"Yes. That's more or less the argument I made. She said okay if you agreed."

Wil's eyebrows rose. He was both surprised and flattered. "That's settled, then." He looked through the window, trying to think how the conversation might be turned to the topic that was really bothering him. "You know, Della, I had a family. From what I read in GreenInc, they lived right through to the Extinction. I hate to think that Monica is right-that humankind just committed suicide. And Juan's theories are just as obnoxious. How do you think it ended?" He hoped the camouflage hid his real interest. And it wasn't entirely camouflage: He'd be grateful to get a nonviolent explanation for the end of civilization.

Della smiled at the question. She seemed without suspicion. "It's always easier to seem wise if you're selling pessimism. That makes Juan and Monica seem smarter than they really are. The truth is... there was no Extinction."

"What?"

"Something happened, but we have only circumstantial evidence what it was."

"Yes, but that `something' killed every human outside of stasis." He could not disguise his sarcasm.

She shrugged. "I don't think so. Let me give you my interpretation of the circumstantial evidence:

"During the last two thousand years of civilization, almost every measure of progress showed exponential growth. From the nineteenth century on, this was obvious. People began extrapolating the trends. The results were absurd: vehicles traveling faster than sound by the mid-twentieth century, men ors the moon a bit later. All this was achieved, yet progress continued. Simple-minded extrapolations of energy production and computer power and vehicle speeds gave meaninglessly large answers for the late twenty-first century. The more sophisticated forecasters pointed out that real growth eventually saturates; the numbers coming out of the extrapolations were just too big to be believed."

"Hmph. Seems to me they were right. I really don't think 2100 was more different from 2000 than 2000 was from 1900. We had prolongevity and economical space travel, but those were in the range of conservative twentieth-century prediction."

"Yes, but don't forget the 1997 war. It just about eliminated the human race. It took more than fifty years to dig out of that. After 2100 we were back on the exponential track. By 2200, all but the blind could see that something fantastic lay in our immediate future. We had practical immortality. We had the beginnings of interstellar travel. We had networks that effectively increased human intelligence-with bigger increases coming."

She stopped, seemed to change the subject. "Wil, have you ever wondered what became of your namesake?"

"The original W.W.?... Say," he said, with sudden realization, "you actually knew him, didn't you?"

She smiled briefly. "I met Wili Wachendon a couple of times. He was a sickly teenager, and we were on the opposite sides of a war. But what became of him after the fall of the Peacers?"

"Well, he invented too many things for me to remember. He spent most of his time in space. By the 2090s, you didn't hear much about him."

"Right. And if you follow him in GreenInc, you'll see the trend continued. Wili was a first-rate genius. Even then he could use an interface band better than I can now. I figure that, as time passed, he had less and less in common with people like us. His mind was somewhere else."

"And you think that's what happened to all mankind eventually?"

She nodded. "By 2200, we could increase human intelligence itself. And intelligence is the basis of all progress. My guess is that by midcentury, any goal-any goal you can state objectively, without internal contradictions-could be achieved. And what would things be like fifty years after that." There would still be goals and there would still be striving, but not what we could understand.

"To call that time `the Extinction' is absurd. It was a Singularity, a place where extrapolation breaks down and new models must be applied. And those new models are beyond our intelligence.

Della's face was aglow. It was hard for Wil to believe that this was the fabrication of an "exterminator." In the beginning at least, these had been human ideas and human dreams.

"It's a funny thing, Wil. I left civilization in 2202. Miguel had died just a few years earlier. That meant more to me than any Big Picture. I wanted to be alone for a while, and the Gatewood's Star mission seemed ideal. I spent forty years there, and was bobbled out for almost twelve hundred. I fully expected that when I got back, civilization would be unintelligible." Her smile twisted. "I was very surprised to find Earth empty. But then, what could be less intelligible than a total absence of intelligence? From the nineteenth century on, futurists wondered about the destiny of science. And now, from the other side of the Singularity, the mystery is just as deep.

"There was no Extinction, Wil. Mankind simply graduated, and you and I and the rest missed graduation night."

"So three billion people just stepped into another plane. This begins to sound like religion, Della."

She shrugged. "Just talking about superhuman intelligence gets us into something like religion." She grinned. "If you really want the religious version... have you met Jason Mudge? He claims that the Second Coming of Christ was sometime in the twenty-third century. The Faithful were saved, the unfaithful destroyed-and the rest of us are truant."

Wil smiled back; he had heard of Mudge. His notion of the Second Coming could explain things too-in one respect better than Lu's theory. "I like your ideas better. But what's your explanation for the physical destruction? Chanson isn't the only person who thinks that nukes and bioweapons were used towards the end of the twenty-third."

Della hesitated. "That's the one thing that doesn't fit. When I returned to Earth in 3400, there was plenty of evidence of war. The craters were already overgrown, but from orbit I could see that metropolitan areas had been hit. Chanson and the Korolevs have better records; they were active all through the fourth millennium, trying to figure out what had happened, and trying to rescue short-term low-techs. It looks like a classic nuclear war, fought without bobbles. The evidence of biowarfare is much more tenuous.

"I don't know, Wil. There must be an explanation. The trends in the twenty-second century were so strong that I can't believe the race committed suicide. Maybe it was a fireworks celebration. Or maybe... do you know about survival sport?"

"That was after my time. I read about it in GreenInc."

"Physical fitness has always been a big thing in civilization. By the late twenty-second, medical care automatically maintained body fitness, so people worked on other things. Most middle-class folk had Earthside estates of several thousand hectares. There were shared estates bigger than some twentieth-century nations. Fitness came to mean the ability to survive without technology. The players were dropped naked into a wilderness-arctic, rain forest, you name it-that had been secretly picked by the judges. No technology was allowed, though medical autons kept close track of the contestants; it could get to be pretty rough. Even people who didn't compete Would often spend several weeks a year living under conditions that would be deadly to twentieth-century city-dwellers. By ?200, individuals were probably tougher than ever before. All they lacked was the bloody-mindedness of earlier times."

Wil nodded. Marta had certainly demonstrated what Lu was saying. "How does this explain the nuke war?"

"It's a little farfetched, but... imagine things just before the race fell into the Singularity. Individuals might be only slightly' superhuman, and might still be interested in the primitive. For them, nuclear war might be a game of strength and fitness."