19. Personal
identity, or the identity concept applied to persons, is different from the
identity of objects, because it comes from our direct personal experience.
The concept of identity applied to my
person comes from the realization that I can directly control and feel
sensations from a limited part of the outer world that I identify as “my body”
or “me”. It is the existence of a mental world that allows us to assign an
identity to our material counterpart, not the other way around.
It is this connection that creates our
experience of being discrete physical subjects, which is not reducible to a mere
communication convention. (Note:
Julian Jaynes in his book The Origin
of Consciousness in the Breakdown of the Bicameral Mind suggests that
anthropologically we gained the matching between the identity of our mind and
the identity of our body during centuries of social evolution).
20. The concept of identity applied to objects derives from an
arbitrary extension of the concept of identity that we apply to ourselves and then to other persons. But
this view raises the question about the origin of the identity of our mental
world. Have we to accept it as “given”? If personal identity cannot be anchored
to the identity of something material or structural, then
the identity concept in itself seems to be intrinsically dualistic. We will
see that only Open Individualism can
solve this question, avoiding all the problems related to dualistic
theories, but for now let us suspend our judgement about the origin of personal
identity, acknowledging that at the
moment we have no complete theory of personal identity. Notwithstanding
this, let us start examining the problems
that arise when, once we accept that the identity concept comes from the
direct experience of our personal identity,
we continue thinking that every person has their own separate personal identity.
21. All
reductionists agree that every mental
phenomenon has a physical counterpart, but they have to face the fact that
our direct experience of the existence of
a mental world appears to be something like an
unexpected and unnecessary phenomenon that arises from brain activity, which
is expected to respect only physical laws. It is difficult to find a reason to
deny that a fully materialist world could
work the same without any mental world emerging from brain activity;
we know that a mental world exists just
because we have a direct experience of it, and then we assume that it is
true also for other people. In fact, we infer that other people have conscious
experiences based only on their behavior and, more recently, on our knowledge of
the functioning of the brain. Because we can see that they act in about the same
way that we do, we figure that everybody else has their own “experience of
thinking” in the same way we have. Making this generalization we integrate the objective knowledge
that we get from observation with the subjective experience of the mental world
that we undergo in the first person. This is the main reason why
Reductionism asserts that it is possible
to map any mental state onto a specific physical brain state, but it does not
justify the existence of the mental state. This is why reductionists have to
say that mental phenomena “emerge” from the brain (whatever that may mean), and
this is why the hard problem of consciousness described by
David Chalmers is so hard to solve.
22. To avoid
focusing the discussion on consciousness instead of personal identity, and
thereby avoid the questions about various degrees and limits of consciousness, I will use the term “subjectiveness”
instead of “consciousness” to refer to the experience of having a mind, a mental
world that “emerges” from the brain of a living being. The term “subjectiveness”
highlights that having a first-person point of view is what is missing in
inanimate objects and is what is occurring in living beings, and for that
reason they can be properly called “subjects” instead of “objects”. The mind, or the mental world that each of
us experiences personally, can according to this terminology be called the “subjectivity phenomenon”; this term
also refers to the lower levels of perception. The subjectivity phenomenon is
originated by brain activity, but it does not exclude the possibility of other
sources. This allows us to apply the discussion to a wider range of living
beings instead of only to humans.
23. Because in
a reductionist world, every mental state corresponds to some brain state, I will
call the process that is able to
transform a brain state into a mind
state “the subjectivity function”.
The applying of the subjectivity function to a series of ordered brain states
results in the appearance of a series of mind states that constitutes the mind
or the “subjectivity phenomenon” as defined before. Each different brain,
through the subjectivity function, originates an (apparently) numerically
different instance of mind, which we usually identify as
a subject with its own personal identity.
24. By
referring to a “subjectivity function”, I do not mean that the mind is a passive
result of a physical process that may be driven only by chance or necessity, but
rather I just point out the strict
correspondence between the brain and the mind in a reductionist sense.
I do not exclude the possibility that
mind may interact actively with physical world, even if this does not appear
to be compatible with reductionism. This problem is related to free will and
can be considered separately from the
issues relating to subjectiveness and personal identity. I will discuss it
in more detail at the end of this document, explaining how Open Individualism
may help to manage this problem.
