Hope this is the right board for this…

Suppose some wacko scientists kidnap you. They freeze you somehow so that you stay in the exact same state, and every cell will remain the same.
Then they clone you so they have two EXACT same copies. They put you on the left, and the clone on the right

Next they painstakingly switch your cells, one by one, and attach them to the clone and his (hers) cells to you. Untill finally, you have completely switched places.

Then they revive you and the clone. Which one are you now, the one on the left or the one on the right?
Now, what if they would do this while you are awake (I don’t care how, nano technology, or whatever, it doesn’t even matter if it’s possible or not). Switching one cell won’t make you another person. But eventually they will all have been switched. So will there be a moment when you think “hey, just a while I ago I was on the left, and now all of a sudden I’m on the right?”?


Come again?

Sounds like a variation on the old ‘How does consciousness tie into matter’ question.


isn’t the question clear? it might be because of my English (I’m form Belgium)…

Let me ask a different but similar question.

Suppose scientists replace one half of your brain with a cloned half which does the exact same functions. Then they take the half that they replaced and put it inside the clone where they took the other half from. So you switch half your brain with an exact clone (I don’t care if it’s not possible, suppose it is).
Which one of these two will YOU be?

First of all, clones are not exact duplicates. They may have the same DNA, but they will not have the same number of cells, organs will have developed differently, etc. If they were somehow to create an exact copy, then the switching of the cells would not result in any change. (There would be 2 of you frozen having the exact same thoughts and personality, and so each cell that was removed and replaced would be exactly the same.)

still “you” would only be one of the two. and what is it that would distinguish (sp?) you from the copy? your “soul”?

The question is not clear.

here’s a re-wording of it.

If someone did an impossible and poorly specified thing, ignoring the fact that it is impossible, what would be the outcome?

Given that you are defining an impossible and implausible scenario, the answer is whatever you want it to be today.

Perhaps you just didn’t mean to put this ‘question’ into a forum described as

Unfortunately, there is no factual proof of the existence of a soul. Therefore, we must assume that everything making you “you” exists in the known universe. Each of the bodies would think of itself being itself; it would have no concept of being on the right or the left, else the cells would not be in the same state.

This is the standard “what if there were ST style transporters?” question. How do we know it’s really the same person who comes out the other end?

This is not something that will ever be do-able. Really.

I recon that if you did somehow duplicate a person then both copies would at the first instant be the same person. If it was you then they’d both say they were you. They would start to develop as separate individuals from then on as their experiences began to differ.

Or maybe if you copy someone you always get a good copy and an evil copy?

The question makes perfect sense to me. There’s an excellent book on this, the title and name of the author of which escape me, as I read it years ago whilst studying philosophy. The way the matter was stated in the first post is often used in philosophy of the mind and when they do they often use it as a “thought” expirement by which they mean that the the fact that we can imagine the scenario is enough to make the questions it raises valid. Mind you, whether and when this holds is a bit controversial. Nevertheless, I think the question is interesting enough (but may be a Great Debate) and Fall didn’t really deserve the grumpy replies (s)he got.

As for the answer…This one has always does my head in. Some vague musings. I think it is not so much the soul as consciousness that causes problems when you want to say that the identity is somehow split between the two clones. If seems strange to say that two bodies can share one consciousness as the fact that you could be in two places at once would seem to defy logic. Well instinctual logic, at least. So it seems that you could only have one body per consciousness. I would venture a guess that the reason you can’t have the same consciousness at the same time is that from the minute you are aware of anything you are not in the same place, therefore have different experiences and therefore are not the same person. So the minute you start this experiment you already have two different persons. Which one corresponds to the original seems to me to be arbitrary.

p.s. Sorry is this argument is a bit muddled. My philosophical skills are a bit rusty.

If an object is replicated down to the very smallest detail, that every single quantum state and/or string is identical then there is no difference between them. It would be like asking “what’s the difference between two photons?”. There is none.

The fact that this procedure is likely impossible makes the question more of an exercise in theology. I mean for the question to be debated, you need to introduce the assumption that each of us possesses a uniquely, unreplicable essence. That’s a fairly grand assumption.

But photons don’t have brains. What I was trying to get at in my previous post is that the minutes the to identical persons perceive anything ever so slightly different, they will be different. As they are of necessity not in the same place, a difference, if ever so slight would immediately occur. You don’t need any essences to explain this as you could presumably see a slight difference in brain activity if you had sensitive enough measuring equipment.

