John Heisel
October 9, 2001
The Myth of Personal Identity
Good afternoon ladies and gentleman of the Philosophy Club. I am very excited to
speak with you today about personal identity. The issue of personal identity has been
much discussed, and I am here today to summarize it for you and present you with the
theory I believe to be the most acceptable. By the end of my presentation, I would hope
that you would agree with me that personal identity is completely and utterly nonexistent.
If not, though, I will be presenting some other theories of personal identity that you may
find more plausible.
Personal identity is an attempt to answer the question of what are persons. We
seem to have a good idea of what makes a person by using our senses, but are these
senses reliable? Is there anything that identifies us as persons, and more importantly, is
there anything that identifies us as unique and distinct persons? Since we think we are
able to reidentify persons over time with a high degree of success, the answer would
initially seem to be yes. So the question now is what gives people identity, so that they
are recognizable as time passes.
The first theory I would like to discuss with you is what we call the “thick”
psychological theory. This theory posits that a person’s identity is contained in her
psychological capacities. The continuance of these capacities over time – character traits,
skills, preferences, etc. – is what makes a person the same person. That is to say that
person X at time T1 is the same person as person Y at time T2 if and only if person Y at
T2 has all of the same psychological capacities as X at T1 and the capacities of Y must be
causally connected to those that X had.
Causal connection is a very important aspect of the “thick” psychological theory.
The addition of causal connection overcomes a fairly obvious fault in this theory. The
problem is that a highly skilled doctor could remove and duplicate person X’ brain, return
it to X, but put the duplicate into person Y’s head. Persons X and Y would now share all
of the same psychological capacities, however person Y’s capacities would not have been
properly caused. This lack of causal connection in person Y’s psychological capacities
allows the “thick” theory to survive even in this bizarre case.
However, this theory does not have a built-in mechanism to fight every potential
counterargument. Let’s examine some of the “thick” theories other problems. First, we
are aware that memory is fallible. We forget things over time, and our psychological
capacities change. Our preferences are a prime example of this change: When I was in
high school I subsisted on a diet of frozen pizza and Mountain Dew. Although I still
enjoy frozen pizza, I absolutely cannot stand Mountain Dew. According to the “thick”
psychological theory, does this mean that I am no longer the same person as I was in high
school? What if I lose memories or psychological capacities through an accident? There
are well-documented cases of accident victims [especially those involving head trauma]
who lose some or all of their memory after their accident. If person X at time T1 with
capacities C1 is involved in a car accident and loses his psychological capacities, is
person X at time T2 with capacities C2 the same as person X at T1 with C1? It seems
absurd to say that these two people are not the same, but according to the “thick” theory,
it would seem that they are no longer the same person.
These counterarguments are only the tip of the iceberg. Perhaps the biggest
problem facing the “thick” psychological theory is fission. The idea of fission is rather
simple: an object divides into multiple parts. In this case, we’re going to going to split the
psychological capacities of person X and implant them in persons Y and Z, destroying
person X’ body. The “thick” psychological theory would suggest that persons Y and Z
are both person X. However, we know that two things cannot be identical. Leibnitz’ Law
states that two things are identical at a time if and only if they share all the same
properties. Persons Y and Z absolutely cannot be the same person, because they are not
identical: to start with, they have different bodies. Conversely, if we say that neither
persons Y or Z are person X, then we contradict the “thick” theory again: persons Y and
Z share all the psychological capacities of person X, so one of them must be person X,
but we are committed to saying that neither is person X.
Perhaps the strongest argument for psychological continuity is put forth in
Bernard Williams’ essay, The Self and the Future. Although ultimately it seems that
Williams comes out in favor of a body-based theory of personal identity and continuity,
he does present an interesting example regarding psychological continuity. Williams
presupposes that a machine could exist that would take a person’s mind and
psychological traits and move them to a new body. If person X and person Y consented
to this operation, X’ mind would end up in Y’s body and vice versa. Williams further
writes that if you approached persons X and Y before the operation and told them that
after the operation one of them would be tortured whereas the other would be given
$100,000, persons X and Y would choose selfishly to inflict the torture on their former
bodies, and reward their new bodies with the money. This would seem to show that
people believe that their identity is carried in their minds and psychological traits rather
than in their bodies.
Another theory of personal identity is the brain theory. As its name suggests, the
brain theory posits that personal identity resides in the brain, and that as long as a brain is
continuous over time, personal identity is retained, regardless of which, if any, body the
brain resides in. We could then say that person X at time T1 is the same person as person
Y at time T2 if and only if person Y at T2 has the same brain as person X had at T1.
This theory treads much of the same ground as the psychological theory. It does
seem to answer some of the questions we have posed to the psychological theory. For
example, if our abovementioned accident victim is looked at with the brain theory, we see
that he is the same person as he was before, because he still has the same brain. This is
true even if he has lost many of his memories and cannot remember his previous
experiences. If his body were to become so badly damaged that it could no longer
function, doctors could transplant his brain to a healthy body and the person would
remain intact.
