XV

Aidan looks like he’s about fourteen. In reality, he’s somewhere between twenty-five and forty-one, depending on how you want to count the distended years he experienced in a crash. But he looks like a kid, and he’s clearly playing it up as much as he can. It’s part of some whole gangly math-prodigy aesthetic that he’s just a bit too naturally good-looking to pull off. The Newton wig looks even more awkward than usual, dangling around his teen popstar face.

“Okay so what I’m here to tell you guys about is. Basically. So for the most part, in sum. This lecture is going to be about. The MM. What it is, what it means.”

Grant wonders if he’s faking the awkward pauses. He’s definitely faking the parts where his voice cracks.

“Now as Marika said to all you guys, this is basic stuff. 100 level stuff. My fellow Einsteins out there can totally just tune me out. Not like you don’t already know that, since you heard me say it before, when I rehearsed this material. You were really patient, by the way, really helpful, good comments. Love you guys. Einstein Squadron, my peeps! My preferred basis. So much love.”

He probably didn’t rehearse it even once, Grant thinks.

“So right, my lecture tonight will be a really elementary overview of the MM. Because it’s why we’re all here. Both in the narrow sense of the reason why we’re in this whole situation we’re in right now, and in the broader sense that yeah, the Higgs is cute, but if anything has a claim to being the God particle, it’s the Maryon. It’s probably the love that holds the universe together, or something, and it’s the most predictively fruitful and abstractly gorgeous field theoretic innovation since the days of Dirac, and its properties would scare Weierstrass out of his grave.

“But I wax poetic. Excuse me.

“So the MM is the Mirzakhani Mechanism. After Maryam Mirzakhani, praise be. Brilliant mathematician before physics even came knocking on her door for real. Fields medalist at thirty-seven, Wolf Prize winner at forty-three, we would have given her the Nobel if we’d only had time. Not that prizes mean anything, it’s all about what you’ve done, what you’ve proven, but I’m just trying to give all the normals here a sense of the stature we’re talking about.”

Aidan’s going at a good clip now, and the false hesitance is falling away.

“Why was the Mirzakhani Mechanism such a breakthrough? That is my topic tonight. A part of the answer is that it resolved multiple fundamental questions in theoretical physics in the same perfect stroke. To understand those questions, we’re going to have to zoom way out and talk about some big stuff. Big questions. Like, what is time? Let’s strap on our philosophy beards, and really think about time.

“So a commonplace claim made about many physical theories is that they’re time-reversible. You hear this said most often about Newtonian mechanics—that’s the stuff we did before the twentieth century—but arguably it’s just as true for a lot of the stuff later too.

“The way the laws of physics are usually written down, they look like equations you feed the present moment into, and out pops a moment in the future. Physics tells you how to predict the future from the past: you tell it what’s happening now, and it tells you what will happen later. A recipe for prophecy.

“All well and good, if that’s what you want to do. But the laws of physics work just as well, identically in fact, for reverse prophecy. If you want to ‘postdict’ the past from the future, you can do that too, and the equations for it look just the same. Give the laws of physics a single moment, and they’ll tell you the entire future ahead—and the whole past behind.

“In fact, since physics looks the same in predict mode and ‘postdict’ mode, you can’t even tell which way you’re pointed if you don’t know beforehand. Are you deriving tomorrow from today, or today from tomorrow? Physics don’t care. In fact, if you stare at these equations enough, time starts to look just like any other direction, like space. Sure, time always insists on being a bit special. It’s the rebel with the punk haircut next to its preppie siblings x, y and z. But that’s just a haircut.

“Underneath, when you grok what the equations are telling you, there’s only a bunch of different directions you can walk in. Some of them happen to be left and right, and up and down, and some of them happen to be forwards and backward in time. And that might matter a lot to the ape homo sapiens sapiens, but you can’t really see the difference when your brain’s up there in physics heaven.

“Except the thing is, though, that conflicts with a fact from everyday experience that’s also a fact from another major area of slightly less fundamental physics. That being the thermodynamic arrow of time.

“Get a camera and an egg, drop the egg off a table, catch the splatter on video. Now play the video. Egg falls and breaks, completely normal.

“Okay, now play the same video backwards. Here’s what you’ll see. Yolk and whites gather together under some mysterious force into a perfect egg shape. The puzzle pieces of the shell miraculously find each other and re-form. A reborn egg leaps.

“It will look wrong, because that never happens.

“Perfect round egg-shaped wholes sometimes break apart into messy shards. Messes never un-break into perfect wholes. Things fall apart by nature; they only come together through effort and will, and physics doesn’t have those unless there’s some ape or anomaling around screwing with the picture.

“Resolved: forwards looks way different from backwards. But how can that be, if time is just another direction? North and south aren’t different in such a deep way.

“There has to be an answer in the equations somewhere. And there is an answer, kinda. Lots of working physicists were perfectly content with it for a long time.

“The answer is called the Second Law of Thermodynamics, or more technically its consequence the H-Theorem, and even more technically that’s not quite right but I don’t have all night, here.

“It has to do with entropy, a much-misunderstood idea. I don’t have all night, so I can’t go into it in a way that doesn’t magnify the misunderstanding. The gist, and please take this cum magno grano salis, is this.

“There’s a lot more ways to be messy than to be ordered. A room can be messy by virtue of many different arrangements of the matter inside it. Your clothes are on this part of the floor, or this other one—doesn’t matter, as long as they’re on the floor, it’s messy. Whereas, the clean state where your clothes are all hung up is very special. Messy clothes on the floor can take many shapes. Hung-up clothes only take one shape, or you didn’t do it right.

