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A peer-reviewed electronic journal published by the Institute for Ethics and ISSN 1541-0099 22(1) –November 2011 |
Personal Identity and Uploading
Mark
Walker
Richard
L. Hedden Chair of Advanced Philosophical Studies
Department
of Philosophy
New
Mexico State University
Journal of Evolution and Technology - Vol. 22 Issue 1 – November 2011 - pgs 37-52
Abstract
Objections to uploading may be parsed into substrate
issues, dealing with the computer platform of upload and personal identity. This
paper argues that the personal identity issues of uploading are no more or less
challenging than those of bodily transfer often discussed in the philosophical
literature. It is argued that what is important in personal identity involves
both token and type identity. While uploading does not preserve token identity,
it does save type identity; and even qua token, one may have good reason to think
that the preservation of the type is worth the cost.
1. Uploading: prospects and perils
You arrive
at one of the thousands of kiosks run by the late twenty-first century’s
largest corporation: U-Upload. With some trepidation you step into the
superscanner. There is a slight hum as it inventories the molecular building
blocks of your brain. Your brain is destroyed in the process, but you are not
dead – or
so the marketing materials from U-Upload claim. For information about the
building blocks, along with a general program that describes the fundamental
laws of molecular interaction, is uploaded to the shiny new robotic brain you
purchased (Sandberg and Boström 2008). For your friends and family, a few
terrifying moments pass before the robotic body stirs. To their relief, your
first words are: “It’s me. I made it.” You then go on to crack a joke – just as your
family and friends have come to expect of you. Of course you have changed in
some respects: gone is your human carbon-based body. Now you experience the
world through camera eyes and microphone ears, you dance the fandango with
robotic legs and speak through a voice synthesizer. But it is still you. You
have migrated to a silicon substrate: you have been uploaded.
At
least that is one interpretation of these events. The contrary construal is
that although a robot was created that acts and talks like you used to, claims
to have your memories, and indeed, claims to be you, this robot is not you. You
are dead. You died when your brain was destroyed during the scanning process.
If,
like me, you think that uploading is possible (at least in principle), and so
you hold that the first interpretation of these events is correct, then you
must hold true the following three theses:
[1] Computers
are capable of supporting the important properties constitutive of personal
identity, e.g., thought and consciousness.
It is
clear that uploading will not preserve all properties we associate with Homo sapiens, e.g., basic facts about
the human digestive system are not likely to be preserved in uploading to a
robotic body. But these facts are not typically thought to be important for
personal identity. Candidates for important properties include thought,
consciousness, emotions, creativity, aesthetic experience, sensory experience,
empathy and so on. For the most part, the question of which properties are
important is not as serious as it may first seem, since uploading promises to
preserve the essential aspects of the brain and nervous system, which overlap
with the usual lists of important properties for identity.
A
famous challenge to thesis [1] is
made in Searle’s Chinese Room argument (Searle 1980). It is beyond the scope of
this paper to explore this argument; suffice it to say that if Searle is
correct, then [1] may be false. For
Searle thinks that a computer can never consciously think merely in virtue of
instantiating a computer program, and the uploading process seems to be one of
merely instantiating a computer program (Agar 2010, 2011).
[2] It is
possible to capture the information necessary to emulate the important
properties of individual humans.
The
technical challenge of thesis [2] is
to capture the information in all parts of the brain in a manner that preserves
the relevant information. Clearly this won’t be easy. If we slice off layers of
your neurons, and record the information of each layer, the lower layers will
change (due to trauma or death).1 If we flash freeze your brain, we
may destroy some essential information. Philosophical questions arise as to whether
the information encoded in the brain is sufficient to account for all the relevant
properties. For example, consider a dualist who believes that we have souls in
addition to brains, and much of what is morally important (e.g., conscious
thought) resides in the soul. If the dualist is right, then scanning your brain
could never be sufficient, for it would be necessary to scan your soul to
access at least some of what is important. If it is unlikely that we will be
able to scan souls, there will be an insurmountable obstacle to uploading.
Notice how theses [1] and [2] may differ on this point: a dualist
could consistently hold that a computer might have a soul; it is just that if
computers have souls, it is not because we obtained the soul-building information
from humans. (Perhaps God implants souls in humans and computers.)
[3] It is
possible to survive the uploading process.
To
see how [3] differs from [1] and [2], imagine that at some point in the future we have created
computers of sufficient complexity that it is agreed that they have the same morally
relevant properties as humans: these advanced computers think and are
conscious, they are accorded rights, and the scanning problem has been solved
so that we are able to scan the brain in such a way that we are not worried
about loss of information. None of this answers the question of whether you
have been preserved during uploading or whether uploading merely makes a very
good copy of you. The worry that only a copy is created is often fueled by this
thought: the information about the building blocks of an individual human brain
could be uploaded to multiple computers with robotic bodies. The number of
copies of a person is limited only by the available computing power. If an
individual can be uploaded once, then it seems the same individual could be
uploaded twice into separate computers, and indeed, billions of the same
individual all embodied in separate robotic bodies could be created.
