With the recent glut of teleportation technologies showing up, we now have a situation where two [initially] identical copies of a person can exist at the same time.

Consequently, while their brains start out identical, they accumulate different experiences and memories.

Supposing we can't afford to keep these clones around long term, so the telecloning technology is used to make duplicates at remote locations, where the clone has the subjective experience of "being there", and when they're done with that they step into the "teleporter" that will take them home, where they are scanned and disintegrated.

The original is also taken into a corresponding machine which receives the scan, and then the clone's memories are spliced into the original. Essentially Total-Recall style.

So staying as close as possible to our current understanding of human neurology and the way in which memories are stored, how do we explain the operation of this technology, which manipulates a brain to combine all of the experience of two clones? Also, what caveats are there?

Leave the physics of actually manipulating the brain out of it. We have teleporters, so we use that technology to scan both brains and to beam out the original brain and beam it back in with the merged memories. It's the neurology that's interesting. Do you have to fundamentally rewire things in a form that is similar to neither of the originals, or do you just subtly tweak the strength of connections, or what? If the science is absent, invent it.

I assume that if the wrong person steps in there and their brains are found to be incompatible, the process aborts, and the clone does not die. This could, in some situations happen even when the clone is the right clone, but something serious has happened, like a head injury.

I acknowledge that the clone, being a perfect copy of the original and having all the same sense of self preservation may have reservations about stepping into a dematerialisation machine. To address this, we attempt to socially condition people before they're telecloned. Making them understand that when they wake up and discover that they are a clone, that the return trip which dematerialises them will not mean their death because the reintegration of their experiences will result in them appearing back home (among their friends and family, so they're motivated). This doesn't have to be accurate. They just have to believe it.

  • $\begingroup$ As a side note; since the original is the one whose body is being retained, that's probably the one who spends the most time in the gym. We still need their memory, though, because there are mental and neural factors involved even there. $\endgroup$
    – sh1
    Commented Jan 30, 2016 at 19:25
  • $\begingroup$ I would hide some of my clones. Just in case, and because I'd feel guilty destroying myself. Even if they were clones. $\endgroup$ Commented Jan 30, 2016 at 19:45
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    $\begingroup$ Runaways would certainly be a significant consideration in this world. $\endgroup$
    – sh1
    Commented Jan 30, 2016 at 19:52
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    $\begingroup$ As an odd quirk: we do similar every time we send children to school to learn about the experiences of their predecessors. $\endgroup$
    – Cort Ammon
    Commented Jan 31, 2016 at 2:04
  • $\begingroup$ @sh1 Why retain the original body print? If this is light-speed telecloning to distant systems, the cloned pattern will be a much younger version. It's the local pattern that will have clocked the most time. $\endgroup$ Commented Feb 1, 2016 at 10:45

3 Answers 3


Of course, we don't know how to do this yet, even in theory. But it is fun to speculate.

I think we can assume that different people will not be mergeable, the differences are simply too big. In fact, I think that teleport-clones can diverge to the point where merging will be inadvisable. However, that will probably take years.

To avoid jarring discontinues, I sternly suggest that all scanning and merging take place while the subject is unconscious, sedated if necessary. That way they will wake up with two different "yesterdays" instead of two different "five minutes ago". In other words, no short term memory.

We know quite a bit of how memory works, a quick Google search gives this link from LiveScience. In short, memories are stored as very small changes to existing cells, sometimes a single molecule can make a difference.

This means that our scans have to be very detailed, which again means that storing or transmitting it will be expensive. On the other hand, the same technology should be able to solve just about any medical problem.

To get the best results from a merge, you really need (at least) three scans. One stored historical scan from the point of divergence, and the two (or more) present versions that are to be merged. That way you can see what has changed from the past to each present version and put both (all) sets of changes into the same template. One can make a merge from just the present versions, but that would result in a lower quality result.

One problem is that human memory isn't designed for storing too many memories. As people grow older, memories grow fuzzier and fuzzier. This is probably an effect of trying to store too much in a limited space, and I doubt it can be helped. Repeated splitting and merging will make this worse.

If you have a hundred subjective years of memories it doesn't matter if they have been accumulated serially or in parallel. That head is full either way.


You're talking about something the "fax-machines" of Wil McCarthy's Queendom of Sol series. Those were nano-tech three-D printers that could not only fabricate objects on demand, but store, transmit, and retrieve patterns for human bodies - including merging divergent copies of brain patterns as though they were digital documents. (Lots of hand-waving there.)