“So there are more disordered ways for matter to be than ordered ones. Thus, if you figure that from the lofty POV of physics heaven all the matter sitting around might as well be in some randomly chosen state—physics doesn’t discriminate, put any state in the front and you get its past and future out the back—then your predictions are almost always going to show the level of disorder increasing. Level of disorder AKA the entropy. Most ways you can move stuff around in a bedroom will make it messier. Only one set of special motions make it what we call ‘clean.’ So the motions of physics, acting on typical matter sitting around, is going to make it messier as time goes forwards.

“Except here’s the catch. Remember, going backwards is as easy as going forwards. You may know you’re ‘predicting the future,’ not ‘postdicting the past,’ but the equations don’t. The argument says a physical state will become messier in the future. But the same argument, taken to its logical conclusion, says the same physical state will ‘become’ messier in the past. I.e., that it was messier in the past.

“But that’s just plain wrong. The egg may be broken now, but in the past it really was a whole egg. The entropy argument can tell you why eggs tend to break, and not re-form, as we go into the future. Yet it seems to say that the past was equally full of broken eggs. Shown the video played in reverse, it admits defeat.

“Then what is the answer? Well. Another way the future is different from the past: we feel comfortable specifying initial conditions, not final conditions. It’s only natural to suppose that matter and energy were arranged in some particular way at the very beginning of time, maybe at the Big Bang, and then everything else followed from that in succession, like a video played forwards.

“The initial state can just be whatever, according to the whims of God or metaphysics. Physics has no say here.

“That’s how the game works, remember? Given a single moment, physics can tell you the whole past and future. But physics does need to be given that single moment, to get its engine started. There is one moment that comes from outside physics, always.

“And, as I’ve said, it’s only natural to suppose that this moment is the first moment. At the beginning of time, at the start of the whole cosmic video, space was filled with stuff lying about in . . . whatever arrangement it happened to be lying about in. No reason behind it, no past to explain it. Just because. Then God or metaphysics presses play, physics takes the wheel, and out pops the whole timeline of the cosmos from beginning to end.

“Looking down from physics heaven, you might equally well imagine the same story flipped time-wise. At the end of time, stuff will be lying about in whatever arrangement it will be lying about, just because. God or metaphysics hands the final moment over to physics, and physics coughs up the whole timeline of the cosmos from end to beginning.

“But we don’t find that so ‘natural to suppose,’ do we? Our brains work in predict mode, not ‘postdict’ mode. Why is my room messy? Because I didn’t clean it yesterday. Not because of what will be true tomorrow.

“Physics doesn’t care one way or the other, but let’s just roll with this ape intuition. Things were sitting some particular way at the start. Feed one moment in the front, every moment comes out the back. Put stuff in place at the beginning, and the whole of time is but a step of logic away.

“This was the best answer we knew, before Mirzakhani. Because the initial state is wholly arbitrary, up to God or metaphysics, we can take all the order we can’t explain and hide it in that initial state. It’s an arbitrary move, a cheat, but the equations don’t know we’re cheating. Any state is as good as any other to physics.

“Physics makes eggs break. It doesn’t make eggs form. Physics has no reason to make eggs, or for that matter, to make apes with all our tissues so carefully arranged that we can properly boggle at these imponderables. Physics only wants to make blurry patches of random nothingness, and sometimes black holes.

“The one thing physics can’t control is the way things happened to be in the very first moment. So maybe, we used to say, the first moment was the most exquisitely ordered moment in all of time. Maybe God or metaphysics was very careful in setting it up, and took care to put the seeds for eggs and apes—everything that isn’t a uniform gas or a black hole—somewhere in there. Carefully encoded in the exact arrangement of stuff as it lay around at the beginning.

“It has to be extremely special, that magical initial state. Almost any arrangement of matter and energy that you could think of would turn into uniform gases and black holes, run forwards or backwards. Almost none of them turn into apes, eggs, and the Hector G. Stein Academy. God or metaphysics must have been punctilious to more orders of magnitude than you and I can conceive. The tiniest of wrong moves in that darn initial state, and whoops! Uniform gas and black holes again!

“Here I depart the Bad Old Days of physics—sorry, insensitive turn of phrase, my bad—and invite you to the golden age of the SMMM. Standard Model with Mirzakhani Mechanism. Perfect physics that will probably explain everything, once we get the time to work out its consequences.

“Oh, I shouldn’t have said that part yet. It comes after the CPT part. Sorry. One last thing.

“I said the equations were time-reversible. That’s not quite right. It was true of Newton’s equations”—he flicks the curls of the wig charmingly—“and at first we thought it was true of the twentieth-century equations. Almost, but not quite.

“Newton’s equations have lots of symmetries. Lots of ways you can flip the camera around, without changing the equations one bit. Turn up into down, and down into up. Or past into future and vice versa. And that’s only the beginning.

“The twentieth-century equations? Subtler beasts. We used to think they could be flipped in lots of ways they really couldn’t, upon closer inspection.

“First there was parity, the one nearest and dearest to us bilaterals.” He makes a familiar gesture, representing a failed attempt to superimpose left hand on right.

“Mirror symmetry. We’ve talked about flips across time or space. Time and space are just dimensions, and in physics heaven, parity AKA mirror symmetry looks about the same. Flip the whole world in a mirror, left hands become right and so on. Do the equations notice anything has changed?

