Time

Malenfant sucked aggressively at a beer. “Eschatology,” he snapped. “The study of the end of things. Right? So tell me about the end of the world, Cornelius. What? How?”

“That we don’t know,” Cornelius said evenly. “There are many possibilities. Impact by an asteroid or a comet, another dinosaur killer? A giant volcanic event? A global nuclear war is still possible. Or perhaps we will destroy the marginal, bio-maintained stability of the Earth’s climate. As we go on, we find more ways for the universe to destroy us — not to mention new ways in which we can destroy ourselves. This is what Escha-tology, Inc., was set up to consider. But there’s really nothing new in this kind of thinking. We’ve suspected that humanity was doomed to ultimate extinction since the middle of the nineteenth century.”

“The Heat Death,” Malenfant said.

“Yes. Even if we survive the various short-term hazards, entropy must increase to a maximum. In the end the stars must die, the universe will cool to a global uniformity a fraction above absolute zero, and there will be no usable energy, anywhere.”

“I thought there were ways out of that,” Malenfant said. “Something to do with manipulating the Big Crunch. Using the energy of a collapsing universe to live forever.”

Cornelius laughed. “There have been ingenious models of how we might escape the Death, survive a Big Crunch. But they are all based on pushing our best theories of physics, quantum mechanics and relativity, into areas where they break down — such as the singularity at the end of a collapsing universe. Anyway we already know, from cosmological data, that there is no Big Crunch ahead of us. The universe is doomed to expand forever, without limit. The Heat Death, in one form or another, seems inevitable.”

“But that would give us billions of years,” Malenfant said.

“In fact more,” Cornelius replied. “Orders of magnitude

more.”

“Well, perhaps we should settle for that,” Malenfant said

dryly.

“Perhaps. Still, the final extinction must come at last. And the fact of that extinction is appalling, no matter how far downstream it is.”

“But,” Emma said skeptically, “if you’re right about what you said in the desert, we don’t have trillions of years. Just a couple of centuries.”

Cornelius was watching Malenfant, evidently hoping for a reaction. “Extinction is extinction; if the future must have a terminus, does it matter when it comes?”

“Hell, yes,” Malenfant said. “I know I’m going to die someday. That doesn’t mean I want you to blow my brains out right now.

Cornelius smiled. “Exactly our philosophy, Malenfant. The game itself is worth the playing.”

Emma knew Cornelius felt he had won this phase of the argument. And, gradually, step by step, he was drawing Malenfant into his lunacy.

She sat impatiently, wishing she wasn’t here.

She looked around the small, oak-paneled conference room. There was a smell of polished leather and clean carpets: impeccable taste, corporate lushness, anonymity. The only real sign of unusual wealth and power, in fact, was the enviable view — from a sealed, tinted window — of Central Park. They were high enough here to be above the park’s main UV dome. She saw people strolling, children playing on the glowing green grass, the floating sparks of police drones everywhere.

Emma wasn’t sure what she had expected of Eschatology. Maybe a trailer home in Nevada, the walls coated with tabloid newspaper cuttings, the interior crammed with cameras and listening gear. Or perhaps the opposite extreme: an ultramodern facility with a giant virtual representation of the organization’s Mister Big beamed down from orbit, no doubt stroking his white cat.

But this office, here in the heart of Manhattan, was none of that. It was essentially ordinary. That made it all the more scary, of course.

Malenfant said now, “So tell me how you know we only have two hundred years.”

Cornelius smiled. “We’re going to play a game.”

Malenfant glared.

Cornelius reached under the table and produced a wooden box, sealed up. It had a single grooved outlet, with a wooden lever alongside. “In this box there are a number of balls. One of them has your name on it, Malenfant; the rest are blank. If you press the lever you will retrieve the balls one at a time, and you may inspect them. The retrieval will be truly random.

“I won’t tell you how many balls the box contains. I won’t give you the opportunity to inspect the box, save to draw out the balls with the lever. But I promise you there are either ten balls in here — or a thousand. Now. Would you hazard which is the true

number, ten or a thousand?”

“Nope. Not without evidence.”

“Very wise. Please, pull the lever.”

Malenfant drummed his fingers on the tabletop. Then he pressed the lever.

A small black marble popped into the slot. Malenfant inspected it; it was blank. Emma could see there was easily room for a thousand such balls in the box, if need be.

Malenfant scowled and pressed the lever again.

His name was on the third ball he produced.

“There are ten balls in the box,” Malenfant said immediately.

“Why do you say that?”

“Because if there were a thousand in there it’s not likely I’d reach myself so quickly.”

Cornelius nodded. “Your intuition is sound. This is an example of Bayes’ rule, which is a technique for assigning probabilities to competing hypotheses with only limited information. In fact—” He hesitated, calculating. “ — the probability that you’re right is now two-thirds, on the basis of your ball being third out.”

Emma tried to figure that for herself. But, like most probability problems, the answer was counterintuitive.

“What’s your point, Cornelius?”

