangement of them in all subsequent universes as well by virtue of that continuity." He sat back, sipping his wine, to allow time for the others to reflect on what had been said. Eventually Cartland shook his head and frowned.

  "Sorry, old boy, not quite with you," he confessed. "Are you saying that the whole universe is just a part of some bigger continuum, and that things like particles somehow extend right through the whole thing? The objects we see are only really parts of what they are completely?"

  "Yes," Charles replied. He pointed toward the center of the table. "That candle there has burned about a quarter of the way down, but in the universe that's an hour or so behind us, it's still intact; in a universe that's a few hours ahead, it probably doesn't exist as such at all. The whole candle is the sum of all those, and all the points between. But all we see is the part of it that exists in the particular universe that we happen to be part of. The 'real' candle is all of them put together."

  "I hear what you're saying," Cartland murmured slowly. "It's a bit difficult to visualize though."

  "Try thinking of a two-dimensional analogy," Murdoch suggested. "Imagine that the universe is flat, and that everything it contains is flat. It's a plane, okay? Now form a solid continuum by stacking an infinite number of zero-thickness planes like that together, like the pages of an infinitely thick book. Every page is a universe. The basic particles are ink particles, and they form character shapes, that is, objects. But unlike in an ordinary book, where all the pages are different, the ink particles continue through like 'threads,' so the patterns they form can only change gradually, not abruptly. Also all the pages move together in one direction along the threads as they slide down the entropy slope that Elizabeth talked about earlier. So anybody inside one of those universes, us for example, will see the patterns changing sequentially. That's what he calls time."

  "Ah… " Cartland nodded and pulled his moustache. "Yes… I think I can see what you're driving at."

  Murdoch thought for a moment, then fished inside the pocket of his jacket and retrieved a piece of paper, which he unfolded. "Here's a sketch I drew when Grandpa and I were talking about it yesterday," he said, smoothing the paper out and placing it in the center of the table. The others leaned forward to look at it more closely except Charles, who continued to drink from his glass.

  "That's supposed to be a solid continuum of stacked, two-dimensional universes," Murdoch informed them. "Each universe consists of a space containing objects and inhabitants that are all made up of particles, at least that's what it looks like to you if you happen to live inside one of them. But we, in our privileged position as superobservers looking in from the outside, can see that every particle is really an infinitesimally thin slice of a thread that passes through all the universes. As the universe moves along the threads in some kind of supertime, the particles, or slices, appear to move through space. That gives a visible rate of change that is observed as normal time within the universe."

  "You can see there how, to Murdoch's superobserver, all of the universes are equally real," Charles commented. "Only the one that you happen to be part of and moving with gives the illusion of appearing more real to you than the rest."

  "So in theory it ought to be possible to send signals from one to another," Lee observed.

  "Aye," Charles agreed. "And I maintain that that is exactly what we've managed to do."

  Morna and Robert entered at that point to clear the dishes and prepare the table for the next course. The conversation reverted to small-talk for a while, mainly among Murdoch, Charles, and Lee. Cartland picked up Murdoch's sketch and exam
ined it silently while Elizabeth stared thoughtfully at the center of the table.

  Cartland looked up just as Morna was about to leave the room behind Robert. "Compliments to Mrs. Paisley," he called out. "Tell her the duck was splendid. Absolutely first-class." A murmur of endorsement rose around him. Morna nodded, smiled, and closed the door. A few seconds elapsed while the former mood around the table reestablished itself.

  "Okay," Lee said. "We've explained how they're all real and how they're connected. So what about events in one universe affecting other universes ahead of it? I can see how causal influences can move forward in time and affect the future. That much is everyday experience. But the universe that a cause happens in is moving forward too, so the effects would be observed inside the same universe, which makes sense intuitively. But you sound as if you're saying the causes can run on ahead and get into other universes that lie in front. Am I right?"

  Murdoch glanced at Charles, who motioned for him to continue. "That's the way it looks," Murdoch said. "If they only propagated at the same rate as the universes themselves move, then it would be the way you said: The effects of a cause would be permanently trapped inside the same universe that the cause occurred in. But that would give you a simple serial model, and we've already rejected that possibility."

  Lee stared at him dubiously for a few seconds, then said, "You mean that the patterns that exist in all the future universes could be rearranged into something different?"

  "Yes," Murdoch replied simply.

  "Wait a minute, wait a minute," Cartland broke in, raising a hand. "What are we saying now? Is this how the universe in which the jar was broken managed to get itself 'erased,' as Charles put it? Is that what we're into?"

  "Yes," Murdoch said again. "A universe existed in which the objects and inhabitants formed by the thread pattern included a broken jar. It broke because of causes that lay behind it, in the past. Then a signal was sent back that eliminated those causes. The pattern from that point onward was re-formed into a new one that represented a different sequence of events."

  "What, all of it?" Cartland sounded distinctly skeptical. "The whole universe? Surely not."

  "Not necessarily all of it," Murdoch agreed. "Probably only a small part of the total pattern was altered—the part that corresponded to the fraction of the universe that the lab downstairs represents. I wouldn't think the signal caused any alteration of the threads that made up a fisherman off the coast of Thailand or somewhere and changed anything in his life, or an event that took place in the Andromeda galaxy. But it certainly did alter what happened to us."

  "But what about the people in the lab who did break the jar?" Cartland demanded, still looking unhappy. "What happened to them? Where are they now? Do you mean that these threads simply… 'jumped' somehow into a completely new arrangement when the signal was received? The people who broke the jar were simply… 'reset' into us, who didn't?"

  "That is just what I mean," Murdoch said, nodding emphatically.

