Robert Sawyer: Iterations

“Oh, Erik,” said Mary, shaking her head, then letting out a sigh. “Go to sleep.”

She kissed me and lay down.

I lay down too, but it was hours before I fell asleep.

If I’m a computer simulation, created millions or billions of years in the future of what I think of as the present, and if I was created simply as one possible human being with one possible set of memories, do other versions of me exist?

Did the simulators—whoever they are—pick one state of humanity at random for their experiment? Maybe. But Tipler said they would actually simulate all the possible states.

And if they did—

If there are other versions of me—

All the horrid things I’d ever thought about doing: the stealing, the cheating, and, yes, the murders. In other parts of this vast computer simulation, there must exist other Erik Hansens who had done those things. Some, of course, will have been arrested for their crimes, and will be paying their debts to their simulated societies.

But others…

I once heard a statistic that ninety percent of men would commit rape if they felt sure they could get away with it. I’d never believed that figure; rarely did I meet an attractive woman that I didn’t have at least a passing thought about having sex with, but never would it occur to me to force myself upon her.

Well, almost never…

If they had simulated this me, they could have simulated that me, too—indeed, all the other possible mes: a me who had raped Connie Hughes in high school, when she hadn’t wanted to go as far as I’d wanted to; a me who had stolen a thousand dollars from Gideon Dillings; a me who…

Mary and I hated to even mention his name: my bête noire , the bane of my existence. Roscoe Harada, that goddamned son of a bitch…

Yes, the version of me who had done what I had fantasized about doing. The version of me who had caved in Harada’s brow-ridged cranium with an aluminum baseball bat…

And the version of me who had shot him in the face, watching his skull open up like time-lapse film of a rose blooming…

And the version of me who had pushed him off the Bloor Street viaduct, letting him fall to the Don Valley Parkway, his body going splat , and then being run over by car after car after car…

They were all conceivable memory states. And if they were possible, then perhaps they did exist in other iterations of this simulation.

And that was intolerable.

It took a while to work it out, but I could now slip between worlds. I rather suspect the designers of the simulation didn’t know I was doing it. Sure, murders were occurring as I eliminated other versions of myself—versions whose existence I couldn’t countenance. But murders happen all the time. And if there were billions of versions of reality, well, on any given day, the same person would be snuffed out in millions of them anyway.

As I’d guessed, the simulators apparently had constraints on how much memory they could use, and so had decided to reconstruct Earth but none of the rest of the universe—at least not in any detail. And since therewere memory constraints, some sort of data compression was being employed. Whenever the operating system saw that there were two or more identical versions of any given object, rather than code them both twice, it apparently would code only one version and simply put a pointer to it in the other iterations of the simulation.

I’ve always had an eidetic memory and a vivid imagination—I dream in color, unlike Mary. By fully and completely imagining myself to be as I would have been in one of the alternative realities, by essentially convincing myself that I had killed Roscoe Harada, even for an instant, the operating system saw this me and the other version of me as identical. And then—don’t ask me how I did this; I can’t explain it any more than I can explain how I walk—I manage somehow to access the pointer registry, and slip into the version of the simulation in which that other me, the one I was imagining, does exist.

Granted, not everything I could imagine is possible. I could imagine—indeed, relish—an image of a world in which Harada had fallen down some stairs and broken his back and then, later, in which he and I had ended up in a knockdown, drag-out fistfight in which I pounded him into a bloody pulp. But, of course, if he were paralyzed, the subsequent brawl wouldn’t have been possible. No, there was no pointer to that world.

But to other possibilities, the pointers did exist.

And I traveled to them, world after world, iteration after iteration, putting an end to the unconscionable versions of me.

“I’m sorry, Erik,” I said, “but I’ve got to kill you.”

Of course, the other me wasn’t in my office at CanScience—he couldn’t be. In any iteration in which I still had that office, cramped though it had been, Harada would still be alive. Instead, I was confronting him in the basement of our house; it was 10:00 a.m. on a weekday, but I guess his shift didn’t start until later today.

The voice of the other me was edged with panic. “Why would you want to kill me?”

“Because you murdered Roscoe Harada.”

The brown eyes darted left and right. There was only one way out of the basement—up the wooden staircase—and I was blocking that. “You can’t prove that.”

“I don’t have to prove it to anyone but me. I’m here—in this version of the simulation—because I imagined a world in which we’d killed Harada with a knife to the left kidney. If that wasn’t what really happened here, I wouldn’t have been able to transfer to this iteration.”

The other me hesitated, as if unsure what to say. Then he frowned. “So what if I did do it? You must have wanted to do it, too. After what he did to us—”

“I don’t dispute that he should be dead. But what makes us better than Harada is that we never did anything awful to him to get even. And I can’t live with the knowledge that a version of reality exists in which we did.”

“But if you kill me, then you’ll be a murderer, too.”

“Is it murder? Or is it suicide?” My turn to frown. “Perhaps it’s neither. Perhaps it’s just me setting things straight.”

“This won’t bring Harada back to life in this iteration.”

“No. But it will serve as a fitting punishment for his death, allowing me to enjoy my existence without guilt.”

“But, look, the many-worlds interpretation of quantum mechanics says that—”

I cut him off. “It says that even in the real, non-simulated world that must have existed at one time, whenever an action can go two ways, it does go both ways, but in separate universes, spinning off new timelines for each possible version of reality.”

The other me nodded vigorously. “Exactly. So this vast multiplexed computer simulation is no different from that.”

“Except that John Cramer’s transactional interpretation solves all the quandaries of quantum physics without recourse to parallel universes. If this were the real world, I could believe that Cramer was right and Hugh Everett was wrong, and there was only one timeline. But here I know— know! —that there are versions of the simulation in which all the base things I’ve ever thought of doing actually happened. And if I’m going to have peace—”

“If you’re going to have peace,” said the other me, with resignation, “you’re going to have to put an end to me.”

I squeezed the trigger and said “Exactly,” but the bark of the Glock drowned out the word.

What did Roscoe Harada do to me, you might ask? CanScience was a small publishing company, and he was the buyer for a large bookstore chain. We solicited pre-pub orders for a book called Y2canucK: A Canadian Guide to Preparing for the Year 2000 . For us, a thousand copies was a normal print run. Chapters had taken four hundred copies; Indigo, a hundred and seventy-five. And then Harada’s order came in for his company: 25,000 copies, by far the biggest order we’d ever had.