Just as with the psychological theory, where the brain theory really falls apart is
with fission cases. If we take a person X’ brain and divide it into two equal parts, destroy
X’ body, and put one half of the brain in body Y and the other half in body Z, which of
the bodies is person X? The answer is that both bodies are person X: they both have the
same brain – that, for argument’s sake, contains the same psychological traits and
characteristics, memories, etc. in each half – so they are both person X. However, we
already know that two things cannot be identical if they are different in any way.
Therefore, neither body Y nor body Z can be person X. Yet if we look at this from
another perspective, it seems absurd to say that neither body Y nor Z can be person X.
Why is this absurd, you ask? Look at it this way: we know that a person can survive
without the full use of his brain. It is well documented. Not being a biologist, I don’t
know the minimal amount of brain that must remain for a person to survive, but it does
not seem absurd to say that one could survive with only fifty percent of their brain. So
how can it be the case that if I were to lose half of my brain I could survive, and yet if my
brain were divided into two parts with both parts placed in new bodies I would not
survive? In the words of Derek Parfit, “how can a double success be a failure?”
Derek Parfit is an anti-realist. So far we have only discusses realist views of
personal identity. Realist views insist that personal identity is an objective feature of
reality. Anti-realism denies this viewpoint. The main idea of Parfit’s anti-realism is that
there is no identity as mentioned in previous theories, there is only survival. Parfit’s
vision of survival is that of a relationship of degrees between two person states. Antirealism also provides a handy solution for fission cases.
The relationship of degrees works something like this: rather than focusing on the
psychological continuity of two person states, we must look at the psychological
connectedness of two person states. Because of this idea of connectedness, there is no
transitivity between two person states. There is only a degree of a relationship. This
relationship allows for persons Y and Z to have a certain degree of relationship with
person X, but neither person Y nor Z is identical to person X.
This relationship of degrees also helps solve the problem of fission cases. If
person X splits into persons Y and Z, persons Y and Z will only share a certain degree of
similarity with person X. If we want to identify whether person Y or Z is the same as
person X, we can attempt to determine the degree of similarity between X and Y or Z.
Whichever of the two has a higher degree of similarity could be identified as X.
I realize this may all sound a little crazy at first, but allow me to explain the
theory as I understand it and hopefully you’ll all come around to my point of view. First
of all, if we deny that personal identity is an objective feature of reality, I think that we’ll
realize that we already live our lives in this way. We tend to assume that personal identity
is contained in body identity. If we look around at our neighbors, we are reasonably
convinced that they are the same people we’ve spoken with every day of our university
careers. But I would be willing to bet that every one in this audience has had at least one
experience where they attempted to greet someone that fit a certain body identity but did
not share the personal identity that you wished. Or, have you ever called someone who
had roommates and accidentally spoken to the roommate and not the intended party as if
she was the intended party? The point I am trying to put forward here is that we already
cannot reliably identify people over time. External appearances can trick us, and we
currently have no way of knowing whether a person has the same soul, brain, or
psychological content as they did previously. Furthermore, I suggest that we are not the
same person on a day-to-day basis. Every day, we are experiencing new things, changing
ideas, values, and opinions. Every day, we become less of the person we were the day
before. I believe that body X today and body X in ten years will be completely different
people, even if no sort of fission as I have previously discussed occurs. This is solely
because every day we lose a little bit of who we were yesterday and gain a little bit to
make up for it. We’re always connected at each stage in our life, but to say that the
person speaking to you today from this body is the same person in the same body that
will be flying to London next week is utterly absurd. If one likes, one could reduce the
interval of degrees/stages to anything: hours, minutes, seconds. There are no two times
that we are the same person: if we refer back to Leibnitz’ Law, we can see this. For
person X at time T1 to be the same as person X at time T2, time T2 would have to be the
same as time T1, otherwise a relationship of identity could not exist. I believe that we are
already living our lives without the specter of personal identity, but that most people
either are unaware of this fact, or do not want to admit to it.
There are myriad reasons why people would not want to admit to an anti-realist
slant on life. One might think denying personal identity would destroy relationships,
make emotion irrelevant, and make it awfully difficult to deal with concepts like
responsibility, punishment and reward. I would like to argue that adopting an anti-realist
stance and denying the existence of personal identity will have absolutely no effect on
these concepts, precisely because it is already the case that personal identity is nonexistent, and we’re able to get along just fine.
