The replicators were not immortal. As individual entities they lived, reproduced, and eventually died. What remained in place was the network they built: a coral reef of gated, interconnected nodes in which novel data accumulated and drained toward the network's point of origin.
"The last time we talked," I reminded Jase, "you said there was a problem. You said the replicator population was dying back."
"They encountered something no one had planned for."
"What was that, Jase?"
He was silent a few moments, as if gathering his thoughts.
"We assumed," he said, "that when we launched the replicators we were introducing something new to the universe, a wholly new kind of artificial life. That assumption was naive. We—human beings, terrestrial or Martian—weren't the first sentient species to evolve in our galaxy. Far from it. In fact there's nothing particularly unusual about us. Virtually everything we've done in our brief history has been done before, somewhere, by someone else."
"You're telling me the replicators ran into other replicators?"
"An ecology of replicators. The stars are a jungle, Tyler. Fuller of life man we ever imagined."
I tried to picture the process as Jason described it:
Far beyond the Spin-sequestered Earth, far beyond the solar system—so deep in space that the sun itself is only one more star in a crowded sky—a replicator seed alights on a dusty fragment of ice and begins to reproduce. It initiates the same cycle of growth, specialization, observation, communication, and reproduction that has taken place countless times during its ancestors' slow migrations. Maybe it reaches maturity; maybe it even begins to pump out microbursts of data; but this time, the cycle is interrupted.
Something has sensed the replicator's presence. Something hungry.
The predator (Jase explained) is another kind of semiorganic autocatalytic feedback system—another colony of self-reproducing cellular mechanisms, as much machine as biology—and the predator is plugged into its own network, this one older and vastly larger than anything the terrestrial replicators have had time to construct during their exodus from Earth. The predator is more highly evolved than its prey: its subroutines for nutrient-seeking and resource-utilization have been honed over billions of years. The terrestrial replicator colony, blind and incapable of fleeing, is promptly eaten.
But "eaten" carries a special meaning here. The predator wants more than the sophisticated carbonaceous molecules of which the replicator's mature form is composed, useful as these might be. Far more interesting to the predator is the replicator's meaning, the functions and strategies written into its reproductive templates. It adopts from these what it considers potentially valuable; then it reorganizes and exploits the replicator colony for its own purposes. The colony does not die but is absorbed, ontologically devoured, subsumed along with its brethren into a larger, more complex, and vastly older interstellar hierarchy.
It is not the first nor the last such device to be so absorbed.
"Replicator networks," Jason said, "are one of the things sentient civilizations tend to produce. Given the inherent difficulty of sublight-speed travel as a way of exploring the galaxy, most technological cultures eventually settle for an expanding grid of von Neumann machines—which is what the replicators are—that costs nothing to maintain and generates a trickle of scientific information that expands exponentially over historical time."
"Okay," I said, "I understand that. The Martian replicators aren't unique. They ran into what you call an ecology—"
"A von Neumann ecology." (After the twentieth-century mathematician John von Neumann, who first suggested the possibility of self-reproducing machines.)
"A von Neumann ecology, and they were absorbed by it. But that doesn't tell us anything about the Hypotheticals or the Spin."
Jason pursed his lips impatiently. "Tyler, no. You don't understand. The Hypotheticals are the von Neumann ecology. They're one and the same."
* * * * *
At this point I had to step back and reconsider exactly who was in the room with me.
It looked like Jase. But everything he'd said was casting that into doubt.
"Are you communicating with this… entity? Now, I mean? As we speak?"
"I don't know if you'd call it communication. Communication works two ways. This doesn't, not in the sense you're implying. And real communication wouldn't be quite so overwhelming. This is. Especially at night. The input is moderated during daylight hours, presumably because solar radiation washes out the signal."
"At night the signal is stronger"
"Maybe the word 'signal' is misleading, too. A signal is what the original replicators were designed to transmit. What I receive is coming in on the same carrier wave, and it does convey information, but it's active, not passive. It's trying to do to me what it's done to every other node in the network. In effect, Ty, it's trying to acquire and reprogram my nervous system."
So there was a third entity in the room. Me, Jase—and the Hypotheticals, who were eating him alive.
"Can they do that? Reprogram your nervous system?"
"Not successfully, no. To them I look like one more node in the replicator network. The biotechnology I injected into myself is sensitive to their manipulation, but not in the ways they anticipate. Because they don't perceive me as a biological entity, all they can do is kill me."
"Is there any way to screen this signal or interfere with it?"
"None that I know of. If the Martians had such a technique they neglected to include the information in their archives."
The window in Jason's room faced west. The roseate glow now penetrating the room was the waning sun, obscured by clouds.
"But they're with you now. Talking to you."
"They. It. We need a better pronoun. The entire von Neumann ecology is a single entity. It thinks its own slow thoughts and makes its own plans. But many of its trillions of parts are also autonomous individuals, often competing with each other, quicker to act than the network as a whole and vastly more intelligent than any single human being. The Spin membrane, for instance—"
"The Spin membrane is an individual?"
"In every important sense, yes. Its ultimate goals are derived from the network, but it evaluates events and makes autonomous choices. It's more complex than we ever dreamed, Ty. We all assumed the membrane was either on or off, like a light switch, like binary code. Not true. It has many states. Many purposes. Many degrees of permeability, for instance. We've known for years that it can transit a spacecraft and repel an asteroid. But it has subtler capabilities even than that. That's why we haven't been overwhelmed with solar radiation in the last few days. The membrane is still giving us a certain level of protection."
"I don't know the casualty numbers, Jase, but there must be thousands of people in this city alone who have lost family since the Spin stopped. I would be very reluctant to tell them they're being 'protected.'"
"But they are. In general if not in particular. The Spin membrane isn't God—it can't see the sparrow fall. It can, however, prevent the sparrow from being cooked with lethal ultraviolet light."
"To what end?"
At that he frowned. "I can't quite grasp," he began, "or maybe I can't quite translate—"
There was a knock at the door. Carol entered with an armful of linen. I switched off the recorder and set it aside. Carol's expression was grim.
"Clean sheets?" I asked.
"Restraints," she said curtly. The linen had been cut into strips. "For when the convulsions start."