- seCtIon tWo: tHe BRAIn
inferences from information. They cannot be said
to be either aware or unaware of anything.
(Hacker and Bennett, 2003, p. 391)
Only whole human beings can be said to be conscious.
In their view, a split-brain patient is deprived of the
capacity to carry out normally coordinated functions,
not split into two people. This is just one example of
what Bennett and Hacker call the ‘mereological fallacy’:
the widespread and almost unquestioned tendency of
neuroscientists to say that brains or parts of brains can
see, hear, think, make decisions, or experience things
when all these abilities are functions of whole human
beings, not bits of brain.Along similar lines, philosopher Michael Tye (2003)
argues that split-brain patients are persons whose
phenomenal consciousness is briefly split during the
experiments but is otherwise unified, whereas Tim
Bayne (2005) responds that although a person might
have two streams of consciousness, it doesn’t make
sense to think of subjects of experience as doing so.
We have met several theories that assume a differ-
ence between ‘conscious’ and ‘unconscious’ processes
and try to explain it, and Zeki specifically links his
micro-consciousnesses to specific nodes in the brain.‘the life of a second
rudimentary self lasts a
few minutes at most’
(Dennett, 1991, p. 425)
FIGURE 6.9 • The split-brain patient P.S. was
shown a snow scene to the right
hemisphere and a chicken claw to
the left hemisphere, and asked to
choose from an array of pictures.
He chose the shovel with his left
hand and the chicken with his right
(Gazzaniga, 1992, p. 127).
FIGURE 6.10 • When the silent right hemisphere is given a command, it carries it out. At the same time, the left doesn’t
really know why it does so, but it makes up a theory quickly (reprinted from Gazzaniga and LeDoux, 1978, in
Gazzaniga, 1992, p. 128).