"Esh wasn't an experiment. He was a child, Dr. Dvali. And he was my friend."

"You're evading the issue."

"I'm evading nothing. I'm not an accessory to your work. Had it been possible, I would have prevented you from beginning it."

"But you didn't, and you're here now. I think you should examine your own motives, Ms. Moi. I think you're here for the same reason we created Isaac. Because you've spent a lifetime trying to understand the Hypotheticals, and after—what, eighty years? Ninety?—you're no farther ahead than you were when you were young."

Certainly the Hypotheticals had never been far from her thoughts, not since they devoured Esh. An obsession, yes, maybe, but it had never influenced her judgment—had it?

As to whether she understood the Hypotheticals… "They don't exist," she said.

"Excuse me?"

"The Hypotheticals. They don't exist, not the way you imagine them. What do you picture when you think about them? Some great wise ancient presence? Beings of infinite wisdom inscrutable to our petty minds?

That was the mistake the Martian Fourths made. What risk would not be justified by the possibility of conversing with God? But they don't exist! There is nothing in all the starry sky but some vast operative logic connecting one thoughtless machine to the next. It's ancient, it's complex, but it isn't a mind."

"If that's so," Dvali said, "then who were you just talking to?"

Sulean opened her mouth and then closed it.

* * * * *

That night, for the first time in many days, Lise and Turk made love. The privacy of a separate room was an instant aphrodisiac. They didn't discuss it, didn't need to discuss it; in the candlelit darkness Lise had undressed and watched Turk undress, and then she had blown out the candle and found him by the faint light of the dust-dimmed moon. He smelled rank, and so did she. It didn't matter. Here was the communication at which they always excelled. Briefly she wondered whether, elsewhere in this ruin, the Fourths could hear the creak of the bedsprings. Probably, she thought. Probably good for them if they did hear it. It might enliven their old, juiceless lives.

Turk eventually fell asleep with his arm across her ribs and she was content to lie with him in the fading glow.

At last, though, she had to shift herself out of the embrace. Despite everything, she couldn't sleep. She thought about how far they had come, and she remembered a line she had read in some old book: The thin end of nowhere, whittled down to a fine point.

The night was cold. She curled against Turk again, seeking his warmth.

She was still awake when the building began to tremble.

* * * * *

Diane Dupree was awake in the room she shared with Sulean Moi, Mrs. Rebka, Isaac.