This
quick survey of the conceptual terrain suggests that there are substantial
philosophical (not to mention technical) obstacles to uploading. To make the
discussion manageable, I will focus on thesis [3], and assume without argument that [1] and [2] have been
resolved in favor of uploading. So our question is this: assuming that
computers can be conscious, have memories, and (robotic) bodies, and assuming
that it is possible to scan and capture all the information of a human brain,
does uploading preserve personal identity?
I
will argue that uploading does preserve personal identity; at least identity of
a certain sort.
2. The equivalency thesis
The
fact that we are assuming that computers are capable of embodying all the same
type of properties necessary for personal identity means that we can make use
of the equivalency thesis:
Equivalency thesis: If
it is possible for an individual to survive migration from a carbon to a carbon
body, then it is possible for individuals to survive migration from a carbon to
a silicon body.
To
spell this out, I’ll say first what I mean by occupying different human bodies,
and then say what use the equivalency thesis will serve for us.
Let
us start by considering a familiar fictional example of people switching human
bodies, i.e., carbon-to-carbon transfers. One of my personal favorites is a
schlocky episode in the original Star
Trek series. Captain Kirk finds himself in the body of his jilted ex-lover,
Dr. Janice Lester, after an alien “personality swapping” device is used on him.
She, jealous of his power, takes control of his body, and, what is worse, his
spaceship. This plot device has been used numerous times since, including in
the movie Freaky Friday where a
mother finds herself in her teenage daughter’s body and vice versa. These works
of fiction are premised on the idea that whatever makes individuals the
individuals they are is only contingently related to the bodies that they find
themselves in. Captain Kirk grew up in a male body, but we are asked to believe
that, at least for a short while, he inhabited a female body.
In
Kirk and Lester’s body swap, the idea is helped along by the visual effects
(such as they were in the 1960s) that showed what apparently we are to understand
as soul swapping. (A soul, it turns out, looks much like a translucent version
of one’s body. Who knew?) We do not need to have recourse to the idea of souls,
however. Imagine the scanner used to encode all the relevant biochemical
information from a brain was used to scan both Kirk’s and Janice’s brains.
Nanobots – nanoscale
robots – then
rearrange the biochemicals in each brain to encode the relevant memories,
personality and intellectual abilities and so on. This differs then from brain
swapping, because each brain is reorganized using nothing but the locally available
biochemicals. Here the information is uploaded to a different human body rather
than a computer. Using this procedure, it makes perfect sense why Captain
Kirk’s body would act much like we would expect Dr. Janice Lester to act, and
vice versa.
There
are a couple of reasons for invoking the equivalency thesis. The first is so
that we are not misled by a new form of racism: substratism (Walker 2006).
Substratism is the view that one’s substrate is inherently superior to that of
other substrates along the lines that racists think their race is inherently
superior to some other race. In the present case, it would suggest the idea
that carbon-based humans are inherently more morally worthy than silicon based
beings. Consider the fact that we would not accept this argument: it is not
possible for persons to migrate from one body to another because then it would
be possible for people of skin color X to move to bodies of skin color Y, and Y
skin color is morally inferior. We want to avoid the same bad argument in
considering moving from one substrate to another. Notice that this does not beg
the issue at hand, since it is possible to say that having a certain substrate
(or even skin color) is constitutive of my identity; it merely prohibits saying
that this property in itself makes for moral superiority.
The
second is that it makes directly relevant an enormous amount of philosophical
effort that has gone into exploring the possibility of carbon-to-carbon
transfers. The question of carbon-to-silicon transfers thus may piggyback on
this effort.
3. Personal identity: psychological and somatic
accounts
Historically,
there are two main schools of thought about what is required for personal
survival; the psychological and somatic approaches (Olson 2002). Derek Parfit’s
famous thought experiment may serve as illustration:
I enter the Teletransporter. I have been to Mars
before, but only by the old method, a space-ship journey taking several weeks.
This machine will send me at the speed of light. I merely have to press the
green button. Like others, I am nervous. Will it work? I remind myself what I
have been told to expect. When I press the button, I shall lose consciousness,
and then wake up at what seems a moment later. In fact I shall have been
unconscious for about an hour. The Scanner here on Earth will destroy my brain
and body, while recording the exact states of all of my cells. It will then
transmit this information by radio. Travelling at the speed of light, the
message will take three minutes to reach the Replicator on Mars. This will then
create, out of new matter, a brain and body exactly like mine. It will be in
this body that I shall wake up. (Parfit 1987, 199)
Those
that hold the psychological account of personal identity will tend to endorse
the view that one survives teletransportation. For the psychological account
says that what is essential for survival is continuity of psychological states
such as memory, beliefs, desires and personality. John Locke, an early
proponent of this view, famously described personal identity in terms of
psychological continuity, within an analysis of personhood as consisting in
existence as “a thinking intelligent being, that has reason and reflection, and
can consider itself as itself, the same thinking thing, in different times and
places...” (Locke 1975). The person on Mars who awakens will claim to remember
being Derek Parfit, and to have memories and a personality that are
psychologically indistinguishable from the person on earth whose body was
destroyed. Locke, then, would say that Parfit survived teletransportation.
