William Morse  wrote:

> wilkins{at}wehi.edu.au (John Wilkins) wrote in
> news:bmp254$153c$1{at}darwin.ediacara.org: 
> 
> > William Morse  wrote:
>  
> >> wilkins{at}wehi.edu.au (John Wilkins) wrote in
> >> news:bm77kg$29rc$1{at}darwin.ediacara.org: 
> 
> 
> >> >> Well, even in statistical mechanics that is the case
(at least if
> >> >> Tsallis is right about the proper equation for
entropy). But I can
> >> >> still make predictions based on the statistics, so even if the
> >> >> actual cause is historical the net cause is teleological.
> >>  
> >> > Now that I have choked on "teleological" (are
you reading my
> >> > diatribe against teleology in That Other Group?), let me just note
> >> > that fitness is also a statistical property, just like entropy. As
> >> > to whether this is, as Darwin thought, following Laplace,
> >> > randomness due to our ignorance or there is some contingent
> >> > randomness in the physical properties of organisms, I leave to
> >> > another, more philosophical, discussion.
> >> 
> >> I guess if I was willing to write "teleological" 
as an opposite of
> >> "historical" I deserve a response that refers to
"contingent 
> >> randomness" :-) 
> > 
> > Well there is deterministic randomness, non? Or else what is a
> > gaussian distribution? The Hardy-Weinberg Equilibrium is surely a
> > deterministic random distribution.
> 
> I hate philosophers. They insist on asking questions that get me 
> thinking, and it makes my head hurt. 

I aim to pain.
> 
> 
> Let's suppose that I grant you that there is deterministic randomness. I
> will also grant that there is random determinism (I have to grant that,
> since I have argued that that is what entropy is about). That still 
> doesn't mean I have to swallow "contingent randomness"
without a fight.
> Contingent on what? If it is contingent on a factor which is predictable,
> then it is deterministic randomness. If it is contingent on a factor 
> which is unpredictable, then it is random randomness. You could argue
> that it might be chaotic randomness, but then I will go back to using
> teleological as an opposite of historical:-)

OK, I suppose I mean that there are two kinds of stochastic processes -
constrained (determined in how it can randomly vary) and unconstrained
(not). Something that is contingent is not constrained in a consistent
and predictable manner. It is between the two kinds. Such constraints as
it has are applied by a series of other processes about which we know
nothing or little.

Chaos is, of course, fully deterministic. 8
 
> More seriously, I do think that randomness is a "deep" property. 
> Statistics overcomes it at the level of most of biology, so that most of
> what we ascribe to randomness in evolution is probably ignorance. But
> evolution almost has to be chaotic, since it involves a feedback loop,
> with the succesful phenotypes recreating the genotypes of the next 
> generation, affected by the nonlinear results of drift and selection. And
> the sensitivity of chaotic systems means that randomness at even a small
> scale is important.

Yes. Evolution is massively nonlinear. [See, Guy? I am not so
objectionable...]

-- 
John Wilkins wilkins.id.au
For long you live and high you fly, 
and smiles you'll give and tears you'll cry
and all you touch and all you see is all your life will ever be
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