Permutation City

made a difference to the Earth’s evolutionary history. So they may or may not be crucial, but they’re hardly irrelevant.”

Maria said carefully, “That’s true—but nobody will ever be able to run a system that big in the Autoverse, so what’s the point of describing it? On Earth, the system is that big, we’re stuck with it. The only way to explain the entire fossil record, and the current distribution of species, is to look at things on a planetary scale. Migration has happened, it has to be taken into account. But… in the Autoverse, it hasn’t happened, and it never will. Effects like that will always be completely hypothetical.”

Durham said, “Hypothetical? Absolutely. But that doesn’t mean the results can’t be considered, can’t be imagined, can’t be argued about. Think of this whole project as… an aid to a thought experiment. A sketch of a proof.”

“A proof of what?”

“That Autoverse life could—in theory—be as rich and complex as life on Earth.”

Maria shook her head. “I can’t prove that. Modeling a few thousand generations of bacterial evolution in a few microenvironment.…”

Durham waved a hand reassuringly. “Don’t worry; I don’t have unrealistic expectations. I said ‘a sketch of a proof,’ but maybe even that’s putting it too strongly. I just want… suggestive evidence. I want the best blueprint, the best recipe you can come up with for a world, embedded in the Autoverse, which might eventually develop complex life. A set of results on the short-term evolutionary genetics of the seed organism, plus an outline of an environment in which that organism could, plausibly, evolve into higher forms. All right, it’s impossible to run a planet-sized world. But that’s no reason not to contemplate what such a world would be like—to answer as many questions as can be answered, and to make the whole scenario as concrete as possible. I want you to create a package so thorough, so detailed, that if someone handed it to you out of the blue, it would be enough—not to prove anything—but to persuade you that true biological diversity could arise in the Autoverse.”

Maria laughed. “I’m already persuaded of that, myself. I just doubt that there could ever be a watertight proof.”

“Then imagine persuading someone a little more skeptical.”

“Who exactly did you have in mind? Calvin and his mob?”

“If you like.”

Maria suddenly wondered if Durham was someone she should have known, after all—someone who’d published in other areas of the artificial life scene. Why else would he be concerned with that debate? She should have done a much wider literature search.

She said, “So what it comes down to is… you want to present the strongest possible case that deterministic systems like the Autoverse can generate a biology as complex as real-world biology—that all the subtleties of real-world physics and quantum indeterminacy aren’t essential. And to deal with the objection that a complex biology might only arise in a complex environment, you want a description of a suitable ‘planet’ that could exist in the Autoverse—if not for the minor inconvenience that the hardware that could run it will almost certainly never be built.”

“That’s right.”

Maria hesitated; she didn’t want to argue this bizarre project out of existence, but she could hardly take it on if she wasn’t clear about its goals. “But when it’s all said and done, how much will this really add to the results with A. lamberti?”

“In one sense, not a lot,” Durham conceded. “As you said, there can never be a proof. Natural selection is natural selection, and you’ve shown that it can happen in the Autoverse; maybe that should be enough. But don’t you think a—carefully designed—thought experiment with an entire planet is a bit more… evocative… than any number of real experiments with Petri dishes? Don’t underestimate the need to appeal to people’s imaginations. Maybe you can see all the consequences of your work, already. Other people might need to have them spelled out explicitly.”

Maria couldn’t argue with any of that—but who handed out research grants on the basis of what was evocative! “So… which university—?”

Durham cut her off. “I’m not an academic. This is just an interest of mine. A hobby, like it is with you. I’m an insurance salesman, in real life.”

“But how could you get funding without—?”

“I’m paying for this myself.” He laughed. “Don’t worry, I can afford it; if you take me up on this, you’re not going to be shortchanged, I can promise you that. And I know it’s unusual for an amateur to… subcontract. But like I said, I don’t work in the Autoverse. It would take me five years to learn to do, myself, what I’m asking of you. You’ll be free to publish all of this under your own name, of course—all I ask is a footnote acknowledging financial support.”

Maria didn’t know what to say. Lorenzo the insurance salesman? A private citizen—not even an Autoverse junkie—was offering to pay her to carry out the most abstract piece of programming imaginable: not simulating a nonexistent world, but “preparing” a simulation that would never be performed. She could hardly be disdainful of anyone for throwing their hard-earned money away on “pointless” Autoverse research—but everything that had driven her to do that, herself, revolved around firsthand experience. However much intellectual pleasure it had given her, the real obsession, the real addiction, was a matter of putting on the gloves and reaching into that artificial space.

Durham handed her a ROM chip. “There are some detailed notes here—including a few ideas of mine, but don’t feel obliged to follow any of them. What I want is whatever you think is most likely to work, not what’s closest to my preconceptions. And there’s a contract, of course. Have your legal expert system look it over; if you’re not happy with anything, I’m pretty flexible.”

“Thank you.”

Durham stood. “I’m sorry to cut this short, but I’m afraid I have another appointment. Please—read the notes, think it all through. Call me when you’ve made a decision.”

After he’d left, Maria sat at the table, staring at the black epoxy rectangle in her palm, trying to make sense of what had happened.

Babbage had designed the Analytical Engine with no real prospect of seeing it constructed in his lifetime. Space travel enthusiasts had been designing interstellar craft, down to every last nut and bolt, since the 1960s. Terraforming advocates were constantly churning out comprehensive feasibility studies for schemes unlikely to be attempted for a hundred years or more. Why? As aids to thought experiments. As sketches of proofs.

And if Durham, who’d never even worked in the Autoverse, had an infinitely grander vision of its long-term possibilities than she had, then maybe she’d always been too close to it, too wrapped up in the tedious contingencies, to see what he’d seen…

Except that this wasn’t about long-term possibilities. The computer that could run an Autoverse world would be far bigger than the planet it was modeling. If such a device was ever to be constructed, however far into the future, there’d have to be far better reasons for building it than this. It wasn’t a question of a visionary born a generation or two before his time; Autoverse ecology was an entirely theoretical notion, and it always would be. The project was a thought experiment in the purest sense.

It was also too good to be true. The Autoverse addict’s dream contract. But short of some senseless, capricious hoax, why should Durham lie to her?

Maria pocketed the chip and left the cafe, not knowing whether to feel skeptical and pessimistic, or elated —and guilty. Guilty, because Durham—if he was genuine, if he honestly planned to pay her real money for this glorious, senseless exercise—had to be a little insane. If she took this job, she’d be taking advantage of him, exploiting his strange madness.

+ + +

Maria let Aden into the house reluctantly; they usually met at his place, or on neutral ground, but he’d been visiting a friend nearby, and she could think of no excuse to turn him away. She caught a glimpse of the red cloudless sunset behind him, and the open doorway let in the hot concrete smell of dusk, the whirr of evening traffic. After seven hours cloistered in her room, reading Durham’s notes for his Autoverse Garden of Eden, the