25. So far, we
have seen how personal identity is not
reducible to a mere communication convention like the identity of objects
was: on the contrary, this is the basis on which we build our concept of
identity. Even if we cannot imagine where
to anchor our personal identities, we assume that in some way the identity of my
mind is something definitely different from the identity of your mind. We
are here at the same time, me and you and everybody else, so how on earth can we
have the same personal identity? To see that even this trivial conviction has
serious problems, we have to consider some cases that currently seem to belong
only to science fiction, but actually in part are already possible and have
already been discussed by many philosophers of the mind, and are summarized by
Derek Parfit in
Reasons and Persons. These cases are
about the extreme possibilities that result from
personal identity transforming, splitting and
melding.
26. In
Reasons and Persons,
Derek Parfit describes a thought
experiment called “the combined spectrum”, where the body and the brain and the
psychological content of the brain of one person are gradually transformed into
the body and the brain of another person. From a reductionist point of view,
nothing else determines personal identity but the matter and the structure of
the body and the brain (considering the psychological content as an expression
of some physical structure in the brain). For this reason, he concludes that personal identity changes smoothly
during the experiment, so that the person after the experiment has a
completely different personal identity from the person before the experiment. He
says that after a certain amount of transformation, the personal identity is not
the original one, and yet it is not the final one. At some point in the
spectrum, the resulting person will believe him or herself to be a different
person from the original one. We may think that there is a sharp borderline
between the two different personal identities, where the first one is suddenly
replaced by the second one, but Parfit thinks that the change will happen
smoothly, so at every intermediate step in the spectrum of the transformation,
the resulting person is still the original one to some degree. But because the
final person has been set to be a completely different person from the original,
he excludes the possibility that anything of the original person may still
survive at the far end of the spectrum, when the person has completely become
the final person.
27. Parfit
acknowledges that this thought experiment raises a problem.
During our life, the matter that
constitutes our body continuously changes, as does the structure of our body.
The body and brain structure of a child are very different from the body and
brain of the same individual when old, so much so that the differences are
comparable to those existing between two different individuals.
Parfit concludes that necessarily the
personal identity of each individual changes gradually over the years. He is
forced to this conclusion because he does want to keep reductionism and the
personal identity concept together.
28. Here I want
you to notice that Open Individualism could have already been deduced from this
consideration, if we assume that the starting point and the end point of the
imaginary transformation between two persons has no special role, and that
therefore, they may well be considered to still be the same person, a
possibility that Parfit excludes. He does not define any critical factor that
necessarily determines if two people can or cannot be the same person: he just
observes that one person could be smoothly transformed into another person, even
a person arbitrarily chosen from among the ones already in existence, and from
this fact he deduces that the original and the final person
necessarily have to be two different
persons. But such a critical factor may well exist: it could be a percentage of
changes in the individual characteristics, and/or individual faculties, that
together cause the lacking of the psychological connectedness needed to consider
the personal identity to still be the original one.
Open Individualism may follow even from this view, if we hypothesize that
differences in psychological characteristics have no influence, and that the
only psychological faculty required to maintain enough psychological
connectedness to consider the personal identity to still be the same is the bare
faculty of “being a subject”, and therefore “having a brain supporting the
subjective phenomenon”. This would eliminate any chance of finding the
personal identity concept in a reductionist way, but there would be no need to
appeal to non-reductionist theories: Open
Individualism can be achieved by giving up the personal identity concept,
denying that any absolute “identity” may ever be defined, and therefore
believing that all of our apparent personal identities should be considered
undefinable. We will see later how
this can be compatible with the mere fact that there exist many physically
separate individuals.
29. The
possibility of mind splitting by
surgical brain splitting is described
by Parfit and other authors, referring to the surgical separation of the two
hemispheres of the brain. In the 1960s
experiments with this procedure were carried out to cure some severe epilepsy
cases. It turned out that people who
underwent this operation behaved like they were two persons sharing the same
body. Each half of the split brain seems
to generate its own mind.
