Permutation City (29 page)

"Possibly."

"So you are a fraud then, aren't you? Even if your 'sanctu-ary' really does come into existence -- even if you prove your precious theory right -- what have your backers gained? You've sent their clones into solitary confinement, that's all. You might as well have put them in a black box at the bottom of a mineshaft."

Durham said mildly, "That's not quite true. You talk about Copies surviving ten thousand years. What about ten billion? A hundred billion?"

She scowled. "Nothing's going to last that long. Haven't you heard? They've found enough dark matter to reverse the expansion of the universe in less than forty billion years --"

"Exactly.
This
universe isn't going to last."

Maria nodded sarcastically, and tried to say something belittling, but the words stuck in her throat.

Durham continued blithely, "The TVC universe will never collapse.
Never.
A hundred billion years, a hundred trillion; it makes no difference, it will always be expanding."

Maria said weakly, "Entropy --"

"Is not a problem. Actually, 'expanding' is the wrong word; the TVC universe grows like a crystal, it doesn't stretch like a balloon. Think about it. Stretching ordinary space increases entropy; everything becomes more spread out, more disordered. Building more of a TVC cellular automaton just gives you more room for data, more computing power, more order. Ordinary matter would eventually decay, but these computers aren't made out of
matter.
There's nothing in the cellular automaton's rules to prevent them from lasting for ever."

Maria wasn't sure what she'd imagined before; Durham's universe -- being made of the same "dust" as the real one, merely rearranged -- suffering the same fate? She couldn't have given the question much thought, because that verdict was nonsensical. The rearrangement was in time as well as space; Durham's universe could take a point of space-time from just before the Big Crunch, and follow it with another from ten million years
b.c.
And even if there was only a limited total amount of "dust" to work with, there was no reason why it couldn't be reused in different combinations, again and again. The fate of the TVC automaton would only have to make
internal
sense -- and the thing would have no reason, ever, to come to an end.

She said, "So you promised these people . . . immortality?"

"Of course."

"Literal immortality? Outliving the universe?"

Durham feigned innocence, but he was clearly savoring the shock he'd given her. "That's what the word means. Not dying after a very long time. Just not dying, period."

Maria leaned back against the wall, arms folded, trying to cast aside the feeling that the whole conversation was as insubstantial as anything Durham had hallucinated in the Blacktown psychiatric ward. She thought:
When Francesca's been scanned I'm going to take a holiday. Visit Aden in Seoul, if I have to. Anything to get away from this city, this man.

She said, "Ideas like that are powerful things. One of these days you're going to hurt someone."

Durham looked wounded himself, at that. He said, "All I've tried to do is be honest.
I
know:
I lied to you, at first -- and I'm sorry. I had no right to do that. But what was I supposed to do with the truth? Keep it locked up in my head? Hide it from the world? Give no one else the chance to believe, or disbelieve?" He fixed his eyes on her, calm and sane as ever; she looked away.

He said, "When I first came out of hospital, I wanted to publish everything. And I tried . . . but nobody reputable was interested -- and publishing in the junk-science journals would have been nothing but an admission that it was all bullshit. So what else could I do, except look for private backers?"

Maria said, "I understand. Forget it. You've done what you thought you had to -- I don't blame you for that." The cliches nearly made her gag, but all she could think about was shutting him up. She was sick of being reminded that the ideas which were nothing but a means to an end, for her -- the ideas she could turn her back on forever, in eight hours' time -- were this man's entire life.

He looked at her searchingly, as if genuinely seeking guidance. "If you'd believed everything I believe, would you have kept it all to yourself? Would you have lived out your life pretending to the world that you'd merely been insane?"

Maria was saved from answering by a beep from Durham's terminal. The Garden-of-Eden configuration had been recomputed; Thomas Riemann's snapshot was now built into their cellular automaton equivalent of the Big Bang.

Durham swung his chair around to face the screen. He said cheerfully, "All aboard the ship of fools!"

Maria took her place beside him. She reached over and tentatively touched his shoulder. Without looking at her, he reached up and squeezed her hand gently, then removed it.

Following a long cellular automaton tradition, the program which would bootstrap the TVC universe into existence was called FIAT. Durham hit a key, and a starburst icon appeared on both of their screens.

He turned to Maria. "You do the honors."

She was about to object, but then it didn't seem worth arguing. She'd done half the work, but this was Durham's creation, whoever cut the ribbon.

She prodded the icon; it exploded like a cheap flashy fire-work, leaving a pincushion of red and green trails glowing on the screen.

"Very tacky."

Durham grinned. "I thought you'd like it."

The decorative flourish faded, and a shimmering blue-white cube appeared: a representation of the TVC universe. The Garden-of-Eden state had contained a billion ready-made processors, a thousand along each edge of the cube -- but that precise census was already out of date. Maria could just make out the individual machines, like tiny crystals; each speck comprised sixty million automaton cells -- not counting the memory array, which stretched into the three extra dimensions, hidden in this view. The data preloaded into most of the processors was measured in terabytes: scan files, libraries, databases; the seed for Planet Lambert -- and its sun, and its three barren sibling planets. Everything had been assembled, if not on one physical computer -- the TVC automaton was probably spread over fif-teen or twenty processor clusters -- at least as one logical whole. One pattern.

Durham reduced the clock rate until the blue-white shimmer slowed to a stroboscopic flickering, then a steady alternation of distinct colors. The outermost processors were building copies of themselves; in this view, blue coded for complete, working processors, and white coded for half-finished machines. Each layer of blue grew a layer of white, which abruptly turned blue, and so on. The skin of this universe came with instructions to build one more layer exactly like itself (including a copy of the same instructions), and then wait for further commands to be passed out from the hub.

