[ExI] The alleged existence of consciousness

Stathis Papaioannou stathisp at gmail.com
Mon Feb 22 11:03:03 UTC 2010

On 22 February 2010 04:34, Dave Sill <sparge at gmail.com> wrote:
> On Sat, Feb 20, 2010 at 7:47 PM, Stathis Papaioannou <stathisp at gmail.com> wrote:
>> There may be other ways to make a zombie (although there are separate
>> arguments against that possibility also) but following the
>> architecture of the brain is not one of them. Any structure that
>> reproduces the pattern of neural firing in the brain will also
>> reproduce the intelligence and the consciousness of the brain.
> Agreed.
>> If the brain's intelligence would remain intact despite changes that
>> would eliminate consciousness, then consciousness would be a useless
>> complication.
> But what if the changes required resulted in more complication? Then
> removing consciousness would be a useless complication.

That's possible but it seems very unlikely. Consciousness is extremely
elaborate, and it closely mirrors intelligence. It seems incredible to
suppose that, let's say, water has this intrinsic ability to produce
consciousness, such that if our cells were instead based on liquid
ammonia as a solvent we would have been zombies. How did we get so

>>>> The best explanation is that the brain we happen to
>>>> have ended up with is not specially blessed, and any other brain based
>>>> on similar patterns resulting in similar behaviour would have also had
>>>> a similar consciousness.
>>> Intuitively, that seems likely. But we just don't know.
>> We do know. The partial brain replacement thought experiment makes it
>> true as a matter of logical necessity; in other words more certainly
>> true than any mere empirical fact, which could be proved false
>> tomorrow. I would really like to hear a rebuttal, but no-one has yet
>> attempted one.
> The partial brain replacement thought experiment only covers the case
> of a brain that works exactly like ours. It seems possible to me that
> evolution could have taken a different path, and conceivable that one
> or more of those paths might have resulted in intelligence without
> consciousness.

As you replace more and more neurons you end up with a large volume of
artificial brain. This volume does not have to be structurally similar
to normal brain tissue on the inside: all it has to do is process
environmental inputs normally and interact with the remaining
biological tissue normally. Eventually almost the entire brain will be
replaced, behaving normally and sending normal signals to one
remaining neuron. When that last neuron is replaced, we have an entire
artificial brain which has as its essential characteristic that it
reproduces the I/O behaviour of the original human interacting with
the environment. That is, at this end point it need not share any
structural features with the original brain, as long as it behaves
exactly like the original human. And this artificial brain would have
to give rise to consciousness in the same way as the original human,
since it is not plausible that the consciousness gradually fades or
suddenly disappears at some point during the replacement process. The
conclusion is that any entity which exactly reproduces the behaviour
of the original human will also reproduce the consciousness of the
original human. Entities which behave differently will, of course,
have different consciousnesses, but again it is implausible that
consciousness could simply disappear altogether with some small
increment away from standard human behaviour.

Stathis Papaioannou

More information about the extropy-chat mailing list