So far we have divided theories of self crudely into two categories: ego theories,
which entail some kind of continuing entity, and bundle theories, which do not.
In their extreme versions, neither deals adequately with unusual cases like multi-
ple personality, nor with ordinary self-awareness. On the one hand, extreme ego
theories entail mysterious untestable entities. On the other, simplistic bundle
theories do not explain why we feel as though we are a continuing entity. In this
chapter we will consider some theories that try to avoid these shortcomings.
First, we must be as clear as possible about the difference between the two types
of theory. For a bundle theorist, it makes no sense to ask how many selves may
be inhabiting one body, or which self is the real one. We encountered this sort
of question, and a sceptical objection to it, in our discussion of split brains in
Chapter 6. Whereas most scientists try to answer the question ‘how many selves
in a split-brain patient?’, for those who believe ego theory to be false, this is a
nonsensical question. Derek Parfit (1987) asks us to imagine an experiment in
which one hemisphere sees a red screen, and the other sees blue. When asked
how many colours there are, both hands write ‘Only one’, but when asked to
say which colour, one writes ‘blue’ and the other ‘red’. Now, assuming that this
imaginary experiment worked as Parfit said it would, are there two streams of
consciousness? Are there two conscious selves? Parfit concludes that there are
indeed two separate streams of consciousness, one stream seeing red and the
other seeing blue, but there are not two conscious persons who do the seeing.
Why? Because only an ego theorist can count the number of persons involved.
For a bundle theorist, there is no such thing as a continuous self who experiences
the stream. So whether we consider split brains or whole brains, ‘the number of
persons involved is none’ (1987, p. 20).
It might seem obvious that materialist scientists should agree with Parfit, accept
Hume’s denial, and be bundle theorists. After all, if the brain consists of millions of
interconnected neurons whose activity gives rise to behaviours, memories, and
perceptions, then there is no need for an experiencing self as well. Yet, as we have
seen, some scientists still try to count the number of selves in a split-brain patient,
or ask whether multiple personalities are really separate selves.
The situation may be rather like that with the Cartesian theatre. While it is easy, intel-
lectually, to deny the existence of a persisting experiencing self, it is another matter
to accept all the consequences of such a view. Some classic philosophers’ thought
experiments can bring these consequences to life. Remember that the point of
thought experiments is not that they could be carried out, but that we use them
to clarify our thinking, and to do that we must follow the rules exactly (Chapter 2).
THOUGHT EXPERIMENTS WITH THE SELF
Imagine that in the middle of the night, without leaving any traces or doing any
harm, a mad Martian scientist comes into your room, removes your brain, and
inserts it into your friend John’s body, and then his brain into yours (impossible
of course, but this is a thought experiment). In the morning you stir, your dreams
recede, and you wake into full consciousness. But who has woken up? Have ‘you’
woken up in John’s body? Will you scream and protest, and hope you are only
dreaming that you are in an unfamiliar room and have hairy legs and a bushy
‘the greatest scientific
and philosophical riddle
of all – the nature of the
self ’(Ramachandran and Blakeslee,
1998, p. 255)