by Greg Egan
The resulting zygotes drift, slowly, along a vast conduit. They undergo cleavage, redistributing their cytoplasm amongst more and more cells. Between four and six days after fertilisation, blastocysts form: hollow balls of cells, with a cluster at one end which is destined to become the embryo. Other cells will, in time, give rise to the protective foetal membranes.
Cultured slabs of uterine endometrium―hormonally stimulated into a swollen, receptive state, and replete with artificial blood circulated by electric pumps―are introduced into the conduit at the point where the blastocysts are ready to implant. Within days of implantation, chorionic villi―the links between the placental and “maternal” blood supply―will form, guaranteeing essential nutrition for the haemotropic development to come.
Tonight, after passing Mary’s dark house―on the far side of the street, as always―Harold stops and turns back. Why? Because certain of his motor neurons fire in the necessary sequence. Why? Because sufficient excitatory signals are received at their dendrites. Why? Because of the neural topology of Harold’s brain, the product of his genome, and his life history, and the way the quantum dice have fallen.
A rubbish-strewn alley leads to a back window, very slightly ajar. Harold can fit only his fingernails into the crack, and clawing the window open causes him a lot of pain, but this doesn’t deter him at all.
The window leads into a damp, warm bathroom, between a toilet and a dripping shower. He fears that the sound of the dripping will betray him; it rings so loudly in his head that he believes Mary might be wakened, not by the sound itself, but by his amplified perception of it. He tightens the hot water tap with all his strength, and then the cold, but there’s a leaky washer, and no amount of force is going to change that.
He tip-toes into the kitchen, opens the drawers and searches them methodically. It’s not until he has the carving knife in his hand that he reflects on his likely use for it. Part of him is shocked, but part of him is delighted; it’s one thing to muse and fret like a tenth-rate philosopher, but here at last is a test for his ideas that goes beyond inconsequential speculation.
A proportion of the embryos are simply liquefied; the cell walls, and indeed all intracellular structures, are ultrasonically disrupted. The broth of chemicals this produces is then fed into a sophisticated purification system, based mainly on electrophoresis and affinity chromatography, and many valuable substances are extracted.
The remaining embryos are broken into individual cells. In theory, perhaps, almost anything can be achieved with engineered bacteria, or some modified tumour cell line, but in practice there are still many properties of healthy human tissue that can’t be faked. Persuading E. coli to churn out hormones like insulin or dopamine is simple enough; turning it into a perfectly functional equivalent of an islet cell or a dopaminergic neuron―an integral part of a complicated regulatory system―is something else entirely. It’s simply not economical, trying to make all that human DNA work in a foreign environment, when the real thing is available for a fraction of the cost.
Harold passes the refrigerated storerooms every morning as he arrives for work, and every evening as he departs. It’s a relaxed, cheerful place; the storemen always seem to be whistling, or playing a radio loudly. Vans come and go at all hours, picking up the large, but light, containers of insulating foam in which the small, precious vials are packed. When Harold sees a crateful of the end product of his work being loaded into a van, when he sees the driver sign for the consignment, slam his door, and drive away, he says to himself aloud, nodding, “Yes! This is it. This is life.”
Harold stands by Mary’s bed. She’s lying on her side, turned away from him. He breathes slowly―through his mouth, hoping that this is the quietest way―and thinks about the trillions of cells of her body. If he stabbed her in the heart, only the tiniest fraction of them would be killed directly by the blade―just a few million cells in her skin, her soft tissue, her heart muscles. The death of her neurons would be almost coincidental, more a product of this organism’s poor design than anything else. A slime mould would easily survive similar treatment.
He stands for a while, waiting to see what he will do. Part of him―a small, vestigial subsystem with no interest whatsoever in brain physiology, the philosophy of consciousness, or even obsessive love―pleads fervently to be allowed to put down the knife and flee, but Harold pays it about as much attention as the soundtrack of a child’s cartoon overheard playing on a neighbour’s TV. He stands, and he waits.