“We thought not. And in fact, three of the four known fundamental forces truly didn’t care.

“Three, though, not four.

“There are particles in nature that are like hands, where the mirror version looks different. And one of the forces, the weak force, cares which side of the mirror we’re on. Left-handed particles do something that right-handed particles do not. The guys who first predicted this, Lee and Yang, won the Nobel for it, and in December 1956 a lady named Wu confirmed it experimentally.

“Anyone here who was on Stein’s Rock knows about Lee and Yang and the Wu experiment. We celebrate it every December on Wusmas. With hand-shaped cookies.

“There was a stretch there where we figured, sure, physics could tell if we flipped everything in a mirror, but it would be none the wiser if we also flipped something else when we did it. Physics cared about parity AKA ‘P,’ but maybe it couldn’t see a simultaneous flip between left and right and between positive and negative charge. Reflect the universe in a mirror, turn all the matter to antimatter and vice versa, and why, that’s just the same universe you started out with, and for all you know you were there to begin with. ‘CP’ symmetry, C for charge, P for parity.

“Even that wasn’t right. Most of physics doesn’t care, but this one fundamental particle with a hipster haircut and a Think Different poster—the K meson—looks different in its mirror-flipped antimatter version, versus the matter version. So reality is not CP symmetric. Fitch and Cronin, result in 1964, Nobel in 1980.

“Here’s our friend time again. Reality is not CP symmetric. But for a long time, we were damn sure it was ‘CPT’ symmetric. Charge, parity, time. Flip the mirror, flip matter and anti-, and play the video backwards, and at last that’s just the same physics you started out with. This was an honest-to-god theorem. It was perfectly true, of the old Standard Model. Just not of the SMMM.

“Enter Mirzakhani. Forget about time, stroke those philosopher beards in a different direction, and think about parallel universes.

“Don’t get too excited, Berensteins. These aren’t the sexy kind of parallel universes. Usually. They’re more like very slight variants of the recent history of the physical universe, over a very short span of time. Where ‘very slight’ is defined in a boring, physics-y way.

“The Mirzakhani Mechanism, or MM, is a fifth fundamental force whose mechanics single out special moments in time. At these moments, aspects of the physical state of our universe are replaced with the versions of themselves which obtained in a parallel, different history. The dynamics of the MM constrains the other histories to be similar to ours. Particles zigging and zagging in slightly different trajectories, for the last micro- or nano- or atto-second, mostly.

“When the MM acts, these alternate trajectories are made real. Specifically, all the particles, or really fields, sitting around at the moment of action suddenly acquire the positions, momenta, energy, et cetera—or generally, combinations of such properties—which they had in the alternate history. And didn’t in this one. The whole past is just like it was before. But the future is forever shaped by the interruption.

“When I say moment, I mean moment. Literally an instant. Nothing else in physics is like this, except in approximation. The MM acts in discrete moments. Lots of them: between the start and end of this sentence it’s acted trillions of trillions of trillions of times. Actually the trillions go on for a while but I don’t have time to say all of them. The point is that they are moments. Start at the Big Bang and count up Mirzakhani’s miracles. At the very end of time, you’ll get a finite number. An extremely large number, but finite.

“With the MM, a lot of things snap into place. Stroke that philosopher beard in the temporal direction again. Time. Why is going forward not exactly like going backwards?

“Play the video forward. Watch the egg closely. Watch it closely enough, and you know everything you need to imagine every relevant parallel history that egg might have taken, in the MM notion of ‘relevant’ and ‘history.’ You’re ready for what comes next.

“The MM acts upon the state. It ‘selects’ one alternate history and replaces our egg with the egg from that history. Or a few of this egg’s qualities with a few of the alt-egg’s qualities. This ‘selection’ is entirely deterministic. Predictable physics. Equipped with the equations, you can prophesy it before it happens. Put the present moment in the front, the future comes out the back.

“What does the same video look like, played backwards? The egg is the egg it is, until the miracle moment, and then it just isn’t. It flips to a different egg.

“Can you predict which egg it will be? That depends on which parallel history was ‘selected’ by the MM. And that’s a parallel history of the recent past. To imagine it, and understand why it was ‘selected’ among other variants, you have to know what happened in the recent past. Which, playing the video backwards, is really the ‘near future’—the very thing you’re trying to infer to begin with.

“You can predict the later parts of the video from the earlier ones just fine. To ‘postdict’ the earlier parts from the later, you would need to know what the earlier parts contained, so you could construct appropriately close parallels for the MM to choose between. Going backwards, you can’t answer the question unless you already know the answer.

“This is true in a strict sense. You can try to be clever and imagine all the different ways the recent past might have been, and then imagine all the parallel histories for all of those pasts, and try to find a consistent solution where the projected reality is close enough to its projected parallel. Turns out those equations, which Mirzakhani also developed, are vastly underdetermined. Meaning there are many different pairs of real-pasts-and-alt-pasts which would do equally well, and no way to know which one was real, if you’re projecting time backwards. The present logically specifies a unique future. But the future is consistent with trillions of trillions of trillions of pasts.

“So why was the initial state so magically ordered? Easy. It wasn’t. But it was the Big Bang, and things were different then. Not in some magically prepared way. Just different. Notice there isn’t a Big Bang happening now. But there was back then. See? Different.

