The Grandmother Hypothesis

When my daughter was born, her eyes were blue. Sometimes I wonder whether they would have stayed blue, or turned brown, like her mother’s.


If I were to write a guide to many-worlds travel (which is about the last thing I’d ever do), it would start, and end, with: “Don’t.” But if you would go anyway, then I would say that the one thing that you should not do when crossing between different universes, is to do so because of an emotional decision. Cross only on the basis of careful, rational thought (and, naturally, very, very careful calculation). I have made that mistake only twice before. It is, of course, only too late that I realise I am about to make it for the third time.


It would be a falsehood to say that I had a sense of foreboding when I arrived in this universe, that something about it felt off. I did not, and it did not. It is one of those indecisive April days; blue sky one minute, until you feel warm enough to take your jacket off, then clouds scudding in and dropping furious rain the next, chilling you through. I catch the edges of one such shower on the way down to the little cottage in the village. When I knock on the door, it is so long before someone answers that I start to turn away, deciding to come back later. It opens a crack, then a couple of inches, and finally swings wide. I expect to see myself. Instead, I see my daughter.

“You said you’d be here two days ago!” she exclaims immediately, in that angry tone people use when they have been intensely worried. I am about to explain, but now there is a clear – secondary – recognition in her vivid blue eyes: that I am not her mother.

“You shouldn’t have come here,” she says, then, in apparent contradiction.

“You’d better explain,” I reply, amazed at the steadiness in my own voice. Perhaps I am getting used to it after all: universes in which my daughter lives. And what, in any case, can be worse than all those in which she did not?


The first time I ever crossed between universes, it was in reaction to that impossible grief; to the irrational anger that comes when there is no one to blame; to that endless despair. A desperate attempt to escape the ceaseless clamouring in my head that chanted what if what if what if. This, of course, was the first mistake, and the most obvious one.

That first time I arrived in the chapel ruins, it was a warm and windless day, and my clothing took a few moments to adjust from the chill rain of before. It had evidently been dry for some days; my feet kicked up dust. Funny how the weather is never quite the same from one universe to the next. It is probably something to do with the strange laws of probability and causality that even I do not fully understand. The afternoon light glinted off pieces of coloured glass down amongst the base of the flinty walls, likely from old broken bottles: the stained glass would have long since gone. The ruins themselves I have since found to be fairly stable from one universe to the next: the long-ago ravages of Henry VIII that destroyed the chapel and the adjacent convent are a Prime Decision Node that occurred long, long ago. Generally, nobody has built on them, and there is the elevation. It is as safe a place to cross as any; not that I was thinking of that, after that first tumultuous activation of the machine.

It was very still. It sometimes is, out here, on the hilltop, when the wind drops. I remember I hesitated, but it was already too late to second-guess myself. So I shouldered my pack and headed for the village where I knew that I would find myself, or rather, another version of myself.

She knew as soon as she saw me – which did not stop her from leaping back in fright, a cry stifled before it was quite born, her hand going to her breast in a gesture I found irritatingly melodramatic. I wondered, inevitably, if I do that without realising it.

“You built it,” she said, straightaway, “You used it.”

“Yes,” I said, simply, whilst a host of frightful possibilities settled back into the dust in my mind. I have done it, and done it well; it is still a close universe, close enough for her to guess; to know, immediately, where our paths have diverged. I found myself stilling on a held breath, wondering if the rest was as close. Her eyes darted, searching my face as if to read an answer there. Perhaps she did.

“The child,” she said, after a moment more, as the possibilities settled in her mind. It comes out in a gushed breath, like a dam breaking. “Oh gods, the child.”

“Yes,” I said again, the bitter triumph of my success swamped by the sudden self-pity in her eyes.


That was the first universe, but it was too close; so similar to my own that when I came to the cottage, I ended up staring at my own grief-ravaged face, only in the flesh, not the mirror. Several more followed, a nightmarish string of personal catastrophes; mine, but not mine, until, nearly a year later, I finally found one where things had turned out differently, or, rather, enough differently.


It was another sunny day that next significant time I appeared at the chapel, but there were small white clouds in the sky and a light breeze made it cooler. There was a pleasant burble of summer birdsong, a more distant rumble of traffic, carried on the air. A startled hiker looked up from where he had spread his map across an uneven remnant of the convent wall, evidently wondering why he didn’t see me before.

“Good afternoon,” I said, cheerfully. I used to arrive after dark, but after a few times in which I surprised drunks or amorous teenagers, I decided against it. It’s so much harder to explain in the middle of the night, somehow. I never disturbed anybody but the occasional walker, and, usually, I just looked like one of them.

“Hello,” he replied, with an uncertain smile, then looked back down at his map. Which way should he go? Southeast down to the village, Little Marwash, alongside the river, and perhaps an early pub lunch? Or should he wander east, skirting along the base of the hills and into the woods, out the other side, to Great Marwash, where there is more choice, but it’s not so pretty? I didn’t wait to find out, but strode on ahead, and found that in this universe, which looked like all the other universes, my daughter had lived, but only just.

I remember looking at this damaged daughter; a curled-shell implant at the base of her skull sending electrical impulses to the limbs that did not quite move properly.

“She’s getting better,” that other me had said, defensively, “And they’re going to try another stem cell treatment when she’s older. Anyway, there’s nothing wrong with her mind, that they can tell.”

