Abstract

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.