I believe that relationships are interchangeable and temporary. Another bet I
would be willing to make is that you have very few, if any, close friends remaining from
your kindergarten class. Little Johnny that you used to play with every day in
kindergarten has grown into a Big Johnny, whose whereabouts and whatabouts you
cannot ascertain. What I mean to point out here is that when Johnny and you attended
different schools for the first grade, you made a number of other friends to fill the void
Johnny’s departure left in you. What I believe this means is that when you enter into a
relationship with someone, you are really entering into a relationship with certain
qualities the person has. In looking to make friends, you are looking for a body that
possesses certain characteristics that you find attractive and valuable. I don’t think that it
really matters in whom you find these characteristics, only that you find them. If the body
that possesses these characteristics should go through a change and lose some of the
characteristics that drew you to it as a friend, I think that most people would probably
gradually stop associating with this body, and would find a new body to take its place. I
believe the same is true of romantic relationships: how many of us can say that we are
still in love with the first body we ever fell in love with? Those of you that raised your
hands – consider yourselves lucky, and hope that it lasts.
I would now like to discuss the notion of anti-realism destroying the concept of
emotion. This too is utterly absurd. Emotions would still exist in the exact same form
they are now. I believe that when we attach an emotion to something – be it person or
object – we are really attaching that emotion to a set of qualities and object carries. So to
say the Hermann loves Pauline is to say that body H finds a set of qualities on body P to
be especially attractive to its sensibilities. Should body P’s qualities change, body H
would probably find itself less and less attracted to body P and would find a body R with
the qualities it desired to replace body P. So, far from destroying emotion, anti-realism
only serves to illustrate how emotion actually works.
Another problem that has been raised about anti-realism is the question of
responsibility, punishment, rewards, etc. Many realists believe that an anti-realist
approach will make it utterly impossible to deal with these values. Obviously, I disagree.
The idea of punishment is threefold: to punish a body for an act it committed, to
rehabilitate the set of ideas that set the action into being, and to deter further actions
based on these ideas. Can anti-realism still achieve this threefold punishment? Yes and
no. I will attempt to address all three forms of punishment together, because I believe
they are all heavily interconnected. If a body were to fission immediately after a criminal
act, can anti-realism still make a decision over which body is to be punished? I believe
the answer is yes. For a body to commit a negative action, the body must not only have
the idea that the action is acceptable, but must carry a strong enough conviction in that
regard so as to carry out the action. It would seem that a psychological study of negative
behavior could likely figure out how strongly one would have to hold negative ideas in
order to act on them. Arbitrarily, let’s say that the threshold where a negative idea
manifests itself into a negative action is a seventy-five percent belief that the idea is
acceptable. So, if the body fissions, we could examine the subsequent bodies to see which
if any have a percentage of the belief similar to that of the body that committed the
criminal act. By this I mean that if body A commits a negative act and his belief that the
action was acceptable was eighty percent, we would examine his fissioned bodies B and
C to see if they had the requisite seventy-five or more percent of body A’s eighty percent
belief. Should the bodies fission further, I believe we can still examine them to see if they
hold this relation. If none of the bodies hold this relationship, I would say that it is
already unnecessary to punish the body, as it has already punished itself. I believe that if
fission were to occur, a significant number of cases would carry enough of the negative
ideas and beliefs in the necessary percentages to still achieve punishment, rehabilitation,
and deterrence.
Finally, how can we discuss survival over time in an anti-realist perspective? My
idea is that in an anti-realist environment, most people have the opportunity to live long
beyond their physical death, and some people will have the opportunity to become
immortal. In the absence of a “real” basis for personal identity, I would like to suggest
that the only identity we can possibly have is that of thoughts and ideas. By this I mean
not only the ideas that we communicate with others, but also the simple ideas of our own
existence. To quote a singer whose name I will not mention for reasons the quote makes
obvious, “Here today, gone tomorrow. Don’t need my self remembered, but what I help
create and leave behind is important to me.” I think this pretty much sums up how we
should think of ideas as containing personal identity. If my body were to die immediately
after giving this presentation, I would still live on in some form through all of you who
remember any of my words. If you even remember that I existed, then I will still live on. I
believe that fission – far from being a case we generally examine as a hypothetical
situation – is not only real, but is going on every day. Every interaction, every spread of
ideas helps to fission personal identity. If we look at it this way, I lose absolutely nothing
when I fission. With every word I speak, I retain all parts of myself and yet
simultaneously give parts of myself away. The only problem I see with this view of ideafission as personal identity is that of abortion cases. I am pro-choice and do not think that
an unborn baby is a person. However, if one were to accept what I am saying then it
would seem that an unborn child is a person, simply because its mother is aware of its
existence. This poses a problem for my personal beliefs, but conversely, we must base
our beliefs around what is true and not around what we simply like.
As I end my presentation today, I would like to say that I hope you have found
something interesting to take with you from my presentation. Not just for your benefit,
but for my own immortality. I hope that I’ve made some inroads to convincing you that
anti-realism is not only the most logical way of looking at personal identity, but that anti-
realism is how our world already functions. While I hope I have explained things clearly
and succinctly, I am sure that I have created many questions and left many unanswered.
As philosophy is always a work I progress, I am always willing to hear critiques of my
beliefs and would be more than happy to address any questions or concerns you may
have. Thank you.