“Of course,” I said, vaguely, watching those wobbling toddler steps, rendered from cute to grotesque in exaggeration. I remember feeling ashamed of that thought, ashamed that I was disappointed; thinking that if it had been me in her place, I would only be glad that she was alive. That disabled did not mean less. Then I thought that actually I would just be resentful that it had happened at all, and she had suffered this injury; that in yet another universe, she was completely fine. Perhaps seeing me made that other self realise that it could have been worse. That she could have died. That, in many universes, she did die. Sometimes shortly after birth, like mine, sometimes a few agonising days later, when the alternating wave functions of wild hope and panicked despair suddenly collapsed into the absolute finality of flat-out denial in the face of the worst. And left nothing but the insupportable grief. The endless questions. Why her? Why me? Why why why? We looked at each other, that other mother and I, and found nothing to say to each other to make any of it any better.

I saw the same hiker that was on the hilltop pass by the window of the cottage, much later. Evidently, he had decided on the ambitious long loop, with the weather fine.

“What do you need?” this me asked, before I left. Sometimes I am not always this understanding.

“Clean clothes,” I said at once, “Some food supplies, in case. A toothbrush. Money.”

“Don’t tell me the currency isn’t the same.”

“It’s best to keep everything as similar as possible,” I explained, patiently. “Small changes…accumulate.” It’s true, but in an oddly selective sense: I once went through twelve universes on the same bank PIN (nobody changes their PIN enough). I know what the next question is.

“How long have you been doing this?” I didn’t answer. It wasn’t worth the response. We’re close enough that she could calculate it herself. It took her a few moments, a few wrong guesses, but she worked out what happened. She must already have been picturing possibilities in her head. In my world, it was near instantaneous, for a definition of ‘near’ that meant fifty minutes of agonising helplessness. And I passed through hundreds that were the same before I found one where things began to change…not quite instantaneous…brain damage…sepsis…organ failure.

Why are you doing this?” came next, when it became clear that I was not going to answer the last question. “You can’t travel backwards in time. You can’t change anything.”

“Nobody can change anything,” I said, because I didn’t want to answer that stupid question either. In more patient moods I’ve said: ‘But I can see what would have happened if things were different,’ which isn’t quite the whole truth either. At the start, it wasn’t even half a truth.


Probably many people would think that I cross from one universe to the next to change things, but this is a mistake. If you acknowledge that I was intelligent enough to build the machine that can do this in the first place, then you must acknowledge that I am not stupid enough to make that mistake. There are many mistakes, of course. And there are also accidents, and sheer bad luck.

After that, after so many universes nearly the same, and that one so different, so close, I grew bold, and so I cast the machine’s net farther afield. It still took a long time to find the universe that I was looking for. When I arrived, it turned out that it was flying ant day. They swarmed out of the chalky soil near the old walls, searching for their queen. They crawled onto my pack and stuck to my clothes as I escaped down the hill, and I brushed them off, trying not to squash them.

This me was no more nor less startled than the rest.

“You built it,” she said, “You used it.” Then, unexpectedly, “But why? Curiosity get the better of you?” And she actually laughed. It felt like a slap in the face. Like I’d slapped myself in the face.

“The child…” I began, stuttering, searching her eyes, “My daughter, the birth…” Her eyes looked like all the others – and not like mine. They darkened beneath a frown.

“What about her?” So, I had found it at last. A universe where she not only lived, but nothing went wrong at all. For the first time, I had to explain it, and it was so very difficult, to tell it to this other me, that this could have happened to her. That it did, in so many other universes. She asked the question too, the one they all get around to in the end.

“Time’s arrow only goes forward. You can’t change anything. Why are you here?”

“I just want to talk to her. Just for a few moments.”

“You’ve been doing this for – how long? That doesn’t – that can’t add up to a life.”

“No,” I said calmly, for I have been doing this for years, already, “It doesn’t. It just adds up to moments.” But that’s all that life is, I thought, silently. Moments.

“Your hair is all wrong. She’ll know.”

“Did you tell her about the machine?”

“Of course I didn’t. She’s seven. She wouldn’t understand, and she’d tell all her friends too.” My other self looked unhappy, like she wished me gone. I waited.

“She’s upstairs,” she said eventually, “Supposedly doing her homework. She’s sulking because I turned off the television, so I hope you’re not expecting anything grand.”

“Five minutes,” I said, “That’s all. I’ll shout through the door if you like.”

“Make sure you sound suitably pissed off then.”


Once, after I had been following that branching trail of successful universes for some months, I tried to count how many times I had heard another version of myself say almost the exact same words upon meeting; as the light dawned, as that quicksilver intellect added one and two and four and did not add wrong. Perhaps it is true, after all, and we have no free will. There are different universes for different outcomes of events. But after all these years of travel, I still don’t know, yet, if there are different universes for different decisions. Those are not quite the same thing, and the machine does not quite work like that.

That was fifteen years ago, back when I used to still make contact. As she grew up, we grew apart, just not in the usual way. The difference between what happened to me and what happened to them widened, until it was a gulf that could not be crossed. They were just baffled strangers in an unfamiliar house.

“Why didn’t you have another child?” one said to me, once, that unforgivable question.

“It wouldn’t have been the same one,” I stated as coldly as possible.