@ Small Clanger : obviously, I started thinking like this when I was thinking about transporters :slight_smile:

PookahMacPhellimey : thank you for defending my question (sorry if it’s in the wrong forum). your post makes sense. so you’re saying we become a different “person” all the time, we just think we are the same person, right? (I tought of that too, so to further complicate it all, I said both the original and the copy would be frozen)?
but if that is true, isn’t that kind of depressive? we die all the time, being replaced by a different instance of ourselves that still thinks it’s the same person, but really isn’t.

There’s another version of the question that might be a little clearer:

Suppose you have two ships of the same make in a harbor. You begin switching their various parts, one at a time, until you’ve switched all of them. At what point did the ships switch places?

Hmmm, not sure I did say that, although it might just follow from my argument. What I was saying is that the two cannot be the same person because right from the word go they are having different experiences. I think what I’m clumsily trying to get at is that I think personal identity is defined by conscious experience and memory (consciousness over time, if you will). So at the stage when there was only body there was one person: simple. At the time there were two, there’s two, sorry to be stupid about it. BUT, I hear you cry, what about the exact point in the middle? What I’m saying is that it is impossible (and logically impossible rather than just physically impossible) to have two bodies in the exact same state of conscious experience because they are not in the same place. So basically I would say that what you’d end up with is two people who can remember being one person. Which sounds bizarre but to me not as counter-intuitive as saying there are two persons running around who have the same consciousness.

“You” would be both of them. Both the original and the clone would have the same exact memories and personality.

Now if you’re asking which body your consciousness would be in after being unfrozen, well, there is really no answer to that, because there would now be two of “you”, with the exact same consciousness. So both bodies would think that their consciousness had passed directly from the original “you” to them.

Of course, the two "you"s would immediately begin to diverge into separate individuals, much like the you that exists right now is different from the you that would have existed had you not posted this question. They would both still be you. Just different yous. Likewise, the two clones would both be you, they’d just be different yous.

No, the OP states that every thing is identical. That means everything down to the smallest physical piece of matter/energy. Every single quantum string in the “clone” is expected to be identical in energy, topology, etc. (Note. WILD HANDWAVING ASSUMPTION. I’m assuming that the background structure of the universe is uniform in effect around these two twins). My photon analogy is fine, two photons of equivalent energy are identical, protons et. al. are the same. So if two quantum particles can be indistinguishable, what’s to prevent a collection of 4, or 1034 particle pairs from being indistinguishable? Nothing that I can see. Unless you posit an unknown quality that having “consciousness” provides to matter.

But memories make up a person? Fine, but what are they ultimately? Ultimately arrangements of quantum particles collected in the brain. Is there anything else? I don’t know, but I don’t think there is.

So it does, but I guess it was the possibility of that that I took issue with. But as you rightly say there isn’t really anything that would logically stop anyone from creating identical surroundings for our clones. Having hung up my theory on consciousness, I would then indeed have to say that the there’s is one consciousness in the two bodies. When I really think about it, though, that wouldn’t really bother me that much because as far as consciousness goes, place is taken out of the equation. I think consciousness can be talked about in the sense of place only by virtue of perception. If there’s no difference consciousness only perceives one place, so we’re not dealing with one person’s consciousness being in two places at once.

let’s refer to


which of these two ‘cloned’ OP do you think is the original? they are an exact copy of each other, yet their ‘experiences’ and the replies they’ve had received have been different since they were posted. does it matter (and can you tell?) which is the original?

the answer is neither of them is the original. your written post in the reply box was the original, yet they are no different from the original as far as we are concerned, what matters is that they are now two different threads that started off being the same.

therefore, IMHO there are now two of you. two copies of you that will be different the moment you are released from the experiment and am exposed to ‘outside’ stimuli.

“i am shijinn!”
“i am shijinn!”

The Star trek episode you want is Second chances in which a younger version of Will Riker is discovered trapped on a doomed planet after a transporter accident.

Was there a point where the two men were the same? Yes, at the moment they finished rematerialising. At the next instant they became distinct individuals.

If they had been held in transporter suspension and their components swapped one at a time by [technobabble] then they would be the same until they finished rematerialising.

If they were rematerialised in a stasis field and their components swapped one at a time by some precise transporter handiwork they would be the same until the field was lowered.

As consciousness is tied to movement (of electrical impulses, etc., in the brain) there is no way to swap the brains without affecting the conscious. But, if one could, you would not be the you on the left (Leftie) until your entire brain was swapped from Rightie as it takes all of your brain to create the being called you (we’ll ignore the rest of the body for the sake of argument).

Distinct from that is your final question: When would one notice the change? That would depend on where the mad scientist is standing and where things are in his lab (i.e. how easy it would be to notice the difference between photographs taken from the two positions). It’s all down to YOUR ability to notice change rather than any particular particle in your body (notwithstanding the fact that you need most of an eye in order to be able to see things).

Or, I could be typing through a hole in my head.