don't know if anyone will read this, but just a random thought I had:

Try to imagine the following: you wake up in a hospital bed, with no recollection of how you got there. You look over at the bed next to you and see a person who looks identical to you, down to your birthmarks and scars, staring back at you. You talk for a moment and realize that you both identify using the same name and seem to share childhood memories. The other person also has no recollection of how they got there.

Please someone explain to me, how you would argue either that you know you are the original or argue for why you can't possibly have that knowledge. While forming your argument, please also explain where "you" are and who "you" are.

You may want to consider issues such as what it means to Know what your identity is, what identity means, and whether it even makes sense to claim that your identity even survives.

  • Too broad for this site; it's not a bad question but for these very subjective questions you have to narrow down the scope as much as you can so you aren't asking people to write whole novels. What you ask is a huge question in philosophy, touching on many ideas which you yourself name — identity, personhood, what it means to to be the "same" person over time, etc.
    – stoicfury
    Commented Feb 10, 2015 at 10:45

4 Answers 4


I responded to a similar question here. If we would split my brain would there be two of me?

And in that answer, I reference my answer to an even earlier incarnation of this same question ... Assuming a mind could be uploaded, how would we know if it worked?

You can read both of my prior responses for the details.

The analogy is with an executing process spawning another process in a multi-processing computer operating system. At the moment of the spawning operation, both processes are identical, having the same execution state. From that moment onward, they're separate processes each having a private memory and their own state.

It's a very well-understood phenomenon in computers and it's a perfect analogy for how instantaneous cloning would work. Same way the Star Trek replicator would work if it preserved the original as well as the transported version of the person being transported.

Now there is a refutation of the entire idea of this type of cloning, including Star Trek-like matter transport. The problem is that in order to reconstruct an atom-by-atom copy of anything, you have to measure each atom to sufficient accuracy. The inherent uncertainty of physical measurement, both classical and quantum, would most likely prohibit sufficiently correct measurement to product a perfect copy. Rather, all the copies would be subtly broken, like Jeff Goldblum's early experimens in The Fly.

  • Interesting refutation. Would that also be like the Heisenberg Uncertainty principal where measuring an atom will alter it in some way? Thus, the original would have the altered atoms while the clone would have the unaltered atoms.
    – Okopp
    Commented Feb 9, 2015 at 5:12
  • @Okopp Yes, you couldn't measure down to the atomic level without changing it. And you can't measure both position and momentum to arbitrary precision. That's also Heisenberg. But even in classical physics, all measurement is approximate. Teleportation needs to measure the exact position of trillions of atoms. It seems very unlikely even with advanced technology.
    – user4894
    Commented Feb 9, 2015 at 5:28

I think this may be close to an opinion question, because there are ways it can be answered both yes and no. It is very dependent on how you define "person," and that definition is not agreed upon.

Consider the legal hoops. Siamese twins are considered distinct individuals legally, even though they share a body. On the other hand, if this were easy, consider "expendable" yous. If you could clone yourself just before committing a murder, and have your clone do it, did you get away with murder?

Each religion, of course, would have its own thing to say about cloning. If you followed a religion, it should have something to say about this cloning event regarding ownership of "the real you."

In the end, the answer may be that you are each yourself (no special behavior there). However, society is going to have to give you room to share a history between yourselves. Or, along those lines, you wake up as "one person in two bodies" and effectively get a divorce from yourself, where each gets half of your "life." After all, the only things that cannot be shared are things that must, for one reason or another, be owned by a single mind in a single body. Most consider the best parts of life to be those you can share.

  • Thank you for shedding light on the subject. The siamese twin point is interesting. Would just the fact that their brains would receive different blood molecules change their experiences is some finite way that would ultimately change their personality?
    – Okopp
    Commented Feb 9, 2015 at 5:14
  • That is an open question. I like to believe that there would be a difference, but whether one wishes to treat that as two different individuals, or if one wishes to treat them as we do a right hand or a left hand, that becomes a very interesting question with broad reaching implications.
    – Cort Ammon
    Commented Feb 9, 2015 at 5:33

Opinion-based, but with some thought: I would consider the two individuals as very different people.

First, 'real' cloning means that one has been grown from part of you at a different timeframe altogether, without similar memories, and potentially very different environments and experiences. I assume, though, that you mean an instant replica.

I think the second a replica is made, each individual begins having different experiences to differentiate themselves. Ex: The one closer to the door, may want to exit, while the one closest to the window is thinking about the weather. Their similarities may even drive their behavior to be purposefully different from each other, as many siblings are thought to do.

At that 'instant' of replication, I don't know, but immediately after, they are already two very different people. They can then fight over who gets to keep the name, possessions, etcetera.

Interesting question. And a light side-note, in agreement with my 'answer': a friend, who is gay, was speculating on whether he could date a replica of himself. He concluded that he could not, as they would drive each other mad. Sometimes similarities drive people behaviorally into very different people.


You talk for a moment and realize ....

This only remark itself shows that the other person is different because he is answering your question. Otherwise he would be repeating the same question you are asking; as in a mirror.

What I mentioned above is the case in duality.

But Non-duality says Tat tvam asi

And the 'you' you are trying to find out is YOU

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