Personal Identity and Brain Swapping

When last we left this perplexing topic, many of you were trying to get me arrested for a crime another I committed. (I say “many of you” even though only my mom and my lawyer were trying to do that, but my circle of friends has scant points about it, so ‘many’ it was.) When we are looking at memories as the signpost of identity-pointing, there are detours aplenty. Today, we are going to move on to the third of the potential candidates for identity fixing: the physical body.

Are You Your Body?

The pros and cons of the body as a candidate for personal identity here are pretty intuitive, and much of them we have seen earlier (with memories), if in slightly different form. The body is easily recognizable, and, in fact, is how we identify others. Slight changes, such as haircuts or tanning, seem to do little to distort or erase the recognizable features. However, which features matter the most? How many of them are necessary to maintain if one’s identity is to remain constant? Suppose you gain or lose three hundred pounds, you may well feel and be unrecognizable to both yourself and others. Are you a different person?Many soldiers are returning from Iraq and Afghanistan with missing limbs; are they different people? Both examples will result in the individual’s feeling different, but is that enough for identity to change as well? Think of the liquor store example from my previous post. How would that apply here?

Suppose that I rob the liquor store, but instead of getting hit by a car I instead cut off one of my arms.

Losing an arm

Is the the one-armed man the guilty person (I know Harrison Ford’s answer)?

What if I gain a lot of weight during the six weeks the police look for the robbing murderer?

Getting fat

I doubt there is much controversy to either of these scenarios, and almost every one of you is going to think that identity has remained constant, that the same person is still there or here or whatever, even if that same person is not exactly the same (what’s the difference?, you might wonder, and good for you, you wondering person; the topic of identity when not dealing with people is going to be dealt with soon).

Remember when we talked about the Ship of Theseus, and I suggested that there are some who suggest that every possible change results in new identity. Such an individual, if she is consistent, would have to say that I am not the person who robbed the liquor store because I cut my fingernails or because I removed some hair. Such a person, though, is not really a person in the traditional sense of the word ‘person’, but is more of a collection of experiences that are joined together. Such a person cannot recall her first date, as all her recollections belong to someone else, just as such a person cannot look forward to a happier time in her life, as it will not be she that is enjoying that time, only someone who looks and thinks much as she does.

Few of you think like that, though. But why? If you are not in the memory camp and the physical features have changed beyond recognition, why is a person still the same even after extensive physical changes? What’s that? Sorry, the sound on my computer is muted — what are you saying at your screen as though Skype were on and our conversation was being passively monitored by virtuous government agencies? Ah, I see. Thoughts! The thoughts have not changed. Good! It’s almost as though you knew where I wanted this post to go. Thanks!

Thoughts and Brains

Of course, by ‘thoughts’ what your philosophically ignorant train of thinking was suggesting was the brain. What most members of the physical camp believe to be the defining feature of identity anchoring is the brain. So long as you have the same brain, you are the same person.

Another way to get to the brain is by elimination. Which parts of the body matter? For the body, that is pretty simple: beards, arms, legs, livers, ears, moles, etc., are all pretty superfluous. The part that matters is the brain. How much of the body matters? Really, again, almost all of the body is superfluous except the brain. What if the brain is damaged and the thoughts no more work good? Well, that is not the same brain then, is it? As far as which parts matter and how much of those parts matter, what am I, a brain scientist? (Yes. Yes, I am. Not in the United States, of course; regulations and all that have proven quite the obstacle to my life goals).

The solution to those worries is normally dealt with by a kind of common sense functionalism. Most of us don’t know Broca’s area from the pubic bone, but if you cannot remember anything from last night back, your brain… it don’t work too good. So the parts and amounts that matter for personal identity are the ones, whichever they are (and brain scientists know which those are), that affect the functioning of the brain.

Simple enough then. You are your functioning brain, and wherever it goes, so go you. Right? Right. Right? Well, dammit.