Somaticist
accounts suggest the survival of a particular body is critical for personal
identity over time. Since the body on Earth is destroyed during the scanning
process, Parfit ceases to be. A different person will awake on Mars. This
person will of course have psychologically indistinguishable memories and
personality to those of the late Parfit, but this person will not be Parfit. The
new person will be but an infant in terms of chronological age: only a few
minutes old.
We
will think of “somaticism” as the view that continuity of one’s body is
necessary for personal identity from one time to the next.2 There
are two ways that one might be a somaticist: one can believe that bodily
continuity is necessary but not sufficient, or that it is necessary and
sufficient. One easy case to distinguish these two is as follows: a piano falls
on your head, and causes you to go into a permanent vegetative state. Your
relatives discuss whether to “pull the plug.” Those who think that bodily
continuity is necessary but not sufficient may say that you no longer exist,
but your body continues to exist. Those who think that bodily continuity is
necessary and sufficient will say that you continue to exist, albeit your
cognitive capacities are non-existent. Both views qualify as “somaticism” in
our sense.
In my
extremely limited and informal survey of students and friends, most would be
unwilling to step into Parfit’s Teletransporter.3 The usual response
is that it is equivalent to committing suicide: the person here is killed, and
a new duplicate is created. Nothing of the original survives. Locke and others
who endorse the psychological account would retort that this is just an
irrational attachment to a certain set of molecules. If a molecule-for-molecule
identical copy is made, then it seems irrational to prefer one set of molecules
to another. Parfit compares this to an attachment to a wedding ring: there may
be sentimental value in having the original rather than a molecule-for-molecule
identical copy, but such attachments are “merely sentimental” and have nothing
to do with personal identity.4
The
reluctance to use the transportation device seems hard to explain other than by
the fact that people hold, at least implicitly, to somaticism. This provides a
robust challenge to psychological accounts in general, and a challenge to
uploading in particular. In the next three sections I will offer arguments
against somaticism.
4. Against somaticism: the big stroke
The
Vorlons,5 a mysterious and intellectually advanced alien species,
make this offer: you can have an original undiscovered play by Shakespeare
written in his hand, or a copy of the play made by one of his lackeys. You
salivate at the joy this will bring to the world (not to mention the fame and
fortune it will bring you personally). Since you can have only one, the choice,
it seems, is a no-brainer. You should opt for the one written by the bard’s
hand. But now consider this variant: the Vorlons tell you that the text written
in Shakespeare’s hand is missing the last two pages, while they assure you the
copy written by the lackey is a perfectly faithful reproduction of all the
words in the original. While it would be great to have both, you reason that the
most important thing is the play itself be preserved, not Shakespeare’s
handwriting. The copy here is in some sense better than the original because
the original has been damaged. This tips the scales in favor of the copy,
because while being written by the bard’s own hand is good, having the whole
play is even better.
We
can apply this lesson to thinking about personal identity. The Vorlons, with
their ability to see into the future, say the news is grim. In less than twelve
hours you will have a massive stroke that will cause you to lose many of your
memories and some mobility, and impair your intelligence. Your stroke will not
be as bad as some: the damage from the stroke will not leave you completely
cognitively impaired, but you will no longer be able to work as an academic. You
will have to find some relatively mindless job befitting your new level of
intelligence, perhaps in academic administration. Friends and family will say
that your once keen memory has been dulled such that your memory is now fuzzy,
and you seem to remember the most superficial things. It is a shame, and
totally unexpected at your young age. Even with their immense power, there is
nothing the Vorlons can do to prevent the stroke. They provide a radical
alternative: creating a perfect replica of you – down to the
molecular level – with
the exception that the problems with the arteries to your brain will be fixed
in the body replica. They insist, however, that only one body can survive. You
must choose tonight whether the replica or your current body survives.
Most
people I’ve asked about this would rather see the replica survive, for the replica
best embodies what is most important about you: your memories, your
personality, your beliefs and desires. None of this is to say that the loss of
one’s body is trivial. One can be quite attached to one’s body; but, when given
this tragic choice, more of what is essential to you as a person survives in
the replica.
Obviously,
this example is structurally similar to Parfit’s, but with one big exception:
what is gained by having the replica survive is much more significant in this
case than in the Teletransporter to Mars case. Parfit offers the incentive of
avoiding three weeks of space travel. (We might not even sacrifice our original
wedding ring for an exact replica if the benefit is merely avoiding three weeks
in a spaceship). Here the incentive is the possibility of not having one’s life
radically altered by the stroke. The attachment to one’s body does not seem
worth the cost in this case.
