On Oct 30, 9:01�am,
c...@tiac.net (Richard Harter) wrote:
> On Sat, 29 Oct 2011 23:19:36 +0200,
nos...@de-ster.demon.nl (J. J.
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> Lodder) wrote:
> >Richard Harter <
c...@tiac.net> wrote:
>
> >> On Sat, 29 Oct 2011 17:11:21 +0200,
nos...@de-ster.demon.nl (J. J.
> >> Lodder) wrote:
>
> >> >Ernest Major <{$
t...@meden.demon.co.uk> wrote:
>
> >> >> In message <
1k9vb3m.128aumg1r4qw...@de-ster.xs4all.nl>, J. J. Lodder
> >> >> <
nos...@de-ster.demon.nl> writes
> >> >> >Devils Advocaat <
mankygo...@gmail.com> wrote:
>
> >> >> >> is the human brain the most complex thing known to exist?
>
> >> >> >Of course not.
> >> >> >The human genome is of order one gigabyte,
> >> >> >so at best 100 MB for the brain.
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> >> >> >There are plenty of things
> >> >> >that require more info to describe,
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> >> >> The position that a genome describes a phenotype is disputable; the
> >> >> genome is not a blueprint.
>
> >> >Sure, tiger's stripes and all that.
> >> >Phenotype is genotype plus noise.
> >> >That doen't generate more complexity though.
>
> >> No, phenotype is genotype + environment. �
>
> >Not what we were talking about.
>
> >We have
> >genome + noise � � � � � � � � � � � -> brain at birth
> >brain at birth + noise in + growth � -> adult brain
>
> >The second step can't be seen as the cause
> >of the inherently complicated structure
> >of the human brain.
>
> >Whatever is inherent, as opposed to coincidental,
> >must be coded for in the genome,
>
> You miscomprehend, mon ami. �To begin with the immediate environment
> for the genome is the cell within which it is embedded. �This is true
> whether we are talking about prokaryotes or eukaryotes. �More than
> that there is the immediate chemical environment around the cell. �So
> we always have
>
> d(cell_contents(t))/dt =
> F(cell_contents(t),cell_environment(t),genome)
>
> When we consider multi-cellular organisms such as mammals things get
> much more complicated. �The organism is a complicated environment for
> the gametes so they are not in fact all the same. �Then we have the
> course of development of the fertilized egg which is not simply the
> unfolding of a predefined program embedded in the genome; rather it is
> aided and partially directed by the mother's physiology as the fetus
> develops.
>
> In short, the organism sans genome has information about the
> phenotype, information acquired during the course of living.
>
> To cavelierly dismiss the environment as noise as dreadfully
> superficial.
Moreover, the genomic programming for brains specifically senses
and responds to environmental stimulus, and that response includes
active manipulation of the external environment which effects changes
in other cells that in turn effect changes in the environment. All
these
affects are in part programmed, in part chaos, and in part reinforcing
switches to environment.
A brain is much more than the set of instructions for cellular growth,
just as a large real crystal is more complex than a fragment of
that crystal. As a brain has adaptatively evolved, with programming
that favours a certain degree of utilitarian connectivity, it is less
complex (in the Kolmogorov sense) than a similarly sized random
tangle of interconnecting neurons.
It may indeed be interesting to speculate about how specific the
actual structure of a "typical" human brain is, as compared to a
random collection of similar cells with similar numbers and
proportions
of neuronal connections. The numbers involved are very big.