Quentin Anciaux wrote:



2010/1/12 Brent Meeker <meeke...@dslextreme.com <mailto:meeke...@dslextreme.com>>

    Quentin Anciaux wrote:



        2010/1/12 Brent Meeker <meeke...@dslextreme.com
        <mailto:meeke...@dslextreme.com>
        <mailto:meeke...@dslextreme.com
        <mailto:meeke...@dslextreme.com>>>


           Stathis Papaioannou wrote:

               2010/1/12 Brent Meeker <meeke...@dslextreme.com
        <mailto:meeke...@dslextreme.com>
               <mailto:meeke...@dslextreme.com
        <mailto:meeke...@dslextreme.com>>>:


I know. I'm trying to see what exactly is being
        assumed
                   about the
                   computation being "the same".  Is it the same Platonic
                   algorithm?   Is it
                   one that has the same steps as described in
        FORTRAN, but
                   not those in LISP?
                    Is it just one that has the same input-output?  I
        think
                   these are questions
                   that have been bypassed in the "yes doctor" scenario.
                    Saying "yes" to the
                   doctor seems unproblematic when you think of
        replacing a
                   few neurons with
                   artificial ones - all you care about is the
        input-output.
                    But then when you
                   jump to replacing a whole brain maybe you care
        about the
                   FORTRAN/LISP
                   differences. Yet on this list there seems to be an
                   assumption that you can
                   just jump to the Platonic algorithm or even a Platonic
                   computation that's
                   independent of the algorithm.   Bruno pushes all this
                   aside by referring to
                   "at the appropriate level" and by doing all possible
                   algorithms.  But I'm
                   more interested in the question of what would I
        have to do
                   to make a
                   conscious AI.  Also, it is the assumption of a Platonic
                   computation that
                   allows one to slice it discretely into OMs.
               Start by replacing neurons with artificial neurons
        which are
               driven by
               a computer program and whose defining characteristic is
        that
               they copy
               the I/O behaviour of biological neurons. The program has to
               model the
               internal workings of a neuron down to a certain level.
        It may
               be that
               the position and configuration of every molecule needs
        to be
               modelled,
               or it may be that shortcuts such as a single parameter
        for the
               permeability of ion channels in the cell membrane make no
               difference
               to the final result. In any case, there are many
        possible programs
               even if the same physical model of a neuron is used,
        and the same
               basic program can be written in any language and
        implemented
               on any
               computer: all that matters is that the artificial
        neuron works
               properly. (As an aside, we don't need to worry about
        whether these
               artificial neurons are zombies, since that would lead
        to absurd
               conclusions about the nature of consciousness.) From the
               single neuron
               we can progress to replacing the whole brain, the end
        result
               being a
               computer program interacting with the outside world through
               sensors
               and effectors. The program can be implemented in any
        way - any
               language, any hardware - and the consciousness of the
        subject will
               remain the same as long as the brain behaviour remains
        the same.


You're asserting that neuron I/O replication is the
        "appropriate
           level" to make "brain behavior" the same; and I tend to
        agree that
           would be sufficient (though perhaps not necessary).  But that's
           preserving a particular algorithm; one more specific than the
           Platonic computation of its equivalence class.  I suppose a
        Turing
           machine could perform the same computation, but it would
        perform
           it very differently.  And I wonder how the Turing machine would
           manage perception.  The organs of perception would have their
           responses digitized into bit strings and these would be
        written to
           the TM on different tapes?  I think this illustrates my point
           that, while preservation of consciousness under the digital
        neuron
           substitution seems plausible, there is still another leap in
           substituting an abstract computation for the digital neurons.

           Also, such an AI brain would not permit slicing the
        computations
           into arbitrarily short time periods because there is
        communication
           time involved and neurons run asynchronously.


        Yes you can, freeze the computation, dump memory... then load
        memory back, and defreeze. If the time inside the computation
        is an internal feature (a counter inside the program), the AI
        associated to the computation cannot notice anything if on the
        other hand the time inside of the computation is an input
        parameter from some external then it can notice... but I
        always can englobe the whole thing and feed that external time
        from another program or whatever.

    That assumes that the AI brain is running synchronously, i.e. at a
    clock rate small compared to c/R where R is the radius of the
    brain.  But I think the real brain runs asynchronously, so if the
    AI brain must do the simulation at a lower level to take account
    of transmission times, etc. and run at a much higher clock rate
    than do neurons.  But is it then still "the same" computation?



        The fact that you can disrupt a computation and restart it
        with some different parameters doesn't mean you can't restart
        it with *exactly* the same parameters as when you froze it.


    That's arbitrarily excluding the physical steps in "freezing" and
    "starting" a computation, as though you can pick out the "real"
    computation as separate from the physical processes.  Which is the
    same as assuming that consciousness attaches to the Platonic
    "real" computation and those extra physical steps somehow don't
    count as "computations".


But it is the same... When I write a program in say java... that's not my "program" that is run on the machine, it is a translation in the target machine language. Yet it is the same, that's what we use UTM for.

Also the restarted computation has no knowledge at all of having been freezed and restarted in the first place.

Well maybe I'm confused about this, but you're talking about a program that has the same input/output and therefore all the processes after the input and before the program halts are irrelevant. You're saying it's "the same" if the same inputs halt with the same outputs - which is the abstract Turing machine or Platonic meaning of "the computation". I don't see that as being the same as attaching consciousness to brain processes which don't halt? How are you mapping the Turing computation to the brain process? If you replace each neuron with a Turing machine that reproduces the same input/output, I can understand the mapping. But then you reproduce that collection of interacting Turing machines with a single, super-Turing machine which includes some simulation of the local environment too. Because the neuron level Turing machines ran asynchronously, the super-Turing machine has to include a lot of additional computation to keep track of the signal passing. Yet we are to bet that it instantiates the same stream of consciousness because - exactly why?...because it will halt on the same outputs for the same inputs?

Brent
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