"It's an embedded loop in the cycles and seasons of the… the Hypothetical…" Seasons, he felt the appropriateness of the word: seasons within epochal seasons, the ebb and flood of the galaxy's ocean of life… "In a… in what you might call a mature solar system, the elements of the Hypotheticals expand their mass, accumulate information, reproduce, until at some critical moment the oldest surviving specimens undergo a kind of sporulation… produce compact elisions of themselves that resemble clouds of dust or ash… and those clouds follow long elliptical orbits that intersect with planets where they gather…"

"Have they gathered here?" Sulean asked.

Here, yes, he said or thought, on this rocky planet made habitable for the potential civilization to which it had ultimately been connected…

"Do they know us, then?" Sulean Moi asked sharply.

Isaac was bewildered by the question, but the memory of Jason Lawton seemed to understand it. "The network processes information over light-years and centuries, but some biological civilizations survive long enough to be perceptible to it, yes, and civilizations are useful because they generate new machine life, to be absorbed and understood or, or—"

"Or devoured," Sulean Moi said.

"Or, in a sense, devoured. And civilizations generate something else that interests the network."

"What?"

"Ruins," the memory of Jason Lawton said. "They generate ruins."

* * * * *

Outside, beyond the walls of concrete and debris impenetrable to human vision, the ballet of memory proceeded at a quickening pace.

Memory, he told Sulean Moi, was what was happening here: ten thousand years of relentlessly gathered and shared knowledge was compressed into the spheres that made the canopy of the Hypothetical forest, information to be collated and carried forward, Isaac said, through the temporal Arch, which was opening its mouth to inhale all that knowledge: representations of the orbits and climates and evolution of local planets, of the millions of interlaced trajectories of icy cometary bodies from which the Hypothetical machines had drawn and would continue to draw their mass, of signals received from elsewhere in the galaxy and absorbed and re-emitted…

"Why memory?" Sulean Moi demanded. "To what end? Isaac— what is it that remembers?"

What remembered was the thing he couldn't see, though he saw much else. Not even Jason Lawton could answer the question Sulean Moi had posed. What was happening here was only a trivial event in the network, in the mind of—of— oh, Diane, has it really grown out there among the stars, the thing you used to want so badly to believe in?

"Isaac! Can you hear me?"

He fell back into the abyss of his own thoughts.

* * * * *

Because Isaac remembered Jason, it was also true that Jason remembered Isaac. Jason's adult understanding of the world had been overlaid on Isaac's raw experience, and that created a kind of double vision that was deeply discomforting.