On Fri, Feb 4, 2011 at 12:05 PM, Colin Hales
<c.ha...@pgrad.unimelb.edu.au> wrote:

> > Can the behaviour of the neurons including the electric fields be
> > simulated? For example, is it possible to model what will happen in
> > the brain (and what output will ultimately go to the muscles via
> > peripheral nerves) if a particular sequence of photons hits the
> > retina? If that is a theoretical impossibility then where exactly is
> > the non-computable physics, and what evidence do you have that it is
> > non-computable?

> Lots of aspects to your questions.... and I'll try and answer Bruno at the
> same time.
> 1) I am in the process of upgrading neural modelling to include the fields
> in the traditional sense of simulation of the fields. The way to think of it
> is that the little capacitor in the Hodgkin-Huxley equilvalent circuit is
> about to get a whole new role.

Great! That is another step towards simulating brains.

> 2) Having done that, one can do simulations of single unit,  multiple unit,
> populations etc etc...You may be able to extract something verifiable in the
> wet-lab.
> 3) However, I would hold that no matter how comprehensive the models, no
> matter how many neurons ... even the whole brain and the peripheral
> nerves...they will NOT behave like the real thing in the sense that such a
> brain model cannot ever 'be' a mind. The reason is that we 'BE' the fields.
> We do not 'BE' a description of the fields. The information delivered by
> 'BE'ing the field acts in addition to that described by the
> 3rd-person-validated system of classical partial differential equations that
> are Maxwell's equations.

I understand that this is your position but I would like you to
consider a poor, dumb engineer who neither knows nor cares about
philosophy of mind. All he cares about is making an accurate model
which will predict the pattern of motor neuron firings for a human
brain given a certain initial state. Doing this is equivalent to
constructing a human level AI, since the simulation could be given
information and would respond just as a human would given the same
information. Now, I take it that you don't believe that such
predictions can be made using a mathematical model. Is that right?

> 4) A given set of photons,  can result from an infinity of different
> configurations of the distal world. A single red photon can come across the
> room from your xmas decorations or across the galaxy from a supernova. It is
> a fundamentally degenerate relationship. Yet the brain inherits enough
> information to converge on a visual scene that captures the difference. HOW?
> I think I know, but that explanation is too long and doesn't matter. The
> fact is that the EM fields deliver _extra_ information inherited from their
> relationship with space itself. It has to. There's no place else or it to
> come from!

I don't think it's possible to work out where a photon comes from
except in context. Regardless, we can bypass the complexities of
perception by discussing only information imparted by written

> 5) Regardless of my wacky ideas about space, I'd like to reinforce the
> implications of the particular case of the scientist, who is trying to find
> out about the distal natural world from position of fundamental ignorance.
> If you claim that we have enough information to overcome the degeneracy,
> then you already have what the scientist wants...knowledge of the unknown
> external distal world....so you are not actually doing science. You already
> know. This is the killer logical position. If you say a computer can do it,
> you are saying, in effect, that science does nothing/already knows
> everything.

Science makes hypotheses and tests them for internal consistency and
against empirically obtained data. Why couldn't a computer do the

> ============
> In the end, then, I am not saying that there is something uncomputable in
> the sense that it is impossible to 'simulate' it. You can simulate anything!
> What I am saying is that if you could _you wouldn't bother_ because you'd
> already know everything. To accurately simulate a scientist you have to
> simulate (a) the scientist and (b) the entire environment of the scientist,
> when the scientist is trying to uncover the unknown and you can't simulate
> it because you don;t know it. I use the scientist as a model for the
> generally intelligent behaviour.

I don't understand what problem you have with information provided to
the simulated scientist by instruments connected to the computer or
even written data compiled by another scientist.

Stathis Papaioannou

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