Anthology 2. Luminous [1998, 2010]

by Greg Egan

  Bausch says, ‘Then you accept that all it takes to generate experience is to carry out computations on data structures which encode the same information as the structure of the brain?’

  The jargon sounds gratuitous to me, and I don’t understand why she’s labouring the point, but I say blandly, ‘Of course I accept that.’

  ‘Then think about what it implies! Because the whole process of creating the finished piece of software which runs a Gleisner robot – the perfect Copy of the unconscious person who was scanned – is one long sequence of computations on data structures which represent the human brain.’

  I absorb that in silence.

  Bausch continues, ‘We don’t set out to cause the transition dreams, but they’re probably unavoidable. Copies have to be made, somehow: they can’t spring into existence fully formed. The scanner has to probe the organic brain, measure the NMR spectra for billions of different cross-sections, and then process those measurements into a high-resolution anatomical and biochemical map. In other words: carry out several trillion computations on a vast set of data which represents the brain. Then, that map has to be used to construct the working computer model, the Copy itself. More computation.’

  I think I almost grasp what she’s saying, but part of me flatly refuses to accept the notion that merely imaging the brain in high enough resolution could cause the image itself to dream.

  I say, ‘None of that computation sets out to mimic the workings of the brain, though, does it? It’s all just preparing the way for a program which will be conscious, when it’s finally up and running.’

  ‘Yes – and once that program is up and running, what will it do in order to be conscious? It will generate a sequence of changes in a digital representation of the brain – changes which mimic normal neural activity. But creating that representation in the first place also involves a sequence of changes. You can’t go from a blank computer memory, to a detailed simulation of a specific human brain, without a few trillion intermediate stages, most of which will represent – in part or in full, in one form or another – possible states of the very same brain.’

  ‘But why should that add up to any kind of mental activity? Rearranging the data, for other reasons entirely?’

  Bausch is adamant. ‘Reasons don’t come into it. The living brain reorganising memories is enough to give rise to ordinary dreams. And just poking an electrode into the temporal lobes is enough to generate mental activity. I know: what the brain does is so complex that it’s bizarre to think of achieving the same results unintentionally. But all of the brain’s complexity is coded into its structure. Once you’re dealing with that structure, you’re dealing with the stuff of consciousness. Like it or not.’

  That does make a certain amount of sense. Almost anything that happens to the brain feels like something; it doesn’t have to be the orderly process of waking thought. If the random effects of drugs or illness can give rise to distinctive mental events – a fever dream, a schizophrenic episode, an LSD trip – why shouldn’t a Copy’s elaborate genesis do the same? Each incomplete NMR map, each unfinished version of the simulation software, has no way of ‘knowing’ that it’s not yet meant to be self-aware.

  Still—

  ‘How can you be sure of any of this? If nobody remembers the dreams?’

  ‘The mathematics of consciousness is still in its infancy, but everything we know strongly suggests that the act of constructing a Copy has subjective content, even though no trace of the experience remains.’

  I’m still not entirely convinced, but I suppose I’ll have to take her word for it. The Gleisner Corporation has no reason to invent nonexistent side-effects, and I’m suitably impressed that they bother to warn their customers about transition dreams at all. So far as I know, the older companies – the scanning clinics founded in the days when Copies had no physical bodies – never even raised the issue.

  We should move on, there are other matters to discuss, but it’s hard to drag my thoughts away from this unsettling revelation. I say, ‘If you know enough to be certain that there’ll always be transition dreams, can’t you stretch the mathematics a little further, and tell me what my dreams will be?’

  Bausch asks innocently, ‘How could we do that?’

  ‘I don’t know. Examine my brain, then run some kind of simulation of the Copying process—’ I catch myself. ‘Ah. But how do you ‘‘simulate’’ a computation without doing it?’

  ‘Exactly. The distinction is meaningless. Any program which could reliably predict the content of the dreams would, itself, experience them, as fully as the ‘‘you’’ of the transition process. So what would be the point? If the dreams turned out to be unpleasant, it would be too late to ‘‘spare yourself’’ the trauma.’

  Trauma? I’m beginning to wish I’d been satisfied with a reassuring smile and the promise of perfect amnesia. A few forgettable dreams.

  Now that I – vaguely – understand the reasons for the effect, though, it’s a thousand times harder to accept it as inevitable. Neural spasms at the onset of hypothermia might be unavoidable, but anything taking place inside a computer is supposed to be subject to limitless control.

  ‘Couldn’t you monitor the dreams as they’re happening – and intervene, if need be?’

  ‘I’m afraid not.’

  ‘But—’

  ‘Think about it. It would be like prediction, only worse. Monitoring the dreams would mean duplicating the brain-like data structures in still more forms, generating more dreams in the process. So even if we could take charge of the original dreams – deciphering them, and controlling them – all of the software which did that would need other software watching it, to see what the side-effects of its computations were. And so on. There’d be no end to it.

  ‘As it is, the Copy is constructed by the shortest possible process, the most direct route. The last thing you’d want to do is bring in more computing power, more elaborate algorithms … more and more systems mirroring the arithmetic of the experience.’

