Justifying why mind uploading destroys the brain

Question

So, in the relatively-far future, humans, in their endless quest for immortality, develop a form of mind uploading. This involves scanning the brain, cell by cell, and creating an electronic model of the neurone patterns in which all the information about the subject, their memories, likes and dislikes, is housed. This information represents the living soul.

However, in order to have the “soul” transferred rather than simply copied, the process has to destroy the nerve cells as they are scanned, so that the information is removed from the brain as it is reconstituted in digital form.

Why would the scanning process destroy the neurones? I am leaning towards a reason involving radiation or something like that destroying living tissue, but am open to suggestions. Please note that a reason need not be particularly in-depth, just believable.

Answer 1

Solution #1: your scanners don't have the penetration they need to read through brain matter (or skulls). There is no scanner with the kind of penetrative power you need to scan things at an atomic level without first getting rid of the matter that's in the way.

That is, in order to scan the second millimeter of brain, the first millimeter must be removed. The machine literally kills you during the scanning process, layer by layer, removing brain matter as it goes.

Fortunately it's a very quick process. The whole process is so fast that subjects report not noticing a thing. (In the Bobiverse series, this was basically their solution, except additionally they started with a cryogenically frozen brain, basically scraping through it layer by layer for the scan.)

Solution #2: the scanners are flawless. The original is destroyed on purpose. For a darker explanation, you could try what was done in The Fare. That story was about teleportation, but the short version is that it actually generated a copy, and the original was secretly killed. Perhaps the scanning process is completely non-destructive, but the implications of having two of you was a problem, so the copy process simply destroys the original as a separate act, by design.

Alternatively If I recall correctly, Old Man's War simply did the transfer and never fully explained why this caused the original to die. I recall thinking maybe there were some shenanigans that would be revealed, but really I think the "how" was not a focus of the story so it was glossed over. It just worked. If the "how" is not important to your story, you could do the same. The old you just loses brain functionality and it's never really explained.

Answer 2

This is extremely easy, I feel some answers are overcomplicating it.

It's more scientifically plausible that mind uploading WOULD destroy the brain than that it would leave it intact. This is because (in reality) there are two kinds of brain-scanning: non-destructive (including MRI, EEG, and all those) and destructive brain-scanning, which is done at autopsy.

Mind-uploading really just means scanning a brain fully/perfectly (as per this question). Naturally the best way to get a close look at a brain is to take it apart. The brain being intact in a head makes it hard to get a good look in there (real facts, not worldbuilding).

Answer 3

The No Cloning Theorem

Brains are special. The mystery of consciousness and free will was unravelled when we discovered the brain fundamentally relies on quantum behaviour to function.

It is impossible to take a quantum object and create an independent, identical copy. That means we cannot duplicate the brain while preserving the original object.

This is unlike, for example, a painting. We can duplicate a painting because we are not interested in the quantum probabilities of the various molecules.

Answer 4

Heisenberg's Uncertainty Theorem (Sort of).

This is in relation to particle physics - the more accurate you make the speed of (IIRC) a Subatomic particle, the more imprecise you make it's location and vice versa.

Brainwaves in a functioning brain have the same issue, even unconscious thoughts/processes cause 'traffic' in the Brain. Even relatively simple things like Breathing trigger so many neurons firing that the Scanner simply cannot keep up with the changes in order to map it correctly.

The solution to this is that the brain must be 'frozen' - that is, made so that all activity, conscious, unconscious etc. is stopped. This is to allow the Scanner to scan the ~2.5 Petabytes of data in the Human Brain in order to map it accurately.

Unfortunately this process isn't reversible - Neurons that have been 'frozen' (Not temperature frozen - I mean all activity stopped - although this could be done using a cryo-type tech) cannot be restarted and so the organic brain dies.

Answer 5

Synchronization issues

While your scanners are fast, they just are not fast enough. Especially if you want to be reasonably sure you did no major reading errors.

What you can do however, is to flash-freeze the brain and instead of recording the electrical patterns scan the frozen-in-place neuro-chemical state. Since the signals travel as a ion concentration shift, interrupted by transmitters and inhibitors, reading them provides the information necessary to recreate the exact thought-pattern at the time of flash-freeze.