Harold doesn’t mourn for the brief lives he helps create; he knows they die long before the most primitive thoughts or feelings have a chance to arise, and he can’t believe there’s a machine up in heaven, churning out a white-robed feather-winged soul for each of these tiny clusters of cells.
Rather, he rejoices. Because The Vat says something about human life―human life of every age―that had to be said, and although today he is alone in heeding this message, he knows that in time the insights he’s gained will be the common heritage of all humanity.
Harold retraces his steps. He returns the knife to its place in the kitchen. He leaves by the bathroom window, and closes it behind him.
He wanted to kill her, he muses, more than he’d ever wanted anything before. He wanted, very badly, to be free. But something in his genome, or something in his past, declared that it wasn’t to be. Or perhaps the quantum dice simply happened to fall in her favour. This time.
He walks home slowly, his face uplifted to the photons flooding down from the stars, and he counts them one by one.
IN NUMBERS
I dream that I’m floating in the void between the stars. Untethered. No ship in sight. Suitless, naked to the vacuum. I search frantically for the sun, as if merely knowing its direction could save me, but I’m spinning much too fast to find my bearings, and each time I catch a glimpse of what might be the home star, I lose sight of it again before I can be sure.
“Last night”—as day nineteen came to a close, with Callaghan’s condition unchanged—the orders arrived from Earth, officially canceling the mission.
We shut down the drive for six hours while we rotated Cyclops one hundred and eighty degrees. Now we are decelerating at 1.3 gees—as fast as we can, within safety parameters—but we’ll still be traveling away from the solar system for fourteen and a half more days before we even come to a halt, and then it will take as long again just to get back to the point where deceleration began. I have no right to be even mildly surprised by this—to shed the velocity gained over nineteen days’ ship time at 1 gee requires 14.6 days at 1.3; any intelligent child could do the calculation—but some Earth-bound, commonsensical part of my mind still can’t quite accept a twenty-nine-day U-turn.
Callaghan is facing away from the door as I enter the infirmary, but a glance at his EEG tells me he’s awake. I call out in what I hope is a calm, reassuring voice, “Andrew? It’s only me. How are you feeling today?” The words are picked up by the microphone in the helmet of my quarantine suit, pumped out by the external speaker, bounced off the gleaming, tiled walls, then fed back to me through my headset—creating the unsettling illusion that my skull is several meters wide, and hollow.
He turns at the sound, emits a series of angry grunts, and makes a show of trying to break free of his restraints, but after a short while he goes limp, and just glares at me resentfully.
I stand by the foot of the bed, suddenly feeling drained, lethargic, hopeless. Or maybe just heavy; the extra weight is going to take a while to get used to. Twenty-four more kilograms, distributed uniformly, isn’t exactly crippling, but even the slightest movement now requires a conscious effort.
“How are you?”
I’m convinced by now that he can’t understand a word I say, but I’d still rather make a fool of myself than deal with a living, conscious patient in silence. There’s no evidence that the sound of my voice is even any comfort to him, but I’m damned if I’m going to treat him like a cadaver.
“Is the g
ravity getting you down?”
Three days ago, Andrew Callaghan would have winced at the lame pun, and then lectured me on my sloppy terminology: “Kindly remember, ‘Doctor’ Dreyfus—and I use the title loosely—that the Principle of Equivalence does not grant ye license to refer to the inertial force ye are experiencing as ‘gravity.’ In that glorious, over-the-top Scottish accent that he put on when he was being jokingly pompous, in place of his usual pan-European amalgam. His father was Irish, his mother Scottish, but he grew up in Switzerland; three days ago, he spoke five languages. Now, my words mean no more to him than his grunts mean to me.