Perhaps
it might be remonstrated thus: “If I survived in a brain damaged state, I would
be a terrible burden on my family and the world. It would be better for my
family and the world that I died and a replica replaced me.” To avoid this
objection we can simply stipulate that the decision is to be entirely selfishly
motivated, and that we know this about your preferences: you would rather
survive a stroke than not survival at all. So, if the Vorlons did not offer you
a chance to survive as a replica, you would rather live after the stroke than
die. If the choice is still to have your present body die (the one with the bad
arteries), then this can only be explained by thinking that you will survive as
a replica.
It
may be thought that even the most selfish person might prefer death if it meant
something else he or she valued might result, e.g., you value the finishing of
your novel more than you value your own life. If a replica of you can better
realize this project, then it is consistent with selfishness to prefer death to
oneself for the sake of the great unfinished novel. Again, we may simply
stipulate around this objection. We may say simply that what you want most is
for you to finish writing the novel,
not someone else. If you die, you would rather it remain the “great unfinished
novel” than be finished by someone else. If this is your most important desire,
then preferring the stroke body’s death cannot be explained away by the thought
that what you wish for is the completion of your projects.
It is
worth noting that not all somaticists are likely to be convinced by this
example.6 But it should convince a few, and points out one of the
heavy costs of somaticism.
5. Against somaticism: retrospective replicas
In
this section we will examine an alternative explanation to somaticism for why
people might be reluctant to use Parfit’s Teletransporter, namely, fear of the
unknown. Notice that Parfit’s case is prospective: he asks us to imagine the
decision to walk into the scanner with the hopes of being teletransported. The
thought is that fear of the unknown may be muddying the waters here. That is, perhaps
it is this fear of the unknown, rather than a commitment to somaticism, that
explains the reluctance to use the Teletransporter. We can test this thought by
considering a retrospective rather than a prospective version of a replication
scenario.
Suppose
that every night when people sleep their bodies (including their brains) are
scanned by a swarm of nanobots and a molecule for molecule identical body is beamed
from a hidden alien spaceship in orbit; the old body is vaporized in a manner
that is undetectable by the human eye. Scientists discovered this fortuitously:
physicists noticed a spike in neutrino levels every time psychologists in the
adjoining lab conducted sleep experiments. Intrigued, scientists built a
chamber to isolate subjects from neutrino influences and then had test subjects
sleep in the chamber. Once the experiment was initiated, a hologram of a Vorlon
appeared in the lab and spoke thusly:
We are an ancient race known as the “Vorlons.” We
battled another species, the “Shadows,” just as your species was beginning to
evolve on this planet. One of the toxic effects of our war was a type of
radiation that kills all higher intelligences within three days. We have no way
of eliminating the radiation, but we have left advanced technology to recreate
your bodies from different molecules every day so that the radiation will not
harm you. We left the galaxy eons ago. You are hearing this message now because
you have advanced technologically to the point where you can detect our
technology. If you interfere with our replicator technology, you will quickly
die of radiation poisoning.
What
should we make of this? It is clear that dismantling it is out of the question
since all humans will die within three days. If you are a somaticist, you must
conclude that you have been alive only for a very short while. In fact, you
have existed only since last night. After all, the physical continuity of one’s
body has lasted only this length of time. However, most of us, I think, would
conclude the opposite. That is, that we have existed for years: that we do not
cease to exist every night and a new person comes into being.
This
example may not be a decisive refutation of somaticism, but it does at least
pull out one pillar of support. Somaticists ask why so many would be reluctant to
step into the Teletransporter that Parfit describes, intimating that our
reluctance has to do with the fact that our bodies will not survive. The retort,
suggested by this example, is that the reluctance is explained more simply as a
fear of the unknown. Contrariwise, the somaticist must now explain how so many
people could be mistaken about their own identity retrospective case; after
all, it seems very likely that, upon learning about the Vorlons’ technology,
most would conduct their lives as if they hadn’t just come into existence that
day. Who is going to say such things as: “I do not have to look after these
children you call mine: how can I have children if I myself was born today. I
can’t use this driver’s license, it is someone else’s – I was just born today. I’m not
qualified to teach any classes: a postgraduate degree is required, which takes years
to earn, and I was just born today?”
6. Against somaticism: practical ethics
Many
of the problems of personal identity are simply extensions of the more general
problem of identity; for example, a meteor falls on a family dining room table
smashing exactly half of it beyond repair. The other side is virtually
unscathed. Expert carpenters are brought in to fix the missing half. Has the
table survived? Most say yes. Here is a variant on the story: siblings fight
over who gets to inherit the family dining room table. In the end they saw it
exactly in half and each sibling hires expert carpenters to replace the missing
half. Did the original table cease to exist when it was cut in half by the
siblings? If we say yes this seems to conflict with the original intuition that
a table can survive the loss of half of its material. If we say no, then it
seems we have the impossible situation where numerically distinct tables (each
owned by one of the siblings) are not in fact numerically distinct. As
intimated above, we can construct parallel cases for personal identity. My
point here is that there are complex metaphysical issues of which at least some
personal identity issues look to be merely specific instances of more general
problems.