  I shift in my chair, trying to shake off a growing sense of light-headedness. The more I ask, the more surreal the whole subject becomes, but I can’t seem to keep my mouth shut.

  ‘If you can’t say what the dreams will be about, and you can’t control them, can’t you at least tell me how long they’ll last? Subjectively?’

  ‘Not without running a program which also dreams the dreams.’ Bausch is apologetic, but I have a feeling that she finds something elegant, even proper, in this state of affairs. ‘That’s the nature of the mathematics: there are no short-cuts. No answers to hypothetical questions. We can’t say for certain what any given conscious system will experience … without creating that conscious system in the process of answering the question.’

  I laugh weakly. Images of the brain which dream. Predictions of dreams which dream. Dreams which infect any machine which tries to shape them. I’d thought that all the giddy metaphysics of virtual existence had been banished, now that it was possible to choose to be a Copy living wholly in the physical world. I’d hoped to be able to step from my body into a Gleisner robot without missing a beat …

  And in retrospect, of course, I will have done just that. Once I’ve crossed the gulf between human and machine, it will vanish seamlessly behind me.

  I say, ‘So the dreams are unknowable? And unavoidable? That’s close to a mathematical certainty?’

  ‘Yes.’

  ‘But it’s equally certain that I won’t remember them?’

  ‘Yes.’

  ‘You don’t recall anything about your own? Not a single mood? Not a single image?’

  Bausch smiles tolerantly. ‘Of course not. I woke from a simulated coma. The last thing I remember was being anaesthetised before the scan. There are no buried traces, no hidden memories. No invisible scars. There can’t be. In a very real sense, I never had the transition dreams at all.’

  I finally sight a target for my frustration. ‘Then, why warn me? Why tell me about
an experience I’m guaranteed to forget? Guaranteed to end up not having been through? Don’t you think it would have been kinder to say nothing?’

  Bausch hesitates. For the first time, I appear to have discomfited her – and it’s a very convincing act. But she must have been asked the same question a thousand times before.

  She says, ‘When you’re dreaming the transition dreams, knowing what you’re going through, and why, might make all the difference. Knowing that it’s not real. Knowing that it won’t last.’

  ‘Perhaps.’ It’s not that simple, though, and she knows it. ‘When my new mind is being pieced together, do you have any idea when this knowledge will be part of it? Can you promise me that I’ll remember these comforting facts when I need them? Can you guarantee that anything you’ve told me will even make sense?’

  ‘No. But—’

  ‘Then what’s the point?’

  She says, ‘Do you think that if we’d kept silent, you would have had any chance at all of dreaming the truth?’

  * * *

  Out on the street, in the winter sunshine, I try to put my doubts behind me. George Street is still littered with coloured paper from last night’s celebrations: after six years of bloodshed – bombings and sieges, plagues and famines – the Chinese civil war finally seems to be over. I feel a surge of elation, just looking down at the tattered remnants of the streamers and reminding myself of the glorious news.

  I hug myself and head for Town Hall station. Sydney is going through its coldest June in years, with clear skies bringing sub-zero nights, and frosts lasting long into the mornings. I try to picture myself as a Gleisner robot, striding along the very same route, but choosing not to feel the bite of the wind. It’s a cheerful prospect – and I’ll be untroubled by anything so tedious as the swelling around my artificial knee and hip joints, once I’m wholly and harmoniously artificial. Unafraid of influenza, pneumonia, or the latest wave of drug-resistant diphtheria sweeping the globe.

  I can hardly believe that I’ve finally signed the contracts and set the machinery in motion, after so many years of making excuses and putting it off. Shaken out of my complacency by a string of near misses: bronchitis, a kidney infection, a melanoma on the sole of my right foot. The cytokine injections don’t get my immune system humming the way they did twenty years ago. One hundred and seven, this August. The number sounds surreal. But then, so did twenty-seven, so did forty-three, so did sixty-one.

  On the train, I examine my qualms one more time, hoping to lay them to rest. Transition dreams are impossible to avoid, or predict, or control … just like ordinary dreams. They’ll have a radically different origin, but there’s no reason to believe that a different means of invoking the contents of my scrambled brain will give rise to an experience any more disturbing than anything I’ve already been through. What horrors do I think are locked up in my skull, waiting to run amok in the data stream from comatose human to comatose machine? I’ve suffered occasional nightmares – and a few have been deeply distressing, at the time – but even as a child, I never feared sleep. So why should I fear the transition?

  Alice is in the garden, picking string beans, as I come over the hill from Meadowbank station. She straightens up and waves to me. I can never quite believe the size of our vegetable patch, so close to the city. We kiss, and walk inside together.

  ‘Did you book the scan?’

  ‘Yes. Tenth of July.’ It should sound matter-of-fact, like that; of all the operations I’ve had in the last ten years, this will be the safest. I start making coffee; I need something to warm me. The kitchen is luminous with sunlight, but it’s colder indoors than out.

  ‘And they answered all your questions? You’re happy now?’

  ‘I suppose so.’ There’s no point keeping it to myself, though; I tell her about the transition dreams.

