"I guess," Don said. They’d come to where Betty Ann Drive crossed Senlac Road, and they turned right. Senlac had sidewalks, but Betty Ann didn’t.

"For sure," she replied. "It’s the ultimate in Marshall McLuhan: the medium is the message. Just detecting it, even if we don’t understand it, tells us the most important thing ever."

He considered that. "You know, we should have Peter de Jager over sometime soon.

I haven’t played go in ages; Peter always likes a game."

She sounded irritated. "What’s Peter got to do with anything?"

"Well, what’s he best remembered for?"

"Y2K," said Sarah.

"Exactly!" he said. Peter de Jager lived in Brampton, just west of Toronto. He moved in some of the same social circles as the Halifaxes did. Back in 1993, he’d written the seminal article "Doomsday 2000" for ComputerWorld magazine, alerting humanity to the possibility of enormous computer problems when the year 2000 rolled around. Peter spent the next seven years sounding the warning call as loudly as he could. Millions of person-hours and billions of dollars were spent correcting the problem, and when the sun rose on Saturday, January 1, 2000, no disasters occurred: airplanes kept flying, money stored electronically in banks didn’t suddenly disappear, and so on.

But did Peter de Jager get thanked? No. Instead, he was excoriated. He was a charlatan, said some, including Canada’s National Post, in a year-end summation of the events of 2000 — and their proof was that nothing had gone wrong.

Don and Sarah were passing Willowdale Middle School now, where Carl was just finishing grade eight. "But what’s Y2K got to do with the aliens not signaling their existence?" she asked.

"Maybe they understand how dangerous it would be for us to know that some races did manage to survive technological adolescence. We got through Y2K because of lots of really hard work by really dedicated people, but once we were through it, we assumed that we would have gotten through it regardless. Surviving into the year 2000 was taken as — what was your phrase? — ‘an existence proof’ that such survival had been inevitable. Well, detecting alien races who’ve survived technological adolescence would be taken the same way. Instead of us thinking it was very difficult to survive the stage we’re going through, we’d see it as a Cakewalk. They survived it, so surely we will, too." Don paused. "Say some alien, from a planet around — well, what’s a nearby sunlike star?"

"Epsilon Indi," said Sarah.

"Fine, okay. Imagine aliens at Epsilon Indi pick up the television broadcasts from some other nearby star, um…"

"Tau Ceti," she offered.

"Great. The people at Epsilon Indi pick up TV from Tau Ceti. Not that Tau Ceti was deliberately signaling Epsilon Indi, you understand; they’re just leaking stuff into space. And Epsilon Indi says, hey, these guys have just emerged technologically, and we did that long ago; they must be going through some rough times — maybe the guys on Epsilon Indi can even tell that from the TV signals. And so they say, let’s contact them so they’ll know it’s all going to be okay. And what happens? A few decades later Tau Ceti falls silent. Why?"

"Everybody there got cable?"

"Funny," said Don. "Funny woman. No, they didn’t all get cable. They just stopped worrying about somehow surviving having the bomb and all that, and now they’re gone, because they got careless. You make that mistake once — you tell a race, hey, look, you can survive, ’cause we did — and that race stops trying to solve its problems. I don’t think you’d ever make that mistake again."

They’d come to Churchill Avenue, and had turned east, walking by the public school Emily, who was now in grade two, attended. "But they could tell us how they survived, show us the answer," said Sarah.

"The answer is obvious," said Don. "You know the least-best-selling diet book of all time? Losing Weight Slowly by Eating Less and Exercising More."

"Yes, Mr. Atkins."

He made his tone one of mock umbrage. "Excuse me! Going for a walk here!

Besides, I am eating less, and more sensibly, way more sensibly than I was before I started cutting back on carbs. But you want to know what the difference is between me and all the others who lost weight quickly on Atkins, then put it back on as soon as they quit? It’s been four years now, and I haven’t quit — and I’m never going to.

That’s the other piece of weight-loss advice no one wants to hear. You can’t diet temporarily; you have to make a permanent lifestyle change. I have, and I’m going to live longer for it. There are no quick fixes for anything."

He ceased talking as they crossed Claywood, then began speaking again. "No, the answer is obvious. The way to survive is to stop fighting each other, to learn tolerance, and to put an end to the huge disparity between rich and poor, so that some people don’t hate the rest of us so much that they’d do anything, including even killing themselves, to hurt us."

"But we need a quick fix," said Sarah. "With terrorists having access to biotech and nuclear weapons, we can’t just wait for everyone to get enlightened. You have to solve the problem of high-tech terrorism really quickly — just as soon as it becomes a problem — or no one survives. Those alien races who have survived must have found a solution."

"Sure," said Don. "But even if they did tell us their answer, we wouldn’t like it."

"Why?"

"Because," he said, "the solution is that time-honored sci-fi cliche, the hive mind.

On Star Trek, the reason the Borg absorb everyone into the Collective, I think, is that it’s the only safe path. You don’t have to worry about terrorists, or mad scientists, if you all think with one mind. Of course, if you do that, you might even lose any notion that there could be other individuals out there. It might never occur to you to even try to contact somebody else, because the whole notion of ‘somebody else’ has become foreign to your way of thinking. That could explain the failure of SETI. And then if you did encounter another form of intelligent life, perhaps by chance, you’d do exactly what the Borg did: absorb it, because that’s the only way you can be sure it’ll never hurt you."

"Gee, that’s almost more depressing than thinking there are no aliens at all."

"There’s another solution, too," said Don. "Absolute totalitarianism. Everyone’s still got free will, but they’re constrained from doing anything with it. Because all it takes is one crazy person and a pile of antimatter, and — kablooie! — the whole stinking planet is gone."

A car coming toward them beeped its horn twice. He looked up and saw Julie Fein driving by and waving. They waved back.

"That’s not much better than the Borg scenario," Sarah said. "Even so, it’s so depressing not to have detected anything. I mean, when we first started pointing our radio telescopes at the sky, we thought we’d pick up tons of signals from aliens, and, instead, in all that time — almost fifty years now — not a peep."

"Well, fifty years isn’t that long," he said, trying now to console her.

Sarah was looking off into the distance. "No, of course not," she said. "Just most of a lifetime."