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Author Topic:   Doesn't Natural Selection lead to Specified Complexity?
Peter
Member (Idle past 2310 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 1 of 138 (614708)
05-06-2011 6:07 AM


Specified Complexity is billed as an explanatory filter, and it is suggested that such 'specified' complex function cannot come about by chance.

Since Natural Selection can be viewed as a filter over the random mutations that we KNOW accur in biological systems, couldn't Natural Selection be the source of this supposed 'specificity'?

Natural Selection, surely, means that what we can observe in the natural world has not, in fact, come about by chance, but has been 'directed' by the environment -- that is only changes that 'work' are carried forward.


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Peter
Member (Idle past 2310 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 4 of 138 (614933)
05-09-2011 9:20 AM
Reply to: Message 3 by PaulK
05-06-2011 7:50 AM


So: 'If it was designed intelligently then it is the product of intelligent design.'
According to Dembski:

The signature of an intelligence in design is an event that is "contingent and therefore not necessary; if it is complex and therefore not easily repeatable by chance; and if it is specified in the sense of exhibiting an independently given pattern" (Dembski in Natural History Magazine).

He uses the concept of 'not easily repeatable by chance' ... which seems to be a subjective measure, and so of little use.

But, assuming that 'chance' (in some form) is an issue, then the natural process of selection due to environmental pressure means that we are not dealing with 'chance' any more.

Although highly complex, Natural Selection must be somewhat deterministic (i.e. given the exact same inputs, the process will provide the exact same outputs).

The random nature of mutation tends to make the inputs change, but those inputs are not purely random, just highly chaotic.


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Peter
Member (Idle past 2310 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 6 of 138 (614966)
05-09-2011 1:08 PM
Reply to: Message 5 by PaulK
05-09-2011 12:56 PM


Re: So: 'If it was designed intelligently then it is the product of intelligent design.'
By deterministic I meant that given the same set of 'genes', the same 'environment', and the same 'mutations' the outcome would be the same.

However (as I said) the 'randomness' of the inputs (i.e. the mutations part) would make going back to the beggining and starting over lead to different results (by and large).

The variables are vast and have complex interactions so deliberately setting up for a particular outcome would be near impossible ... but since the process is, well, a process, if one could recreate the exact conditions one could repeat the process.


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Peter
Member (Idle past 2310 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 8 of 138 (615091)
05-10-2011 9:15 AM
Reply to: Message 7 by PaulK
05-09-2011 1:28 PM


Re: So: 'If it was designed intelligently then it is the product of intelligent design.'
PaulK writes:

quote:

By deterministic I meant that given the same set of 'genes', the same 'environment', and the same 'mutations' the outcome would be the same.

Unless you define "the environment" as a complete and fully detailed description of every event that occurs in the relevant time period, you would be wrong. A beneficial mutation will give an overall advantage, but it is perfectly possible to encounter situations where the advantage does not come into play or is inadequate or even where the mutation is a disadvantage. A beneficial mutation is quite vulnerable in the early stages when it is present in only a few individuals and could easily be lost.

Equally drift can cause even weakly deleterious mutations to spread, overcoming natural selection. As you would expect with a statistical outcome the effect is strongest when the population is small, and chance can cause proportionally greater variations in the outcome.

That IS how I define 'the environment'.

Changes within the environment (even restricting it to the Earth's bio-sphere) are not random, they are the result of interactions of such a vast array of variables that we are unable to accurately predict the changes -- but that's out limitation not a fundamental feature of 'the environment'.

The 'process' of natural selection operates at a fairly simple level, but has vast numbers of variables with unclear interactions.

It would appear that the necessary precision of the starting point may be lower than 'absolutely the same' or else the evolution-loss-re-evolution of features (at the level of the individual) would not be seen, nor would we see squid-eyes and mammal-eyes sharing so much common structure.

the 'process' is detreministic -- there is so much latitude in the variables that it has the appearance of 'randmomness'


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Peter
Member (Idle past 2310 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 10 of 138 (615173)
05-11-2011 5:49 AM
Reply to: Message 9 by PaulK
05-10-2011 6:19 PM


Re: So: 'If it was designed intelligently then it is the product of intelligent design.'
Treating the environment as non-random (which it isn't, it's just too intricate for us to model accurately) does not make natural selection unimportant.

The environment exists in time, and changes over time. For biological entities to persist they have to have a mechanism for keeping up with the changes.

All I am saying is that that process is NOT random. In fact, it is deterministic (in the computing sense) in that setting the same initial conditions and letting the process run will result in the same outcome.

Change the initial conditions, or any of the steps along the way and the outcome will be different.

Using statistical models to investigate systems which are too intricate for us to model accurately is perhaps the best we can do at present -- so long as we don't confuse our 'best approach' with a 'perfect match'.


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Peter
Member (Idle past 2310 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 11 of 138 (615177)
05-11-2011 7:10 AM
Reply to: Message 3 by PaulK
05-06-2011 7:50 AM


The 'Specified' Bit.
Hang on .... so natural selection can be viewed as providing the 'specified' bit ... but there is some question over the 'complex' bit?