“Given the way things were back then, the physics predicts an intense storm of MM action, and it predicts that these moments, on average, ‘selected’ higher-entropy parallels. There are ways of arranging matter and energy which predictably pull in entropy from more ordered parallel universes, moment by moment. Not especially special ways of arranging matter: anything that looks remotely like a Big Bang will do this.

“How about baryogenesis? There’s a lot more matter than antimatter in the universe, as you may have noticed.

“At the very start, at the Big Bang, there was neither matter nor antimatter. They were made later, in the early universe, by some physical process—and that process must have made more of the one than it did of the other.

“It’s not easy to cook up a process like this, within the confines of the old SM. Remember our friends CP and CPT. Three of the SM’s fundamental forces have CP symmetry. So any action of those forces which produces more matter than antimatter should also produce just as much more mirror-flipped antimatter than mirror-flipped matter. Leaving matter and antimatter equal at the end.

“You can ask for salvation from K mesons and other snowflakes that refuse to be CP symmetric. Turns out the snowflake stuff is just rare, and there can’t possibly have been enough of it in Big Bang times to produce the matter/antimatter gap we observe. No initial state, no matter how magical, can seed our matter/antimatter gap on its own while remaining consistent with observational data.

“The MM made the gap. You can predict this too, from any Big Bang-y state. The MM is not CPT symmetric, and when you add it to the SM, the whole theory loses its CPT symmetry.

“No trick with mirrors and charge will make the video as predictable backwards as it is forwards. The MM selects one direction in the CPT cube, charge goes this way, parity goes that way, and time goes forwards. We’re in that universe. We are not in its CPT flip.

“Still with me? Good. I’m finally getting to some material more relevant to the crisis on our hands.

“The MM is a fundamental force, AKA a quantum field. When interpreted as a particle, it’s the Maryon. Like anything in physics, the MM field has a temperature. Sometimes it’s ‘hot,’ vibrating fast in nearly random ways. Sometimes it’s ‘cold,’ only vibrating a little.

“In the relevant approximation, the duration of the parallel universes is inversely proportional to the temperature. When the field is hot, MM events are frequent, but their alts are short. They’re likewise limited in spatial range, because the speed of light is finite. Very short alternate histories of a very small region of space are permitted to affect the here and now.

“This high-temperature regime characterized the Big Bang, and to a lesser extent, it characterizes the present. The MM field was hot in the early universe, and it’s still hot now, mostly. But now there are low-temperature modes of the MM field, too, superimposed on the hot ones. Eventually the hot ones will all cool down. Until, in the far future, the MM is only cold.

“What is the high-temperature MM like? Not very sexy. I mean, it explains baryogenesis and the origin of time, which is sexy to us physicists. But the parallel universes aren’t, like, parallel universes, you get me? They’re just variant histories where molecules zigged and zagged a little differently inside a tiny patch of matter. Yawn.

“They are, however, very useful. A physical being coupled to an MM field interacts with that field. It plays a role in ‘deciding’ which parallel history the MM ‘selects.’ When the fields are hot, the selections happen trillions of trillions et cetera times per second, so you have plenty of alts to play with.

“What can you do with a tiny parallel universe? You can ask it questions.

“Let’s say you have some tiny math problem in mind, and you need the answer so quick, you can’t possibly work it out in time. But you have an ace up your sleeve: an encoding system that expresses the structure of tiny math problems as the structure of tiny events in a parallel universe. An alt where the fields zig over here if the math works out one way, whereas they zag over there if it works out another way, et cetera. Get yourself set up to measure the zigs and zags, in the tiny circumscribed region of space where the alt differs from the real world. Now, influence the MM such that the universe in question is ‘selected.’ Measure what happens, as a consequence, in that circumscribed region. There’s your answer.

“Evolution picked up on this quick. This mechanism is used in every biological cell, albeit mostly in dull ways. Crawl up the evolutionary ladder, and the uses become more interesting. Cells start to think with the MM’s aid. You can do computation this way. Computation with discrete timesteps, even, closer to Turing than we used to think was possible. You can do computation this way . . . and in fact, someone does. We do. Our cells do. The ones up here.”

He taps his forehead suggestively. The curls wiggle.

“The low-temp field, though. A different ball game. At low temperature. The alts get longer and wider. The physics allows them to be less ‘similar,’ again in Mirzakhani’s notion of ‘similarity’ among alts. Bigger and bigger miracles, less and less frequently.

“At low temp, Mirzakhani’s magic almost fades away. You don’t see it if you don’t look closely. In long intervals between miracles, you could almost imagine CPT symmetry was back again. In these long spans between MM moments, the video played forward and backward really are the same, modulo the requisite mirror and charge flips.

“Think about this seriously. At low temp, time really just is another direction, mostly. You might think of yourself ‘going’ back and forth along the time axis, as easily as you’d go west or east. The universe becomes a fixed block which does not ‘change,’ where no time ‘passes.’ Every slice of it logically implies every other slice. An organism in this cold MM state could have a notion of subjective time, but there’s no reason it should have much to do with the direction we call ‘time,’ back here in the hotter parts of spacetime.

“We used to call the eventual fate of the universe ‘heat death.’ In the Standard Model plus gravity with no MM, physics wants its uniform gases and black holes, and eventually it gets them. Eventually disorder is so complete there’s no structure left worth caring about. Once that happens, we’re stuck there forever. We can’t even measure time at that point, because the only stuff left moves at lightspeed. Forever is equivalent to a moment, and there’s nothing there.