  She says, ‘I love the first few seconds after waking from a dream. When the whole thing’s still fresh in your mind but you can finally put it in context. When you know exactly what you’ve been through.’

  ‘You mean the relief of discovering that none of it was real? You didn’t actually slaughter a hundred people in a shopping arcade? Stark naked? The police aren’t closing in on you after all? It works the other way too, though. Beautiful delusions turning to dust.’

  She snorts. ‘Anything which turns to dust that easily is no great loss.’

  I pour coffee for both of us. Alice muses, ‘Transition dreams must have strange endings, though, if you know nothing about them before they start and nothing again by the time they finish.’ She stirs her coffee, and I watch the liquid sloshing from rim to rim. ‘How would time pass, in a dream like that? It can’t run straight through, can it? The closer the computers came to reconstructing every detail of the comatose brain, the less room there’d be for spurious information. At the very beginning, though, there wouldn’t be any information at all. Somewhere in the middle, there’d be the most leeway for ‘‘memories’’ of the dream. So maybe time would flow in from the start and the finish, and the dream would seem to end in the middle. What do you think?’

  I shake my head. ‘I can’t even imagine what that would be like.’

  ‘Maybe there are two separate dreams. One running forwards, one running backwards.’ She frowns. ‘But if they met in the middle, they’d both have to end the same way. How could two different dreams have exactly the same ending, right down to the same memories of everything which happened before? And then, there’s the scanner building up its map of the brain … and the second stage, transforming that map into the Copy. Two cycles. Two dreams? Or four? Or do you think they’d all be woven together?’

  I say irritably, ‘I really don’t care. I’m going to wake up inside a Gleisner robot, and it will all be academic. I won’t have dreamed any dreams at all.’

  Alice looks dubious. ‘You’re talking about thoughts and feelings. As real as anything the Copy will feel. How can that be academic?’

  ‘I’m talking about a lot of arithmetic. And when you add up everything it does to me, it will all cancel out in the end. Comatose human to comatose machine.’

  ‘Ashes to ashes, dust to dust.’

  Words just come out of her mouth sometimes: fragments of nursery rhymes, lines from old songs – she has no say in it. The hairs stand up on my arms, though. I look down at my withered fingers, my scrawny wrists. This isn’t me. Ageing feels like a mistake, a detour, a misadventure. When I was twenty years old I was immortal, wasn’t I? It’s not too late to find my way back.

  Alice murmurs, ‘I’m sorry.’

  I look up at her. ‘Let’s not make a big deal of this. It’s time for me to become a machine. And all I have to do is close my eyes and step across the gap. Then in a few years, it will be your turn. We can do this. There’s nothing to stop us. It’s the easiest thing in the world.’

  I reach across the table and take her hand. When I touch her, I realise I’m shivering with cold.

  She says, ‘There, there.’

  * * *

  I can’t sleep. Two dreams? Four dreams? Meeting in the middle? Merging into one? How will I know when they’re finally over? The Gleisner robot will emerge from its coma, and blithely carry on; but without a chance to look back on the transition dreams, and recognise them for what they were, how will I ever put them in their place?

  I stare up at the ceiling. This is insane. I must have had a thousand dreams which I’ve failed to remember on waking – gone now, for ever, as surely as if my amnesia was computer-controlled and guaranteed. Does it matter if I was terrified of some ludicrous dream-apparition, or believed I’d committed some unspeakable crime, and now I’ll never have the chance to laugh off those delusions?

  I climb out of bed and, once I’m up, I have no choice but to dress fully to keep from freezing. Since moonlight fills the room, I have no trouble seeing what I’m doing. Alice turns over in her sleep, and sighs. Watching her, a wave of tenderness sweeps through me. At least I’m going first. At least I�
��ll be able to reassure her that there’s nothing to fear.

  In the kitchen, I find I’m not hungry or thirsty at all. I pace to keep warm.

  What am I afraid of? It’s not as if the dreams were a barrier to be surmounted – a test I might fail, an ordeal I might not survive. The whole transition process will be predetermined, and it will carry me safely into my new incarnation. Even if I dream some laborious metaphor for my ‘arduous’ journey from human to machine – trekking barefoot across an endless plain of burning coals, struggling through a blizzard towards the summit of an unclimbable mountain … and even if I fail to complete that journey – the computers will grind on, the Gleisner robot will wake, regardless.

  I need to get out of the house. I leave quietly, heading for the twenty-four-hour supermarket opposite the railway station.

  The stars are mercilessly sharp; the air is still. If I’m colder than I was by day, I’m too numb to tell the difference. There’s no traffic at all, no lights in any of the houses. It must be almost three; I haven’t been out this late in … decades. The grey tones of suburban lawns by moonlight look perfectly familiar, though. When I was seventeen, I seemed to spend half my life talking with friends into the early morning, then trudging home through empty streets exactly like these.

  The supermarket’s windows glow blue-white around the warmer tones of the advertising signs embedded within them. I enter the building, and explore the deserted aisles. Nothing tempts me, but I feel an absurd pang of guilt about leaving empty-handed, so I grab a carton of milk.