“That’s not what I – I’m sorry. It’s just, surely, if you wanted a child, then why not have another one, rather than never try again? You would have had to move on, eventually.” I did move on, I thought to myself: I moved universes. Away from the one in which she died, such a rare, improbable event that it almost never happened to anyone anymore. Except that in thousands of universes, it had. The one in which people did not know what to say to me, or where they said stupid things and asked stupid questions. The one where because the child had died at the moment of its birth, it somehow wasn’t real to everyone else, didn’t scale as a tragedy on the same level as if I had lost her later in her life. As if such things could be quantified. The one in which her father had said,

‘You have to let it go. We have to move on. We have to live.’ And perhaps he had been right. Apart from the letting go. Because you do not let things like that go.

“I know it must feel like the world ends when a child dies…” she began again, awkwardly, trying to comfort, which was even worse.

“No,” I cut her off, coldly, “Many worlds end when a child dies. An infinity of them.” The terrible truth is, though, that many universes are born when a child dies too.


People think that – that is, if they think of it at all – if you cross from one universe to another, then it is a linear, stepwise progression, each universe a tiny bit different from the previous one, and the next slightly more different than that. This is a misconception. Events branch, spreading out in infinitely thinning twigs of probability. The moment you choose one branch, you cut yourself off from all of the others, and are destined to follow that original branch and its descendants. Actually, that is not entirely true, because the machine does not work on quite that principle. You can jump farther afield. Leap branches. But only by taking a quite literal shot in the dark, or by accident. The mathematics cannot calculate such distant, uncertain probabilities, but the branching nodes at points before large clusters can be detected from outside one’s own local cluster. Nevertheless, it took me years to manage this even semi-accurately: the uncertainty is inbuilt.


The second time I crossed universes on an emotional decision, it sent me wrong. Badly wrong. I arrived very late one October night, having been delayed by some silly wedding party taking photos in the ruins of the chapel in the last universe. It was not one of those romantic nights you would imagine such a moment to be as it had been for the wedding party, starlit and crisp with autumn freshness, but damp and chill, a sullen gibbous moon half-heartedly shining through the overcast. The wind had gone straight through me and out the other side by the time I found the right house; that ancient cottage in the valley I had fallen in love with and bought on my promoted professor’s salary. It was nearly 3am, and there was only pale blue nightlight glow shining through the bedroom window, though the curtains were open. I heard noise; just a tiny cry, but it almost pulled the sinews off my bones. I crept closer, and peered in. She was there, sitting in a chair, nightgown and hair in disarray; not me, but the daughter, and her baby in turn, nursing at her breast – and I, outside, a little sneak-thief of emotion. Something turned over inside me, and I smiled, but then tears came as well, for the first time in years. Then she looked up and saw me, and the exhausted lines of her face were suddenly tear-streaked in turn. She rose to her feet.

“Mum?” I could make no reply. A sudden almost-laugh from her and she clutched the child closer even as she addressed me. “I heard you could get grief hallucinations. I always thought I was too rational for it to happen to me.”

“You’re sleep-deprived,” I said in a quivering voice, wanting to run but unable to move. She stepped closer to the window and lifted the protesting infant up; his quick tiny breaths made a little circle of fog on the glass.

“Maybe it’s just a dream. I’m glad anyway. Look. Look at your beautiful grandson.” She unlatched the window; the catch was stiff, like mine. Against my own will, I did the thing you always do; held out a finger, and watched the baby as he curled a chubby, tiny fist around it. His hands had dimples where adults have knuckles; he was so soft; soft and warm and I was so cold; it was like being held by a tiny sun.

“I wish…” she began.

“I know,” I said.

“I miss you now more than ever. You’ll never see him grow.” I disentangled my hand gently. I felt brittle with grief, like the washed-up skeleton of a sea thing, all the fleshy love gone. He rooted against her again.

“He’ll catch cold,” I said, and pushed the window to. I flung myself back up the path, in the dark, stumbling over frost-slicked stones, breath coming in cold, painful pants as I ran, dangerously, back up the way I came, to the ruins. I calculated the next leap in the pitch black, scratching out the maths in the unyielding dirt of the former nave floor, by torchlight. In haste and choked with a flood of emotion, all the things that I was beginning to think that I was coming to terms with. So of course I made a mistake.

I arrived still in starlight, and an even deeper chill, an even darker dark. The chapel was gone. Great standing stones loomed all around me, blotting out the stars – I am standing in the middle of their circle – and my heart slammed in my chest. The chapel was not gone. The chapel has never been here. I made an error, a misstep somewhere, and the machine slipped, losing the universe it locked on to – so instead it was drawn towards one far away, anchored by the pull of a Prime Decision Node.

It seems strange now to describe how terrifying it was; how soul-crushing, even. I knew that I had strayed so far from my home cluster of universes that I was in one in which she had never existed, in which I had never existed, nor anybody else I knew, or most of humanity in my universe, for that matter. The course this world had taken was so far removed it was another history, another humanity, altogether. I suspected, at least, that Christianity had never taken hold on this island; perhaps, had never existed. A bitter irony then: maybe, in trying to find the universes in which my daughter had never died, I had instead found one in which Jesus had never died. I spent all night fiddling with the machine, scrawling out maths, trying to find the error – a dropped decimal, of all the humiliating things, the sort of thing I used to castigate my students for not checking properly – and then trying to find a way back, which could not be quick. I worked until the dawn, until I was frozen through, knowing that that was the one thing you could never do: go back. The machine does not – cannot – work like that. I was stuck, forever cut off from my local branch of universes. My only chance of ending up anywhere remotely similar was to find the Prime Decision Node of my local universe cluster, which I had never done before, and work backwards from there, hoping to get back onto my universe’s main branch.