Since
issues of personal identity are acknowledged by all to be deeply contested, and
since they may be intimately intertwined with the more general and equally contested
issue of identity, it looks like we won’t be able to resolve these issues
anytime soon. Hence, we are left in a quandary about how to proceed. To
emphasize, let us suppose that despite the fact that the preponderance of
reasons seem to be against somaticism, imagine that the metaphysical reasons
for and against somaticism are exactly balanced.
Does this imply that we should be neutral on
the issue? I think not. It may be that there is a further court of appeal to
decide the issue, specifically, practical ethics. That is, the suggestion is
that if our metaphysical arguments and intuitions cannot decide the
metaphysical issue of personal identity, it is permissible to decide the issue
on non-metaphysical grounds. I won’t argue for this claim here, as it will take
us too far into the meta-philosophical issue of how different areas of
philosophy, in this case, metaphysics and practical ethics, are related. Suppose,
for the moment, it is true that practical ethics can tell us something about
metaphysical issues, it is then reasonable to ask: What does practical ethics
tell us about the issue of personal identity?
Imagine
two persons, McCoy and Hatfield, who want to kill one another. They are
co-inventors of the first replicating machine. McCoy thinks it should be used
on humans, Hatfield believes that it never should be so employed. McCoy believes
in the psychological continuity thesis of personal identity, whereas Hatfield believes
in somaticism. How should we reason about personal identity in terms of what is
good for society? We can imagine two possibilities: society adopts for, social
and legal purposes (its “public norm” for short), somaticism or psychological
continuity. Which is better for society?
Consider
first using somaticism as the public norm. McCoy could kill Hatfield and then
hop in the replicating machine. We would be forced to say, because we have
adopted somaticism as our public norm, that McCoy is dead and the replica of
McCoy (call this person “McCoyson”) is a different person. Since McCoyson was
born after the crime, McCoyson cannot be responsible for the crime. (We have
long abandoned the idea that one can inherit personal responsibility for the
sins of one’s ancestors). This crime would be ruled a murder-suicide in a
somaticist jurisdiction. Of course McCoy then has every reason to commit the
crime, as he does not believe in somaticism. We can easily imagine that the
number of murder-suicides would greatly increase. Indeed, mass murder hardly
seems out of the question. If you are looking for a job in philosophy, you
could plant a bomb at the American Philosophical Association conference and
kill off hundreds of philosophers at once. Before the police capture you, you
could hop into the replicator. The person created by this process, according to
the public norm, died by replication. The new person is not responsible for the
crime, having just been born. Now this new person can apply for one of the many
philosophy jobs that have suddenly become available.
If
psychological continuity is the public norm, then neither Hatfield nor McCoy will
have reason to commit the crime based on replication. As before, Hatfield will
not because he will consider this equivalent to suicide. McCoy will not because
the public norm says that McCoy will survive the replication and be subject to
criminal sanctions. Since a public norm of somaticism is more likely to lead to
negative social consequences, this gives us some reason to reject somaticism.
(There
are other policy options we might explore, e.g., we could simply shoot anyone
who is not a somaticist, or ban replicating technology. For some, these two
policies might be very similar in terms of their practical effects. Imagine,
similar to the stroke case, that without replication someone will die. Banning
replication technology will end his or her life just as surely as being shot
would. Obviously the two policies are not morally equivalent. Rather, it is to
point out that banning such technology would come with some huge costs for
some.)
7. No branching
Debates
about identity preservation and uploading invariably get hung up on the
“branching” problem, and this probably provides the strongest support for
somaticism. The problem is that it seems there is only one of me. But uploading
seems to allow the possibility that there could be hundreds, if not millions,
of “me.” But if there can be only one of me, then uploading does not preserve
my identity. It is clear how this problem arises given our previous discussion
of the uploading process. Imagine my brain is scanned and the relevant
information is recorded. Instead of being uploaded to a single computer with
robotic body, imagine a thousand robot brains are encoded with the information.
Of course it seems possible that thousands of robots could awaken in the same
instant, all claiming to be Mark Walker. (And what a wonderful world this would
be!)
Using
the equivalence thesis we can see how this is exactly the same problem as the
problem of branching that philosophers discuss in connection with
carbon-to-carbon transfers. Parfit extends his Teletransporter case in exactly
this way:
Several years pass, during which I am often
Teletransported. I am now back in the cubicle, ready for another trip to Mars.
But this time, when I press the green button, I do not lose consciousness.
There is a whirring sound, then silence. I do not lose consciousness. I leave
the cubicle, and say to the attendant: “It’s not working. What did I do wrong?”
