24.00: Problems of Philosophy
Prof. Sally Haslanger
October 22, 2001
Personal Identity III
1. Review soul criterion and body criterion
Soul criterion: x is the same person as y iff x and y have the same soul.
Problems:
i) There is no way to establish body-soul correlations; and no way to establish personality-soul correlations. So soul
criterion doesn't make sense of our practices of recognizing and identifying people.
ii) We have no special access to souls, so even in our own case we can't be sure it's the same soul "inside" us whenever we
are conscious.
iii) The problem of identity is "pushed back": what is it for person-stage x to have the same soul as person-stage y? What
makes for sameness of souls?
Body criterion: x is the same person as y iff x and y have the same living human body.
Problems:
i) If I were my body, then I would have no special access to myself. So the body criterion does not do justice to our
practices of self-recognition and self-identification.
ii) It is possible to be the same person without the same body. Body criterion doesn't allow this possibility.
1. Review memory criterion
Memory Criterion (basic form): x and y are stages of the same person iff y remembers x's experiences, thoughts,
feelings, etc. (either directly or indirectly), or vv.
Advantages:
1) Memory criterion allows me to know who I am without inspecting my body;
2) Memory criterion allows me to know who you are by conversational cues.
3) Memory criterion does justice to the forensic sense of personhood: the basis for a unified self who is responsible for
his/her actions.
Problems:
i) Circularity Problem
Does this revision avoid the circularity problem?
Memory Criterion (causal continuity version or "MC
ccv
"): x and y are stages of the same person iff y really
remembers x's experiences, etc. (the memories are caused "in the right way") either directly or indirectly. (Call this
"real-memory linked".)
ii) Duplication Problem
Review duplication argument: The challenge is to provide a criterion of PI that (a) captures the loose links that unite stages
of us throughout a life, and at the same time (b) doesnít allow for duplication. Should we accept the following principle?
Single Successor Principle: nothing can preserve personhood that can be duplicated in a number of different
successors.
If so, then we should consider the following revision:
Memory Criterion (no competitor version or "MC
ncv
"): person-stage y is a successor of x iff y really
remembers x's experiences (directly), and no other stage does; x and y are stages of the same person iff they are
linked by successor stages.
iii) Intrinsicness problem
Should my continued existence depend on whether there is someone else who happens to have the same memories?
Whether I continue to exist should depend only on facts about me and my candidate future self, not on facts about who
else happens to exist. MC
ncv
goes against our intuitions about what makes for identity. We normally assume:
Principle of Intrinsic Identity: whether or not x=y depends on x and y and no one else.
Should we also make the related assumptions?
Whether or not x is the same person as y depends on x and y and no one else
OR:
Principle of Intrinsic Unity: Whether or not x is part of the same person as y is part of depends on x and
y and no one else.
The last principle isnít satisfied in the case of MC
ncv
. Does that matter?
2. Reconsideration of the body criterion
So what should we do? If the memory criterion is sunk, should we return to the bodily criterion? What about body
swapping? Consider the example of: Julia North, Mary Francis Beaudine, and the "Medical Wonder"
(=JNbrain+MFBbody).
Question:
Does JN = MW? (common view)
Does MFB = MW? (Gretchenís view)
Does neither = MW? (?)
Do both = MW? (not possible, if you accept the single successor principle)
Should we decide the matter by majority vote? Gretchen says no. Supreme court, public opinion, etc. are not good enough.
Individual identity is not like boundaries of countries. (e.g., E. & W. Germany? Is Russia today the same country as the
one Nicholas and Alexandra ruled?) Whether I survive or not is an objective matter, not a conventional matter, i.e., not one
to be decided by public opinion.
OK, but what makes it objective? Why think that there is a fact of the matter? Itís because in some cases you are genuinely
entitled to anticipate the experiences of someone else, and in other cases you arenít. Or in other words, in some cases youíd
be right to anticipate, and in some cases not, no matter what convention dictates.
Cohen argues:
1) What I especially care about is my continued existence.
2) I donít especially care about the continued existence of my body, but do care about the continued existence of my
consciousness, my mental life.
3) So my continuation is a psychological matter, and not a bodily matter.
This argument suggests that JN = MW. But note that if psychological continuity is what really matters then we should be
willing to consider a brain transplant: if your brain is injured, put your psychology in a new brain and transplant it into
your body...but then the duplication argument reemerges: if you could give one new brain your psychology, presumably
you could give it to two! Remember the Single Successor Principle: nothing can preserve personhood that can be
duplicated in a number of different successors. Assuming that the brain is a particular collection of cells in an individual's
head that can only exist at one place at a time, maybe we should try:
Memory Criterion (same brain version): x and y are stages of the same person iff y really remembers x's
experiences, etc. (the memories are caused "in the right way") either directly or indirectly, and x and y have the
same living brain.*
This prevents duplication (unless you think that the brain could be split and both halves count as "the same brain"...). But
remember two main advantages of the memory criterion:
1) It allows me to know who I am without inspecting my body.
2) It captures the idea that what concerns me in survival is the preservation of my psychological traits.
Both of these advantages are lost when we move to MC
sbv
. Moreover, MC
sbv
doesn't have some of the advantages of the
body criterion either, since it requires psychological continuity and doesn't allow me to consist of both conscious and
unconscious stages. Are we better off just dropping psychological continuity:
Brain criterion: x and y are stages of the same person iff x and y have the same living brain.*
3. Return to question of objectivity
Cohen argues that the Supreme Court may be fallible about matters of fact, but "?they are the final authority on the
development of certain important concepts used in law. The notion of person is such a concept." (p. 403) Gretchen
maintains that it is the facts about who I am or who I will be that matter to us in this discussion, and the Supreme Court
can't decide this. But suppose we allow that there are several different concepts at work in our thinking about human
beings. E.g., the (biological) concept of a human being, the (forensic) concept of a person, the (psychological) concept of a
self, the (spiritual/religious) concept of a soul. These might have different conditions of identity. And possibly there exist
entities that correspond with more than one of these concepts (e.g., the living human being and the person may both
exist just as the statue and the clay of which it is made are two things and both exist). If so, then it may well be the job of
the Supreme Court to decide which of these "person-related" concepts should apply in legal contexts when we hold
someone responsible. On this view, it is partly a matter of convention what counts as a person before the law. But
Gretchen will respond, presumably: Which of these "entities" is me?! Am I a living human body, a person, or a soul, etc?
And isn't there a matter of fact which entity I am? What I am what counts as my coming into or going out of
existence doesn't seem to be a matter that anyone can decide. It is a matter of fact to be discovered. Do you agree?
______________________
*In spelling this out, one could opt for either unity between brain stages or numerical identity.