On Mon, Aug 08, 2005 at 09:42:06AM -0700, "Hal Finney" wrote:
> Russell replied:
> > That is indeed my meaning. What difficulties do you see?
> I see a few problems.  The first is the concept that the multiverse
> will contain copies of the machine that execute the counterfactuals.
> While this could happen, it would normally be to a very, very tiny degree,
> and it seems highly implausible that this could cause any actual effects.
> In the case of Maudlin's thought experiment, the intention of the operator
> is to run the machine on the specific inputs that it is pre-programmed
> to handle.  In effect, it is doing a replay of a previously computed
> calculation.  The counterfactual machinery is not intended to be
> activated.  All of the effort and skill of the operator will be devoted
> to pre-setting the machine into the precise state necessary for an
> exact replay, as Maudlin describes in detail.

This is actually impossible to achieve in the Multiverse. For every
branch where a given input that is 1, there are as many branches where
the input is 0. In order to achieve the situation you're talking
about, you would need to narrow down the Multiverse to just those
branches in which the environment was fixed to a given sequence. If
the environment is deterministic, and the conscious entity is
deterministic, the universe is deterministic - in other words there is
there is only one branch in your sub-Multiverse. My point is that
Maudlin's argument shows that (assuming computationalism) the
projection of the conscious entity onto that single branch is not
conscious, but does not invalidate computationalism itself.

Look, nobody expects a single neuron to be conscious. So is it not
such an extreme position to require consciousness to be spread across
multiple Multiverse branches.

> My basic problem is that the multiverse is so big, and so much variation
> is possible, that it will not work to say that consciousness depends on
> activity that is spread across the multiverse.  If you try to pin it down
> so that it depends on what happens merely on a particular world and its
> near neighbors, then that will not in general test the counterfactuals.

You do need to subset the Multiverse to those systems that contain a
stable Olympia + unblocked Klara. I don't see this as posing a problem
though. All counterfactuals not fatal to Olympia + Klara will be tested.

> If you expand it to include a wide range of possibilities, then there
> is too much going on, too many variations and bizarre outcomes, so
> that the criteria you are trying to use for consiciousness are met in
> some worlds and contradicted in others.  All in all I don't think this
> approach will work as a general method for making consciousness supervene
> on physicality.
> Hal Finney

If you ask my personal opinion, it is that certain amount of
indeterminism is required within the machinery for consciousness to
supervene on it (ie computationalism is strictly false). Whilst I've
strongly argued that this is essential for free will, unfortunately I
haven't seen an argument demonstrating its necessity for
consciousness. Maudlin's argument does have this escape clause
(computationalism supervenient on multiple branches of a Multiverse),
weird though that may be.


*PS: A number of people ask me about the attachment to my email, which
is of type "application/pgp-signature". Don't worry, it is not a
virus. It is an electronic signature, that may be used to verify this
email came from me if you have PGP or GPG installed. Otherwise, you
may safely ignore this attachment.

A/Prof Russell Standish                  Phone 8308 3119 (mobile)
Mathematics                                    0425 253119 (")
UNSW SYDNEY 2052                         [EMAIL PROTECTED]             
Australia                                http://parallel.hpc.unsw.edu.au/rks
            International prefix  +612, Interstate prefix 02

Attachment: pgp06vCfFLvBX.pgp
Description: PGP signature

Reply via email to