Tim V Kolton
Alan Watts once said, “Trying to define yourself is like trying to bite
your own teeth.” The task of personal identity is to define a quality of a
human which makes him or her a unique self. The person whose identity is in
question must realize themselves, and other people must identify this person.
In other words, what makes John unique from Bob? One must consider both
internal (mind) and external (body) perspectives. There are several general
philosophical theories of this identity problem.
In the following paragraphs
one will find the body theory, soul theory, and a more detailed explanation of
the conscious theory.
One theory of personal identity is known as the body theory. This is
defined as a person X has a personal identity if and only if they have the same
body Y. However there are two problems with this definition. The first is
qualitative. It is necessary to have the same body, but if that body is changed,
is one the same person? Someone’s body is surely different at age 40 than at
Also a problem arrives in alterations to a body. If John goes to war,
becomes injured by a mine, and then has his legs amputated is he not still the
same person, John? Therefore, the preceding definition of body theory is not
sufficient, since it does not account alterations to the same body. Yet another
problem is numerical. If someone were to get a finger chopped off, would that
finger be considered another person? What if a scientist was to use someone’s
DNA and replicate another person with the same body? Surely just because there
are two identical bodies, these bodies cannot be the same person. They would
live two different lives. Therefore, the body theory alone cannot be considered
a necessary and sufficient definition when defining personal identity.
Another common theory of personal identity is the soul theory. This
theory is: a person is has personal identity if and only if they have the same
soul. The problem with this theory is arrived from the definition of a soul.
Soul is a very difficult term. It is thought by many to be a spirit that passes
from your body into another realm (i.e.
, heaven, hell, etc.). However, since no
one has ever seen, felt, touched, smelled, or tasted a soul, it is a mysterious
phenomenon. Since we have no clear and distinct idea of a soul , it would not
be wise to base the definition upon it. For instance, some religions believe in
reincarnation after death. This is when a soul enters another body.
in mind, someone’s soul such as Elvis could become reincarnated in someone else
named John. However, we would not say that this Elvis and John are the same
person . Therefore, the definition of the soul theory fails in that the
definiens does not become sufficient for defining personal identity.
The most recognized true philosophical theory of personal identity is
the consciousness theory. The consciousness theory is believed by most to be
the best definition of personal identity according to most philosophers. However,
there are three different versions of the consciousness theory that will be
discussed in further detail: the conscious self, experiential content, and
connected stream of consciousness theories.
First, we have the theory of a
conscious self: a person has a personal identity if he or she has the same
conscious self. In other words, if two people have a different conscious, then
they each have personal identity. At a first glance, this would be a good
definition of a personal identity. It is analogous to Descartes’ cogito, “I
think therefore I am.” Being conscious would mean knowing that one exists, and
able to think about any experience that happens. However the main fault with
this is that it is a circular definition.
We are using the definiens in the
definiendum which is not a good tactic of defining personal identity. Next, a
common derivative of the consciousness theory is the consciousness of
experiences theory. This is defined as having the same experiential content.
This theory is based upon Locke’s theory of the mind being blank, and building
from experiences. One would have personal identity because only one being can
go through the same experiences in a finite space. This theory does solve some
problems arrived at by other theories.
Say for instance there are two twins.
This would be difficult to explain in the body theory of personal identity, but
with the .