One of the big selling points was that the merged-to body could be retrieved from a (digitally enhanced) archive - a healthier, younger version of the scanned pattern. Of course, the major hurdle of introducing the technology into accepted use was that to use it you had to be disintegrated. But once that hurdle was overcome...

... Towards the middle of the series a colony world was producing children by computer-generating body-mind patterns based on the parent's DNA and 'educated' with standard skill sets and certified stable personalities, then printing them out as teenagers. Avoids all that messy potty training. ...

Anyway. The key idea was that with enough computing power, the pattern in the "teleport buffer" can be stored and manipulated like any other (massively complex) computer document.

And this introduces a whole mess of weirdness you may not anticipate, because if you can manipulate brain patterns to safely merge divergent experience, consider what else can you do with body patterns?

Backups, edits, and splices really complicate a teleclone setting.

Fax in with a broken leg, fax out with a whole one.

Breaking your legs too often because fax-healing is too convenient? No need for surgery. Just have your archive updated with the latest biotech reinforcements.

Need to be in two places, fax yourself into two copies then merge at a later date. Hey, maybe one of them can perform that leg breaking activity while the other takes it easy?

Hey, one of your copies just killed Bob. Okay, we just have to reprint him from his archive, but...

  • $\begingroup$ Your last paragraph made me wonder. Would we hold the original responsible for crimes a clone committed? What about all the copies of a murderer? Each one did it, in a sense... $\endgroup$
    – Zan Lynx
    Commented Apr 29, 2016 at 2:44

You need ability read and write memory traces. Or whatever the correct term is. I think it would probably be derived from the technology used. And probably be trademarked by the original developer.

Human memory is associative. The fact that the memories from different sources overlap in time and possibly in space means nothing to your brain. An attempt to reconstruct what you actually physically saw during an event with more than one copy present might be confusing, but that is about it.

If the merged periods are extended enough for the merged clone to develop significantly different opinions or attitudes, the merged memories would probably feel dream-like because the person they are from would feel different from yourself. So there should be some sort of a time limit between "merge and disintegrate" and "you now have an identical twin". Letting the clone actually choose might be a good idea as it would avoid messy moral questions and avoid security issues. I think splitting the customers property between the two clones and revoking his teleport license due to misuse would be enough to stop this from being a problem. You should also require a large sum of money security that you lose to the company to compensate for the costs of setting up a clone.

As Graham Kemp notes in his answer such editing has lots of implications. I'll refer you to his answer for the case of being able to fully edit the teleport target and just add some notes on the minimum required technology of being able to manipulate just the memories.

This would still enable imprinting skills and education. It would also enable editing the opinions and values of people. And scanning your memories for anything of interest to the state and the teleport company.

The company could for example imprint a memory that you prefer to use particular brands of products and use the advertising income to cover the costs of teleporting. Or just scan your product preferences and sell the data.

The state would routine scan people for signs of crime, extreme political opinions, and mental health issues. All of which could also be edited out. Civil servants and politicians could be scanned for signs of corruption and imprinted with good professional ethics and the background information needed for their duties. Private companies might do the same.

With everyone having high ethics, morale and basic competence for their duties the society would be safe and very efficient. This might lead to a situation where people are so satisfied with how things are that the society stagnates. After all it is too easy and tempting to edit out bit too much of any discontent people have.

There would have to be fairly strict system of oversight to control the memory editing. In practice that would probably require making backups of peoples memories and using comparisons to stored memories to detect any tampering and if necessary to restore proper memories. This would imply that all your memories would always be available for reference from the archived copies and that the information storage and management capacity of the society would be very large.

Additionally there would probably be some sort of cybernetic implant that would manage the memory editing functions and contain very solid anti-tampering and verification functions. The implant would have its own implications. For example it would probably be the default system for identifying people and doing payments.

  • $\begingroup$ Depending on the nature of the human brain and the way it stores things, it may be feasible to achieve a splicing of similar consciousnesses long before it's feasible to understand the contents of either brain. If every idea is editable in transit, then you end up with things like this. $\endgroup$
    – sh1
    Commented Feb 2, 2016 at 17:21
  • $\begingroup$ @sh1 I tried to strike a middle ground that IMHO corresponds to the level needed for splicing memories safely as per scenario. So you'd be able to analyse, remove, write, and overwrite memories, but not necessarily read or edit the details of memories. So you'd be able to recognize undesirable memories and replace them with desirable memories, but not see the details of the issue or tailor the replacement to the individual. $\endgroup$ Commented Feb 2, 2016 at 17:44

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