“It’s
working,” he replies, handing me a printed card. This reads: “The New Scanner
records your blueprint without destroying your brain and your body. We hope that
you will welcome the opportunities which this technical advance offers.”
(Parfit 1987, 199)
Of
course there is no reason to stop at one replica. Using Parfit’s
Teletransporter thousands of organic molecule-for-molecule identical persons
could awaken in the same instant, all claiming to be Mark Walker. (And what a
wonderful world this would be!)
Notice
that I did not say that any of the thousand persons claiming to be Mark Walker
are me. Somaticism will deny that any of the thousand replicas are me; only the
original is me. If the original is destroyed, and a thousand replicas are made,
then somaticism will claim that I did not survive.
What
does the psychological account have to say about multiple replicas? Here
opinions differ. On the one hand, it seems that if there are multiple replicas,
and they are all psychologically indistinguishable from the original, then each
of them has as good a claim to be me, and so they are all me. The contrary “no-branching”
view is that at most one replica is me, for there can be only one me (Shorter
1962).
The
question then is whether there can be “branching”: more than one of me. I will
argue that both sides of the debate are correct; there is a sense in which
there can’t be more than one of me, and a sense in which there can be multiple
versions of me. The first step in our argument is to get a little clearer about
the no-branching argument, which may be schematized as follows (where “P” stands for “premise” and “C” for “conclusion”):
The
No-branching Argument
P1:
Multiple replicas X, Y, Z…. of an individual O (the original) are numerically
non-identical with each other, that is, X is not identical with Y or Z, Y is
not identical with X or Z, and so on.
P2:
Preservation of personal identity requires preservation of numerical identity.
C:
Therefore, not all replicas X, Y, Z… preserve personal identity of O.7
It is
worth distinguishing this argument from a similar but less serious objection.
The less serious objection is that if there are a thousand replicas, then they
will quickly have psychologically distinguishable properties. All thousand replicas
will not fit in the same cab, for example, and so will have different
experiences leaving the replicating center. Their psychological states will
only diverge further over time. Riffing on Parfit’s example, we can imagine a replica
waking on Mars, the Moon, and Pluto all at the same time. Each will almost
immediately have different experiences, and so quickly will be psychologically
different.
Even
if this is conceded, it does not answer the question of the status of the replicas
at the moment they are created. Imagine the thousand replicas are all created
at the same instant, and each awakes in a separate but identical room. At the
instant of awakening, there will not be any psychological divergence8
and so the argument from diverging experience tells us nothing about the
identity of the thousand replicas at this moment.9
I
want to suggest that the problem with the no-branching argument is that there
is a critical ambiguity. To explain the ambiguity it will be helpful to review
the type/token distinction.
8. Types and tokens
The
nineteenth century philosopher Charles Peirce is credited with first making the
type/token distinction. Pierce’s own example involving the individuation of
words is as instructive as any:
A common mode of estimating the amount of matter in
a manuscript or printed book is to count the number of words. There will
ordinarily be about twenty the’s on a
page, and of course they count as twenty words. In another sense of the word
“word,” however, there is but one word “the” in the English language. (Peirce
1906)
There
are twenty tokens of the word the,
but a single type of the word the. The
argument to be canvassed is that if we think of personal identity as ambiguous
between types and tokens, then the no-branching argument may be rejected.
We
may approach the issue by recasting the previous argument by reference to a
work of literature; so let us consider the no-branching argument applied to Shakespeare’s
Hamlet. We may reconstruct the
argument first as about tokens, and then about types.
No-branching
Token Argument
P1’:
Multiple replicas X, Y, Z…. of an individual O (the original Hamlet penned in Shakespeare’s hand) are
numerically not (token) identical with each other, that is, X is not (token)
identical with Y or Z, Y is not (token) identical with X or Z, and so on.
P2’:
Preservation of play-identity requires preservation of (token) numerical
identity.
C’:
Therefore, not all replicas X, Y, Z… preserve play-identity of O.
It is
pretty clear where this argument goes wrong: P2’ is false. The original token of Hamlet, written in Shakespeare’s hand on paper created over four
hundred years ago, is now long lost. But the same play that Shakespeare wrote
can be read today. The no-branching token argument fails.
No-branching
Type Argument
P1’’:
Multiple replicas X, Y, Z…. of an individual O (the original Hamlet penned in Shakespeare’s hand) are
numerically not (type) identical with each other, that is, X is not (type)
identical with Y or Z, Y is not (type) identical with X or Z, and so on.
P2’’:
Preservation of play-identity requires preservation of (type) numerical
identity.
C”:
Therefore, not all replicas X, Y, Z… preserve play-identity of O.
It is
pretty clear where this argument goes wrong: P1’’ is false. I may have bought my copy of Hamlet at a different bookstore than you, but still, we are reading
the same play. At least in the case of plays, the type version of the
no-branching argument fails. Thus, the no-branching argument, in both its token
and type formulation, does not look the least bit plausible when applied to
literature.