“The SMMM predicts a different kind of far future. We call it the ‘dominant aeon.’ The beginning of time was very hot, and we’re outrageously early in the history of the cosmos, so we’re still pretty hot. The hot phase is a transient blip, preceding a stable eternity.

“The MM field gets cold. Physics still gets to create its beloved black holes and uniform gases. A 20th century physicist could confuse this for a state of maximized disorder. It isn’t. It is structured by the successive waves which the MM has crashed into its hull. The colder the field, the rarer these divine interventions become, but the more profoundly structured they can be.

“The alts obey physics. They’re just slight variants of our world. That means they have the MM, so they pull in their own alts-of-alts, which pull in alts-of-alts-of-alts, technically ad infinitum. At high temperature, the ‘range’ of this effect is limited like all the other ranges. The contributions from higher-order histories quickly fizzle into randomness and cancel out, and you can ignore them in your calculations.

“At low temperature, the MM pulls in information from ever longer histories, with ever more complicated structure inherited from their own trees of alts.

“In the dominant aeon, ‘dominant’ because this is all of eternity we’re talking about, the structure of matter and energy is not determined by physical causation as the SM would understand it. It’s determined by the metric the MM uses to judge similarity among worlds, and the self-consistency relations it imposes on arbitrarily long trees of branching pasts.

“The dominant aeon has structures that confound our ordinary notion of cause and effect. Precise correlations between spatial regions arising faster than light could carry them. Precise correlations between past and future that you’d think they were time travel if you didn’t know better. Our understanding of these structures is still in its infancy.”

A subtle phase change occurs in Aidan’s facial expression and overall bearing.

“We might know more about the dominant aeon if Mirzakhani were still with us. She is not. She was taken in the Burial of Scholars. She was at Stanford, when the bombs fell. May her work find worthy minds.”

Sometimes the candlelit room, packed with rapt faces, evokes the spooky good fun of Halloween, seances, sleepovers with the Ouija Board. And then, sometimes, it feels like a funeral service.

 

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The Stein people, chest-pumping partisans of humanity, do not speak often of the brief dark time between first contact and universal imprisonment. Science fiction sometimes imagines mankind putting aside its differences and joining hands in the face of an alien threat. Many of us did, in fact. The movements for world unity, immediate ceasefires, sharing of technology and talent even between enemy nations—these captured the hearts of millions in a hundred nations. They were a touching spectacle. The press loved them.

But in a world crisis, unfolding exponentially on a scale of weeks, with a looming existential threat obscuring the next election from view, public sentiment does not determine the moves and counter-moves of nation-states. Decentralized power bubbles up slowly, but power already centralized can act instantly.

The generals and heads of state asked the scientists which of their wonderful weapons had the best chance against the aliens, and the scientists told them the truth: nothing you would think of as a weapon can so much as touch them. We are doing what we can to produce something which can. This situation resembles nothing in the history of warfare. You are irrelevant.

Heads of state and military generals do not like feeling impotent. And the monstrous thing which lurks in the heart of every general and every head of state yearned to break free at last, in this moment of Total War, mandate without limit.

It was finally time to use all those wonderful weapons. Time to scrap all the treaties, get those simmering ethnic tensions resolved at last. Time to find out which apes really had the power which their flags and borders implied.

Sometimes there was even a fig leaf of purported relevance to the real threat, hiding the lust for domination underneath. These scientists are starting to look like a key military asset, aren’t they? Enemy agents are kidnapping our physicists in the night, or so we have heard. Supremacy on the new battlefield cannot be allowed to fall into their hands, into a rogue state’s hands, into the infidel’s hands, into the zealot’s hands, into unfree hands, into dangerously free hands, into any hands but these two right here. And where we lacked the means to seize scientists, we had at least the means to ensure no one else ever would.

The Burial of Scholars, as we called it later, was a brief nuclear exchange, with garnishes of conventional force applied to taste. Its targets were government labs and universities.

Grant had expected to die, then. But the facility was spared, its location a true secret unknown to all other state actors. Grant owes his life, he figures, to the work of some other, higher director of security, unknown and unseen. A director of security whose job really meant something, as his never had.

One does not speak of the dead lightly. There are rituals that must be followed. Aidan has spoken, with proper reverence, of one dead physicist, and the custom of his tribe now requires a moment of remembrance for the others. Every Einstein in the room whispers a name, and another name, and another. The low voices weave and overlap, forming a prayerful hum with a hint of melody.

“Pais. Arkani-Hamed. Coleman. Yin. . . . ’t Hooft. Tao. Vaniada. Aaronson. . . . Pretorius. Wang. Witten. Chen. . . . Smolin. Tile. Luk. Penrose. . . .

“May their work find worthy minds.”

And then the ritual asks that they say no more of the Burial of Scholars, and honor the dead in the truest way: by talking, instead, of physics.

 

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“We do not,” Aidan goes on, “know what the dominant aeon looks like in anything but the broadest strokes. There is a century’s worth of beautiful theory to develop, and we didn’t get even a decade of time to work on it, before . . .” He trails off.

“Anyway. Here is one thing we do know about the dominant aeon. There’s a kind of life there. Spatiotemporal correlations set up by low-temp MM events, with sub-structures in them that parse to our ape brains as willed actions by willed agents. Noun-like structures which participate in verb-like structures with will and agency, or will-and-agency-like structures, anyway. In the equations time does not pass, there’s no ‘now’ for actions to occur in, there’s no ‘future’ which agents might want to influence. It’s all already there, exactly as it is / was / will be. Yet something like the life timeline of an organism can be followed through the correlations, flitting back and forth through ordinary time and space.