In the end, it took another nine years: I got lucky, but I also got much better at using the machine. After all that time, part of me was wondering whether I should even keep trying to get back. I was finally using the machine for the purpose I had originally intended it for: exploration. Living in those universes was hard at first; nobody there spoke a language I had ever even heard of, but some strange hybrid of Welsh and something else. They had an even stranger religion, evolved from the pagan rites of the ancient Britons; very big on the forces of nature, of witches, and fearful of an uncaring universe. That bit I could certainly understand, anyway. All the rules, the little rules of life, were subtly different. Everything about me declared that I was not from there. I was virtually a vagabond, for a time. All the useful things I had in my backpack, even the tent, and the backpack itself, a huge, expensive mountaineer’s affair, I had to barter away. Hard living. But it was exploration; somewhere so new, so different, yet with some things so similar, that for a while it was almost a true escape. And people were kind, for the most part. They bought me meals, they even put me up for the night. They surprised me, these kindnesses. I felt all out of kindness, myself. Perhaps these Samaritans saw the wounded creature I was – am. Wounded more than I knew, at first; their primitive medicine had to remove the cancerous breasts they could not treat. When I left, in the end, I was travelling light, as I do now; with my faded army green backpack, not big enough to hold much of anything but the machine, and old, worn boots. Possibly the most well-travelled boots in the many worlds.

Seeing that child, that boy, was the last time I ever interacted, and it cost me nine lost years of my daughter’s life, and severed me from my universe-thread completely. Now I just observe. And I told myself that I would not make the same mistake a third time.


When I finally managed to cross back into a local node, I appeared in shadow; no, not even shadow, but gloom,which had never happened either. My heart once more thudded in my chest in sudden apprehension. Perhaps I had not succeeded after all – but wait. It was the chapel, but it was not ruined. It was…preserved? Rebuilt, perhaps. There were yellow sandstone bricks in place of the flint. Had I missed my local web of universes and stumbled into another related cluster? This seemed most likely, more so than that I had inadvertently crossed at another Prime Decision Node. I was standing by the font, in chill church air; the setting sun shone through the window of the Virgin Mary, holding her babe. You have to hand it to the Christians for making a perfect woman, both maiden and mother, and leaving out the crone altogether. Mary escapes time’s arrow…and is damned by it, because to her, her son is always dead. There were candles on the altar. They were lit. I heard footsteps and spun around.

“Hello there?” a voice called. My voice. “I didn’t see you come in.” I faced the other mother. We both stood and stared at each other, mouths open, like a foolish soap opera, long-lost twins found again.

“I cannot conceive that there is any universe in which I became a priest,” I said in clipped, scornful tones. But my other self just laughed; her whole face lifted when she did this, star-bursting wrinkles out from the corners of her eyes.

“I couldn’t have had a twin, surely,” is what she said. I did not even know where to begin. So I turned to go.

“Wait,” with her hand on my arm. She was stronger than me, her fingers thicker.

“I will not explain and you will not believe,” I said, shortly, adding, “And I don’t talk to myself anymore.”

“You’re one of those jumpers from an alternate universe, aren’t you?” It was my turn to be astonished.

“There’s more?”

There was here, apparently.


“There aren’t many, yet,” she explained, after she had somehow persuaded me to come back to her house, brought out steaming cocoa and buttered scones. Very vicar-y, I thought, but I didn’t refuse. “The authorities are getting in a bit of a panic about it. Worrying about people changing history, terrorists, that sort of thing.” I snorted at that. “So why did you come?”

“I invented the machine,” I said, “in my universe, at least.”

“I’m guessing you weren’t naïve enough to make it freely available.”

“Certainly not. And anyway, there’s some quite fiendish calculations you have to do each time. Obviously computers can crunch the numbers, but it’s interpreting them that’s the hard bit…I still shouldn’t have ended up here. There must have been some mistake.”

“You didn’t answer my question.” I took a bite of scone, thoughtfully. It’s true, I hadn’t. So I explained; briefly, tersely, a mere recitation of ingredients on the back of a cereal box that I’ve stared at over the table too long.

“My child died too,” she said, suddenly, unexpectedly, with an unabashed glint of tears in her eyes. And, quite unprompted, she told me. Of the daughter that was not the daughter that I had, of her brown eyes and curling hair; her laughter and love of animals; of the drunk driver that took it all away.

“Don’t you have driverless cars?” I interrupted, puzzled, and only realised how tactless I sounded too late, in a way I would have hated if it were directed at me. “Sorry.” But she did not seem offended.

“For the most part. But the rich like to drive their own. It’s a luxury.”

“It’s stupidity.” A wry smile.

“It is remarkably difficult to engineer out stupidity,” she said, which is exactly the same sort of thing that I would say. How was this other me a priest? Did faith heal grief? I don’t believe that. I’ve never believed that.

“Why do you do it?” The inevitable question, the one they all ask, “You must know, you cannot change what has already happened.”

“Who knows?” I said, flippantly, “Perhaps I just haven’t invented the machine that will do that yet.” But she was, in the end, too old to fall for that, or I was too old to lie anymore, and it turned out that time, unlike universes, was running out. She waited, whilst I ordered my thoughts.

