The Martians had argued over this for centuries. Sulean had spent much of her childhood listening to elderly Fourths debate the question. Sulean didn't have a conclusive answer—no one did—but her suspicion was that the Hypotheticals had no center, no operative intelligence. They did complex, unpredictable things-—but so did evolution. Evolution had produced vastly complex and interdependent biological systems without any central direction. Once self-reproducing machines had been unleashed on the galaxy (by some long lost ancient species, perhaps, long before Earth or Mars had condensed from stellar dust), they had been subject to the same inexorable logic of competition and mutation. What might that not have bred, over billions of years? Machines of immense scale and power, semi-autonomous,

"intelligent" in a certain sense—the Arch, the temporal barrier that had surrounded the Earth—all that, yes. But a central motivating consciousness? A mind? Sulean had come to doubt it. The Hypotheticals were not one entity. They were just what happened when the logic of self-reproduction engulfed the vastnesses of space.

The dust of ancient machines had fallen on the desert, and from that dust had grown strange, abortive fragments. A wheel, a hollow tube, a rose with a coal-dark eye. And Isaac was interested in the west, the far west. What did that mean? Did it have a discernible meaning?

It meant, Sulean thought, that Isaac was being sacrificed to a force as mindless and indifferent as the wind.

* * * * *

In the morning Mrs. Rebka allowed Sulean to visit the boy's room. "You'll see," she said grimly, "why we're all so concerned."

Isaac was limp under a tangle of blankets. His eyes were closed. Sulean touched his forehead and felt the radiant heat of fever.

"Isaac," she sighed, as much to herself as to the boy. His pale inertness provoked too many memories.

There had been another boy, yes, another fever, another desert.

"The rose," Isaac said, startling her.

"What's that?" she said.

"I remember the rose. And the rose, the rose remembers."

As if asleep, eyes still shut, he pulled himself into a sitting position, his pillow compressed under the small of his back and his head knocking the backboard of the bed. His hair was lank with sweat. How immortal human beings seem when they can walk, run, jump, Sulean thought. And how fragile when they can't.

Then the boy did something that shocked even Sulean.

He opened his eyes and the irises were newly discolored, as if their pale uniform blue had been spattered with gold paint. He looked at her directly and he smiled.

Then he spoke, and he spoke a language Sulean had not heard for decades, a Martian dialect from the sparsely inhabited southern wastes.

He said, "It's you, big sister! Where have you been?"

Then, just as quickly, he slept again, and Sulean was left shivering in the terrible echo of his words.

CHAPTER THIRTEEN