“You know what I’m talking about. Anomalings.

“Which is precisely the wrong name, when you think about it. They are the life that can live in low-temp MM fields, and thus the only kind of thing that can live in our SMMM-governed universe, after the anomalous patches of high temperature left over from the Big Bang cool down. Only at the very beginning, while the universe is still getting its footing, can strange things like us briefly thrive. Transient instabilities. Patterns in a dying fire.

“Of course, to the mind of a low-temp native, ‘the beginning’ is just another place you can go. The life in the low-temp fields of the dominant aeon can ‘come’ ‘here,’ if it so ‘wills.’ Or, I guess, when it is ‘forced’ to ‘go’ here by circumstance—same timeless structure, different agent-y interpretation.

“Sure, many of the MM events which formed it have not yet happened. But their seeds are all around us, real events constraining the shape of unseen alts, which will break like waves upon the real world trillions of trillions of years hence.

“And when they’re here, these future lifeforms, the sweltering heat bothers them. That and the weird-ass dynamics of biology-physics coupling. The purity of the MM sullied by all these meddling cellular calculators. Field oscillation patterns utterly alien to them. Infernal wailing from the hottest place in existence.

“So what do they do with these hot shrieking cells? They put them in the freezer. Same cells, same calculators, same MM coupling, just redirected to lower-temp field modes. The calculators vibrate in tune with cold structures, more like the dominant aeon, spanning effortlessly across space, linking distant brains faster than lightspeed. Given pure noise, a brain will invent a pattern. Given a measure of control—the temp’s still high enough for that—a brain will amplify what it thinks it sees. The brains see sky, walls, conspecifics, familiar things, and the more they see them, the more they keep seeing them. A stable shared dream. A crash.”

Aidan makes a voila! gesture with one hand. With the other, he points to the walls, the floor, the ceiling.

“There it is. If we become crashed again—crashed for real, I mean, frozen, not like we are today, naughty warm cells sneaking a peek into the freezer—you will at least know, this time, what is happening to you. Physically.

“Physics provides the problems. It doesn’t provide solutions. Einstein Squadron is where Hector goes for bad news, and then he goes off to Blackhat Squadron to cheer him up.

“Why they cheer him up is not really my area of specialization, I admit. I see a lot of hats and vapes in this crowd. I’m sure any of you could deliver a better lecture on this next piece than I’m going to. I said that to Marika, said we should get a Blackhat to do the part about hacks, but she said—”

“—I said I was very busy and my entire Squadron is very busy and you’ll do just fine, sweetie,” Marika cuts in. Her voice sounds condescending, but it always does, and in fact she sounds abnormally gentle here. Almost sincerely affectionate, maybe. Who knows.

“Thanks for the vote of confidence, M,” Aidan says. “I’m honored.” He sounds like he means it.

“So then. Uh.

“If there’s one weapon we have against the low-temp creatures, it’s the way we think. Trapped in sequential time, unable to touch our future directly, we are creatures of prediction, speculation, imagination. Unable to venture freely through physical spacetime, we seek out the edges of logical spacetime, using our cellular calculators and the MM.

“The patterns that obtain in almost all of spacetime, in the dominant aeon, we don’t take them for granted. We’re such hicks, we don’t even know what normalcy looks like. Something that holds true across all of normal spacetime is bound to seem utterly dependable to a dominant-aeon creature, a ground-level truth, like the very notions of time and space and logic are to us. Like two plus two makes four. And we are the dumbass that has never even heard of two plus two, and asks, but what if two plus two makes twelve? What if two plus two makes a banana? Why not?

“Give a bilateral something—something stable and self-reinforcing, seemingly inevitable—and the bilateral will think of a million wild ways of fucking it up. Most of them are literally, logically impossible. Once in a while, one of them isn’t. When a bilateral recognizes logical possibility, physical realization is not far off. We find the exceptions to rules, and we make everything exceptional.

“Like the crashes. Stable low-temp vibrations, how everything is supposed to be. But if you look very closely, their stability is vulnerable. There are bizarre conjunctions of events, as finicky to arrange as the old magic initial condition of 20th century physics, which unlike every other possible situation will set a crash on an exponential warming spiral. Or link it up to other crashes, other modes of vibration, other parts of space and time, which normal dynamics would screen away from it.

“Not that we can ever really surprise the anomalings, who come from the future. Everything we will ever do, whatever it is, is already in the proverbial history books. But why should that stop us? We are the reason the history books of the future say what they say. Plus, it’s one thing to view the consequences of our fuckery from a future vantage point, and another thing to know how we actually pulled off the fuckery. Because of the MM, remember? Past determines future, future underspecifies past.

“Uh so there are tricks that can make a crash start to warm up exponentially. That’s the simplest trick, Blackhat 101. Very visible from the outside, leaves long-lasting traces in the low-temp spectrum. Anomalings in the future can smell those traces. You try to do this, well, the anomalings will let you warm the crash up to a point—it still has to have left the traces, see—and then they slam a rebase on it.

“What’s a rebase? Okay. Um. So.

“Crashes are low-temp structures. Low-ish. Hot by dominant standards, cold by ours. Fields of this kind are around in our era, having their own MM events now and then, but they’re mostly silent. Off in their own orthogonal world, which to a first approximation does not interact with everything else. Everything else AKA high-temp MM and regular standard model physics.