I close my eyes and fight down a wave of panic. Earth is still forty-six days away. In forty-six days, this could happen to all of us. I want to lean over and shake him, force him to confess that he’s acting, that it’s all a monstrous practical joke. I actually believed that, for the first few hours (in retrospect, a feat of wishful thinking verging on the psychotic—nobody indulges in practical jokes on board an experimental spacecraft). I thought everyone was in on it: make the doctor shit himself, and then laugh about it for the rest of the flight. I would have happily laughed along with them. But when I searched their faces for ill-concealed conspiratorial glee, all I found was the same sickening realization: This could happen to all of us. This could happen to me.
No diagnostic instrument can find the least thing wrong with Callaghan, and the hundreds of experts back on Earth who’ve seen the data can agree on only one thing: so far, there is no direct evidence of any toxin, any infection, any lesion, or any neurochemical deficit or excess. His brain activity has certainly changed, diminishing in specific regions in a manner entirely consistent with his diminished behavioral repertoire, but there is no sign of neurological damage to explain this loss of function.
This proves nothing; there are conditions that cannot be diagnosed until autopsy, even on Earth. And since Callaghan’s medical history—personal and ancestral, physical and mental—is, or was, spotless, if some trace neurotoxin has contaminated the food, or some mutant virus is drifting through the ship’s air, there is no reason to believe that he was uniquely vulnerable. It must be assumed that we are all at risk.
For all the high-powered technology at my disposal, I’d give anything for a simple, verbal report from the patient himself. He’s a long way from being comatose; there must be something going through his mind. Although that begs the question: going through whose mind? Does Andrew Callaghan still exist? At what level of impairment does he lose his identity? And who lies in this bed, then? An unnamed stranger, without a past or a future? The naïve vocabulary of personality fails; the painful fact is that the human brain is capable of states that can’t be categorized in such cozy terminology. Sometimes I think the only way to stay sane—when confronted with malfunctions of consciousness that betray, so starkly, its physical nature—is by adopting a variation on solipsism: other people may be nothing but biochemical robots, run by slabs of interconnected neurons … but me, I’m not like that at all; I’m real.
Via the control plate fixed to his depilated skull, I anesthetize and selectively paralyze him, then I wheel him into the scanning room. I’m still hoping that evidence of a virus is going to turn up; if not the nucleic acid itself, maybe some tell-tale foreign protein. However limited the practical usefulness of such a discovery, it would be a great psychological victory to finally know what it is we’re fighting.
I lock the bed into place inside the NMR cavity, hit a few keys, and the computer takes over. The scan will last nearly an hour, there’s nothing to do but sit and wait.
Perhaps the hypothetical virus is causing the production of an altered form of one of the neurotransmitters, too close to the real thing for this crude heap of coils to tell the difference, but sufficiently deformed to be unable to bind properly to its receptor? It’s possible, I suppose—as possible as any of my other wild guesses. No doubt the experts back home have already thought of it and dismissed it. The world’s best neuroscientists are all busily debating the Callaghan case, and when they manage to agree upon a hypothesis, I’m sure we’ll be told without delay (apart from the unavoidable one: twelve hours now, and growing longer). My expertise is in space medicine; my specialties are radiation sickness, and—amusingly enough—the effects of insufficient gravity. Why should I expect to come up with the answer myself? Just because I’m here in the flesh? Just because my own life may depend on it?
There’s a buzzing in my headset. I hit a button on my belt to accept the call.
“David?”
“Yeah?”
“It’s Jenny. I’m in the maser room. Can you come and take a look at Greta, please.”
“Why? What is it?”
She hesitates long enough to make a reply unnecessary.
This is it. It’s spreading.
I flick off my communicator. For a moment I simply feel numb, but then the ludicrous nature of the situation fills me with a bitter rage. Eight immaculately healthy people, on a milk run of a test flight to an arbitrary point in interstellar space; what are the odds of finding yourself in the middle of a fucking epidemic?
I’m on the verge of letting go and screaming out a string of angry obscenities, but I catch myself. What did I honestly expect? That quarantining Callaghan after he showed symptoms would be enough to contain the disease? I can’t fall to pieces every time a miracle fails to take place.
