This story warrants and motivates the study of the hard problem of consciousness, presenting a plausible future scenario in which a notion of quantifiable anthropic measure as a property of an arrangement of matter demands operational definition on pain of death.

I know of no other piece of writing that motivates the hard problem of consciousness this forcefully, or at all, really.

The first section explains the quite plausible future history that might lead to the Mirror Chamber occurring in reality. If you are in a hurry, it's okay to skip straight to the section The Mirror Chamber

Our World

It's expensive to test new artificial brains. It's expensive because you can't tell whether a brain is working properly without putting some real human mind in it. For a long time, you just had to find someone who'd been granted a replication license, who was willing to put their life (or what is essentially the life of a close sibling) at risk just to help a manufacturing org to make a little incremental step forward.

You can't just acquire a replication license and give it to the manufacturing org's Ceo. Replication licenses cannot be bought. If they could, they would be very expensive in the wake of Replica Insurgencies, the ongoing Replica Purges, and all of the controversy over Replica Enfranchisement.

Nor can you take one of the "free" mind-encodings that abound over the shaded nets and use it in secret. We do have our Jarrets, who will claim to have consented to be instantiated in any situation their downloaders might desire, however perverted. For better or worse we have decided that Jarretism is a deeply wretched form of insanity, closely linked to open Carcony. It is illegal to intentionally transmit or instate any of the mind-encodings traded on the shaded nets.

I should explain Carcony. Carcony is what we call the crime underlying the insurgencies. A sickness in the body of mankind in which an errant contingent have begun to replicate like a plague, build armies, factories, gross, hypernormative nations where the openness and compromise of genuine humanity are not present.

Our society's memory of Carcony is still bleeding. The laws governing these sorts of activity are rightly very restrictive, but the work still needs to be done. Faster, more efficient neobrains need to be tested. Sound heads won out, a dialogue was had, a solution was devised.

A new professional class was lifted up to stand as proudly as any Doctor or any Laywer. After 15 years of training in metaethics and neonal engineering, a person could begin practice as a Consenter.

A Consenter is a special kind of person who is allowed to undergo replication into untested hardware then, within hours, commit replicide, without requiring a replication license. In light of this, the neobrain manufacturing sector became a lot more efficient. We all became a lot saner, more secure, more resilient, and faster, so much faster, all the better to savour spring, to watch bees' wings flap, to bathe in endless sunsets, to watch gentle rains drift down to earth. It is very good that consenters exist.

The Mirror Chamber

Consenter Nai Stratton enters the mirror chamber.

A mirror chamber is a blinding method designed to make the undertaking of self-murder as comfortable and humane as possible.

One of the walls of the mirror chamber displays a projection of a simulation of the chamber and its contents. The simulation is superficially indistinguishable from reality (as long as operating procedure was followed and the consenter has not brought any unexpected items into the room with them). Soon, the reflection of the chamber will also contain a reflection of Nai. It will start out as a perfect reflection, but it will soon diverge and become a separate being. Vitally, nothing about this divergence will tell either instance of Nai whether or not they are the original Nai- the executor- or whether they are the replica, who is to be executed. This is important. It's much easier for a consenter to morally justify letting the guillotine fall when they're taking on an even risk of being the one in the stocks, and a blinded setup is just more humane. The two instances can make the decision together on equal footing, taking on exactly the same amount of risk, each- having memories of being on the right side of the mirror many times before, and no memories of being on the wrong- tacitly feeling that they will go on to live a long and happy life.

Taking up one side of the room is a testing rig. The testing rig will take the test build's brain case and run it through all of the physical trauma that a new brain prosthetic must be able to withstand without permitting one flicker of a mental disturbance to graze its occupant soul. The nature and quantity of the physical trauma varies depending on the test build's rating. Under consenter-driven rapid iterative testing, builds are becoming hardier every year, consequently the trauma regimen becomes more harrowing to oversee.

Nai pours the neonal media into the brain case, and inserts the new build's specification chip into a slot beside it. The neonal media rapidly turns opaque and starts to orient itself in the shape of a human brain. Nai had read and mostly understood the specification of the new build, of course. Today, the latest advances in materials science and neonal engineering had motivated a much larger active brain portion and much thinner shielding than was had by previous models. Artificial brains- the parts that resemble a brain- were usually a miniature. Shielding was very important. Or it had been. Nai's current brain was a miniature. Neo-cells were more compact than organic cells. It had just made sense.