The biological substrate can not be unfrozen fast enough to survive the procedure, thus the person being scanned dies. On the plus side, the frozen mind image can be duplicated since you can take your time before starting the digital substrate.

Live backups of a digitized mind may be difficult to achieve, since synchronization strikes again: Your band-with is just too low. To do a copy you have to slow down the digital substrate, but this has a chance of introducing sensory corruption, as the real world still runs normal speed and thus there's too much information for the slowed mind to work on.

Again there might be a way of "flash-freezing" the digitized mind as well, but it is a rather violent procedure, which literally fries the active pattern into the substrate. The chips and boards become trash, as the burned in patterns break them, but hey, you can use them as a kind of snapshot if you need to revive a mind. If you read them like a modern flash-drive recovery though (which is destructive), you may read them only once, so make a proper copy.

Radiation based: the return of synchronization issues

Your Hyper-CT scan literally fries their brain.

A simple CT / MRI is no problem for the brain to handle. But you need to be FAST. To prevent ripping the mind apart by desyncronization of sections of the brain, you have to scan each and every nerve, each electrical and chemical potential within that corresponds to neural information just about instantly.

In fact the maximum time you have is about a quarter of the time it needs for a single neuron activation to take place. As human neurons can fire at a rate of 200 Hz or slightly more that leaves us with (1/800 s =) 1.25 ms or slightly less. Lets assume 1ms and take the rest for safety margins. You want to be reasonably sure to get all relevant info, so you need MANY pictures and they must be taken all at once.

There are about 86 * 10^9 neurons in a typical human brain. We simplify the brain to a sphere. This means a diameter (in neurons) of about 1.24 (the volume-equivalent sphere diameter compared to a cube) times 4'414 (the cubic root of the total neuron-count), which is roughly 5'480. This is the absolute minimum number of scans you need to do, even if all where perfectly spread. To prevent overlap in your scans you could do spherical swipes, which leaves you at least at pi**2 times the scans. This gives us 54'085 scans, which is about 18.5% of the simple assumption (square-root of neurons count (about 293'258)).

lethality

54 thousand scans within 1 ms for a single full scan. (Of course you might want to do two scans to reduce read-issues...) The aproximate dosage of a CT of the head is between 1.6 and 3.2 milli-Sivert (mSv) depending on exact procedure and if there was a contrast substance involved. That leaves us with about 2.4 mSv * 54k scans for a total of 130 Sv. This irradiation is applied just about instantly.

Here's something about acute dosage:

• The LD50[@30days] is at 4-5 Sv
• The first guy to die from the demon core got 5.1 Sv and 25 days
• The second guy got 21 Sv and died after 9 days.
• Boris Korchilov worked in an unshielded live nuclear submarine reaktor. He had 54 Sv and died after 6 days. Your scan is running 2.5 times that!

Finally, since your scan is VERY LIKELY (read certain) to kill said person, you might want to do twice or more times as many scans to ensure data integrity. You don't have a second chance so you might throw any scans you can do and just average your results.

Answer 6

When you record someone's brain state, it's more than just figuring out where the electrical signals are and how the neurons are laid out.

You need to identify what the electrical potential is in each of the neurons, and pretty much count the number of atoms in every vesicle of every synapse. Doing so imparts energy to the system, which results in neurotransmitters being released, cells bursting, and electrical potentials being severely upset.

The brain is basically cooked from the inside. What's left is nothing like the one that you started off with.

Answer 7

Author John Scalzi handled this in Old Man's War, and since someone already brought this up, I thought I should add his way of handling the issue.

In the series, brains have three things: their physical state, their electro-chemical state (where the charges and chemicals are distributed), and lastly an energy field that is created by the first two things. The energy field is what creates "consciousness", and, importantly, can be transferred but not copied with the technology available (except in one side story).

Thus you can create a second artificial brain that has the first two components, but then have to transfer the conscious energy state from one to the other. The original brain isn't dead, but it's not conscious.