“Since they’re cold, the alts you have to think about w/r/t the MM are wide and long. In case I’m boring you, Berensteins: these are the sexy kind of parallel universes.

“A crash is cold enough that a single MM event can pull in years of alternate history, and replace the crash entirely with the alt. When someone causes an MM event like this on purpose, we call it a rebase. The alt history didn’t really happen, and outside the crash—outside this one low-temp pattern—real history keeps going like usual. But in here, everything is overwritten with the alt. Everyone remembers the alt, mostly. With exceptions: physics is approximation through and through.

“Which means, yeah. Hector swears he left most of history the same during last year’s rebase. Just set us up with provisions and locked the exits. But you guys who were here before, you know better, don’t you? That’s why you’re in this room. You notice little things are off. You’re not crazy, Berensteins. We’re not crazy. Physics is on our side.

“I’m getting ahead of myself, though, talking about what Hector did there. Let’s get back to our stupid bilateral who thinks the warmup trick is going to work. Anomalings drop in, make up a new story where our stupid bilateral is more docile. The new story picks up right where it left off, in the present moment, and our bilateral is nice and crashed for the foreseeable future.

“Unless he’s Hector Fucking Stein. If he’s Hector Fucking Stein, in this crash nine subjective years ago, he’ll go Berenstein on your ass. He’ll piece together what happened to him, and then, and then, he’ll figure out a way to fuck with your own rebases.”

“That was Mom,” someone in the crowd says, fake-muttering, clearly meaning to be heard.

Against one wall near the blackboard, there’s a throng of Blackhats, who have been intermittently vaping throughout the whole lecture. One of them fake-coughs and says, “Hector couldn’t figure out his own ass.”

Chester, who’s been chilling in the same spot since Grant spotted him, stands up in a huff. “If you guys start talking about ‘Mom’ again,” he spits, “I’m walking out of this room.”

Mom is what the Blackhats call their founder. Stein’s number-one accomplice in the Bad Old Days, when he was still trapped in this crash, without access to talent beyond a gaggle of child wizards.

How convenient for him that one wizard girl should be so unusually talented. And we’re not talking relative talent. Go back before it all, back when Berkeley and Princeton and the Plexicorp LLC headquarters were more than radioactive blast sites, have your pick of all the uncrashed bilaterals on earth, and you’d have trouble finding anyone to match Mom for hacker chops. Unparalleled instincts for sniffing out the vulnerabilities in a system. Eerily good intuitions for reverse-engineering crash structure. A real wizard.

Stein missed her so sorely on the rock he invented a whole Squadron to replace her, and gave them her collected notes to get them started. The Blackhats revere her. The inmates who were around in those days do not remember her so fondly.

For a moment, no one says anything.

“Fucking psycho bitch,” Chester says.

“If we’re talking about Mom,” the blue girl interjects out of nowhere—she really doesn’t know how to read a room, the blue girl—“I have some information I think you would all be interested to hear, I’ve been waiting to say it—”

“Shut the fuck up, assholes!” Marika yells.

She bounds to the front of the room, gets Aidan out of the spotlight with a gentle shove.

“Shut. The. Fuck. Up. We’re better than this.” She pauses, and no one speaks.

“We are sticking to the agenda. My word is law. If some of you think the past still needs hashing out, fine, take it outside, after the meeting. Anyone in here got a problem with anyone else, take them out to the courtyard and work it out with your fists. You have my blessing. Trust me, nerds, a good fight clears the air like nothing else.

“In here, my rules. Here’s what I say. Aidan finishes up his very nice talk, and you all listen closely, and don’t interrupt. Then we hear from the Ells.”

She beckons to Aidan, who’s off by the wall, twitching. He looks about ready to cry.

“Uh. I think I was about done, actually. Thanks again all for the opportunity. Double thanks to my Squadron for listening to my beta versions. Love you guys. I think it’s past my bedtime.”

Aidan does not have a bedtime. Aidan is a grown man who once had a PhD, a mortgage, and, briefly, a wife. But no one with a heart, seeing that pitiful child-face look hopefully toward the door, would dare stop the poor thing from slinking away into the night.

Marika cuts through the ensuing awkwardness as though she hadn’t even noticed it. Maybe she hadn’t. Maybe that’s her superpower.

“All right, then. Time for our next segment. Lulu, Lil, come on up here!”

 

---

 

Lucifer and Lilith Vance get up before the blackboard. They look uncomfortable. Marika is still there beside them.

“We have been researching the Old Mantic corpus,” Lilith Vance begins.

There is a titter from the crowd.

“We know,” Lilith says. “We know Old Mantic is not a real language. We know it’s gibberish made up for a few spells and inscriptions in a children’s series, by an author who was not exactly Tolkien.”

“Just like you,” says a voice from the peanut gallery.

Marika’s facial expression right now could raze a city.

The Ells know how to deal with a bad crowd. Lilith continues as though nothing had happened.

“Nonetheless, in the Chester Chrestomath crashes, every detail left to the imagination in the Chester Chrestomath books must be filled in. In the books, only four brief phrases of ‘Old Mantic text’ ever appear on the page. But the books say the Academy library contains thousands of pages of Old Mantic writing, and so they do.

“It’s there. You can read it. It looks just like a real language. Lucifer and I ‘know’ the language as far as we did in the books. For those of you who remember, that’s not very far.

