Who Doesn't Have a Problem of Too Many Thinkers?
by David B. Hershenov
Animalists accuse the advocates of psychological
approaches of identity of having
to suffer a Problem of Too Many Thinkers.
Eric Olson, for instance, is an animalist who
maintains that if the person is spatially coincident
but numerically distinct from the animal,
then provided that the person can use its brain
to think, so too can the physically indistinguishable
animal. However, not all defenders
of psychological views of identity assume
the spatial coincidence of the person and the
animal. Jeff McMahan and lately Derek Parfit
claim we are roughly brain-size, composed of
just those parts of the human animal that directly
produce thought. They claim to avoid
the Problem of Too Many Thinkers because
it is the brain-sized person who truly thinks,
while the animal thinks only in a derivative
sense in virtue of having a thinking proper
part. Waiting in the wings are some dualists
who claim that all materialist accounts fail
to avoid the Problem of Too Many Thinkers.
One such dualist, Dean Zimmerman, insists
that wherever there is an ordinary material
thing like a brain, there is also a mass with
distinct persistence conditions and thus the
threat of two material thinkers. Zimmerman
contends that only positing an immaterial
thinker can avoid the problem.