If we could take you, take your essence, upload it to a computer system, and put it in a synthetic replica body, would you do it? Never mind the process, we’ll get to that later, let’s start from whether you’d even want to or not. So let me give you a plausible reason to answer in the affirmative. You’re sick with cancer and going to die, but we can put you in a different body, the same body, but without the cancer. You’ve been horribly burned in an accident, scared from head to toe, but we can build this new body for you and put you in it and you’ll be beautiful again (or at least the same old ugly you). You’re old and frail and dying, but we can build you another body, maybe even a younger body if you want, that won’t have the frailties of your current one. In fact, in all these situations we can dream up any incentive you might desire; you’ll be stronger, faster, you won’t age, you can be better looking, whatever you can think of. Would you do it?

The question you should be asking yourself if presented with this offer is, “would that person be me?” Obviously, if the answer to that question is “no”, most sane individuals would justifiably refuse the offer. For me to want to go through with this thing, I’d have to be sure that this new being really would be me. And to do that, we need to first figure out what exactly it is that makes you up as a person. And what possible changes you could undergo that would cause something to cease to be you. So why don’t we start by going over some common arguments made about what makes us a person, and see if they hold water.

“We are the physical form that makes us up”

This form of argument is the easiest to discard. As we go through life we all change physically over time. And yet as we change physically, few would argue that these changes make you a different person. Each and every one of us grows from a small child to an adult and slowly becomes more and more frail as time goes by.  Even as a relatively static looking adult, you might dye your hair (or lose it) or get a nose job, work out and develop muscles, or stop exercising all together and gain 50 pounds. When you see this you think, “man, Charlie really let himself go,” not, “who is this new person with more weight and a vague resemblance to Charlie?”  You might even lose your arm in a freak accident or suffer some other profound physical change. And yet through all of these physical changes, we would say that it is one and the same person that exists at any of these moments, it is you that undergoes these changes. We consider the baby in the stroller and, many years later, the adult with a baby of their own as the same person. And so it’s certainly not outward appearance or physical make up that defines us as individuals. Many would say there is something more that persists over time, and it is this essence that persists over time that allows us to make the connection between disparate physical appearances. Which is the second argument for personhood:

“I am my thoughts and behavior and personality”

But we also each go through constant personality and behavior changes. John is a very trusting individual. Then John gets involved in a series of romantic relationships where his partner cheats on him and lies to him. After years of these types of relationships John is now much wearier and in general less trusting of those around him. His personality has changed, but no one would say that this person is no longer John. Or let’s take Sally. Sally is a very selfish individual, but after meeting a group of very kind hearted and compassionate friends, she slowly over time becomes a more caring and selfless person. This is not a different person right? It’s still Sally. As we go through life and experience the world and learn, we often have significant changes in our values and thus in our day to day behavior. These are not just minor changes in preferences (i.e. – I used to like vanilla ice cream, now I like strawberry), these are full fledged personality changes, changes that dictate not only the way you behave, but even the very thoughts that you think. From the rebellious teenage slacker to the corporate lawyer, a fundamental personality change has occurred, but the individual has remained the same.

“I am the matter that makes up this body”

You might at this point say, “well, this is the nature of life, we grow, we change, but it is this physical being that I call (insert your name here) that stays consistent over time.” But this argument is problematic. While to any outside observer your physical body looks relatively the same over time (besides these gradual changes I spoke of above), the stuff that you’re made of is actually always constantly changing. Individual cells in your body are constantly dying while others are being created to take their place. What makes up your heart or your liver or your skin is a collection of cells that function in certain specific ways, any one cell may die at any time and the whole unit remains. So take your heart now, and take it a few months from now, and the two hearts will not be made up of the same physical matter at all! You literally have a new body hundreds of times over in your life.

This is true for all the cells in your body except your neurons, which for the most part survive for life. “AHA!” you say, your neurons are what make up your thoughts, what lead to your sense of self and your conscious experience, and these are solid and consistent! In one way this is true. But in another sense, far from.  An individual neuron may persist as a distinct cell for a longer period of time…true, but the molecules that make it up are constantly being replaced. The persistence of a neuron over time is rather like the persistence of a baseball team over time. The New York Yankees remain the New York Yankees, whether Babe Ruth, Don Mattingly, or Dereck Jeter happen to be playing for them at the moment. No one player from the 1970 New York Yankees team might still be active, and yet we still think of the team as the same team. Because it is the function of the team that defines it. The Yankees are the team called the Yankees that plays baseball out of New York. No matter who the players are, who the coach is, what their uniforms look like, and even what stadium they play in. And the reason we believe this is because there is a connection, a flow over time that connects every moment in time of Yankeeness, to the next moment in time of Yankeeness. It is the pattern that we call Yankees that persists over time. The same is true for your neurons, and what’s more, the same is true for you, but I’m jumping ahead of myself here.