Durham zoomed in by a factor of two hundred, slowed down the clock rate further, and then changed the representation to show individual automaton cells as color-coded symbols. The processors were transformed from featureless blue or white boxes into elaborate, multicolored, three-dimensional mazes, rectilinear filigree alive with sparks of light.

In the throes of reproduction, each processor could be seen sprouting hundreds of pairs of fine red and green "construction wires," which grew straight out into the surrounding empty space -- until they all reached the same predetermined length, abruptly turned a tight one-hundred-and-eighty degrees, and then started growing back in the opposite direction. Glowing with elaborate moving striations, the wires zig-zagged back and forth between the surface of the mother computer and an unmarked boundary plane -- until between them, they'd filled in the region completely, like some strange electronic silk weaving itself into a solid cocoon.

In close-up, the wires resolved into long lines of cells marked with arrowheads, some rendered in the brighter hues which represented "activated" states. Glowing stripes built from the binary code of bright and dim moved down the wire from arrow to arrow: the data of the blueprint for the daughter machine being shuffled out from the central memory.

With the clock rate slowed still further, the process could be followed in detail. Wherever a pulse of brightness reached the end of a construction wire, the transparent "Vacuum" of the null state was transformed into an "embryonic" cell, shown as a nondescript gray cube. Subsequent data told the new cell what to become -- each pulse, or absence of a pulse, converting it into a slightly more specialized transition state, zeroing in on the particular final state required. The construction wires grew out from the mother computer using this principle, extending themselves by building more of themselves at their tips.

Having filled the entire region which the daughter machine would occupy, they then worked backward, retracting one step at a time; unweaving their
zig-zag
cocoon, and leaving behind whatever the blueprint required. The whole process looked grotesquely inefficient -- far more time was spent on extending and retracting the wires themselves than on creating the cells of the daughter machine -- but it kept the rules of the automaton as simple as possible.

Durham said, "This all looks fine to me. Okay to proceed?"

"Sure." Maria had grown mesmerized; she'd forgotten her urgency, forgotten herself. "Crank it up." At any speed where they could keep track of events at the level of individual processors -- let alone individual cells -- nothing useful would ever get done. Durham let the clock rate revert to the maximum they could afford, and the grid became a blur.

In contrast, the next stage would be painfully slow. Durham made coffee and sandwiches. All the overheads of running a Copy on a system of computers which was, itself, a simulation, addled up to a slowdown of about two hundred and fifty. More than four real-time minutes to a subjective second. There was no question of two-way communication -- the TVC universe was hermetic, no data which hadn't been present from the outset could affect it in any way -- but they could still spy on what was happening. Every hour, they could witness another fourteen seconds of what the Copy of Durham had done.

Maria spot-checked at other levels, starting with the software running directly on the TVC grid. The "machine language" of the TVC computers was about as arcane and ridiculous as that of any hypothetical Turing machine, six-dimensional or not, but it had been simple enough to instruct a metaprogrammer to write -- and rigorously validate -- a program which allowed them to simulate conventional modern computers. So the processor clusters in Tokyo or Dallas or Seoul were simulating a cellular automaton containing a lattice of bizarre immaterial computers . . . which in turn were simulating the logic (if not the physics) of the processor clusters themselves. From there on up, everything happened in exactly the same way as it did on a real machine -- only much more slowly.

Maria munched cheese and lettuce between thick slices of white bread. It was a Tuesday afternoon; most of the flats around them were silent, and the street below was lifeless. The neighboring office blocks had no tenants, just a few furtive squatters; where the sun penetrated the nearest building at just the right angle, Maria could see clothes hung out to dry on lines stretched between office partitions.

Durham put on music, a twentieth-century opera called
Einstein on the Beach.
He didn't own a sound system, but he called up the piece from a library he'd bought for the Garden of Eden, and had a background task play it through his terminal's speakers.

Maria asked, "What will you do with yourself when this is over?"

Durham replied without hesitation. "Finish the whole set of fifty experiments. Start Planet Lambert unfolding. Celebrate for about a week. Stroll down the main street of Permutation City. Wait for your little locking device to disengage. Wake up my passengers in their own private worlds -- and hope that some of them are willing to talk to me, now and then. Start catching up on Dostoyevsky. In the original --"

"Yeah, very funny. I said
you,
not
him."

"I'd
like to think of us as inseparable."

"Seriously."

He shrugged. "What will you do?"

Maria put her empty plate down, and stretched. "Oh . . . sleep in until noon, for a week. Lie in bed wondering exactly how I'm going to break the news to my mother that she can now afford to be scanned -- without making it sound like I'm telling her what to do."

"Perish the thought."

Maria said simply, "She's dying. And she can save herself -- without hurting anyone. Without
stealing food from the mouths of the next generation,
or whatever it is she thinks makes being scanned such a crime. Do you really think she -- honestly -- doesn't want to stay alive? Or wouldn't want to, if she could think it through clearly, without all the guilt and moralizing bullshit her generation saddled her with?"

Durham wasn't taking sides. "I don't know her, I can't answer that."

"She was a child of the nineties. Her kindergarten teachers probably told her that the pinnacle of her existence would be fertilizing a rainforest when she died." Maria thought it over. "And the beauty of it is . . .
she can still do that.
Scan her, put her through a meat grinder . . . scatter the results over the Daintree."