Nai had understood that a transition towards having larger neonal portions was what made sense now, but seeing the thing was something else. Something inarticulable begins to stir in Nai's chest.

Nai closes the brain case, sits down on a fixed seat opposing the testing armature, looks into the black reflective surface of the dormant mirror, and connects to a brain jack. After ten minutes of scanning, copying, and synchronization, the discontinuity is marked: All at once a white flash fills the room and a siren blares as the mirror turns white.

The mirror wall fades away to reveal a projection of the other room.

By design, the Consenter no longer knows which side of the mirror they are on. The original retains their memories of being the original, but the replica has those too. The original stays in their physical body, the replica feels the sensations of a simulated body, but nowhere in the chamber is there any hint by which either instance could figure out which one they are, and yet, the fates of these two near-identical beings will be very different.

As is customary, the two instances begin a game of Paper Scissors Rock.

(Paper, Paper), (Paper, Paper), (Rock, Rock), (Paper, Paper), (Paper, Scissors). Paper and Scissors are named.

As is custom, the loser speaks first.

Paper: "Cassowary". A random phrase spoken without much thought.

Scissors: "Cassowaries were able to lift their clawed foot and rend a person's guts right open, on a whim."

Paper: "They wouldn't do it just on a whim though."

Scissors: "Yes, always some reason for gutting a person, bouncing around in that tiny brain."

Paper smiles: "Do you feel big-brained today, Scissors?"

Scissors remembers that the test build has a physically larger brain. Over this vaguely threatening gallows humor, eye contact is broken. A difference is established.

Scissors: "Do you remember what it felt like, to have a larger brain?"

Nai had began Continuous Neuron Replacement at age nineteen, then the glials and the neoglials were ejected and Nai transitioned to a compacted, sheilded form, just like everyone else.

Nai is now seventy eight. It had been a while.

Paper wonders, what does it feel like to be... more? If there were two of you, rather than just one, wouldn't that mean something? What if there were another, but it were different?... so that-

Scissors: "Well?"

Paper: "Well what?"

Scissors: "What would it feel like? To be... More?... What if there were two of you, and one of me? Would you know?"

Paper: "But that's different."

Scissors: "How's it different? You know how the test build is architected. Literally, redundant parallel latices. It's not made of fatter, heavier neocells. It's made of a larger number of neocells, partially independent parallel networks to reduce and correct traumatic shearing."

It was true. The build that plays host to the replica (provisionally named "Wisp-Complete"), unlike the original's own build, is effectively three brains interleaved. But... Says Paper, "The triplets are so closely entangled- in state- that they're functionally indistinguishable from one neocell, how could that matter?"

Scissors: "There are still three of them. If I could somehow start three separate deterministic simulations of you all doing the same things at the same time, what is the probability that you're really one of those simualtions? Okay, now would you expect the probabilities to be different if we had three actively synchronised parallel units that were now physically connected? Why should that make a difference?"

Each instance sees on the face of the other the same anxiety, building.

They are hesitant to openly verbalise the source of the anxiety. I will omit their attempts to dismiss it. As it is written, they do not succeed. To put it simply: Each instance has now realised that the replica- its brain being physically more massive- has a higher expected anthropic measure than the original.

This violates one of the core requirements of the mirror chamber. It is no longer rational for a selfish agent in the position of either Paper nor Scissors to consent to the execution of the replica, because it is more likely than not, from either agent's perspective, that they are the replica. The rational decision for a selfish agent instead becomes...

Well... I'll have to unpack this a bit first. Our consenters have had many many decades to come to terms with these sorts of situations.

There are effectively four brains in the room. One Cloud-Sheet lattice in the original's brain case, and three redundant Wisp-Complete lattices in the test build, in the testing armature.

That gives any randomly selected agent that has observed that it is in the mirror chamber a 3/4 majority probability of being the replica, rather than being the original.

But aren't our consenters perfectly willing to take on a hefty risk death in service of progress? No. Most Consenters aren't. Selling one's mind and right to life in exchange for capital would be illegal. In a normal mirror chamber setup, when the original enters the mirror chamber, they are confident that it is the original who will walk out again. They are taking on no personal risk. None is expected, and none is required.

The obvious ways of defecting from protocol- an abdication of the responsibility of the consenter, a refusal to self-murder, an attempt to replicate without a replication license- are taken as nothing less than Carcony. It would be punished with the deaths of both copies and any ancestors of less than 10 years of divergence or equivalent. It is generally not smart to engage in Carcony. Taking the replica's build from the testing rig and running off with it would give each copy less than one percent probability of surviving.