After what happened, I kept wondering how things could have been different – well, of course I did. We all would. We all do. In the end, the what ifs consumed my every waking thought. So I set out to answer them. To see if what if I had done this, or not done that, or this had happened, or that had not happened.

“To see if anything I could have done, or not done, would have made a difference,” I said at last, trying to condense this confusion into something tangible.

“But what could you have done? If the doctors didn’t find anything wrong before she was born, how could you have known?”

“Rational thought doesn’t help in such moments.”

“Well, did it? Make a difference, I mean. You must have been looking long enough now that you know.”

I knew before, I thought. But knowing and feeling something don’t necessarily agree. “There was nothing I could have done. Not without precognition, anyway.”

“Did you build a machine for that yet?”

I had to laugh. “No, there’s no machine for that.”

“Then why don’t you go back?”

I stared at her, surprised, wondering if she simply hasn’t thought about it, “There’s no way back. The decision nodes, whatever it is that creates the universes, they happen all the time. You can’t retrace your steps. They disappear as fast as they are made.”

She looked briefly appalled, but hid it quickly. “So what do you travel for now?”

“The what ifs.” Strictly speaking, for the might-have-beens. The lives my daughter might have led had she not been cheated of them. That I might have shared in, and can now only observe ephemeral glimpses of. She only ever lived as a possibility. And I wanted so much more for her than that. I didn’t say any of this, but I suspect she understood.

“I wonder about that too. The might-have-beens. All the time, some days.” A long pause. “You can’t live like this forever,” she said, at last.

“No,” I agreed. But it’s got to the point where I don’t know what else to do. What else I can do. I’m fated to drift farther and farther from my own reality, seeing lives that are not mine. Assuming I can ever even get back to my own local node, that is.

“Why did you build it in the first place?” she asked, eventually. I had to think for a moment, it’s been so long. The woman who built that machine seems almost from another universe herself.

“To explore. To go far out of our local decision nodes. To see alternative histories unfold. Perhaps to learn something in the process. Something that might prove useful, or a forewarning. But I realised soon after I embarked on the project that, because of the nature of the many worlds, you would never be able to retrace your steps. So it became hypothetical. Until the day it wasn’t.”

“Did you ever meet anybody else? Another you, I mean, who decided to cross, for the same reasons you did?” It’s a horrifying thought, and I wonder why it never occurred to me.

“No,” I said, truthfully, “But there are so many millions of alternative universes that anyone who crossed would almost certainly disperse into different ones. The chances of us meeting would be utterly remote.”

“Does crossing itself create another universe?”

I hesitated. “I don’t know if decisions create universes. I think only events do, but then crossing is an event.”

“Decisions are events, aren’t they?”

“Are they, if they affect nothing?”

“They affect you. They change you.

I hesitated, pondering, briefly, those familiar imponderables. The sort of things I used to philosophise about with my partner.

“I don’t have the data to answer that question,” I said, in the end, but I was thinking of something else she told me. “You said there were others who crossed.”

“Yes. You should be careful. The authorities are really cracking down on it. Our government – well, there was one traveller, they shot someone – a high court judge. Killed them. There was a big scare about it. Everybody started talking about terrorists. We’ve had steadily more authoritarian governments for the past ten years anyway. That was the catalyst for what I will choose to call some fairly unpleasant people to win an election on the back of that fear. These aren’t good times.”

“Were they?” I asked. “A terrorist?”

“I don’t know. The government said so, but I don’t know on what evidence. It was probably something personal, if you ask me. Some vendetta they couldn’t solve in their own universe.”

I smiled a tight, bitter smile. The desperate and the deluded, I thought: that’s who is crossing, in these universes where they got hold of copies of the machine somehow. I could have told them that. They won’t find many terrorists, or explorers. They’ll find those who think they can win the lottery because they still don’t get that the machine doesn’t predict the future, and nor does it take you back in time. And so, so many of the desperate; who have lost loved ones, and realise they cannot regain them; who are losing them, and realise they cannot rescue them, cannot find the cure. Lovers looking for the other version of the somebody who didn’t reject them. Or whatever it is. Lives ruined one way or another, and this the only way out. The one factor they think they can change. Or that can be changed. Those who are not in their right minds, and never will be, because to their minds they are not in the right reality – and the only way left to change their reality, is to change all of it. The whole universe.

“I have to go,” I said, which I always say.


So now here I am. Every daughter who lived in every universe has had brown eyes. I am puzzling over why this one has blue eyes as she hustles me into the house, still scolding.

“I hope no one saw you. It’s curfew in less than an hour. And your face is very recognisable.” I stop dead as I enter the living room. It is covered in toys and bright books, the presumed owner sitting in the middle of them; he beams at me with a wide, gummy smile as I come in. He must think I’m his grandmother. I perch awkwardly on the edge of a chair. He starts trying to crawl over, burbling. I ignore him, even as I am trying to puzzle it out: he cannot be another version of the other child in the universe where I died and my daughter lived; he is too young. Is he a child of the same father, or another? And what of his blue-eyed mother?

“Curfew?” I query, suddenly honing in on another incongruity, “In a tiny village in the middle of nowhere? What the hell kind of universe is this?”

“Not a good one, and people like you don’t help.”

“What did I do?”

“You invented that wretched machine!” I don’t reply. The child is pulling at my trousers. “Well, didn’t you?”

“Yes. I assume your mother invented the one here then.” And isn’t dead. She scoops up the boy and sits down with him on her lap, absently carding her fingers through his brown curls, agitated.