“It is my memories that make up who I am”

You might want to use this notion of the flow over time to jump to the conclusion that it’s memories that make up who we are, since our memories in a sense contain that flow within them.  But this would be an oversimplification. What about implicit memories? What about events that have happened to you in your life that affected your psychology and neurophysiology, that have in a sense “made you who you are today”, but which you have forgotten, which you don’t have explicit access to anymore? Think about the many formative experiences we went through as children which we don’t remember as adults. What about people who have neurological conditions and either lost all their old memories, or can’t form new memories, or both? Do they not have selves? Or are they different selves? Are you a different person every time you form a new memory or forget an old one? So while memories, and your ability to bring them to the forefront of your consciousness, play an important role in your sense of self, it is not the memories themselves that define you. Rather, memories are the conscious remnants of (some subset of) the causal interactions that you engaged in, of which you are the result.

What we’ve done is disprove a theory that says that what makes you up as a person is the physical material you are made of.  But we’ve done more than that. We’ve come to the conclusion that you can change your physical appearance, your mental states and behavioral patterns, your memories, and even the very particles you are made of and still be you. The reason for all of this seems to be that we take the continuity of self to be important above all. You are a pattern that persists over time, and each moment of that existence is tied to each previous moment in a chain of connections.

If this is the case though, let’s take this idea to its logical conclusion. If someone gets a lung transparent or a heart transplant we would never say they were a different person, right? What if we put in a synthetic heart or lung? Still the same person right? What about a synthetic hand (Bob’s was amputed in the war, the government just hooked him up with a sweet new bionic one).  Larry was going blind, we put in some new state of the art synthetic eyeballs. Melissa has been deaf but just got herself a snazzy new cochlear implant. These changes may strike us as odd or unnatural, but not many of us would stop being friends with Melissa, just because she had a “fake ear”. What if this all happened to one person? What if, piece by piece, one limb or organ at a time, we replaced every part of you. But left your brain intact. Given what we’ve said above, no one would have any reason to state this is not you, correct? Your experience has been one continuous experience, and the stuff that makes up your thoughts and sense of self hasn’t changed.

What if we went further? What if we took one little neuron, one neuron out of billions, and replaced it with a synthetic unit that served the same function. What if I did this one at a time, until there were no original neurons anymore. Are you still you? Think about this question, it’s an important one. At no point was there a discontinuity of your consciousness self. Does it make a difference that every part of you is inorganic? Is that change any different from the fact that your molecules are constantly changing? If, what started was you when you had all your neurons, but ended up with a different person when they were all changed, you have to answer the question of when did this new person cease to be you? Was it when the last real neuron was changed? The first? Somewhere in between? Was there one point where the number of different neurons become such that the person that used to be you now was changed?

If the person at the end of this process is still you, then you have to ask yourself, would there be any difference if instead of doing this gradually, we just replaced the whole brain at once, with a functionally equivalent brain? “Yes there is!” you might say. “This complete replacement breaks the continuity we talked about earlier! This causes a discontinuity, and thus can’t be you.” But lets think about this more deeply. When we talk about continuity, we’re talking about continuity from one physical state to the next. That State A directly leads up to and causes State B and State B directly leads up to and causes State C. Is continuity in time necessary for this? Every night you go to sleep and your consciousness shuts down, and every morning you wake up and feel like the same person. But there’s been an 8 hour lapse in time, so what makes this new you the same as the old you? It’s the continuity of the pattern that matters, regardless of whether there was a break or not in time. Imagine technology has advanced to the point where mid thought, we can freeze you, and years later thaw you out. You are physically exactly the same, and there has been no discontinuity in your brain function or consciousness (even more so than the sleep example, as there is literally no brain function in the frozen state). Neurons that were in the middle of firing, continue to fire. Electrical and chemical reactions continue from the exact point they stopped at. You’d be hard pressed to argue this is a different person from before, just because there has been a discontinuity of experience in time.

