Hassan shrugged. "I know, " he said. Then he sat up, alert again, having found an argument. "It doesn't mean that circularity is proved false," he said. "The Spaniards behaved exactly as they would have anyway, so any change that came about because she saw us watching her made no difference in the future because she and all her people were so soon dead. Maybe that's the only time the TruSite II has a backwash effect. When it can't possibly make a difference. So the past is still safe from our meddling. Which means we're also safe."

Tagiri did not bother pointing out that even though the Spaniards had killed or enslaved everyone, it didn't change the fact that because of what Putukain saw in her vision, the people were chanting a prayer as they were taken. That had to have an effect on the Spaniards. It had to bend their lives, just a little bit, the sheer strangeness of it. No change in the past would fail to have some kind of reverberation. It was the butterfly's wing, just as they taught in school: Who knew whether or not a storm in the North Atlantic might not have been triggered, far back in the chain of cause-and-effect, by the flapping of a butterfly's wing in China? But there was no point in arguing this with Hassan. Let him believe in safety while he could. Nothing was safe now; but neither were the watchers powerless, either.

"She saw me," said Tagiri. "Her desperation made her believe I was a god. And her suffering makes me wish that she were right. To have the power to help these people -- Hassan, if she could sense us, it means that we're sending something back. And if we're sending anything back at all, anything, then perhaps we could do something that would help."

"How could we save that village?" said Hassan. "Even if it were possible to travel back in time, what would we do? Lead an avenging army to destroy the Spanish who came to take this village? What would that accomplish? More Spanish would come later, or English or some other conquering nation from Europe. And in the meantime, our own time would have been destroyed. Undone by our own intervention. You can't change great sweeps of history by changing one small event. The forces of history go on anyway."

"Dear Hassan," she said, "you tell me now that history is such an inexorable force that we can't alter its onward march. Yet a moment ago you told me that arty change, however small, would alter history by so much that it would undo our own time. Explain to me why this isn't a contradiction."

"It is a contradiction, but that doesn't mean it's untrue. History is a chaotic system. The details can shift endlessly, but the overall shape remains constant. Make a small change in the past, and it changes enough details in the present that we would not have come together at exactly this place and time to watch exactly this scene. And yet the great movements of history would be largely unchanged."

"Neither of us is a mathematician," said Tagiri. "We're just playing logic games. The fact is that Putukam saw us, you and me. There is some kind of sending from our time to the past. This changes everything, and soon the mathematicians will discover truer explanations for the workings of our time machines, and then we'll see what's possible and what isn't. And if it turns out that we can reach into the past, deliberately and purposefully, then we will do it, you and I."

"And why is that?"

"Because we're the ones she saw. Because she ... shaped us."

"She prayed for us to send a plague to wipe out all the Indies before the Europeans ever came. Are you really going to take that seriously?"

"If we're going to be gods," said Tagiri, "then I think we have a duty to come up with better solutions than the people who pray to us."

"But we're not going to be gods," said Hassan.

"You seem sure of that," she said.

"Because I'm quite sure the people of our time won't relish the idea of our world being undone in order to ameliorate the suffering of one small group of people so long dead."

"Not undone," said Tagiri. "Remade."

"You're even crazier than a Christian, " said Hassan. "They believe that one man's death and suffering was worth it because it saved all of humankind. But you, you're ready to sacrifice half the people who ever lived, just to save one village."

She glared at him. "You're right," she said. "For one village, it wouldn't be worth it."

She walked away.

It was real, she knew it. The TruSite II reached back into the past, and the watchers were somehow visible to the watched, if they knew how to look, if they were hungry to see. So what should they do? There would be those, she knew, who would want to shut down all of Pastwatch to avoid the risk of contaminating the past with unpredictable and possibly devastating results in the present. And there would be others who would trust complacently in the paradoxes, believing that Pastwatch could be seen by people of the past only under circumstances where it could not possibly affect the future. Fearful overreaction or smug negligence, neither was appropriate. She and Hassan had changed the past, and the change they introduced had in fact changed the present. Perhaps it had not changed all the intervening generations between then and now, but certainly it had changed Hassan and her. Neither of them would think or do or say anything that they would have thought or done or said without having heard the prayer of Putukam. They had changed the past, and the past had changed the future. It could be done. The paradoxes didn't stop it. The people of this golden time could do more than observe and record and remember.

If that was so, then what of all the suffering that she had seen over all these years? Could there be some way to change it? And if it could be changed, how could she refuse? They had shaped her. It was superstition, it meant nothing, and yet she could not eat that evening, could not sleep that night for thinking of their chanted prayer.

Tagiri got up from her mat and checked the time. After midnight, and she could not sleep. Pastwatch allowed its workers, wherever they dwelt, to live in the native manner, and the city of Juba had chosen to do so, as much as possible. So she was lying on woven reeds in a loose-walled hut cooled only by the wind. But there was a breeze tonight, and the hut was cool, so it wasn't heat that kept her awake. It was the prayer of the village of Ankuash.

She pulled a robe over her head and went to the laboratory, where others also worked late -- there were no set working hours for people who played so loosely with the flow of time. She told her TruSite to show her Ankuash again, but after only a few seconds she could not bear it and switched to another view. Columbus, landing on the coast of Hispaniola. The wrecking of the Santa Maria. The fort he built to hold the crew that he could not take back home with him. It was a miserable sight to see again -- the way the crew attempted to make slaves of the nearby villagers, who simply ran away; the kidnapping of young girls, the gang rapes until the girls were dead.

Then the Indies of several tribes began fighting back. This was not the ritual war to bring home victims for sacrifice. Nor was it the raiding war of the Caribs. It was a new kind of war, a punishing war. Or perhaps it was not so new, Tagiri realized. These oft-viewed scenes had been completely translated and it appeared that the natives already had a name for a war of annihilation. They called it "star-at-white-man's-village war." The crew awoke one morning to find pieces of their sentries' bodies scattered through the fort, and five hundred Indie soldiers in feathered splendor inside the stockade. Of course they surrendered.

The Indie villagers did not, however, adopt their captives preparatory to sacrifice. They had no intention of making these miserable rapists, thieves, and murderers into gods before they died. There was no formula declaration of "He is as my beloved son" when each Spanish sailor was taken into custody.