Swapping Brains

Let’s swap brains, then, you and I, and see where we go. Who wakes up in a svelte killing machine of evolutionary perfection and who wakes up in body aimed at child predation? No, no. There are no trick questions on this site. You will wake up, most of you think, in a body not originally yours. If the swap is permanent, maybe your personality will change based on how people around you treat you (either with sexual fearsomeness or with fear of your sexual perversity), but you are still basically the same person. You are your brain.

Note that this is different from those mind swap movies that are made every other week or so. In those instances, it is, or seems to be, the memories that are swapped and not the brains. A brain-based identity theorist watches those movies and laughs (partly at their sheer delightful hilarity) because the only change is that the individuals involved wrongly believe themselves to be someone else. How could they be, though, since their brains are still where they have always been?

There is really no way to confound anyone’s intuitions about the brain as it relates to identity, is there? Hahahahahahahahahahahahaha! Sorry, sorry — whoo, man. You really had there for a minute. Alright, let’s get to the confounding.

Suppose a man, let’s call him Gary, was born with half a brain. This happens, you know. Gary can still function and get about, but he only has half a brain. Maybe he cannot recall as much stuff as you can, maybe his motor skills are shaky in places, but he is a person and his name is Gary. Everyone okay with this?

Now let’s suppose that another person, Harry, has a regular, whole brain. But, egads! Harry is hit by a crazed Canadian driver and the resulting life-saving operation leaves him with half a brain. Now, this is not how it would work, but let’s suppose he still has around half his memories and the like. Is anyone here, aside from the identity-extremists, going to suggest that Harry is no longer Harry? Harry is still Harry even if only half of his brain is there since Harry can still function, to some degree, to some recognizable degree, as Harry used to.

Alright, and if we were to swap Harry’s half brain and Gary’s half brain, I suspect that you are going to think they, the people, go whither their brains do. Fine, fine. And if there was a third person, Terry, who lost his brain altogether, where is Terry? Gone. Right.

Brain swaps

What about this, though (and this is due to philosopher Derek Parfit): let’s take Gary’s half and Harry’s half and put them together into Terry’s head. Who is that? It has half of each person’s brain (well, I guess, it has all of their available brain, so whatever) and, so, we are suggesting here, it has half of each person’s memories, is it both Gary and Harry? If not, why not?

If Harry with a brain in his head was still Harry and not dead, then Harry’s half with Gary’s half should make them both be (please try not to laugh) who they once were. Can the one body be two persons? What if both Harry and Gary had had whole brains that we split, combining one half from each in two separate bodies? Can two bodies then be four persons? Oh, philosophy, what have you done to our so carefully coddled beliefs about all that is personally identical in the world?

Next Time…

Next time: clones! And light sabers! And sex!!! But mostly, and only, just clones.

Identity and the Ship of Theseus

The Ship of Theseus is a great example of identity, though it does not work for everyone when it comes to personal identity, or the identity of people. Here is the basic idea. A guy named Theseus has a phenomenal ship that everyone wants, but he is not selling for any amount. However, one day, a merchant from a distant land offers Theseus an enormous sum to build an identical ship. The merchant wants the exact same sort of timbers from the same forest, the same nails from, uh, wherever the hell nails come from, the same sail material from the same cotton plants, and so on. If there is a plank of wood that has a knothole in it, the merchant wants an identical knothole in the same place on the duplicate ship. Sounds crazy, right? Well, most rich people are crazy. Theseus agrees and loads his ship with everything he needs to build a duplicate ship and then sets sail. He is only out of port for a couple of hours when one of the planks on his ship warps slightly and allows water into the ship. Theseus could return home and patch it, but he would just as soon get to the merchant, build the duplicate ship and then roll around on his big pile of money. With that in mind, he takes the corresponding piece, its identical counterpart, from the supplies and swaps the two planks out. (If you like, he makes a note of this switch, but his honesty does not matter for how the example works). As the journey continues, he needs to swap out more pieces: sail is torn, carpet is frayed, he needs a new wi-fi router, and so on. For ease of talking points, let’s make the following supposition: Once Theseus is 1/4 through his journey, he has 75% original parts and 25% new parts; at the 1/2 part, he has 50% original parts and 50% new parts; at the 3/4 mark, he has 25% original parts and 75% new parts; and finally, at the end of the journey, he has 0% original parts and 100% new parts.