“Let’s think about the future.” Cornelius tapped the softscreen embedded in the tabletop before him. The small monitor before Emma lit up, and a schematic graph drew itself elegantly on the screen. It was a simple exponential curve, she recognized, a growth rising slowly at first, steepening up to a point labeled NOW. Cornelius said, “Here is a picture of the growth of the human population over time. You can see the steep rise in recent centuries. It is a remarkable fact that ten percent of all the humans who have ever existed are alive now. More than five percent of all humans, Malenfant, were born after you were.

“But that is the past. Let’s imagine how the future might develop. Here are three possibilities.” The curve continued to climb, steepening as it did so, climbing out of Emma’s frame. “This,” Cornelius said, “is the scenario most of us would like to see. A continued expansion of human numbers. Presumably this would require a move off-planet.

“Another possibility is this.” A second curve extrapolated itself from the NOW point, a smooth tip over to a flat horizontal line. “Perhaps our numbers will stabilize. We may settle for the resources of the Earth, find a way to manage our numbers and our planet indefinitely. A bucolic and unexciting picture, but perhaps it is acceptable.

“But there is a third possibility.” A third curve climbed a little way past the NOW marker — then fell spectacularly to zero.

“Jesus,” said Malenfant. “A crash.”

“Yes. Studies of the population numbers of other creatures, lower animals and insects, often show this sort of shape. Plague, famine, that sort of thing. For us, the end of the world, soon.

“Now. You can see that in the first two cases, the vast majority of humans are yet to be born. Even if we stay on Earth, we estimate we have a billion years ahead of us before changes in the sun will render Earth’s biosphere unviable. Even in this restricted case we would have far more future than past.

“And if we expand off-planet, if we achieve the kind of future you’re working for, Malenfant, the possibilities are much greater. Suppose we — or our engineered descendants — colonize the Galaxy. There are four hundred billion stars in the Galaxy, many of which will provide habitable environments for far longer than a mere billion years. Then the total human population, over time, might reach trillions of times its present number.”

“Oh. And that’s the problem,” Malenfant said heavily.

“You’re starting to see the argument,” Cornelius said, approving.

“I’m not,” Emma said.

Malenfant said, “Remember his game with the balls and the box. Why are we here now? If we really are going on to the stars, you have to believe that you were born in the first one-billionth part of the total human population. And how likely is that? Don’t you get it, Emma? It’s as if I drew out my ball third out of a thousand—”

“Far more unlikely than that, in fact,” said Cornelius.

Malenfant got up and began to pace the room, excited. “Emma, I don’t know statistics from my elbow. But I used to think like this as a kid. Why am I alive now? Suppose we do go on to colonize the Galaxy. Then most of the humans who ever live will be vacuum-sucking cyborgs in some huge interstellar empire. And it’s far more likely that I’d be one of them than what I am. In fact the only pop curve where it’s reasonably likely that we’d find ourselves here, now, is…”

“The crash,” said Emma.

“Yes,” Cornelius said somberly. “If there is a near-future extinction, it is overwhelmingly likely that we find ourselves alive within a few centuries of the present day. Simply because that is the period when most humans who ever lived, or who will ever live, will have been alive. Ourselves among them.”

“I don’t believe this for a second,” Emma said flatly.

“It is impossible to prove, but hard to refute,” said Cornelius. “Put it this way. Suppose I tell you the world will end tomorrow. You might think yourself unlucky that your natural life span has been cut short. But in fact, one in ten of all humans — that is, the people alive now — would be in the same boat as you.” He smiled. “You work in Las Vegas. Ask around. Losing out to one in ten odds is unlucky, but not drastically so.”

“You can’t argue from analogy like this,” Emma said. “There are a fixed number of balls in that box. But the total number of possible humans depends on the undetermined and open-ended future — it might even be infinite. And how can you possibly make predictions about people who don’t even exist yet — whose nature and powers and choices we know absolutely nothing about? You’re reducing the most profound mysteries of human existence to a shell game.”

“You’re right to be skeptical,” Cornelius said patiently. “Nevertheless we have thirty years of these studies behind us now. The methodology was first proposed by a physicist called Brandon Carter in a lecture to the Royal Society in London in the 1980s. And we have built up estimates based on a range of approaches, calling on data from many disciplines—” Malenfant said hoarsely, “When?”

“Not earlier than one hundred and fifty years from now. Not later than two hundred and forty.”

Malenfant cleared his throat. “Cornelius, what’s this all about? Is this an extension of the old eggs-in-one-basket argument? Are you going to push for an off-planet expansion?”

Cornelius was shaking his head. “I’m afraid that’s not going to help.”

Malenfant looked surprised. “Why not? We have centuries. We could spread over the Solar System—”

“But that’s the point,” Cornelius said. “Think about it. My argument wasn’t based on any one threat, or any assumptions about where humans might be Jocate4 or whafJeveJ oftecb-nology we might reach. It was an argument about the continued existence of humanity, come what may. Perhaps we could even reach the stars, Malenfant. But it will do us no good. The Carter catastrophe will reach us anyway.”

“Jesus,” said Malenfant. “What possible catastrophe could obliterate star systems — reach across light years?”

“We don’t know.”

There was a heavy silence in the wood-laden room.