“These Old Mantic books have been a favorite diversion to the two of us, in the long years since Hector’s ascension. We know they are just details the crash has painted in, because they have to be there. But it makes for a fascinating little puzzle.

“How deep does the crash’s illusion go? Did it invent unknown legends of the first mancers, and then write them down in a language no one can read? Do the words just have the surface structure of human language, or do they really mean something?”

In their more routine public appearances, the two Ells take turns speaking. Not tonight, for some reason. Lucifer is just standing there, looking uncomfortable. There’s a big, tattered book in his hands.

“Stein’s return brought us the Blackhats,” Lilith says. “Who know more about deciphering codes than anyone does.”

“The Old Mantic corpus is wild,” Marika says, by way of encouragement.

“They set their computer programs to work on it,” Lilith says.

“We tried everything,” Marika says. “Nothing worked, except one we tried just out of total desperation. An old chess AI, standard neural net amplified tree search, tried and true tech. We let it think it was playing a game, when it was really guessing words in the corpus from other words. And that got us somewhere.”

“Like the books are a kind of chess notation,” Lilith says, “writing down old games. Not chess, exactly. A similar game. Same principle. They were even able to work out the rules.”

“It’s kind of fun!” Marika says. “If we’re all still here next week, I’ll get you guys playing it.”

Grant isn’t sure if he’s imagining how sad Marika looks as she says this.

She looks . . . ancient, actually. Old beyond her years, enthusing about a board game at the Old Folks’ Home, as her handlers look on with patronizing smiles. You could almost think she was young again, the way she enthuses about her little game. But look at her face. See eighty years of sad experience, weighing on that face.

“But it isn’t just the game,” Lilith says. “The game is one layer. Underneath it is another code!”

She speaks, but her body is as frozen as a figure in a painting. A witch before a blackboard, a very modern witch who realizes the potential of mass public education for spreading her dark craft. Or is the point that mass public education is, in a sense, an indoctrination in witchcraft? Much to ponder. A very topical painting, very satirical.

The blackboard and the little figures in front of it were starting to look very small indeed. Curios in a little diorama, brought by an acquaintance from abroad.

Were starting to look? Looked. They looked. They looked small. They were small. Were?

Grant thought about how something had changed, long ago. What was it? No matter. Things were different these days. No use worrying oneself over the past.

Behind him, an ancient woman in an ancient wig was saying something.

“ . . . wave of unprecedented magnitude . . . outstrips even the projected exponential . . .”

The blue girl was saying something too.

Cordelia was saying something. That’s what Grant meant. The blue girl? That was what he called her ages ago, when he had a crush on her, and couldn’t admit it even to himself. Why was he calling her this old dumb name in his head? Maybe, he thought, he was losing his grasp on the difference between past and present. Like a demented person.

Hadn’t someone once said, ages ago, that he suffered from dementia? Someone had said that, Grant was pretty sure. Maybe they were all in the Old Folks’ Home. Grant wondered whether Cordelia was just visiting, or whether she was a patient, too. Let it be the former, please. Let her live her life. Whatever happens to me.

“The box!” Cordelia was saying. “I need to get the box, now!”

“No, no, no, are you fucking crazy,” said the small bony person before the blackboard, next to the painted witch. Such language! The demented are not always docile.

“That is a piece of precision equipment,” the small bony person went on.

“It’s a jailbroken comm link with the capacity to hijack rebases, and do all manner of other mischief, if you know what you’re doing, and the time is exactly right. It is not your cheat code out of this. If I knew a way to stop what’s happening using only a jailbroken comm link, I would already be doing it, you fucking moron.”

Once upon a time, a tall sepia-skinned person with a hat, long since crumbled into dust, had said, “there’s a chance the fissile material from the nested crash stack could still be used to bootstrap into a partially isolated subframe.”

Once upon a time, a small bony person had shaken her head, and looked sad.

 

---

 

The classroom was empty, except for the two of them. The room had such lovely picture windows. Grant could see cherry trees outside, their blossoms glinting in the moonlight.

The classroom had many chairs. Grant sat in one, and Cordelia sat in the one beside it. Just the two of them, watching the moon.

“Did you ever really think the whole thing was going to work?” Grant said. “With Stein taking over a school, and trying to do whatever he was trying to do?

“And do you remember us back then, in that stuffy classroom, talking like we’d found some secret that would make Stein’s thing work after all? So full of ourselves.

“I didn’t really believe it even back then, I think. Did you? I won’t think less of you if you did. We don’t have to agree about everything.”

He’s in the classroom, but it’s empty, except for him and the blue girl. The blue girl is saying something.

“Do you need a hug?”

And she stands up and he stands up and she walks toward him and he closes the distance and there they are. What was the last time he had a girl’s arms around him like this? And this girl has curves, such curves, under that foofy dress.

It isn’t pervy, when Grant thinks about her like this. After all, she’s his wife.

“I really thought it would work,” she whispered into his ear. “Really. One hundred percent. True believer. Not in Stein’s bullshit. But I thought we were on to something.”

She whispered this a very long time ago. The moment stuck with him. A precious moment.

“I love you,” Grant said.

According to the reconstructions of expert philologists, a terra cotta figure in an ancient mausoleum was purported to have said, at one point in time, the words

“ . . . the passive instruments continue to function, and the readings we see are consistent with a coupling to . . .”

or something to that effect.

And then the world was still.