Here’s the question: is the ship at the end of the voyage the same as the ship at the beginning of the journey? There are only two answers: yes, and no. A bunch of you are going to, somehow, try to wriggle more than that out of the situation, and your insane hearts are in the right place, but that will not make the insanity any less prevalent. Most of you are going to think the ship is not the same, so let’s talk about that first.

If the ship is different (and why wouldn’t be, you are collectively screaming), then when did it become different? At one point on the journey can we point at and say, “There! Did you see that? A different ship!” Here the answers are not so clear, but are not too difficult to lump together. Most people are in one of three categories: a) the very first change; b) right at or after the 50% mark; and c) the final change or replacement of parts. My question to all three groups is basically the same: why there? Why did you pick the percentage mark or the piece that you did?

The ship becomes a different ship at the very first change. This makes sense, I think, until you think about it and whether it makes sense. Suppose the very first change is a nail and not a piece of wood, does that matter? It shouldn’t. The percentage difference between a nail and a plank when the ship is taken as a whole is virtually negligible. What if a bird crapped on the ship? That is a change, but does it make for a different ship?

Of course, not. Bird crap is an extraneous feature of the ship, but is not integral to the identity of the ship itself “Integral”? Very impressive term! So if the ship loses a nail (one pops free), and that nail is not replaced, does that make for a different ship, Mr. Integral? Perhaps the nail was not an integral part, but then what is? If the sail is replaced, does that matter? What if only the hull is replaced? See, the problem is trying to figure out which parts are integral.

We often think of integral parts as though which cannot be taken away and the object still be whatever the hell it is. That can be due to reasons of either identity or function. If we take away the sail of the ship, it still floats and can haul freight (though it takes much longer), and I suspect none of us would have any issue with calling it the same ship. Is the same true if we took away only the hull? Not only would it look the same, but it is not going to float or hold any freight. So far, all of that is fairly intuitive. Let’s take away just the nails. The ship would probably fall apart very quickly, but until it does, is it the same ship? It looks that way and, at least for the moment, it functions in the same way.

Function As Identity
An issue with identity as function is this: Suppose we identify one another by function. First, how the hell do we ever figure out what our function is? If we are using it to fix identity, it cannot be something general like ‘reproduction’ or ‘making money’, because then how would we differentiate between individuals who are doing both or either? Let’s say that we resolve that issue, though, and fix your identity as ‘runner’ because that is what you do when you get any free time, or you are a competing runner or whatever. Dammit, just accept this as your function. Now, suppose you are hurt and can no longer use your legs, and so can no longer run. You can no longer perform the running function — what does that do to your identity? Is it gone? Is it changed?

More than half of the ship must change for the ship to be different: If one little change, even an little integral one, does not make for a different object, then what about a change of 51%? Again, the same questions can be asked: does it matter at all what that extra 1% change is?

Every single piece must change for the ship to be different: I won’t be petty and go rehash the above paragraph again (though I could, because it works). Let’s instead agree that the identity does not change until the last piece is swapped out. Does that make the last piece integral then? What if it is a nail instead of a plank? What if it is a stitch in the sail instead of a nail? Suppose we take that last piece out but do not replace it? 99% of the ship has been changed and the last one percent is just taken away, what does that mean for its identity? Yeah. I know.

Fine, then — the ship does not change. It is the same at the beginning as it is at the end. I can see, now, why you might think that. And everyone who originally thought it are now crowing to the moon about their daringly correct choice. Let’s suppose we now take all of the original parts and put them back together. It would be a fairly crappy ship, but why would that not be the original ship? Yeah. I know.

What you think about the Ship of Theseus might indicate what you think about identity for people. We will see as we continue on this topic in later (though soon upcoming) posts.