Incandescence

That was the ability, the potential in every one of them. There was, however, no drive to realize it: no curiosity, no joy in discovery, no restlessness, no dissatisfaction. The Arkdwellers needed their full intellectual toolkit in order to master the complex tasks allotted to them in the present social order, so it was not a useless vestigial genetic fossil. It was the living, breathing embodiment of matter's ability to comprehend itself, but it was tamed and caged in a manner that Rakesh had never encountered before. It could rise to the occasion to overcome a limited range of mundane setbacks and challenges, but it would never soar.

Rakesh was not surprised by any of this, inasmuch as it applied to the Arkdwellers as a whole. It fitted his observations of their behavior perfectly. He did not yet understand Zey, though. Her team-mates could not be too different from her genetically, but he'd expected her to carry two copies of some rare, recessive gene that could explain why she alone was compelled to make full use of her intellectual abilities. If that had been the case, though, the coarse-grained simulation would have had no way of knowing what the ordinary version of the gene was, and erasing Zey's atypical urges from the generic map.

This proved that whatever had made her different could not have been entirely genetically determined. The simulation had smoothed out the possible environmental influences on brain development into a plausible average, but in doing so it had clearly missed something that had made all the difference to Zey.

Rakesh probed the data more deeply, looking for genes that might have been triggered only rarely, rather than being rare themselves. He simulated the chemistry of the developing embryo in more detail, looking for possible surges in morphogens, and the wave of changes they might bring.

When he found what he'd been looking for, it was like an elephant stepping out of the wallpaper. There was a vast network of linked genes and proteins that could influence neural structures both in the embryo and in adulthood, and it bore the clear fingerprints of an engineered design. The Arkmakers had had their hands all over this part of their children's genome.

If there was a vital spark missing from the generic Arkdweller, these genes were designed to light the fire. Without imaging Zey's brain, Rakesh couldn't say just how far from the average the random biochemical detour she'd experienced in the egg had taken her, but a one-in-ten-thousand surge would have triggered a cascade of events that guaranteed a thirst for knowledge comparable to all of her other basic drives. The frequency of such individuals in the population would obviously be low, but Rakesh did not believe for a moment that Zey was an accident. The Arkmakers had wanted people like her, but not too many.

He was sure she had been born, or hatched, this way, because if the other trigger he'd found had been the cause then there was no explaining her team-mates' apathy. Extreme stress could bring on the development of the same neural structures in an adult's brain. Mild hardship wouldn't start the cascade, though; it would require a sustained, dramatic change in the environment. Depending on the circumstances, and the exact range of individual susceptibilities, it looked as if anything from thirty to sixty per cent of the population could be transformed by that route, but only if the Ark itself was subjected to a massive upheaval.

From there, the process would snowball, with an ever greater proportion of each subsequent generation driven by an urge to understand the crisis they were facing. If the threat subsided then the status quo would eventually return; the simulations suggested that a few dozen generations of tranquility would be enough to put out the fire. Then, as before, only a handful of individuals would exhibit the trait, until the next emergency.

Rakesh had performed the whole analysis in a couple of Zey's heartbeats, but she already had an air of impatience.

"What's your answer?" she said. "What's the nature of my sickness?"

Rakesh explained everything he'd found, as clearly as he could. He'd already told her all he knew about the Arkmakers, so the idea that her distant ancestors had shaped her people's nature did not come as a shock in itself.

"Why am I here now, though?" she said. "If the world was falling apart, of course it would be good to have people who tried to repair it, instead of just tending their herds and waiting to die. But why did they arrange for people like me to be hatched when there is no need for us?"