That night they lay in sleeping bags, in a clear mushroom tent big enough to hold ten. At this altitude, with its superthin atmosphere, it was impressive to consider the strength of the tent fabric, holding in 450 millibars of air with no sign of untoward bulging at any point; the clear material was nice and taut, but not rock hard; no doubt it was holding many bars of air less than would test its holding capacity. When Sax recalled the meters of rock and sandbags they had had to pile on their earliest habitats to keep them from exploding, he couldn’t help but be impressed by the subsequent advancements in materials science.

Ann nodded when he spoke of this. “We’ve moved beyond our ability to understand our technology.”

“Well. It’s understandable, I think. Just hard to believe.”

“I suppose I see the distinction,” she said easily.

Feeling more comfortable, he brought up memory again. “I’ve been having what I call blank-outs, where I can’t remember my thoughts of the previous several minutes, or up to say an hour. Short-term-memory failures, having to do with brain-wave fluctuations, apparently. And the long-term past is getting very uncertain as well, I’m afraid.”

For a long time she didn’t reply, except to grunt that she’d heard him. Then:

“I’ve forgotten my whole self. I think there’s someone else in me now. In partway. A kind of opposite. My shadow, or the shadow of my shadow. Seeded, and growing inside me.”

“How do you mean?” Sax said apprehensively.

“An opposite. She thinks just what I wouldn’t have thought.” She turned her head away, as if shy. “I call her Counter-Ann.”

“And how would you— characterize her?”

“She is . . . I don’t know. Emotional. Sentimental. Stupid. Cries at the sight of a flower. Feels that everyone is doing their best. Crap like that.”

“You weren’t like that before, at all?”

“No no no. It’s all crap. But I feel it as though it’s real. So . . . now there’s Ann and Counter-Ann. And . . . maybe a third.”

“A third?”

“I think so. Something that isn’t either of the other two.”

“And what do you— I mean, do you call that one anything?”

“No. She doesn’t have a name. She’s elusive. Younger. Fewer ideas about things, and those ideas are— strange. Not Ann or Counter-Ann. Somewhat like that Zo, did you know her?”

“Yes,” Sax said, surprised. “I liked her.”

“Did you? I thought she was awful. And yet . . . there’s something like that in me as well. Three people.”

“It’s an odd way to think of it.”

She laughed. “Aren’t you the one who had a mental lab that contained all your memories, filed by room and cabinet number or something?”

“That was a very effective system.”