I switch the communicator back on; the channel is still open.
“I’m on my way.”
“You’re going to feel nauseous, but that should be the only side-effect; if you experience any other problems, let me know at once.”
They all nod earnestly. Thomas asks, “How nauseous is nauseous? Throwing up?”
“I hope not. The digestive tract isn’t physically affected, although you may feel like it is.”
He grins. “Well, that’s okay, then.”
DDC-XV, a mixture of anti-viral agents, is no guarantee of anything; it’s capable of disabling perhaps 40 per cent of known viruses, and slowing down another 10 percent. Since whatever is on board can only be mutant of something we brought from Earth, the odds are really no different: one chance in two of any useful effect at all.
It’s a strange sight: the crew lined up in front of me like nervous children trying to look brave while waiting to be inoculated. Although I’ve read all their files, although I know all their medical idiosyncrasies backward, they’ve never really been my patients before. Until now, they’ve just been colleagues and friends, and the sudden shift in the relationship is disconcerting. I hate the way they’re looking at me; as if I had some kind of power. As if it were me, and not the virus, they had to fear, or respect, or appease.
Captain Salih al-Qasbi is first to receive the jab. It’s almost funny; since the team was assembled back on the moon, queues have always formed in the precise order of ascension to command: Lidia Garcia, navigator. Kayathiri Sangaralingam, drive specialist. Thomas Bwalya, life-support engineer. Jenny Riley, cyberneticist. (Greta Nordstrom, communications engineer. Andrew Callaghan, astronomer.) Then me, last and least, insurance against some unlikely emergency—like the escape pods, and about as much use.
“What else can we do?” asks Kay. “Shouldn’t we be wearing quarantine suits?”
“It wouldn’t be worth the discomfort. We’ve been breathing the same air as each other for nineteen days; we must all have the virus in our bodies by now.” The notion of anyone engaging in physical intimacy on board Cyclops is ludicrous; there are video cameras in every corner of the ship, recording everything we do, twenty-four hours of every simulated day. For the virus to have passed from Callaghan to Nordstrom, it must be able to survive in air, so the chances are that we’ve all been infected.
Jenny frowns. “You keep talking about ‘the virus.’ What if it isn’t a virus? What if it’s something else?”
“What else can it be? A contaminant in the food doesn’t make sense any more—a toxin doesn’t just appear by mag
ic, there’d have to be a fungus or bacterium making it, and Thomas and I have both done dozens of tests, and turned up nothing.”
Salih says, “But no tests for a virus are positive, either. All we have are negative results.”
“Viruses are more elusive. It’s a process of elimination; if it was anything else, we would have pinned it down by now.” I decline to add that electron microscopy on brain tissue from a dead patient might settle the issue once and for all.
“But are you sure there is no other possibility, David?”
“If there is, I can’t imagine what.” I look around, a little resentful, but trying not to let it show. “Can anyone?”
There’s a long silence, then Lidia says, “This might sound far-fetched, and I know the symptoms are nothing like any recognized form of radiation sickness, but …”
I shake my head vehemently. “Not only do the symptoms make no sense, but the monitors all show that we’re getting no more of any kind of radiation than we’d be receiving on Earth. The shielding is working perfectly, against spillage from the drive, against cosmic rays … nothing is getting through.”
“What about something we can’t measure? Something that would pass right through the shields? Neutrinos, or some other weakly interacting particle? No humans have been out this far before, only robot probes, and none with detectors that could pick up neutrinos.”
“Neutrinos are harmless. We’d be hit with more neutrinos back on Earth, from the sun, than we would be out here. And if it’s some other kind of radiation, where’s it coming from? What’s kept it out of the solar system? What’s kept it off the Earth’s surface—our shielding is just as effective as an entire planetary atmosphere. And if it scarcely interacts with matter, how can it possibly cause brain damage?”