30. The real
cases were irreversible, but it is possible to imagine that the communication
between the two hemispheres was only
temporarily inhibited. Parfit and other authors like
Roger Penrose tried to imagine how it would be to experience such temporary
mind splitting, and wondered whether it would preserve our personal identity.
They agree that it would be preserved, at least when the splitting has a brief
duration.
31. But
reasoning about a temporary splitting of our brain into two independent
hemispheres requires us to imagine that
our mind becomes both the mind
generated by the left hemisphere and
the mind generated by the right hemisphere. This seems to require the
simultaneous existence of two different personal identities, so my original
personal identity seems to not be sufficient to explain the case. For this
reason, some thinkers prefer to argue that actually we
always live with two different
personal identities, one for each hemisphere, even if we are not aware of it.
32. We also
have to know that there exist some
injured people who live with only half of their brain functioning. If we
imagine that we could experience a temporary switching off of half of our brain,
quickly followed by a switching on, nobody would question that the experiment
would preserve our personal identity.
33. Moreover,
we may also imagine that the two halves of
the split brain may be transplanted into
two different bodies. The resulting two people may live and act
independently. In this scenario, it seems absolutely beyond dispute that this
would imply the simultaneous existence of two different personal identities. But it is
difficult to imagine what would happen to
my original personal identity, considering that most of us probably think
that it is possible to survive if I had half of my brain switched off, and then
the functioning half transplanted into another body.
It is the simultaneous existence of two
legitimate candidates to being my future self that undermines my confidence in
the survival of my personal identity.
34. We may
imagine that the resulting two people are left to live their lives entirely
without ever being re-joined in the original body, but we may also imagine
again transplanting the two hemispheres
back into the original body, and reconnecting them
to again form the original whole brain. In this case, we may think that the
original personal identity will reappear. This is called “mind melding”, and can
be generalized using entire brains.
35. Mind
melding represents the complementary hypothesis to mind splitting: it results
from imagining that two or more brains
could be connected together to form a
bigger brain, with a unified brain activity, so that it will generate a
single mind. There already exist some devices that allow us to detect brain
activity, and there also exist some rudimentary devices that can interfere with
our brain activity, so that we can perceive a signal sent directly to our brain.
And actually, some experiments with mice have demonstrated that it is possible
to join the brains of two or more mice so that they form a
brainet behaving as though it
generated a single shared mind (see the article by Dr. Karen S.
Rommelfanger, Emory University, at
http://www.nature.com/articles/srep11869
36. Imagine
connecting your brain to a device that allows many people to directly share all
the signals of their brains, so that they act like a single bigger brain. How do
you think this would feel? Once our brain
is connected with many others, so that the bigger-brain activity becomes a
single, synchronized activity, we have to conclude that all participants will
have a single shared mind, so that all the participants will have the very same personal identity. This
experience would not be like to meeting some friends at a party: we have to
think that the resulting mind would
be unable to discern what brain it comes from. Because it would result from a
single activity of all the connected brains, it
would be equally generated by all of them. In the same way, after a
temporary splitting of your brain hemispheres, you would not find yourself
thinking “I was the left-hemisphere-generated-mind that now has been reconnected
with the right-hemisphere-generated-mind to re-form my entire mind”. You would
simply think, with some relief, that finally your mind is once again being
generated by both the hemispheres of your brain. And similarly, once the melded
mind decides to dissociate the brain that you previously considered to be “your
brain”, you will find yourself again alone with your body, brain and mind, but
certainly shocked by the experience you underwent, and perhaps
doubting whether your personal identity
is really the very same one you had before.
37. The
disconcert regarding these imaginary experiences comes from
our need to think that both mind
splitting and mind melding have to instantly create and destroy one or more
personal identities. But our need to imagine that many personal identities
are involved in these processes is dictated by
our inability to accept that two or more
coexisting minds may have the same personal identity. And actually, if we
were to accept this hypothesis, we
would not need to postulate any personal identity at all: it would become a
concept that refers only to something illusory. But
we have to figure out what it might mean
that two or more minds may have the same personal identity, especially when
they exist simultaneously.