Chris Gordon-Smith  wrote or quoted:
> Tim Tyler wrote:
> > Chris Gordon-Smith  wrote or quoted:

> > [One big organism?]
> > 
> >> Suppose for a moment that we do have such a high level entity, able to
> >> optimise itself by selecting lower level units that are
beneficial to it.
> >> If its environment now changes, the fitness function that it uses to
> >> select the lower level units may no longer be appropriate. However, it
> >> has no way to change this fitness function, because it is part of its
> >> fixed phenotype; it cannot be evolved by the lower level
units (they know
> >> nothing about the fitness function of the high level entity).
> > 
> > AFAICS, nothing need be fixed.
> 
> Suppose the phenotype is not fixed. In that case, it can drift according
> random fluctuations. Under Darwinian evolution, these fluctuations would be
> filtered by natural selection so that only the fit ones survived. The
> majority of flutuations would be disadvantageous and would not survive.

What I think would happen is not random-drift - but rather self-directed
evolution.  The organism would change itself in directions it chose.

> With the high level entity we are discussing, this process of trial and
> error cannot occur. We have said that the entity is a single individual and
> that it does not reproduce. It cannot therefore afford to experiment with
> its phenotype in the hope that occasionally it finds a successful
> variation. Most variations will be disadvantageous and will make it less
> likely to survive.

I gave the example of evolution of the organism by it selectively cutting 
off its own fingers and growing new ones.  You can argue that it's 
fingers were "really" separate organisms, and that the organisms's brain 
was selecting between them (which would be fine) - but I note that if the 
"fingers" are part of the organism's "body", then the
process would 
conventionally be regarded as being more like growth than like 
reproduction.

> Note that I am talking about the entity at the level above the units that
> are being used for experiments. In your earlier post you said that the
> entity could perform experiments on itself. What I am saying is that in
> fact it can only perform experiments on _parts_ of itself. The entity that
> is performing the experiments is above the level of the units that it is
> experimenting on.

Yes - but it's composed of its parts.  If all the parts are replacable,
there's no part of the organism that's fixed - and any and all parts of
in can change their genetic composition.

> >> I think therefore that this entity cannot survive in the long term; it
> >> has no way to adapt to chagning circumstances.
> > 
> > It is still the product of and subject to natural selection.  If it
> > of a type which dies out, we can expect not to see it's like around.
> 
> I hope my notes above explain why I think it is not subject to natural
> selection. It is the lower level units that are subject to selection.

Right - but it is not fair to argue that it can't adapt to changing
circumstances.  It can change all its components according to its
will in response to changing circumstances.

If it has any desire to continue to exist, it is likely to change
itself adaptively, in response to changing circumstances.

If it lacks the desire to continue to exist, then - presumably -
it will fall to bits, disintegrate into multiple warring factions
again - and be replaced by organisms with more staying power.

As a consequence, the organisms we see at any point are likely to be
the ones who still have kept hold of the will to live.

> > There are perhaps fair grounds to doubt whether any such large creatures
> > will come into existence in our universe.  
> 
> Perhaps. However, I think in order to understand life we need to understand
> whether such things are logically possible. Hence I think the topic is well
> worth discussing.

Yes - I too find this "one big organism" stuff to have some (perhaps
rather esoteric) theoretical significance.

Part of my fascination with the idea is that maybe it isn't /that/ 
esoteric.

I.e. maybe our own planet will one day be best regarded as a single, large
organism.  It might still have come competition from inharmonious rebels -
who would play a role something like virus particles - and maybe by the
time it happens, there will be other planets colonised - but I think
the idea of a large single living creature deserves some examination by 
virute of it not quite being totally unrealistic.

If our society continues to value peace, I suspect this is the road
it is heading down.  However there are often alternative visions of
how things could be - and these different ideals have often led to
conflicts in the past - if their differences cannot be reconciled -
and conflict and disharmony are the opponents of a genuinely harmonious 
colonial future.
-- 
__________
 |im |yler  http://timtyler.org/  tim{at}tt1lock.org  Remove lock to reply.
---
þ RIMEGate(tm)/RGXPost V1.14 at BBSWORLD * Info{at}bbsworld.com

---
 * RIMEGate(tm)V10.2áÿ* RelayNet(tm) NNTP Gateway * MoonDog BBS
 * RgateImp.MoonDog.BBS at 8/8/04 9:40:51 PM