“Nothing.”

“Not to hear the Earthies talk. And I’m a tourist guide and have to listen to them. There isn’t anything they say that I haven’t heard a million times, but what I hear most of all”—and she dropped into the clipped accents of the typical Earthie speaking Planetary Standard—“But, dear, however can all you people live in caves all the time? Doesn’t it give you a terrible closed-in feeling? Don’t you ever want to see blue sky and trees and ocean and feel wind and smell flowers—”

“Oh, I could go on and on, Ben. Then they say, ‘But I suppose you don’t know what blue sky and sea and trees are like so you don’t miss them.’... As if we don’t receive Earth-television and as if we don’t have full access to Earth-literature, both optical and auditory—and olfactory sometimes, too.”

Denison was amused. He said, “What’s the official answer to remarks like that?”

“Nothing much. We just say, ‘We’re quite used to it, madam.’ Or ‘sir’ if it’s a man. Usually it’s a woman. The men are too interested in studying our blouses and wondering when we take them off, I suppose. You know what I’d like to tell the idiots?”

“Please tell me. As long as you have to keep the blouse on, it being inside the suit, at least get that off your chest.”

“Funny, funny word play! ... I’d like to tell them, ‘Look, madam, why the hell should we be interested in your damned world? We don’t want to be hanging on the outside of any planet and waiting to fall off or get blown off. We don’t want raw air puffing at us and dirty water falling on us. We don’t want your damned germs and your smelly grass and your dull blue sky and your dull white clouds. We can see Earth in our own sky when we want to, and we don’t often want to. The Moon is our home and it’s what we make it; exactly what we make it. We own it and we build our own ecology, and we don’t need you here being sorry for us going our own way. Go back to your own world and let your gravity pull your breasts down to your knees.’ That’s what I’d say.”

Denison said, “All right. Whenever you get too close to saying that to some Earthie, you come say it to me and you’ll feel better.”

“You know what? Every once in a while, some Immie suggests that we build an Earth-park on the Moon; some little spot with Earth-plants brought in as seeds or seedlings; maybe some animals. A touch of home—that’s the usual expression.”

“I take it you’re against that.”

“Of course, I’m against it. A touch of whose home? The Moon is our home. An Immie who wants a touch of home had better get back to his home. Immies can be worse than Earthies sometimes.”

“I’ll keep that in mind,” said Denison.

“Not you—so far,” said Selene.

There was silence for a moment and Denison wondered if Selene were going to suggest a return to the caverns. On the one hand, it wouldn’t be long before he would feel a fairly strenuous craving to visit a rest-room. On the other, he had never felt so relaxed. He wondered how long the oxygen in his pack would hold out.

Then Selene said, “Ben, do you mind if I ask you a question?”

“Not at all. If it’s my private life that interests you, I am without secrets. I’m five-foot-nine, weigh twenty-eight pounds on the Moon, had one wife long ago, now divorced, one child, a daughter, grown-up and married, attended University of—”

“No, Ben. I’m serious. Can I ask about your work?”

“Of course you can, Selene. I don’t know how much I can explain to you, though.”

“Well— You know that Barron and L—”

“Yes, I know,” said Denison, brusquely.

“We talk together. He tells me things sometimes. He said you think the Electron Pump might make the Universe explode.”

“Our section of the Universe. It might convert a part of our Galactic arm into a quasar.”

“Really? Do you really think so?”

Denison said, “When I came to the Moon, I wasn’t sure. Now I am. I am personally convinced that this will happen.”

“When do you think it will happen?”

“That I can’t say exactly. Maybe a few years from now. Maybe a few decades.”

There was a short silence between them. Then Selene said, in a subdued voice, “Barron doesn’t think so.”

“I know he doesn’t. I’m not trying to convert him. You don’t beat refusal to believe in a frontal attack. That’s Lament’s mistake.”

“Who’s Lament?”

“I’m sorry, Selene. I’m talking to myself.”

“No, Ben. Please tell me. I’m interested. Please.”

Denison turned to one side, facing her. “All right,” he said. “I have no objection to telling you. Lamont, a physicist back on Earth, tried in his way to alert the world to the dangers of the Pump. He failed. Earthmen want the Pump; they want the free energy; they want it enough to refuse to believe they can’t have it.”

“But why should they want it, if it means death?”

“All they have to do is refuse to believe it means death. The easiest way to solve a problem is to deny it exists. Your friend, Dr. Neville, does the same thing. He dislikes the surface, so he forces himself to believe that Solar batteries are no good—even though to any impartial observer they would seem the perfect energy source for the Moon. He wants the Pump so he can stay underground, so he refuses to believe that there can be any danger from it.”

Selene said, “I don’t think Barron would refuse to believe something for which valid evidence existed. Do you really have the evidence?”

“I think I do. It’s most amazing really, Selene. The whole thing depends on certain subtle factors of quark-quark interactions. Do you know what that means?”

“You don’t have to explain. I’ve talked so much to Barron about all sorts of things that I might be able to follow.”

“Well, I thought I would need the Lunar proton synchrotron for the purpose. It’s twenty-five miles across, has superconducting magnets, and can dispose of energies of 20,000 Bev and more. It turns out, though, that you people have something you call a Pionizer, which fits into a moderately sized room and does all the work of the synchrotron. The Moon is to be congratulated on a most amazing advance.”

“Thank you,” said Selene, complacently. “I mean on behalf of the Moon.”

“Well, then, my Pionizer results can show the rate of increase of intensity of strong nuclear interaction; and the increase is what Lament says it is and not what the orthodox theory would have it be.”

“And have you shown it to Barron?”

“No, I haven’t. And if I do, I expect Neville to reject it. He’ll say the results are marginal. He’ll say I’ve made an error. He’ll say that I haven’t taken all factors into account. He’ll say I’ve used inadequate controls.... What he’ll really be saying is that he wants the Electron Pump and won’t give it up.”

“You mean there’s no way out.”

“Of course there is, but not the direct way. Not Lamont’s way.”

“What’s that?”

“Lament’s solution is to force abandonment of the Pump, but you can’t just move backward. You can’t push the chicken back into the egg, wine back into the grape, the boy back into the womb. If you want the baby to let go of your watch, you don’t just try to explain that he ought to do it—you offer him something he would rather have.”

“And what’s that?”

“Ah, that’s where I’m not so sure. I do have an idea, a simple idea—perhaps too simple to work—based on the quite obvious fact that the number two is ridiculous and can’t exist.”

There was a silence that lasted for a minute or so and then Selene, her voice as absorbed as his, said, “Let me guess your meaning.”

“I don’t know that I have any,” said Denison.

“Let me guess, anyway. It could make sense to suppose that our own Universe is the only one that can exist or does exist, because it is the only one we live in and directly experience. Once, however, evidence arises that there is a second Universe as well, the one we call the para-Universe, then it becomes absolutely ridiculous to suppose that there are two and only two Universes. If a second Universe can exist, then an infinite number can. Between one and the infinite in cases such as these, there are no sensible numbers. Not only two, but any finite number, is ridiculous and can’t exist.”