On Wed, Aug 10, 2011 at 4:54 AM, meekerdb <meeke...@verizon.net> wrote:
> There's the rub. What counts as "overall"? Can I replace one hemisphere of
> the brain that is functionally identical at its boundaries and guarantee
> that there is no change in consciousness?
Yes. Suppose your right hemisphere is replaced with a machine that is
functionally identical at its boundaries but has a qualitatively
different consciousness. The left half of your left visual field will
then look different, by definition if the visual qualia are different.
But your left hemisphere receives the usual signals through the corpus
callosum, so you state via the speech centres in that hemisphere that
everything looks exactly the same. In other words you can't notice any
change in your consciousness due to the functionally identical
replacement. I would say that if you continue to behave normally and
you notice no change in your consciousness then there *is* no
difference in your consciousness.
>> The volume of replaced tissue can be made larger and
>> larger until the limit is reached where the whole brain is replaced,
>> leaving only the muscles and sensory organs (and of course these too
>> can eventually be replaced). If the person's behaviour is unchanged
>> then his consciousness is also unchanged,
> Of course one's consciousness is changed all the time, but perception,
> experience, and learning. And consequently their behavior is presumably
> changed too. So when you refer to "the person's behavior" being unchanged
> you mean something rather vague and fuzzy like "his character". I'm
> speculating that within that vague domain there might be room for quite a
> bit of qualia change that would depend on the internal implementation.
The qualia would change only if the replacement were not functionally different.
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