9. The type/token solution to personal identity
In
this section I will say a little about the type/token (TT) account of personal
identity10 and then see whether the no-branching argument has any
traction against it. In the case of literature, the tokens of Hamlet are individuated according to the
physical implementation: my Hamlet is
in a different spatial location from your Hamlet.
The Hamlet type is an abstract entity,
which particular tokens of Hamlet
embody. Similarly, the TT solution to personal identity says that tokens of a
person type are individuated in terms of physical implementation: each replica
will have a different spatial location. The person type is the abstract entity,
which the various tokens are all embodiments of.
We
previously rejected somaticism, but this is because we had yet to survey the
type/token distinction. The version of the type/token view that we should adopt
says that somaticism is correct about tokens, and the psychological account
correct about types. Consider then the case where the original Mark Walker is
scanned and destroyed and a thousand replicas are created. Somaticism, as a
theory about tokens, says that the original token was destroyed, and a thousand
new tokens created. The psychological account applied to types says that the Mark
Walker type continues to exist, and indeed, is multiply instantiated.
The ontological status of abstract entities is
a perplexing and contested issue (Wetzel 2009), but there is no reason to think
that it is more perplexing in the case of persons rather than literature, and
we are committed to types in the case of literature.11
Can
the non-branching argument be deployed against TT? Assuming that types can have
more than one token, non-branchers cannot allow the notion of types to have a
role in personal identity. So, to disambiguate the original non-branching argument,
it must be about tokens:
The
No-branching Argument in terms of Tokens
P1’’’:
Multiple replicas X, Y, Z…. of an individual O (the original) are numerically
[token] non-identical with each other.
P2’’’:
Preservation of personal identity requires preservation of numerical [token]
identity.
C’”:
Therefore, not all replicas X, Y, Z… preserve personal identity of O.
There
are two problems with this argument. First, it is question begging. The entire
issue is whether personal identity can be explained in terms of preservation of
type identity, and so P2’’’
prejudges the issue.12
The
other problem is that it is difficult to see how one can insist on
non-branching without collapsing into somaticism. To see this, consider the
case where the original Mark Walker’s body, O, is destroyed when three replicas
X, Y, and Z are created. Either O is not identical with any of X, Y, Z, or O is
identical with one of X, Y, Z. If the former, then non-branching is simply
somaticism in disguise. If it is asserted that O is identical with exactly one
of X, Y, Z, then any choice would be arbitrary in the sense that choosing one
among the thousand to be The Mark Walker
would not be choosing based on any intrinsic differences. We could, for
example, have all the replicas draw a number out of a hat and designate the
winner of the lottery The Mark Walker.
But an appeal to a lottery shows that precisely no intrinsic properties are
used to individuate: it is the process (the lottery) that does the
individuating. We could do the same for Hamlet.
We could assign a number to every extant copy of Hamlet and have a lottery to find out which is The Hamlet, and which are mere copies. But, of course, no one would
be impressed by this.13
Criticizing
the non-branching argument is not a positive argument for TT, but it does
suggest that TT need do little to prove itself more plausible than
non-branching. However, in terms of a positive argument for TT, the fact that
it provides a number of intuitively plausible consequences speaks in its favor:
- The TT solution explains why people
might be reluctant to enter the Teletransporter in Parfit’s original
example. It requires sacrifice of their token identity, for little
compensatory gain (three weeks in a space craft). In other words, it can
explain how we might survive (as a type), even though we may regret some
loss of identity (since the original token is now dead).
- The TT solution explains why it
would be rational to sacrifice one’s token identity in the stroke case:
the loss of token identity is not inconsiderable, but the replica is type
identical, and the new token replica will be in better shape than the
original token.
- The TT solution explains why, in
the Vorlon radiation case, we are not likely to feel much threat to our
identity: the type survives destruction of each token, and each token is
only a day old. Analogously, other things being equal, I would feel more
upset about having my copy of Hamlet
from my undergraduate days stolen, and less worried about a copy just
acquired yesterday. In both cases, of course, the same play type is
stolen.
- The TT solution explains why in Parfit’s
modified transporter case – where a replica is created on Mars, but the
original on Earth is not destroyed – the person
on Earth has more claim to being Parfit than the replica on Mars. The
person on Earth is both type and token identical with Parfit from the
previous month (assuming he hasn’t used the Teletransporter in the
meantime). The replica on Mars is merely type identical.14
- The TT solution explains in a
satisfactory manner what happens when the original is destroyed to make
multiple replicas. Each replica is type identical with the original, but
none of the replicas are token identical with the original. This avoids
the embarrassment of having to say which of the indistinguishable replicas
is identical with the original.
