Re: Human design and natural "design"

On Wed, 24 Aug 2005 18:41:54 -0600, in talk.origins , dkomo
<dkomo871@xxxxxxxxxxx> in <XcqdnVEAGr5HjpDeRVn-3g@xxxxxxxxxxx> wrote:

>Robert Grumbine wrote:
>> In article <KtqdnVuscLa0yJbeRVn-tw@xxxxxxxxxxx>,
>> dkomo <dkomo871@xxxxxxxxxxx> wrote:
>>
>>>Keith H Duggar wrote:
>>>
>>>>dkomo wrote:
>>>>
>>>>
>>>>>True feedback in a control system is a set of actual
>>>>>*signals* received from the environment which allow that
>>>>>system to make appropriate responses or changes. In the
>>>>>case of evolution this means that the environment would
>>>>>need to supply signals to the organism which would cause
>>>>>*direct* changes to that organism's genome. In other
>>>>>words, directed mutations. This is lamarckism, which in
>>>>>the current received view doesn't exist.
>>>>
>>>>
>>>>Why are you fixated on individuals (Lamarckism)? Think
>>>>POPULATIONS to understand how it is feedback. This Lamarck
>>>>bashing is a red herring.
>>>
>>>Why are you fixated on populations?
>>
>>
>> I hope he's doing it because evolution is defined by populations.
>> I will:
>>
>>
>>>Even in the case of populations the
>>>environment is not making *direct* changes to the genomes of the
>>>organisms. The changes were made by mutations which are completely
>>>decoupled from the needs of those organisms. There is no feedback loop
>>>here.
>>>
>>>Changes to the genomes of those organisms. Not changes to the
>>>statistical distribution of alleles. See the difference?
>>
>>
>> Filters are feedbacks and vice versa,
>
>Huh? Filters can be designed using feedback or not. There are
>recursive digital filters, for example, which feed back the values of
>the delayed output, and there are non-recursive filters which do not.
>In analog filters, a simple RC network can act as a low pass filter, no
>feedback needed.
>
>Also, you can say a filter *uses* feedback, but saying "filters are
>feedbacks" doesn't make a lot of sense.
>
> see signal processing for
>> the mathematics in a simple setting.
>>
>
>I took graduate courses in digital signal processing (and filter design)
>and control theory, although that was some time ago. Just want to
>establish my bona fides so that people don't think I'm talking out of my
>***.
>
>> Selection is a filter, hence a feedback. So natural selection
>> is a feedback on the system, 'system' being the allele distribution
>> in a population.
>>
>
>"Selection is a filter." Hey, I like that! Selection can indeed be
>seen as a filter. But the rest of what you say doesn't follow.
>Filtering something doesn't mean you're applying feedback to it. For
>example passing an audio signal through a filter to boost its base
>frequencies has nothing to do with applying feedback to the signal. It's
>just an input-output change to that signal.
>
>Let's pursue this filter analogy a bit further. Suppose you sift some
>gravel through a screen. You've just altered the size distribution of
>gravel particles of this "population" of gravel. With no feedback
>involved. The screen acted as a filter.
>
>This is exactly how selection acts. It is a filter which sifts through
>a population of organisms and alters the allele frequencies of the
>population. Voila, evolution!
>
>And no feedback was involved. Which is what I've been saying all along.
>Evolution is an open loop, not a closed loop process.

The population is different than it was due to the filter. It was
feedback, a closed loop.

>Thanks for the filter metaphor.
>
>
>> Sampling is also a filter, so neutral drift in a population is
>> also a feedback on the system.
>>
>> In terms of most trivial signal processing, the mutations are
>> introducing noise. The result of that noise after filtering is
>> indeed dependant on the nature of the noise. But it's still
>> noise, and the filtering (feedback) is an essential part of
>> the 'end' signal (biology).
>>
>> While 'allele distribution in a population' is a poor tool
>> for talking about evolution to general audiences, it's appropriate
>> here, and avoiding it seems to be causing problems. If you
>> don't take evolution to involve allele distribution in populations,
>> it'd be good to define what you mean by evolution.
>>
>
>I do agree with this definition. I was trying to stick with individual
>genomes because it more clearly illustrates that there is no feedback
>that changes these genomes. When we look at populations, that seems to
>confuse everybody into thinking that selection is supplying feedback
>just because the allele frequencies change. Not true. We've just shown
>that selection is an open loop filtering process.

If you stick to individual genomes then you don't have selection and
you certainly don't have evolution. You have to have populations, and
reproduction over generations, to have evolution. I am astounded that
after all the time you have been in this newsgroup you don't
understand that. Selection filters genomes from a population. Over
cycles of reproduction with selection and drift we get a different
population. *That* is evolution, not whether some individual
reproduces or not.

--
Matt Silberstein

Do something today about the Darfur Genocide

Genocide is news | Be A Witness
http://www.beawitness.org

"Darfur: A Genocide We can Stop"
www.darfurgenocide.org

Save Darfur.org :: Violence and Suffering in Sudan's Darfur Region
http://www.savedarfur.org/

.