Matthew took the invitation as the compliment it was, but he wasn’t able to respond. He hadn’t made any progress at all in wondering what might substitute for Earthly seasonal changes as a series of cues determining the pattern of Tyrian life cycles. All he was able to do, as yet, was turn the question around.

“Do youhave any ideas?” he asked, humbly.

“Not ideas, exactly,” Tang replied.

Matthew guessed quickly enough what that meant. “You mean you have worries,” he said. “Fears, even.” Matthew belatedly remembered what Solari had said about Tang reportedly having shown recent “signs of strain and acute anxiety.” He had seen none himself, so far—quite the reverse, in fact—but Kriefmann must have had some basis for his opinion.

“It seems to me,” the biochemist said, softly, “that the hidden potential contained in the duplex genomes of Ararat-Tyre must be responsive to ecological shifts of some kind. Perhaps it evolved in an era of intermittent ecological crises—not environmentally generated ecocatastrophes, but ecocatastrophes associated with dramatic population increases. I know that you know exactly what I mean, because I recall the rhetoric you used to employ in your inflammatory broadcasts: the lemming principle, the Mouseworld allegory, and so on. If so, isn’t it possible—perhaps probable—that the arrival of alien beings with radically different genomic systems might constitute exactly such a crisis. Thus far, I admit, the world has not responded to its invaders—unless the arrival in this vicinity of the creature that stung Maryanne can be counted a response—but the establishment of three discreet and understaffed Bases in three years has been the merest scratch on the surface. You understand what I’m saying, don’t you?”

Because he obviously wanted Matthew to be the one to say it, Matthew spelled it out. “You’re saying that we might have avoided tweaking the lion’s tail thus far,” he said, “but that decanting the remainder of the would-be colonists and establishing an ecological base for their long-term survival would be a whole new ballgame. You’re saying that although this doesn’t look like a death trap today, it could turn into one with frightening rapidity.”

“We simply don’t know,” Tang added. “Until we figure out the protocols of reproduction, we have no idea what dangers lurk in all that hidden potential.”

And that, Matthew thought, was exactly why Tang was becoming more and more nervous as time went by, and why he had become an enthusiastic advocate of withdrawal, allying himself with the groundling party to which Konstantin Milyukov was implacably opposed.

He figured that the ice had been sufficiently thawed to allow the raising of more delicate issues. “I hear that you and I are rivals for the empty berth on Bernal’s boat,” he said, biting the bullet.

“It’s not Bernal’s boat,” Tang pointed out, mildly. “Common consent had certainly determined that he was entitled to his place in the expedition, but we have all played a part in the design and construction of the boat.”

Matthew took due note of the fact that the wein question did not include him, although Tang had not said in so many words that he ought not to be entitled to a vote when the time came to settle the matter of who should replace Bernal Delgado on the expedition downriver.

“I’m sorry,” Matthew said. “I didn’t mean to imply that it wasn’t a collective enterprise. I dare say that everybody here would gain some benefit from the opportunity to see a little more of the continent, and to penetrate the dark heart of its mysterious vitreous grasslands. I understand that you want the berth as much as I do….”

“I don’t,” Tang put in.

The interpolation took the wind out of Matthew’s sails. “You don’t?” he echoed. He was about to apologize again for his misapprehension when Tang wrong-footed him again.

“It’s not a matter of wanting,” the biochemist said. “It’s a matter of which of us is best-equipped to make productive use of the opportunity. If I thought that you were the person who could derive the most benefit from the expedition, I would unhesitatingly concede your right to be a part of it—but you have come to this situation three years too late. I feel that it is my duty to place my own expertise and experience at the disposal of the expedition.”

“But you don’t actually wantto go,” Matthew said.

“That’s correct,” Tang said. He still wasn’t showing any glaringly obvious signs of strain or acute anxiety, but Matthew was beginning to realize what it was that Godert Kriefmann had picked up on.

“In fact,” Matthew added, “you don’t actually want to be here at all. You’d far rather be on Hopewith Andrei Lityansky, maintaining a safe distance from your subject matter.” He reminded himself that Tang was a biochemist: a man for whom reality was contained in chemical formulas and metabolic cycles.

“That too is not a matter of wanting,” Tang told him, very calmly indeed. “it is a matter of responsibility and common sense.”

“Responsibility to whom?” Matthew challenged.

Tang sat back in his chair and regarded him very carefully. “Since you were awakened, Dr. Fleury,” he said, “you have been briefed by Konstantin Milyukov and Andrei Lityansky. It’s rumored that you have also talked to Shen Chin Che. You have certainly heard Rand Blackstone’s opinion, and Lynn Gwyer’s. Every one of those five is opposed to the notion of a temporary or permanent withdrawal from Tyre, and every one will therefore have taken some care to represent the opposing case as a matter of cowardice or foolishness—but I do not believe that you are the kind of man to take aboard the ideas of others unthinkingly. I was rather young when I first encountered your work, and not yet twenty-five when you disappeared from the media landscape, but I have had time enough to familiarize myself with your writings and your intellectual legacy. I may be mistaken, but I feel that I know you rather better than some of the people who first encountered you in the flesh—people like Lynn Gwyer and Ikram Mohammed, perhaps even Bernal Delgado. I feel confident, therefore, that you will not have prejudged this question, and that you will understand far better than many others the true significance of the changes in our situation that have taken place since Hopeleft Earth’s solar system.”

Wrong-footed yet again by the earnest flattery, Matthew had no idea how to reply to it. In the end, wariness defeated his reflexive impulse to try to guess what Tang might mean. “Okay,” he said. “I’m listening. Convince me.”

Tang nodded, as if this was no more than he had expected. “When we enlisted for this mission,” he said, “we did so in the expectation that Earth was about to enter a new Dark Age. You joined the ranks of the frozen in 2090 or thereabouts, more than twenty years before me, but you were a prophet of no mean ability and Mr. Solari must have told you that the situation in the early 2110s seemed every bit as desperate as you had anticipated. The ecosphere was suffering a near-universal collapse, and new plagues were in the process of sterilizing every human female on Earth. I always trusted that the human race would pull through, but I expected a drastic interruption of scientific and social progress. It seems, however, that you and I were too pessimistic.

“There was indeed a Crash, but the rebound was more rapid than you or I would have dared hope. The intelligence gleaned by Hope’s patient crew during the last few centuries suggests that the Dark Age lasted less than half a century, and that technological progress had resumed its ever-more-enormous strides by the end of the twenty-second century. Even then, it seems, men dared to hope that they could live long enough to be the inheritors of authentic emortality. It appears that they were wrong, but a potent technology of longevity was discovered soon enough—three hundred years in what is now our past. You and I, Dr. Fleury, would be members of the last generation of mortal men were it not for the fact that we both have mortal children in suspended animation aboard Hope.”