So imagine we freeze you, and THEN replace your brain. Then unfreeze you. The replacement brain is in the exact same state as the original brain.

You may have all sorts of uneasy feelings about the conclusions we’ve come to, but without any obvious contradictions, we’re going to move forward with this thought experiment. So you have no more arguments, we can take the pattern of neuronal firing that makes you up as a person, and put it in a new synthetic body. So let’s do it, what’s stopping us?

Let’s take a second and actually picture how this process would work. We sit you in a chair and hook you up to all sorts of futurist equipment. In another chair is a synthetic body replica of you, waiting to interface with your brain to download your specific brain pattern. The two of you are connected by a machine that will facilitate this transfer.  You turn the machine on, and poof, the synthetic body is now you! But wait, we forgot about something really crucial! YOU are still sitting in your chair, looking at this new synthetic body, what gives! What gives is that there are now two yous, both of which think they are you, one of whom happens to be in a different chair from where he was a second ago. But this doesn’t help you out. Let’s call you Alpha, the organic person who went in to get transferred to a new and better body. You are still Alpha. You’re still old or frail or sick with cancer or whatever thing happened to be ailing you. And while Person B (Beta), a person who thinks and feels exactly like you, is ecstatic to be in their new body, Beta is not you. Beta is a copy. It may look and act exactly like you, but they are not you.

This is the common argument made at this point, and while on one level of analysis it’s absolutely right and needs to be considered (we’ll get to this soon),  I also want to argue that it misses the point of everything else I’ve argued up until this point. It’s neglecting the argument we’ve laid out to think of one as the original and the other as the copy, since this is the old way of thinking, where what mattered was the physical stuff you were made of. But if what makes you you, is actually the functional pattern over time, then “me” is just the feeling associated with a pattern of neuronal firing (or with the sum total of biological interactive processes that make up the organism we call “you”, if you’re uncomfortable with solely explaining consciousness as the result of neuronal firing).  Both Alpha and Beta have the distinct sense that they are me. The only telling of which is classically right and classically wrong is the knowledge of which has an original body. But what if the technology has been so advanced that the new body is actually indistinguishable by even the best of science from the original? Inside and out, cell by cell. Further, what if after making the consciousness upload to the new body, both bodies were put to sleep, removed from their chairs and in a carefully crafted double blind set up, taken to another room where not a single person knew which was which. Both persons are then woken up at a later time. Which is you? And does it even matter at this point? Both feel like you, act like you, and believe they are you. Ten minutes ago there was one you, now there are two yous.

And here we get to the crux of the whole situation, and we realize a startling truth that arises when considering the continuation of the self over time. If what makes you you is the pattern of neuronal firing at any given moment (or functional pattern or configuration of constituent molecules in your body if you’d rather), and that pattern can be paused or stopped and restarted without a change in you, and further, that pattern can exist in multiple instances and all be correct in believing they are you, we have to seriously consider the idea that there really is no you at all that continues.  The same sense of dread you have over admitting that a synthetic copy of you is actually you should be felt whenever you consider whether you from 10 years ago is the same person as the you today, whether the you of this moment is even the same you as a moment ago. If the synthetic you is just a copy, then you right now are just a slightly altered copy of yourself from a moment ago, ad infenitum. This sense that you are you is just the subjective experience of your current pattern of neuronal firing, one that happens to incorporate a set of beliefs, beliefs that we call memories, into its sense of self. In a sense, you only really exist in the present subjective moment, and the subjective experience in the next moment that you are somehow the same person, is just that, an experience, a feeling, a convenient fiction. This is one possible interpretive path we can go down. There’s a more optimistic version though. Which is that we accept not that the self is an illusion, but rather, that all our common conceptions of what a self is, and what allows a person to continue to exist over time, are illusory.

If we can accept that the you of ten years ago is the same person today, if we accept that your subjective sense of existence and continuity over time is something worth caring about, then the question of whether to upload is easy, and may surprise you. Yes, of course upload. But with certain caveats. If you’re uploading to a new body that will be stronger or healthier, you want to make absolutely sure that your old body and your new body will never be conscious at the same time! You want the transfer made while you are asleep, and once the transfer is successfully accomplished, destroy the old body immediately. This is the only way to ensure that when the new body is turned on (wakes up), that there is a fluid continuity of self, and there is no one left to argue otherwise. Harsh maybe…but we’re talking about self preservation here.

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