The problem with the embryonic brain argument (which I actually raised
BTW), is that is almost assuredly not conscious, and not a "person" in
the way we're using the term here.

Obviously its a little hard to find an exact cutoff between consious
and unconscious states, but the onset of self-awareness (or at least
the mirror test passing aspect of it) at age approx 18 months would be
an upper bound.

Already by about 2 years old, there is a massive die off of neurons,
as connections and neurons are culled - which leaves me to suspect
that by the time the brain houses consciousness, no two brains are
structurally alike, even genetically identical ones.


On Wed, May 31, 2006 at 07:51:21PM -0700, George Levy wrote:
> Russell Standish wrote:
> >This would imply that there exist "islands" of indentity, and having
> >limited awareness in time and multispace, we can only ever be aware of
> >one instance from each island, but that might change with technology.
> >
> >BTW another analogy is the islands of geneflow within biological
> >species. Within biology, we have such things as ring species, where
> >two species at a location (eg Britain) cannot interbreed, yet can
> >interbreed with neighbouring species to the east and west in an
> >interrupted chain that circumnavigates the pole. (Sorry I may not be
> >explaining the concept of ring species too well - look up Wikipedia).
> >
> >In such a case, perhaps "ring identities" such as Jesse Mazer <->
> >Bruno Marchal do exist - but I'd like to be surer of the analogy. Also
> >ring species are the exception, not the rule, in Nature.
> >  
> >
> If we can define an intermediary state common to all species then we 
> will have bridged all the isolated island.
> It seems that at the embryonic stage and possibly at the fetus stage, 
> rhe nervous circuitry is so simple that it may be common between all 
> individual of a specie and there are no identity islands. So we could 
> say with near certainty that Bruno Marchal and Jesse Mazer used to be 
> one and the same.
> In addition we may assume that embryonic and fetal development allows 
> for a continuous distribution of neurons in the brain rather than in 
> discrete space positions, and an incremental connectivity of the neurons 
> such that any particular  neuron may differ by a single connection. With 
> these assumptions we may infer that there is a continuity in personal 
> identity from anyone to anyone.
> George
A/Prof Russell Standish                  Phone 8308 3119 (mobile)
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