“It was a very good thing that we had the mice with us,” said Noxon.
“Thank you,” said the alpha mouse. “We’re glad to reward you for refraining from crushing my head.”
“I never wanted to do it,” said Noxon to the mouse.
“Talking to the mice?” asked Wheaton.
“I wonder,” said Ram, “if our presence here, now, accelerated the aliens’ development of the ability to make remote assaults on human computing systems. Having seen us enter their space…”
Wheaton agreed. “Why, it might be that our presence is what led them to attack Earth!”
“No,” said Noxon. “They attacked long before we ever showed up here.”
“We’re here now, and that’s hundreds of millennia before the attack,” said Wheaton.
“Prepare for your head to hurt again,” said the expendable.
“Let me guess,” said Wheaton. “‘Before’ doesn’t always mean ‘before.’”
“The calendar and the clock keep a single line of time,” said Noxon. “But with us, causality jumps all over the place. We’re here before the invasion, by the calendar, but we’re here after the invasion, by the causal chain. Their invasion is what caused us to come, so by cause-and-effect, the invasion was first.”
“I can’t even make my little joke,” said Wheaton, “because the expendable already said it.”
“I anticipated your humor?” asked the expendable.
“You stepped on my joke,” said Wheaton. “Clever, but not polite.”
“You’d already said the joke,” said Ram, “so it wasn’t going to be funny this time. Whereas the expendable stepping on it, that was funny.”
“Amusing, anyway,” said the alpha mouse.
“The mice don’t think any of this is all that funny,” Noxon reported.
“Oh, the women are laughing uproariously,” said the alpha. “I’m the one who isn’t hysterical about it.”
Noxon could see that the female mice were busy at various tasks throughout the ship, and not one of them showed any sign of paying much attention to what they were doing.
“What are you doing to the ship?” asked Noxon.
Noxon could see Ram stiffen a little—he must know Noxon was talking to the mice, and so he feared that the mice might be doing something dangerous and irrevocable.
“We’re making the same alterations to this ship that our counterparts made to the backward-moving ship,” said the alpha. “So we can jump the fold without making nineteen forward copies and one backward one.”
“Are we planning to jump again?” asked Noxon.
“I believe that when the expendable finishes explaining about the civilization on the binary planet, you’ll decide that ten of these twenty ships should jump to a spot much nearer the binary.”
“Will they still skip eleven millennia back in time?” asked Noxon.
“No. Curing the replications also cures the time skip.”
“Are you ready for me to explain about the binary planet?” asked the expendable.
“I am,” said Ram. “Unless the mice now command the ship.”
“They’ve fixed it so we don’t split into nineteen pieces every time we jump,” said Noxon.
“You asked them if we’re planning to jump again,” said Ram. “Why would we do that?”
“Let’s hear the expendable and find out,” said Noxon. “The mice apparently already know what he’s going to tell us.”
The expendable took a breath before proceeding. Such theatricality from a machine that doesn’t need to breathe, thought Noxon. “Earth’s Moon was important to the evolution of life, by causing tides and controlling other cycles,” said the expendable. “But this world is really two planets, nearly equal, as close as they can be without tearing each other apart with tidal forces.”
“So both have atmospheres,” said Ram.
“Both have life?” asked Noxon.
“Both have widespread electricity and radio communications,” said the expendable. “They each monitor the other’s radio broadcasts, and I believe the ability to interfere with and eventually control remote computer systems was developed by the nearer planet in order to use it against the farther one.”
“They have a million kilometers between them,” said Ram, “and they’re attacking each other?”
“That suggests reciprocality,” said the expendable. “The nearer planet is attacking the farther one. The farther one seems to be working only to protect their own systems against attack.”
“Let me guess,” said Ram. “The one that attacked us is this aggressive one.”
“I don’t know,” said the expendable. “Whichever world emerges victorious, it will be convinced that the only way to deal with aliens is to destroy them utterly.”
“So even if it’s the nice guys on the far planet,” said Noxon, “they might still be the enemy that attacks Earth.”
The alpha mouse spoke to Noxon. “We don’t know which one is our enemy. Both must be brought under control.”
“It seems wrong to punish one world for what the other world did,” said Noxon.
“We’re not punishing anyone,” said Ram. “We’re saving the human race against a threat, and we don’t know which of these worlds poses that threat.”
“We know that both of them pose a threat,” said the alpha.
“It’s possible that both pose a threat,” said Noxon. “But to take preemptive action against both seems unfair. Stifling a civilization, a species that might be completely innocent—”
“Hold on,” said Wheaton. “Garden has already tried dozens of ways to forestall the destruction of humanity, so there are lots of timestreams in which one of these species wipes out all rivals and rules this bit of the galaxy. The other one was probably destroyed before the victor ever came near us, so we’re not the ones who snuffed them out. All we’re doing now is creating one slim timestream in which the human race survives. It is not so very much to take for ourselves, compared with what they’ve taken already.”
“So you’re arguing in favor of xenocide?” asked Ram.
“Not at all,” said Wheaton, looking horrified. “Nothing of the kind! Garden has endured for eleven millennia with tight restrictions on their ability to develop high technology, right?”
“Yes,” said Noxon.
“And that was a lid placed on the planet by other humans, right?”
“By computers,” said the expendable, “but obeying human orders.”
“So if we go into the past and put such a lid on both these species,” said Wheaton, “we’re doing to them nothing that we haven’t already done to ourselves.”
“To one portion of our species,” said Noxon. “Earth didn’t put any such lid on themselves.”
“We don’t have to destroy their whole biota in order to set up colonies here, do we?” asked Wheaton.
“It depends on what proteins they produce, and whether we can digest enough of them,” said Ram.
“I don’t suppose now would be a good era in which to make our investigations,” said Wheaton.
“You want to go into the past and see them early in their evolution,” said Noxon.
“I am what I am,” said Wheaton. “But I’m also right.”
“Put us back a few hundred thousand years ago,” said the alpha mouse, “and we’ll be their lid.”
“The mice have already suggested,” said Noxon, “that ten of our ships go to the other world, and ten stay here.”
“I wonder if versions of you are saying exactly the same thing on all nineteen of the other ships,” said Ram.