PHIL 101
INSTRUCTOR: WILBURN
MODEL ANSWERS TO PUBLISHERS’ ESSAY TEST FOR CH. 4
1. If two persons could inhabit the same body, would this show that animalism is false?
Why or why not?
Yes it would. Animalism maintains that having a particular body is sufficient for being a
particular person. If more than one person inhabited a given body, this sufficiency condition
would be violated, as it would show that inhabiting a particular body is not enough to identify a
particular person.
2. If your DNA were fused with that of a cat so that eventually you had the body of a cat
(and your mind was left intact), would this show that animalism is true? Why or why not?
This would not show that animalism is true. Indeed, depending on how you describe the case, it
might be seen as a counterexample to animalism. Again, animalism maintains that having a
particular body is sufficient for being a particular person. If your DNA were fused with that of a
cat, then you would arguably come to acquire a different body while still remaining the same
person. Thus, animalism would be refuted.
3. If your memories were erased but your soul remained intact, would you still be the same
person? Why or why not?
Intuitively, it seems that you would not be the same person. To remain the same person seems to
have everything to do with maintaining psychological continuity over time, irrespective of
whether or not this psychological continuity is implemented in the same individual mental
substance over time. To imagine losing all of your memories is to effectively imagine going out
of existence whether or not the mental substance or soul in which these thoughts and memories
occur continues to exist.
4. Explain why the possibility of a soul switch suggests that the soul theory is false.
Soul switching thought experiments are imagined cases in which one’s thoughts and memories
are transferred from one mental substance to another. The point of such thought experiments is
that what seems to matter to personal identity is the retention of memories and mental continuity,
irrespective of whether or not these things occur in a particular mental substance. This point is
made by both Locke and Kant. If one imagines the contents of one’s consciousness being
transferred from one mental substance to another mental substance, one imagines one’s self
traveling with the contents of one’s mental life rather than remaining with the original container
of this mental life.
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5. Explain John Hick's point about souls and how heredity and environment seem to
account for all of an individual's character traits.
Hick’s point is that we would only have reason to postulate the existence of souls if we needed to
invoke souls to explain the occurrence of those properties which make individual persons the
persons that they are. But all of these properties seem to be explained by heredity and
environment. Thus, the postulation of souls has no explanatory value.
6. How does William's thought experiment about Guy Fawkes undermine the psychological
continuity theory?
The Guy Fawkes thought experiment shows that psychological continuity is a one-to-many
relationship, since we can easily imagine more than one person being psychologically continuous
with Guy Fawkes. But numerical identity is a one-to-one relationship. Thus, personal
(numerical) identity cannot be analyzed in terms of psychological continuity.
7. What is the reduplication problem?
The reduplication problem is, in effect, the very problem posed by the Guy Fawkes example and
other thought experiments (e.g., Parfit’s transporter tale) designed to press the same moral. The
problem is that since psychological continuity is a function of qualitative similarity over time
(via an interlinking series of psychologically connected persons), psychological continuity is a
one-to-many relationship. But, once again, numerical identity is a one-to-one relationship (since
one thing cannot be numerically identical to anything other than itself). Thus, personal
(numerical) identity cannot be analyzed in terms of psychological continuity.
8. What does Parfit's transporter tale show about personal identity?
The transporter tales has us envision a machine that scans a person and reproduces his structural
details in new matter. In reproducing his structural details, it automatically reproduces his
psychology (the set of quasi-memories and quasi-desires that characterize him at the moment of
scanning). But in doing this, it creates a situation in which two people simultaneously exist (i.e.,
the original and the duplicate) who are psychologically continuous with the original. Once again,
this shows that psychological continuity is a one-to-many relationship. And since numerical
personal identity is a one-to-one relationship, personal (numerical) identity cannot be analyzed in
terms of psychological continuity.
9. What is the insufficiency objection?
The insufficiency objection maintains that personal identity determined not only by memories,
but also by values and desires. This is because an individual may often be said to be replaced by
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another in light of a substantial change in driving values, desires and goals. Because many
desires are defined in self-referential terms, however, we must be careful to avoid circularity in
any account of personal identity which takes them into account. We can do this by invoking the
notion of quasi-desires, desires that are caused in the right way by actual desires. We can then
say that persons x and y (at two different times) are identical if and only if they form part of an
overlapping series of persons who share quasi-memories and quasi-desires. Quite a mouthful, I
grant.
10. What is Locke's view of memory, crime, and personal identity?
On Locke’s account, a person p1 can be identical with a person p2 at two different times only if
they share one or more memories. Because of this, Locke is convinced that no one can be
rightfully punished for performing acts he or she does not remember. He concedes that
proclamations that one does not remember doing something are not generally treated as excuses
in court, but this is only because we generally suspect such proclamations to be dishonest.
11. Explain the brain theory of personal identity.
On the stupidly named “brain theory”, identical persons have continuous psychologies caused by
and realized in the same brain. The motivation for this account is to avoid the sorts of problems
described in (1), (2) and (3) above by tying psychological continuity to particular substances
which remain numerically identical with themselves (thus avoiding one-to-many identity
relations).
12. Explain why Parfit says that numerical identity is not what matters in survival?
If numerical identity were what really mattered in survival, then (in order to preserve one-to-one
relationship) Parfit would be motivated to kill any left-over duplicates of himself that might arise
through the multiple reimplementation of his psychology. But because Parfit thinks this is
ridiculous (in light of “the only x and y principle”), he judges that identity cannot be what is
important to survival. Because all of one’s duplicates would be psychologically continuous with
one, they should all be seen as one’s survivors, and the existence of any or all of them should be
viewed as preferable to personal death.
13. Explain what split-brain experiments show about the brain theory.
They (allegedly) show that the “brain theory” is false, since it fails to circumvent the problems
which it is invoked to solve. These problems arise in connection with duplication scenarios on
which one’s psychology is reimplemented in more than one body, violating the conviction that
identity is necessarily a one-to-one relation. The brain theory attempts to solve these problems by
tying psychological continuity with particular neural substrates which must remain numerically
identical with themselves (thus avoiding one-to-many identity relations). But split-brain
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experiments raise the possibility that even when persons are so conceived (i.e., as psychologies
caused by and realized in specific brains), duplication might still be possible. Imagine that one’s
corpus callosum is cut and each of one’s two hemispheres is appropriately wired into the skulls
of two different bodies. This possibility seems to raise exactly the same problems the
counterexamples to the psychological continuity theory (e.g., Williams’ Guy Fawkes, Parfit’s
transporter, etc.).
14. Can personal identity consist in either psychological or physical continuity? Why or
why not?
It wouldn’t seem so. Psychological continuity theory allows for duplication cases and the
subsequent violation of the constraint that identity must be a one-to-one relation. Physical
continuity doesn’t seem to latch onto anything truly essential to personal identity, as the specific
body or brain I possess would seem to be incidental to who I am. The “brain theory” endeavors
to fuse psychological and physical (neural) identity criteria to account for personal identity, but it
is ultimately unable to avoid precisely the kinds of duplication cases that prove so fatal to pure
psychological identity theory.
15. Explain the only x and y principle.
The “only x and y principle” maintains that if x and y are identical, then they are identical by
virtue of the features of x and y alone, irrespective of whatever else may be true of anything else
in the universe. The principle is important when we consider various duplication thought
experiments, which seem to suggest that whether or not a person at one time is identical to a
person at another time is somehow a function of whether or not there happen to be any additional
duplicates left lying around (as in Guy Fawkes cases, transporter cases, etc.).
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