“Tell me about it,” I say. So of course she does, all of it. About the other mother who invented the other machine, and the totalitarian government she was forced to hand the blueprints over to, and the other governments who demanded it, not understanding what it was. Of people jumping in from other universes, even worse than this one, leaving chaos in their wake. Of the protests that didn’t happen anymore, the crackdowns, the disappearances. Of the boy’s father, who had been involved in some clandestine underground resistance she only hints at, mysteriously found drowned in the river; drunk, they had said.

“I should leave,” I say, standing up, “I don’t want to bring down trouble on you.”

“Well then you won’t walk out of here now it’s past curfew then, will you? You’ll have to stay the night.”

I pause, thinking. “You were expecting your mother.”

She runs a fraught hand through her own hair. “We were getting out,” she admits, “It’s not safe for us anymore. After my husband was – they suspect us. And I don’t want to raise my child here anyway.”

“Where to?” I ask, although I already know.

“Somewhere else,” she replies evenly with a steady look, then looks away. “They’ve confiscated any working machines, of course, but Mum was going to get the prototype from her old lab. It’s still there, locked up. She thought she could break in and get it.”

“But she’s two days overdue, and you haven’t heard from her,” I supply. A miserable nod.

“I don’t have anywhere else I can go. If it were just me, I might manage somehow, but…” The boy starts agitating and she gets up abruptly.

“I’ll get some dinner. He’s hungry. Watch him for a bit.” She plops him back on the floor, and he starts his wobbly progress back over to me, apparently not that put off by this severe woman frowning at him; gap-toothed, with thinning iron-grey hair and liver-spotted hands. Sans teeth, sans hair, I think, then adding: sans tits, sans wits, or very nearly, anyway. So many pieces of myself left behind in other universes.

“I’m not your real grandmother,” I tell him, trying to joke in my discomfort. “I’m an evil grandmother from an alternate universe. Practically a witch.” He doesn’t look dissuaded.

Later, as I lie on the small single bed in the spare room with its wardrobe full of outgrown babygros and dead man’s clothes, unable to sleep, I come back to her eyes. Surely, that small genetic change, brown to blue, means that this isn’t my daughter, another version of her anyway; that she is someone else. But she looks otherwise exactly like all the others. It makes me uneasy. There are complexities in the probabilities, calculating universes; subtleties that still elude me. I have returned, so far as I am able to tell, to my local universe cluster; consisting solely of universes that branched out from some point at the moment of my daughter’s birth, everything else being the same up to that point. But that is an assumption. Is the nodal point farther back, at her conception? Just one allelic change between this daughter and that daughter? I don’t know. But the truth is I don’t know what eye colour my real daughter would have had when she grew up. My assumptions may be wrong.

They handed her to me when she was born; my one hand went to cradle her bloody head, the other her body. Her eyes were open and they looked straight at me. They were a startling, intense blue. She opened her mouth to cry, but only the thinnest, tiniest noise came out, abruptly cut off. Then they took her away again, her cries slowly diminishing as my own frantic babble increased, alarms blaring, until it all became noise, outside my head and within. There was only that one, brief moment. When next she was handed to me, her eyes were closed, and she was still. She was a part of me, who gradually became her own person, and I a part of her. But this didn’t happen, so she always remained a part of me. I don’t recognise this blue-eyed woman here, not in the way that I recognised my daughter.

I turn over on the bed. It creaks. What good does it do to still revisit it? There was nothing I could have done that would have changed the outcome in my universe. Those events, those decisions, were all made and taken such that any input I might have made would have made no difference. Some things are fated, but – again, the persistent thought returns – only such that they cannot be changed in your universe. In another universe, something else changed. Perhaps, here, I can do something. This time. For someone else.


“I can take you with me,” I tell her over breakfast, “if your mother…doesn’t come. And drop you off somewhere before I move on.”

She laughs, though it’s not a happy sound. She is feeding the baby in the highchair. He is making a fearful mess. “You make it sound like a car ride.”

“What is it?” I ask, watching her jaw clench, and not, I am sure, because there is yogurt up the walls.

“Mum got in contact,” she says. Her voice is flat. “She’s on her way here, she’ll be here tomorrow. But she doesn’t have the machine. They’ve already taken it.” She looks up. “Will you wait, and take us all? I know it’s a risk, the longer you wait…” I hesitate a moment, and in that moment I think I can almost feel the universes diverging from each other.

“It’s too many,” I admit. “Two adults, and the baby…a squeeze, but doable. But I can’t keep the – call it the field – wide enough for three adults.” She looks stunned.

“That’s why…” she begins, and trails off.

“That’s why she never offered while your husband was still alive,” I finish for her and watch anger flash in her eyes.

“You’re a bitter old woman, aren’t you?”

“Yes,” I agree. “But you can still have my machine. She can take my place. I’ll stay here.”

She puts the yogurt spoon down. “Do you know what they’ll do to you once they catch you up and find us gone? Aren’t you afraid?”

“No,” I say, meeting her gaze blandly. It’s a lie; of course I’m afraid, but I also just don’t care anymore. My life, such as it is, has gone on like this for too long. In a way, it’s a relief, to have a way out that doesn’t feel like cheating. That might actually achieve a purpose. But if she guesses any of this, she does not say, and she is desperate enough that she does not make even a token attempt to talk me out of it.

