Who would you like to be?®

“Welcome back!”

“The hell?”

“Tsk. Language, Mr. Carter. I presume you can show yourself out. Have a safe trip.”

“Where the hell am I?”

“Oh my. One moment, please.” [pause] “50 simyears??? By the stars, you must be wealthy!”

“What’s going on?”

[sighs] “. . . you’d better come with me, Mr. Carter.”


“Your real name is Doug Carter. Your last (perceived) 50 years have been wholly simulated by our software, interacting with other customers as compatibility allows. It is unusual for customers to request more than a simulated week or so, but it seems you bought a whole lifetime.”

[shows signed contract with company logo]

“You’re about 24 real years older, because we use a 2:1 time scale with some scheduled maintenance. But for long-term clients, we use longevity boosters, so you’re only about 6 years older biologically. We block prior memories so that your simulated experience feels real (and for the safety of other participants), but customers usually regain their prior memories shortly after return.”

“Jeanette . . .”

“Hmm? Oh, that’s a name. Unusual. Oh, hmm, I see. It appears you had a child in simspace. That feature’s technically still in beta. How was the conception? Any tips for our dev team?”

“My daughter!”

“Oh, ah. Mr. Carter, so, your daughter doesn’t exist in reality. If you like, I can copy all her logs for you. You own all her IP. Her mother is sim too, so the same there.”

“But . . . !!!”

“Mr. Carter . . .”

“. . . how much for another fifty years?”

[representative smiles]


If you could see the notes they’re taking . . .

As time increases without bound, the probability of
existing within a simulated reality approaches unity.

There are exactly two possibilities: either we exist in a simulated reality, or we do not. If we’re simulated, this almost certainly evidences a creating group of entities in the enclosing universe with a reason for doing it.

At this point, you can speculate on motive. For example, maybe they’re doing a simulation: a group of cosmological grad students. (The idea of a “god” in the classic sense seems cretinous; what depraved being would build a toy universe and then have trite interactions inside of it for eternity?) But these lines of inquiry become dull rather quickly.

More interesting is to speculate on the existence of the parent universe itself. By applying the same logic recursively, we find that they’re probably simulated too. So you have us, inside a parent universe, inside a parent universe, inside, inside, and so on until you reach some root universe. It will always reach a root universe in a finite number of nested universes. (Why? Because by assumption, the probability of existing in a simulated reality only approaches unity. And even if we were to know we’re in a simulated universe, you toss the problem to the next one up, and so on until an assumption breaks. Anyway, you can’t have turtles all the way up.)

For example, let’s say that we think the probability of existing in a simulated reality is ps=0.93. Assuming this is constant for each universe (each universe likes simulating universes approximately the same as itself), we’d expect on average to be the 14th or 15th universe down. If it’s ps=0.5, on average we’re the first universe down.

What’s fascinating is that this implicitly involves a problem: we can’t define time very well. If you observe a universe right at the big bang and then live through until its end, your ps grows monotonically from 0 to 1 but the truth remains constant. What the original conceit really is saying is about time in the root universe. That, as time progresses, the number of recursively simulated beings collectively grows faster than the number of real-lifes. It’s a hyperexponential growth, too, since each simulated reality makes its own recursively simulated universes too.

This suggests something interesting: we can devise an a-priori experiment to see whether we’re in a simulated reality. See, this hyperexponential growth starts exactly when the root universe starts simulating things. The population growth in the root universe continues at an ordinary exponential rate, so the simulated universes very quickly outpopulate the real one.

This means that after the root universe develops universe simulation, your chances of being born in the real world drop abruptly, asymptotically, to zero.

In the absence of better data, we assume that any parent universes are like ours, since people are interested in creating applicable simulations. So:

  1. If we are simulating our own universes, then probably we are the child of a parent universe that is also simulating universes (one of which is us).
  2. If we’re not simulating universes, then we don’t have a parent universe, because that parent universe wouldn’t be simulating us either. So we wouldn’t exist (and yet clearly we do).

The intriguing thing is that the simpletons who authorize science funding get the implication backwards, reasoning that if we don’t invent universe simulation, then we’ll be living in real life (as if such post-hoc decisions could influence the very nature of reality). If this carries back up to the root universe, then no child universes will ever exist (which makes the fallacious chain of reasoning even more appealing).

Ed. note: this isn’t actually strictly fiction.


We’re a little short on crew.





In Case of EMP . . .

Nostalgia costs mass.


Johnson broke the glass.

“The hell is this?”

“It’s a slide rule. And it’s going to save our asses.”

“Lotta fancy numbers. What’s it do?”

“It multiplies, divides, square roots, all the usual things ‘cept addition. This one does trig and exponents too. It’s more precise than your brain, but less so than a computer. That EMP means we don’t have a computer, though. Both backups are dead too.”

“Well, we had no way of knowing that that particular CME would hit us way out here at Jupiter. The chances of that must be pretty absurd.”

“Not really. Happens all the time. But our electrical shielding clearly wasn’t up to par, and this was a particularly big one. Right now, we’re dead fish in a very big sea. See if the emergency sparkgap is working. Tell Ganymede we’re scrubbing the mission—and we’ll use this thing to figure out how to burn for home.”

Ed. note: Idea from Atomic Rockets. I myself restored a K&E for work, and have another at home. They’re useful for one-off calculations that would be too slow to do in my head and too unimportant to boot a shell.

Physical Exam

Your A+ is an F-

“Did I pass, doc?”

“You’ll be pleased to know, you’re in perfect health.”

“Sweet! I’ma be an astronaut!”

“Well . . . no.”

“!!! . . . Why not? You said I’m in perfect health!”

“You have type A-positive blood. Astronauts are required to have type O-positive.”

“That seems arbitrary.”

“No; it’s necessary. If someone got hurt, you couldn’t be a blood donor. The body of any O-type person would reject it. O-positive is the largest blood group type, so we picked that. Sorry.”

In Port

That’s a stiff one.

“Buy you a drink?”


“Ma’am, I’m trying to be considerate. It’s about your ship.”

“The Willow? What?”

“Thought so. Eh bartender!—A double algae on the rocks for the lady here.”

“What are you doing?”

“I think something bad is going to happen to the Willow. Just some talk I heard around the docks. Something about a defective neutron moderator.”

“Are you threatening me?”

“No. I’m offering a deal. I know these guys. Hold some sway. Might be able to convince—”

[leaving] “Disgusting. Keep your drink.”

Ed. note: we last saw Beth here.

Material Science

A song, broken by tears.

“What is it, my dear? What’s wrong?”

“I . . . I broke it, mommy!”

“Well, what did you break?”

[looks up with sorrowful eyes]

“You don’t mean . . .”

“It was dirty! I tried to wash it and—”

“Show me!”

The violin lay on the bed in a crumpled, twisted heap. Traditional violin bonding is water-soluble, and modern strings put nearly 50 pounds of pressure . . .

“I’m sorry!”

[examining] “Ugh, and the wood is all warped too. You should have called me sooner!”

“I’m sorry!”

[sighs] “Well, there’s no way to fix this at all. The wood is cracked and the water warped it more. Even if it weren’t, there isn’t a luthier within half a light-hour.”

“. . .”

“It’s okay sweetie. You couldn’t have known. You’ve never seen wood before.”


Artwork by Dizzy Chen.