Answer 8

Currently, if you want an accurate 3D map of the brain you have to slice the brain in many thin sections. To get a map of the brain that is accurate enough to recreate it in a simulation you not only need to know how many neurons are at a particular location, you also need to know how each neuron is connected to every other neuron. There are ways to reconstruct maps of the brain without destroying it by viewing it from many different angles, like MRI or CT scans. These maps do not give enough resolution to resolve individual neurons. MRI for example can give currently give a resolution on the order of a few hundred micrometres, while axons (the wire-like structures that connect neurons) are on the order of about 1 micrometre.

So a solution based on current technological advancements is that imaging technology cannot give an accurate map of the brain without chopping it up into slices. I think that once the brain is dissected into many thin slices we would qualify that brain as destroyed. This slicing process is absolutely necessary to know how all the neurons are connected to each other, which in turn is necessary to fully preserve the memories/personality of the person. This would mean that scientist are able to run a virtual brain on the computer before we could image a brain without destroying it. At the current rate that AI is evolving this is not too far fetched.

Answer 9

You can't pause an uploaded brain.

The scanner processes one neuron, or one section of the brain, at a time, and it takes some time to complete. It might be only seconds or less, but it's long enough.

Say that the front half of your brain gets scanned first. That front half, as it's being assembled in digital memory, does not have a back half to communicate with, so it ceases function or behaves unpredictably.

This causes all sorts of problems when you then have to unify the back half into digital memory, since until then it was still communicating with the meat front half and suddenly finds that what is now the front half is dead or out of control.

You also can't pause the front while you're working on the back, because there's still this "desynchronization" involved — the back half suddenly finds that the new front half is now having the thoughts that it used to be having a few seconds ago.

These problems, ranging from psychosis to digital coma, are bad enough that mind uploading technology has to take a different approach: destroy one neuron/section/lobe at a time and relay the signals back and forth from the physical world as you go, Moravec transfer-style.

Answer 10

I agree with the answer by @wokopa that says it's scientifically likely that scanning would destroy the brain, and I just wanted to put some perspective on that.

Basically, producing a high fidelity 'copy' of a person would quite likely involve mapping every single synapse in the brain, and the issue is that there are really rather a lot of these. I'm no expert, but a quick google brought up this nature paper, which says there are 100 billion neurons in the human brain and $10^{15}$ synapses, which are the connections between neurons. That's 1,000,000,000,000,000.

Each synapse is a microscopic site where molecules and electrical impulses travel between neurons. To be fair, we don't really know how accurate the simulation would need to be in order to accurately emulate someone's thoughts and personality, but in the worst case, to simulate a person's behaviour accurately, you would need to know some microscopic details of every single synapse, as well as where they all are in space.

Now it's already very hard to imagine any technology that could scan something as large and complex as the brain at a high enough resolution to pick out individual neurons, but if you need to know details about each individual synapse then this is just out of the question - there would just be no way to do it without taking the whole thing apart and performing a miniature chemical assay on every single one. That would destroy the brain without question.

Of course, once you've done that it's all just digital data, and once someone has been scanned there would be nothing to stop someone from copying the data and running two separate simulations of the same person. If you need a way to prevent that it would be a separate question, and I don't really know how I would answer it.

Answer 11

People like it that way

If you're uploaded, that means every secret, every private memory, every password you know is now known by two entities, both of which think they are you. Furthermore, because of its strong similarity to the original, each can conjecture about passwords the other are likely to create and really just do an incredible job of impersonating them.

And not just two - the company that runs the brain scanner also keeps a record of your data, so even if "both" of "you" get along, the company has a hostage that they can interrogate arbitrarily.

After a few messy legal cases, regulations were imposed on brain scanners, requiring them to destroy the original and not retain any data, as well as making it illegal to copy a person's brainscan data except for backup, and illegal to run multiple instances of them.

This is important, because otherwise data can be copied after upload

Even if the original brain is destroyed, if your goal as a worldbuilder is one-human = one-mind, you need some way to address why the data of the brain, once uploaded, can't simply be copied. It's scientifically not possible to have un-copyable data on a computer; computers cannot read or transfer data without copying it, and the data needs to be copied at least once to get it off of the scanner.