  "And we know nothing about it?" Cartland asked disbelievingly. "Surely that's preposterous. Why don't we remember anything connected with the incident?"

  "Because our memories consist of circulating electrical currents and certain DNA structures," Murdoch answered. "Electrons and quarks—basic quanta. They are all threads too! So are data bits in computer memories and characters on printout paper. Everything that formed any record of the original pattern was reset. Hence our memories are consistent with the new pattern that now exists. On the timeline as it now is no jar was ever broken. Yes, it's preposterous, but it accounts for the facts."

  Cartland slumped back in his chair and transferred his gaze to the tablecloth. He had evidently followed what Murdoch had said, but was still having difficulty accepting it. Elizabeth remained very thoughtful and said nothing.

  "It accounts for a lot of the other things we've seen too," Charles added after a while, speaking slowly and seriously. "It would explain, for example, how we could receive a signal and then fail to send it later on. A universe existed that contained in a tiny part of itself a couple of inhabitants who had no record of any signal having been received at some point in the past. They sent a signal to that point. In doing so, they rearranged the threads that constituted themselves, their memories, and their instruments into new patterns that did include memories and records of the event. The fact that they failed to send the signal later wouldn't matter at all, since the people who did send the signal would already have ceased to exist as such anyhow."

  "And here's a sobering thought," Murdoch added. "Exactly the same mechanism explains why we always see records of other 'selves' in the future who tried aiming signals back at points where they'd never received any, but we never get around to trying the same thing ourselves: If we did, we'd simply join the list of the ones who had been reset."

  "Good God!" Cartland exclaimed. "That means we've already been through it—every one of us here at this table."

  "Seems that way," Murdoch agreed. He made an effort to keep his voice nonchalant as he spoke, just to enjoy the expression on Cartland's face.

  Cartland's eyes widened, and his moustache seemed suddenly to bristle of its own accord. His throat convulsed soundlessly for a moment while he struggled to regain his voice. "Good grief," he managed eventually.

  "Obviously this is all very hypothetical at this stage," Charles told them. "The first thing on the priority list is to see if we can devise some way of trying to test the theory more thoroughly."

  Lee had been finishing his dessert and listening without interrupting. When a short silence descended, he placed his spoon in his empty dish, looked up, and said, "You're saying it's like an old newspaper picture that's made up out of dots. Let's say they form a picture of Ted. The dots are really the ends of a bundle of wires that has been cut across. The plane of the cut is a universe; Ted exists as part of that universe. Okay?"

  "That's a good enough analogy," Murdoch agreed.

  Lee nodded. "Fine. Now the threads are suddenly rearranged. We're in the same universe because we're still looking at the same cut, but the ends of the wires now make a picture of Charles, say. Everything in that universe that formed part of Ted is still there, but Ted isn't. And nobody else in it will ever know anything about any Ted ever being there. That it?"

  "That's it," Murdoch said. "The mythical superobserver would remember it because he's on the outside and perceives supertime, but nobody inside the continuum would know about it."

  "It's the 'suddenly' that bothers me," Lee told them, taking his eyes from Murdoch to look around the whole table. "The cross sections of the wires are material particles. To rearrange their pattern, they have to move perpendicular to the time axis. That means they have to move through space in all of the plane universes they pass through. How could they do that instantaneously? They should still be subject to relativity constraints."

  "A good point," Charles agreed, nodding. "We asked the same question. But don't forget that we've never said anything about the process being instantaneous; there could be a finite propagation delay along the continuum that we haven't any data on yet that would enable us to measure it. And there is a theoretical consideration that could turn out to be a way round the problem. You see, the basic entities that constitute the threads may be more fundamental than quarks or photons. If a quark comes apart into something simpler, the attributes that define mass may disappear in the process. Hence you could find that it's possible to decompose mass at one point into components that themselves do not possess mass individually but only when they're combined together, transport those components to some other point without a relativistic restriction, and reconstitute the property of mass there. But that takes us right out on the fringe of the whole business, and there's a lot of work to be done there yet. In fact this is something I'd like to talk to Elizabeth about while she's here." He turned toward her as he spoke. "You haven't been saying very much for a while, Lizzie. What's your opinion?"

  Elizabeth had bee
n listening intently throughout with her fingers pointed together in front of her mouth and her dessert standing untouched before her. "Opinion on what, Charles?" she asked. "Your last point or the whole business?"

  "The whole 'reset model' that we've been discussing," Charles replied.

  Elizabeth brought her arms down to her sides and paused for a moment to collect her words. "I think you're on the right track," she said at last. "As you say, that explanation does account for the observed facts, as extraordinary as it sounds, and for the time being at least I'd be completely at a loss to suggest even the beginnings of any alternative. However, there are two things that bother me about it as it stands.

  "The first is that the model is static, at least if we forget for the moment about being able to send signals up and down the continuum. By that I mean that future events are predefined by the patterns that exist in the threads. The future is already determined but unknown, and is just waiting to be consciously experienced. There's no scope for human decision, free will, and chance. I don't like that. I believe that those things are real and important."

  "I agree," Lee tossed in. "I can't buy that they're just illusions either."

  "But I never said that," Charles protested. "Take the incident with the jar. That was something that had every appearance of chance about it, and the event was changed. That says to me very clearly that such things are not permanently and unalterably predetermined."

  "I know," Elizabeth said. "But the model doesn't explain it. According to the model you described, that event was always written into the timeline until the signal was sent back to change it, which means that only a machine like yours can alter the thread pattern. So was the whole of human history and evolution before that simply a playing out of a fixed script? I can't believe that, Charles. The model has to show how such things as chance could operate before you built your machine, and at present it doesn't."

  "I agree with you," Charles said at once. "And I've no answer to give. What's your second problem?"