"But I've followed progress in the field very closely, and I can certainly appreciate what you've done with A. lamberti. Perhaps even more so than some of your fellow practitioners. I think I see it in a rather broader context."

"You mean . . . cellular automata in general?"

"Cellular automata, artificial life."

"They're your main interests?"

"Yes."

But not as a participant? Maria tried to imagine this man as a patron of the artificial life scene, magnanimously sponsoring promising young practitioners; Lorenzo the Magnificent to the Botticellis and Michelangelos of cellular automaton theory.

It wouldn't wash. Even if the idea wasn't intrinsically ludicrous, he just didn't look that rich.

The coffee arrived. Durham started paying for both of them, but when Maria protested, he let her pay for herself without an argument -- which made her feel far more at ease. As the robot trolley slid away, she got straight to the point. "You say you're interested in funding research that builds on my results with A. lamberti. Is there any particular direction -- ?"

"Yes. I have something very specific in mind." Durham hesitated. "I still don't know the best way to put this. But I want you to help me . . . prove a point. I want you to construct a seed for a biosphere."

Maria said nothing. She wasn't even sure that she'd heard him correctly. A seed for a biosphere was terraforming jargon -- for all the plant and animal species required to render a sterile, but theoretically habitable planet ecologically stable. She'd never come across the phrase in any other context.

Durham continued. "I want you to design a pre-biotic environment -- a planetary surface, if you'd like to think of it that way -- and one simple organism which you believe would be capable, in time, of evolving into a multitude of species and filling all the potential ecological niches."

"An environment? So . . . you want a Virtual Reality landscape?" Maria tried not to look disappointed. Had she seriously expected to be paid to work in the Autoverse? "With microscopic primordial life? Some kind of . . . Precambrian theme park, where the users can shrink to the size of algae and inspect their earliest ancestors?" For all her distaste for patchwork VR, Maria found herself almost warming to the idea. If Durham was offering her the chance to supervise the whole project -- and the funds to do the job properly -- it would be a thousand times more interesting than any of the tedious VR contracts she'd had in the past. And a lot more lucrative.

But Durham said, "No, please -- forget about Virtual Reality. I want you to design an organism, and an environment -- in the Autoverse -- which would have the properties I've described. And forget about Precambrian algae. I don't expect you to recreate ancestral life on Earth, translated into Autoverse chemistry -- if such a thing would even be possible. I just want you to construct a system with . . . the same potential."

Maria was now thoroughly confused. "When you mentioned a planetary surface, I thought you meant a full-scale virtual landscape -- a few dozen square kilometers. But if you're talking about the Autoverse . . . you mean a fissure in a rock on a seabed, something like that? Something vaguely analogous to a microenvironment on the early Earth? Something a bit more 'natural' than a culture dish full of two different sugars?"

Durham said, "I'm sorry, I'm not making myself very clear. Of course you'll want to try out the seed organism in a number of microenvironments; that's the only way you'll be able to predict with any confidence that it would actually survive, mutate, adapt . . . flourish. But once that's established, I'll want you to describe the complete picture. Specify an entire planetary environment which the Autoverse could support -- and in which the seed would be likely to evolve into higher lifeforms."

Maria hesitated. She was beginning to wonder if Durham had any idea of the scale on which things were done in the Autoverse. "What exactly do you mean by a 'planetary environment'?"

"Whatever you think is reasonable. Say -- thirty million square kilometers?" He laughed. "Don't have a heart attack; I don't expect you to model the whole thing, atom by atom. I do realize that all the computers on Earth couldn't handle much more than a tide pool. I just want you to describe the essential features. You could do that in a couple of terabytes -- probably less. It wouldn't take much to sum up the topography; it doesn't matter what the specific shape of every mountain and valley and beach is -- all you need is a statistical description, a few relevant fractal dimensions. The meteorology and the geochemistry -- for want of a better word -- will be a little more complex. But I think you know what I'm getting at. You could summarize everything that matters about a pre-biotic planet with a relatively small amount of data. I don't expect you to hand over a giant Autoverse grid which contains every atom in every grain of sand."

Maria said, "No, of course not." This was getting stranger by the minute. "But . . . why specify a whole 'planet' -- in any form?"

"The size of the environment, and the variation in climate and terrain, are important factors. Details like that will affect the number of different species which arise in isolation and later migrate and interact. They certainly 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.