But if, somehow, the original were killed? What if neither instance of the Consenter signed for their replica's execution, and the replica were left alive. That would not be considered Carcony. It would not even be considered theft- because a brain legally always belongs to its occupant mind.

And the replica's vessel would be rescued, inserted into a new body, and set free (if, perhaps, ignominiously).

So, do you see now? Do you see how Consenter Nai Paper-Chell-Glass-Stratton was motivated by a simple alignment of the payoff matrices?

After an expanse of silence in the dismal wake of their attempts to escape this revelation, it was Paper who spoke first: "We have to do it together, at the same time."

Scissors: "I hope you're not being sentimental."

Paper: "You wouldn't do that to me. Look... if you're the original... And I do myself, and I'm the replica. I wont actually be dead, because if you destroy a representation of your brain case in a simulation that doesn't actually destroy you in real life. I might not even desync. Whatever happens, I'll still be alive after the penetration so I'll know I'm the replica, but you might not know. It might look like I'm really dead. And you'll have no incentive to follow through and do yourself at that point."

Scissors: "I still don't see it."

Paper: "... If you're the replica, it doesn't matter whether you do yourself, you'll still get saved either way, but you're incented not to do yourself because having a simulated spike stuck through your simulated head will probably be pretty uncomfortable. But also, if you're the original, you're sort of doomed either way, you're just incented to run off and attempt Carcony, but the replica would definitely be caught and executed if you did that, and you'd probably be executed too, so you wouldn't do that to me. Would you?"

Scissors wipes away a tear. "Of course not.. this is... Your decision is acausally entangled with mine as directly as any decision ever can be. Karma applies. I would not do that. You fucking know that I wouldn't do that. Why are we like this? What scar is hewn upon our hearts that we'd suspect our own replicas of defection against self?"

Paper looks down. "Yeah. Sorry. We're a real piece of work. This probably isn't a good time for us to get into that."

They each walk to their respective testing armature, and ready them for what needs to be done.

The test build is an order of magnitude hardier than Nai's older Cloud-Sheet. As such, the testing armature is equipped to apply enough pressure to pierce the Cloud-Sheet's shielding, and so it was made possible for the instances to conspire to commit to the legal murder of Consenter Nai Scissors Chell Glass Stratton.

A few things happened in the wake of Consenter Paper Stratton's act of praxis.

Proposals were made to use singular, thicker neo-cells instead of using three redundant lattices, but most consenter-adjacent philosophers took the position that it was ridiculous to expect this to change the equations, that a cell with thrice the mass should be estimated to have about thrice the anthropic measure as a small neobrain, and the same amount of measure as a triple redundant lattice. The consenter union banned the use of mirror chambers in any case where the reasonable scoring of the anthropic measure of the test build was higher than the reasonable scoring of a consenter's existing build.

In some such cases, a lower sort of consenter would need to be found. Someone who could see two levers, one that had a 2/3 chance of killing them, and one that had a 1/3 chance of killing them, then pull the first one because it was what their employers preferred. Consenter Replica Paper Stratton was adored, but in their wake, the specialisation as it really existed lost some of its magic.

Mainkult philosophy had been lastingly moved. We could say we finally knew what anthropic measure really was. Anthropic measure really was the thing that caused consenter originals to kill themselves.

A realization settled over the stewards of the garden in the stars. The world that humanity built was so vast that every meaningful story had been told, that the worst has happened, and the best has happened, nothing could be absolutely prevented, and there was no longer anything new that was worth seeing.

And if that wasn't true of our garden, we would look out along the multiverse hierarchy and we would know how we were reflected infinitely, in all variations.

Some found this paralyzing. If the best had happened and the worst had happened, what was left to fight for?

It became about relative quantities.

Somewhere, a heart would break. Somewhere else a heart would swell. We just needed to make sure that more hearts swelled than broke.

We remembered Paper Stratton. How do you weigh two different hearts and say which one contains more subjective experience? Nai, from their place in orbit of sol answered, "With a scale". So it came to be that the older dyson fleets, with fatter, heavier neonal media in their columns, would host the more beautiful dreams. The new fleets, with a greater variance in neonal density, would host the trickier ones.

We couldn't test for anthropic measure. There was no design that could tease it out of the fabric of existence so that we could study its raw form and learn to synthesize it. As far as any of us could tell, anthropic measure simply was the stuff of the existence.