10. Should I upload?
I
have tried to strike some compromise between saying that there is no loss of
identity in replication (and by our equivalency thesis, uploading), and the
position that survival is impossible. Still, it may look as though this is
tantamount to an argument against uploading: if there is any loss in uploading,
even if it is only token identity, why would anyone want to sacrifice some
identity? The answer is that there are considerable advantages (or at least
purported advantages) to being uploaded, including immortality and enhancement.
Except
for the completely reckless, forgetful or lazy (ahem), everyone backs up his or
her valuable computer files. But once we see that people too can be backed-up,
it appears that virtual immortality is assured. For so long as there are
operating computers, one can simply transfer the files that comprise oneself
from computer to computer. If the hardware on one computer fails, you simply
move to another computer. Suppose a piano falls on your robotic body. No
problem. A new robotic body is brought out of the closet and a backup copy of
you is uploaded. What formerly would have meant certain death is now only a
small inconvenience. As Freeman Dyson long ago realized, the question of how
long one might live quickly resolves to how long the universe will remain habitable
(Dyson 1979), hence, the term “digital immortality” is sometimes used to refer
to this prospect.
As
for enhancement, one possibility is that our senses could be radically
enhanced: robots presently make use of a sensory apparatus that detects light
in parts of the spectrum not available to (unaided) human vision (e.g., infrared,
x-rays, etc.), sounds that are beyond normal human auditory range, and so on.
In terms of enhancing cognition consider that it is a relatively routine matter
to add memory or computing power to today’s computers. If one is uploaded to a
computer, then it seems that it would be a relatively routine matter to enhance
one’s memory or cognition: just add more computer memory or processing power. The
sky is literally the limit here. Anders Sandberg (1999) has done some
preliminary calculations to suggest that planetary scale computers,
“Jupiter-sized brains” might be possible. How powerful and how smart would such
brains be? It is, obviously, hard to say. Certainly they would eclipse us by a
greater margin than we eclipse the cognitive powers of your typical lab rat.
Along with such enhanced cognition would come awesome powers to manipulate the
physical world, for there is some truth to the saw that knowledge is power. In
short, and without too much hyperbole, those who upload may well be on their
way to godhood.15
It is
beyond the scope of this paper to argue that these purported benefits of
uploading really are benefits, but, if they are, the temptation to upload is
clear. And just like in the stroke case, it is clear why it might be rational
to forgo token identity survival for these advantages.
Acknowledgments
I would like to acknowledge the following persons for their
assistance: Nick Agar, Russell Blackford, Jamie Bronstein, and Tim Cleveland.
Notes
1.
Hans Moravec (1988) discusses ways around this challenge.
2.
There are many problems for the bodily criterion of personal identity that I
will not discuss here. See Williams (1973) and Olson (2006).
3.
Parfit has found similar reactions to the case. He even concedes that he has
some residual doubt that he would survive teletransportation (Parfit 1987,
279).
4.
Moravec (1998, 117) suggests that this is like being attached to “jelly.”
5.
From the television series: Babylon 5.
6.
The protagonist and somaticist in John Perry’s fun little dialogue accepts
death rather than ceding ground to the psychological account (Perry 1978).
7.
See Williams (1973). Thomas Reid seems to have had a similar argument in mind:
see Perry (2008) and Martin and Barresi’s editors’ introduction (Martin and
Barresi 2003).
8. At
least where psychological states are narrowly construed (Putnam 1981).
9.
Even Nozick’s (1981) closest continuer theory would not be able to choose one
among the many.
10.
Williams (1973, 80-81) considers something analogous to the present proposal.
11.
This is not to argue, à la
Quine, that we are committed to realism about types. Rather, it is to say that
whatever one’s preferred account, realist or nominalist, of types as applied to
words or literature, the same account can be applied to persons. Nominalism is
not the same as skepticism: nominalists can offer an account of types such that
it makes sense to say that you and I are reading the same play, even if we own different
copies of the play.
12.
Patrick Hopkins has an argument that seems to show that the type construal is
not possible: “The relationship of ‘identity’ is a very strong, and necessarily
strong, concept that strictly refers to literal sameness – not similarity. When
we use ‘identical’ in this sense, we are not saying that two things are just
very like each other (‘identical twins’), or even exactly similar (‘identical
cars’), we are saying that ‘two’ things are actually one and the same specific
thing” (Hopkins n.d.). I’m not sure what Professor Hopkins would say about Hamlet: are he and I reading exactly
similar plays or are we reading the same play? The former sounds perverse to
these ears. But even granting this is the correct description, it seems that
“exact similarity” is all the identity we may want in certain cases (such as
the stroke case).
13.
Indeed, we could solve every paradox – a set of statements that are
individually equally plausible, but mutually inconsistent – by assigning a
number to each statement and rejecting the loser of a lottery. Obviously, this
is no way to solve a paradox.
14.
Parfit (1987, 293-97) discusses the possibility of individuating in terms of
types and tokens. He argues that it is the type that matters, not the token. As
noted above, I disagree: both type and token are important.
15. A
related objection is that radical enhancement will threaten identity (Walker
2008).
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