We agree that I will leave with the dawn and go up to the ruins on the hillside. I dare not activate the machine here – the land, the buildings, can change too much, if one is not crossing closely-related universes. That high, remote point is safe. Besides, two versions of myself will draw attention. When her mother comes, they will make their way up to me. They will take the machine and they will go. Then I will come back to the cottage, as if I never left, finally coming to rest after two thousand, four hundred, and ten universes.


The dawn is cold and grey with a forbidding sky. The walk to the hilltop warms me, but after that, waiting, hidden amongst the ruins, I start to feel the damp chill. I am certain no one saw me, but I have no idea how long I must wait. The day drags, not growing much warmer. I need to urinate, and eventually do so behind the wall. My thoughts churn, my stomach unsettled. Eventually, I admit that I am jealous: jealous of this other mother who has her daughter and her grandson and who will get to carry on living her life. While all I have are hoarded moments from other people’s lives. Another petty, unwelcome emotion. I scratch out calculations in the dirt to pass the time, pondering how far to go. Far enough to be safe, a universe not like this one with the same people in charge. But not too far. Not too unknown. I pull the machine out of my backpack, set it to searching, picking out nodes. There is a lot of confusion, and, for a while, the problem absorbs me, until finally, I settle on a relatively stable node, a goldilocks node: not too near, not too far. Just right. Any one of the universes from there will do; the machine will be pulled into one once it has locked onto the node.

I break for a packed lunch of sandwiches, an apple and a – yes, a baby yogurt, complete with teaspoon. It is eerily quiet. I haven’t seen even a single hiker all the time I’ve been here. The chapel is not as destroyed as in some universes, which I find odd. The east wall is relatively intact. There are shards of blue glass in amongst the weeds at the base of the flints; from Mary, I suppose, thinking of the chapel I saw that was not ruined. If I were Mary, I would have allied with Lucifer and shredded the very fabric of heaven for what God did to my child. But Mary, the most agency-less woman in the world, had no choice in that or anything else. She was buffeted along whilst others created the universes in which she lived. I used to think knowledge was the cure for that, and perhaps it is, but, like the machine, it doesn’t quite work like that.

The day drags on until it is nearly curfew time, and I am deeply worried. The sun starts to set behind grey cloud, and rabbits creep at the borders of the fields and along the base of the hill. The wind picks up, whisking the clouds along. I crouch by the wall, scanning the fields and the little houses below for any sign of them. An owl calls in the nearby wood. And a gunshot rings out, scattering the rabbits. I spring to my feet in alarm, but I can see nothing, and I hear nothing more. It is twilight and hard to see, although the clouds are clearing. There are lights in the houses down below, but the field on the approach to the hill is dark, the road obscured by a hedge. My heart rate begins to slow. A hunter, perhaps? And even as I am thinking: but it’s too dark now to hunt, the waning moon breaks through the clouds and I see figures down below, frantically running, torchlight waving. Another shot rings out, but I have already started to run down the hill.

There is a crumpled body in the field below, and I think it is me. The other mother. The daughter is running, staggering, child in her arms, hurtling up the hill, as if the chapel itself were salvation. But it is not salvation. I am. The crone. I am still running, but she is still far away when a single, clear shot rings out. Her eyes meet mine only briefly; a flash, and then she tumbles like a shot rabbit, curling over the boy as she falls. It happens almost silently. There is no cry from either of them. She does not get up: it is clear, when I reach them, that she never will. I snatch the boy up in one arm and run myself, waiting for a bullet in my back. But the rapidly failing light and my dark clothes save me. I stumble behind the east wall and dump the boy’s clenched form on the ground, grabbing the machine from the ground and fumbling with it with hands that violently shake. Shots whistle and ricochet off the old stone walls, striking sparks from the flint.

The machine cannot find the node I chose. I didn’t know that could happen. I never waited so long after choosing. Where can I go? I have only a moment to make the decision. They are nearly upon us. I must go a long way. It is not that they must not find us, for they will never find us, but that there are so many universes where they exist or may exist and may come…I think of the priest, so motherly, and missing her own child. I think of that other daughter, nursing her infant, long ago and far away. I think of the successes. I think, more than anything, of the failures. The child is frighteningly silent, very still, his clothes bloody. I do not even have time to see if he is hurt. Or worse. I am paralysed with helplessness. And oh, with a rush of bile I remember this: when everything feels like a nightmare. When the mind begins to melt down until you can barely speak, until it runs only one thought in a closed loop, over and over, and then thought itself goes. When you discover that the only emotion other than love that has the capacity to grow and grow until it spreads beyond the boundaries of the universe is fear. But I can still act, here, now. I can still do something. There is no more time to calculate; I cast out for a Prime Decision Node, grab the child. There is a flash of light, a burning streak across my face, and we are gone.

We appear in total darkness; I lurch forward, and something breaks beneath my feet with a resounding crack, making me lurch to a standstill, breathing heavily. Close, earthy, musty air. A crypt in the chapel? Or a barrow, perhaps. Blood is running down my face. I fumble one-handed for my torch; it is slippery in my sweaty grasp and chilled fingers, and the light bounces off stone and bones, is swallowed by empty eye sockets. With a horrible thought I wonder if it is sealed off and we are trapped in this ossuary; but no, the frantic play of the torchlight reveals an entrance, of sorts – an absurdly tiny tunnel I will have to crawl on hands and knees through, barely wide enough for my shoulders. But there is a lighter darkness at the end of it and the drift of fresh air. Sounds too, come to me, as my gasps subside. A dripping of something nearby. The scuff of my feet on the floor as I turn around in the large space, making out ancient runic graffiti in the light of the torch. And, eventually, quick, animal breaths, of the child in my arms who has a death grip on me and I on him. As I struggle out through the earth passageway, one arm clasping him to my ruined breasts, he finally begins to cry; high, and loud, and strong.