Unless your world contains some unknown factors (magic) that physically prevent multiple instances of the same brain from running at the same time, legal restrictions are your only option.

Answer 12

What would happen if it did not destroy the previous brain?

Well, you could end up in a situation similar to time traveller conflicts - two people, who think they're the same person, at the same time, potentially meeting each other. Which is where things can get interesting...Except, of course, time travel isn't happening here, so there's technically no paradox...

More directly, that linked question refers to the idea of why time travellers in the Harry Potter universe would try to avoid being seen while making changes - seeing themselves would drive themselves mad. So you could apply the same effect here, since it's not quite a mirror image they're seeing, but a mirror image with autonomy, and that thinks that they're who they are.

Since this isn't time travel though, we could consider one additional wrinkle to the issue; did the brain uploading process stop after the brain was fully uploaded? Or are we getting continuous upload after the fact?

The brain scanner may not be able to be turned off safely

If the brain scanner is portable enough, it could be uploading to the uploaded brain continuously until the brain is itself no longer transmitting any changed information.

If the brain was still transmitting information to the uploaded brain's brain location, one brain all of a sudden is getting updated signals, and seeing themselves seeing themselves, moving in a way different to the way they're moving, and processing two people's worth of input and output.

Technically, if you could hold the uploading brain in place, and desensitized, this might be less of an issue, but then you run into the issue of the uploaded brain finding the desensitized uploading brain, and having to process that.

There may not be a technical reason to destroy the brain, short of the safety of the uploaded brain to prevent conflict when encountering the uploading brain.

Answer 13

In neuroscience to study brains, we usually stabilize them with formaldehyde, antimicrobials and tampon solutions to block any biological process and freeze their structure.

Then we fine-slice them and analyze them in various ways.

A scifi brain copy tech could perform very fine slicing (harder than it looks) and molecular scanning to exactly the structure and functional status of a brain. As it's obvious from my description that the subject is sacrificed (lab slang) in the process. Furthemore, the death should be immediate and possibly painless (on mice it's common to use either spinal dislocation, decapitation, lethal injection, etc) in order not to release a pain/panic/pre-death biochemical cascade that would greatly change its structure. If you would copy this status, the newly cloned individual would wake up in a quite distressed state (maybe going crazy directly).

Answer 14

"Moving" the consciousness, not copying it

We know perfectly well how to upload a copy of a brain. That's about as difficult as the average middle-school science project.

The problem is that people don't like that, because that means it wouldn't be them, but rather it would be a copy of them. This is true whether you destroy the brain or not.

So, instead, we needed to develop the technology to allow us to slowly move different parts of the brain, which involves rewiring the brain to replace those sections with machines and detaching the original.

Once this process is done, no functioning part of the original brain is left.

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Now one could make the philosophy argument that (1) cloning yourself and then killing the original, (2) "moving" your consciousness and (3) even just going to bed at night and waking up in the morning, are all functionally identical.

But you know how people are...

Answer 15

Scientific Coverup

Once the transfer is finished, a comparison of the new consciousness and the original person could reveal that the technology was pushed out before it was complete. However the differences were slight enough that they couldn't be detected except by comparison to the original.

Rather than lose out on funding the scientists concocted a story (see any other answer to this question, but maybe just pick one) for why the original brain needed to be destroyed as part of the process, codified that into the brain transfer process, and never give a satisfying answer as to why they refuse to undergo the process themselves.

Answer 16

However, in order to have the “soul” transferred rather than simply copied, the process has to destroy the nerve cells as they are scanned, so that the information is removed from the brain as it is reconstituted in digital form.

If souls do exist, we know very little about them. In the future, a way was found to scan brains very accurately, and simulate them but they just wouldn't function. Believing they just didn't get the scan, or simulation to work accurately enough, the process was continually refined, and one day a participant happened to die during the process, and for the first time the simulation came to life. While skeptical, other scientists tried to repeat the process on terminal patients, and came to the conclusion that for some unknown reason the original had to die, for a copy to function. Popular public opinion started believing that the reason was individuals had souls that would be drawn into an identical copy, if the original died. The reason is still heavily debated.