suppose scientists can clone any person both their body and mind. In one case I agree when I am sleep I am killed and cloned again. When I woke up I won't notice any difference. It is just like going to sleep and wake up again. I do not mind doing this if it was possible. I feel I survive the execution.

In case two I am killed when I am awake. They can restore my mind just ten minutes before execution. When it is one minute to the execution, through a monitor the scientist show me my clone which has been waken up. Now, I do not feel good! and do not think I survive my execution.

What is the difference between the two case? Is it the ten minutes delay? Then, how short should it be to feel as if I survive?

I don't think I am the first person to come up with this thought experiment. Are there any resources to study about this? What are the keywords?

  • 1
    I haven't been able to find the exact match, but I recall there is already a question here whose answers might address your question. You might consider using the search function if you haven't already.
    – Dave
    Commented Sep 29, 2016 at 12:23

4 Answers 4


The obvious difference is that someone is experiencing pain in the second scenario. Luckily you have empathy. Empathy evolved for a world that doesn't have cloning paradoxes, so maybe empathy would degrade if true duplicates were possible. (There is a movie about this, but I haven't seen it.)

PS: This goes on all the time at the cellular level, but individual cells are too simple to feel pain or deserve empathy.

  • However, most interestingly while old neurons may die and new neurons formed, neurons have in general the lifetime of the entire organism and many of them survive without replacement until its death. And given such a neuron, while most of its atoms are indeed recycled and replaced, nevertheless the atoms forming its DNA remain the same. So in a sense there is continuity of matter in the part of our body most relevant to our identity, of all places, our brain. Is nature afraid of personal identity paradoxes?
    – nir
    Commented Sep 30, 2016 at 4:45
  • @nir- The continuity of neurons implies that a repair/replacement process would degrade the stored memories. DNA would be an excellent place to hide actual memories, but there is no evidence for that.
    – amI
    Commented Oct 3, 2016 at 16:43
  • Can you provide some references to these ideas or are you just speculating? as a layperson, prima facie I would tend to suppose that fault tolerance is not more problematic in biology than it is in our software and hardware engineering.
    – nir
    Commented Oct 3, 2016 at 19:49
  • Have you ever tried replacing a component in a running computer? DNA atoms do get replaced during a continuous repair process, and DNA does hold the memory of ontogeny (and therefore phylogeny), but it would be too slow for the associations that we make via axonal memory. Neuronal damage is hard to distinguish from learning, since each alters memory. Biology is probably less advanced (despite eons of evolution) than technology at devoting resources to fault tolerance, and so we are left with the dementia of aging because our lifespans have increased faster than evolution could accommodate.
    – amI
    Commented Oct 5, 2016 at 17:15
  • There are plenty of academic results to the google search: fault tolerance in the brain. Coincidentally as a programmer I am working on a system which supports hot swapping of disks and other components. That is, you can pull a disk (broken or not) and replace it with a new, empty one, while the system is running, and the system will continue to work with no data loss.
    – nir
    Commented Oct 5, 2016 at 17:27

Right, you are not the first to think about this. You are right on the heels of famous philosophers:

Here is an interesting video from a documentary interview of the philosopher Derek Parfit describing a very similar scenario: https://youtu.be/uS-46k0ncIs?t=5m54s

A man enters the tele-transporter on his way to work on Mars; the button is pressed but nothing seems to happen. on coming out from the machine the technician informs him that due to a malfunction he was not immediately destroyed, but due to the biological damage he has taken in the scanning process he will die anyway in several days, but not to worry since he was successfully tele-transported to Mars.

The video discusses Parfit's book Reasons and Persons on the subject.

Here is another delightful video with a variation of the same scenario: https://www.youtube.com/watch?v=pdxucpPq6Lc

btw, there is a glaring hole in the scenario described in the animation. can you find it?

And you can probably find more pointers in the SEP entry on personal identity: http://plato.stanford.edu/entries/identity-personal/


I do believe these kinds of thought experiments are common. What makes them tricky is that you are exploring what it means to "clone a mind," which is not always a simple topic (and often avoided when talking about cloning in a dualist philosophy, because it can be trouble). There are countless thought experiments exploring what this could mean. However your combination of cloning and killing suggests that the Ship of Theseus may play an important role in your philosophical inquiry. You're effectively replacing parts of an entity, and having to question whether the entity remains "you."

The other tricky part is your use of the verb "to feel" in "... to feel like I survived." Feelings are not always simple binary relationships. Consider the case of out of body experiences. People who experience out of body experiences on the operating table typically describe seeing their body. Some even describe the process of departing from this body. None of them feel the event "simply didn't happen" after they woke up. Accordingly, you may have to consider a more complicated sense of feeling. You might wake up feeling like you survived, but then see your corpse on display later. After that occurs, do you still feel like "you" survived? Your feelings may be mixed at that point.


Humans are hardwired to survive so even if logically you view the clone as you and that you will survive that does not matter in the second scenario because the fight or flight syndrome will kick in, your brain will automatically start a chain release of chemical reactions which will heighten awareness,sight, and reflexes etc meant to help you survive,but you are trapped and cannot run or fight so that leaves only the intense fear that caused the reaction to begin with. A longer not shorter period of time awaiting your death would help because it would give you time to think and calm yourself.

  • 2
    your answer seems to be a speculation about the psychological reaction of a subject undergoing such an experiment, while the question is a philosophical one. while you are supposed to imagine what it would be like to undergo such a thought experiment, it is to the extent that it enables you to examine your intuitions about personal identity and it is not clear what the speculated psychological reaction has to do with it.
    – nir
    Commented Sep 30, 2016 at 11:42
  • He was asleep in example 1 and therefore he had no personal identity, he says how in in example 2 that he feels bad and does not think he survives. Even during a thought experiment people can have reactions similar to it being a real life scenario. His personal identity at the time of imminent death is only with that version no matter how many clones exist . Now if his consciousness was somehow downloaded into a computer and also linked to him I don't think he would feel the fear because he would know that his personal identity is safe and he survives. I view a clone as copy but not as me.
    – Mr. Durden
    Commented Sep 30, 2016 at 12:39

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