The local children call me the Witch of Marwith, a name I take no small secret satisfaction from. After I appeared from nowhere, crawling from out of the ground and scattering druids like frightened sheep before me, it was clear that I was nothing that they knew. I speak a language that exists nowhere in the world, with coins and clothes the same. The boy’s name is Alfred, a rare name here: the Danelaw took over England, and Christianity was submerged beneath it. When I finally learnt to speak to them, I told them my tale; inexpertly, at first. It is a metaphorical language, and I have refined the story over and over the years, so that now no one can tell if it is true, or if it is the construction of a woman driven mad with grief, who finally made some sort of sense of it. Then they look at the coins, at the bullet scar on my cheek when no bullet was found, at the utter lack of any record of my existence, and they wonder anew. The broken standing stones guard my secret, the machine sleeping safely in the barrow beneath.

We lived in donated clothes for two years and in the doctor’s house for three. I thought about leaving the boy there. They were manifestly better equipped to deal with a child: they had two already. But in those early nights he would crawl to my bed for comfort, taking me for his grandmother, so I delayed, until suddenly the choice was no longer there. I was suddenly so busy, and so tired. I had to learn everything anew. It was harder than inventing the machine. I could barely keep my thoughts straight some days. Then one day I woke up with him sleeping at my side and realised that, somehow, I was in a universe where I was now his, and he mine.

I didn’t expect this. I expected to be the one to make the sacrifice; a redemption, perhaps, for the daughter I still feel, somehow, that I failed. Or perhaps just for the selfishness of grief, that utter inwardness that first sent me careening out, never to return, and placing another burden of grief on those I left behind. I expected, if nothing else, to finally find the universe where I just stopped, until I was only bones scattered on the hillside. I still remember thinking, shortly after I got here: I don’t even know how to look after a child. And now I am suddenly the one responsible for a life again, the one who has to make decisions again, who has to live again, and, what is hardest of all, to live for someone else. And yet…the moments come, thick and fast, new-minted, and mine alone.

This little cottage is more homely than my old one with rickety wooden floors his little boy feet thunder loudly upon, laughter echoing up the stairs. Life is filled once more with a cacophony of intense emotions. Joy and laughter spills out unexpectedly, cascading like toys from over-stuffed cupboards; love, more predictably, swells in the heart like a rising tide that never ebbs. Anxieties scale from atomic dipole shifts to a deep gravity well of fear. Fevers, cars, falls…there is a stream at the edge of the village…he is nearly tall enough to swing up into the oak tree that towers over the cottage, and he will climb up.

Sometimes I go walking, not with my old backpack, the faded army green one with the frayed strap; that rests with the machine. No, I walk with hiking boots and poles, and a nice new rucksack with a water bottle and a slice of flapjack. Walking helps. Something to do with rhythm, perhaps, or solitude, or nature.

Sometimes I think I should have jumped somewhere closer: I could have given the boy to someone who was nearly his mother, and maybe that would have been for the best. Sometimes I think to myself that I could take him, when he is older, to see other universes. Ones in which his mother lived, perhaps. He doesn’t even have a picture of her, and his memory of her will fade. But that, I think, is not a wise road to travel down. In the end, I choose what she would have chosen herself: to keep him safe, as much as one can, in an uncertain world, and let him grow into his own future, make his own universes with his decisions. Or his actions.


There is no machine that can change the past. There does exist, however, a machine that allows you to see all the futures that exist in an indefinite, if not infinite, number of universes, and, in so doing, gives the possibility of changing them. (No, that is not how the machine works, at least, not quite). This machine is made by the universes themselves, and it powers the mind of every human. An imperfect machine that misses as much as it sees, and can change but little. Sometimes, if we are unlucky, it fails catastrophically. But the better ones learn that they must teach the other versions of themselves to see the possibilities, and the risks.

Some people told me that time would eventually heal my grief; others counselled distance. Well in thirty years and over two thousand universes, I can tell you that this is not true. The only cure for grief is what is not possible: to change what happened so that it never was. There is no machine for that. But time and distance are to some degree inter-related; even, interchangeable, and the pain, like that of most illnesses long borne, transmutes from an acute to a chronic one. Only the occasional stab, like a twinge from an old scar, brings back the sharpness. And then, it is as close and real as if it were here, and yesterday, in this universe.


When my daughter was born, her eyes were blue. Sometimes I wonder whether they would have stayed blue, or turned brown. Like her son’s.


Copyright 2024 J.S. Richardson

About the Author

J.S. Richardson

Of Anglo-Norwegian heritage, and a lifelong devotee of both science and science fiction, Joanna Richardson spent ten years as a wandering research scientist, before making her home in Sussex, England, where she now lectures biology in higher education. She was previously shortlisted for the James White and Aeon awards.

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One thought on “The Grandmother Hypothesis

  1. Laura Rift says:

    Wonderful story! Have read many recently published stories in the last few months. This was among the best. Thanks!

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