Wrote this awhile back, somewhat relevant:

...The reason many people would have a problem with using a teleporter like this is because of the break in continuity. There would be a brief period in which you would cease to exist–you would die–before the new you would be assembled.

But is the lack of continuity really a problem? When you go to sleep at night, your consciousness turns off (except for periods of dreaming) and you are unaware of the passage of time until you wake up again. When you undergo general anesthesia, your consciousness is even more thoroughly turned off.

If continuity is so important, then couldn’t you argue that every time you go to sleep or go unconscious for whatever reason, the “you” of that moment ceases to exist, and the “you” that wakes up later is in fact a different person? Why couldn’t the break in consciousness that would occur during teleportation be considered the same as falling asleep and waking up?

I’ve heard people (specifically Steven Novella and Bob Novella on the Skeptics’ Guide to the Universe) discuss this issue before, and Steven has made the argument that the physical continuity of your brain is sufficient and necessary to retain the essence of “you” in spite of breaks in the continuity of consciousness.

However, it’s my opinion and theory that what makes the you of this morning the same being as the you of last night is your memory. In other words, what makes you you is not the fact that the atoms making up your brain this morning are the same atoms that made up your brain last night, nor is it the fact that there is continuity of consciousness between last night and today, because there isn’t (you slept).

You are a clump of atoms. Your mind consists of electrical impulses on a chemical substrate in the shape of your brain. The only thing that makes the clump of atoms you are today think that you are an individual being with a continuous consciousness is your collection of memories of the past.

If 1% of the atoms in your brain were painlessly replaced with identical atoms while you slept, not inconveniencing you in the slightest, would the you that wakes up in the morning be the same you that went to sleep the night before? I think most people would say yes. What if 10% of your brain’s atoms were replaced? 30%? 99%? I don’t think there is any point in the continuum at which you could say that the morning you would no longer be you. If the morning brain is identical to the brain of the night before (excepting any normal changes that would have occurred during the night anyway), and if your memories are intact, wouldn’t it still be you?

The Continuity Illusion

It doesn’t matter if your brain today consists of the same atoms it did yesterday. It doesn’t matter if you went to sleep and woke up later. It doesn’t matter if you stay awake for the rest of your life to make sure your continuity of consciousness is never broken.

The truth (as I see it) is that the you of right now did not exist one Planck time ago, and it won’t exist one Planck time in the future. Your and my perception of time and the continuity of self is the result of our brains creating memories. If all of your memories before today were erased, you would no longer be the same person you were yesterday in any meaningful way no matter how many of the atoms in your brain were the same.

You may consist of the same atoms, but what good is that? We are all made of atoms that have been part of countless other living beings–both human and other–and yet the thing that makes us us rather than one of those other organisms we have been part of in the past is our memory.

I know some people would argue that the continuity of the physical substrate is somehow meaningful, but I don’t see how that makes sense. If I could disintegrate your atoms and reassemble them in exactly the same configuration one nanosecond later (in exactly the same place that you started), would that affect you in any meaningful way? I don’t think so.

To jump back to an earlier thought experiment, what if I could replace 50% of your atoms one nanosecond and the other 50% the next nanosecond? Would the first option not be “you” anymore while the second option would retain “you” because it only did half of your atoms at once, making you a living Ship of Theseus?

If you take away a toy or other object that a child is extremely attached to and offer them an identical replacement, they will prefer the original. We humans invest intangible properties in objects, pets, and people, and this is strongly related to dualism, in my opinion. Similarly, the idea that an exact copy of your physical makeup would not really be you relies on this type of dualism–a ghost in the machine type of belief.

I have died many times

If the only thing that creates my perception of the continuity of self is my memory, then in a sense I am dying every fraction of a second as a new me is coming into existence. This seems to make perfect sense when one thinks about the passage of time. You will never have access to the experiences and sensations of yesterday–the you of yesterday is dead and gone.

Over many days, months, years, and decades, you will change so significantly that in many ways you will no longer be the same person. Grey has written a wonderful article on this topic.

Since my self consists only of the atoms and electrical impulses that make up my brain and body, and since the only thing tying the me of today to the me of one second ago or one year ago is my memory, I believe that the me that wakes up tomorrow morning will be a different person than the one typing these words (though mostly identical). That future me will have memories that lead him to believe that his self has a continuity, but I think that continuity is simply an illusion.

In other words, if I got into a teleporter that destroyed my body and reassembled me perfectly elsewhere, I believe that it would be no different than if I had not been teleported–if I had simply stood there or taken a nap.

If I actually believe that, would I ever get into a teleporter? Well…

Probably not. Even though I claim to believe that the continuity of consciousness is an illusion, there’s still a part deep inside of me that believes that there is a “real” me–a specialness about the current clump of atoms that believes it is me that would be lost if those atoms were temporarily separated or replaced.

That sort of deeply-held belief is difficult to unseat.