Even that means that SC cannot be used as a marker of intelligent design.


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Peter
Member (Idle past 2310 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 14 of 138 (615300)
05-12-2011 6:55 AM
Reply to: Message 12 by PaulK
05-11-2011 12:37 PM


Re: So: 'If it was designed intelligently then it is the product of intelligent design.'
By 'drift' do you mean 'neutral genetic change'?

In order to determine the dererminism (or not) of natural selection one has to 'fix' the inputs ... so drift becomes irrelevant.

If we narrow the environment to a petry dish, and the gene set to a single (at first) bacterium I'm pretty sure we could 'rig' the environment to get a particular genetic change to fix in out petrie dish population.

e.g. one could doubtless manufacture an anti-biotic resistant strain from a non-anti-biotic resistant strain by setting the conditions up (to broadly match what happened in hospitals).

The statistical anaysis is necessary because mutations are random, and the environment is difficult/impossible to accurately model -- not because natural selection is in any way random.


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Peter
Member (Idle past 2310 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 15 of 138 (615301)
05-12-2011 7:05 AM
Reply to: Message 13 by PaulK
05-11-2011 12:45 PM


Re: The 'Specified' Bit.
I was using a common-or-garden understanding of complexity.

Dembski:
The design inference uncovers intelligent causes by isolating the key trademark of intelligent causes: specified events of small probability. Just about anything that happens is highly improbable, but when a highly improbable event is also specified (i.e., conforms to an independently given pattern) undirected natural causes lose their explanatory power.

Doesn't that imply that specified complexity just means 'intended outcome' ... and backs round to not helping at all in detecting 'intelligence'?

If we observe a pattern after-the-fact in which natural selection 'formed' the pattern or an 'intelligence' formed the pattern what difference would there be from Dembski's view point -- nothing I would suggest.


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Peter
Member (Idle past 2310 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 17 of 138 (615307)
05-12-2011 7:22 AM
Reply to: Message 16 by PaulK
05-12-2011 7:14 AM


Re: So: 'If it was designed intelligently then it is the product of intelligent design.'
The way I look at it is:

Inputs { Genetic Mutation, Environmental Conditions} -> Process {Natural Selection} -> Output{Genome Distribution Shift}

If not all of the genetic mutations are 'used' by natural selection, then those are not relevant to natural selection -- but that is, of course, a function of the environment. I could put my view as:

Genome Distribution Within a Population = Natural_Selection(Genetic Mutation, Environment) + Drift(Genetic Mutation)

Making drift independent of natural selection as a process/function.

As for the bacterium thing, the assumption is not necessarily that the gene is there, but that there is a finite probablility of that gene entering the genome (i.e the original bacterial cell doesn't need the resistance provided one of it's successors does -- assuming it lives long enough to reproduce of course).


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Peter
Member (Idle past 2310 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 20 of 138 (615449)
05-13-2011 6:20 AM
Reply to: Message 19 by PaulK
05-12-2011 8:11 AM


Re: So: 'If it was designed intelligently then it is the product of intelligent design.'
Drift is not a function of the environment (if I understand the term correctly) since the prevalence of that 'trait' is not dependent on environment (if it were it would be bound up in the natural selection).

Yes there is a time component such that:

GDiP[k] = NS(Env, Mut)[k-1] + D(Mut)[k-1]

k being a 'snapshot' in time.

Drift affects evolution, but is not a factor in natural selection ... and it's the natural selection that generates 'specificity'.

If a natural process can produce a pattern, then specified complexity is not a marker for design ... no matter what you consider complexity to be.

As for the bacterium: the result is not guaranteed becasue one of the inputs to natural selection cannot be controlled, not because natural selection is non-deterministic.

The idea was to narrow the vast array of variables that are inputs to the process to a manageable sub-set.

Given a mutation that we know can occur, and enough pretie dishes we will see the result.

And could repeat the experiment and get the same result.

... but then if that were not the case the whole concept of natural selection would fall by the way-side.


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 Message 23 by PaulK, posted 05-13-2011 11:49 AM Peter has responded

  
Peter
Member (Idle past 2310 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


(1)
Message 21 of 138 (615450)
05-13-2011 6:27 AM
Reply to: Message 18 by PaulK
05-12-2011 7:34 AM


Re: The 'Specified' Bit.
So .... this whole thing is just an argument from incredulity then.

One consequence of evolution as a natural process is that no particular outcome is actually intended. In fact the whole idea of 'intent' is equivalent to 'intelligent design' ... so doesn't that mean that this whole idea is attempting to say 'If it looks intelligently designed, it was.'

Rather than being meaningful in any way about detecting intelligence in a design.


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Peter
Member (Idle past 2310 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 24 of 138 (615736)
05-16-2011 7:47 AM
Reply to: Message 23 by PaulK
05-13-2011 11:49 AM


Re: So: 'If it was designed intelligently then it is the product of intelligent design.'
How so?

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Peter
Member (Idle past 2310 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 25 of 138 (615737)
05-16-2011 7:50 AM
Reply to: Message 22 by Taq
05-13-2011 11:22 AM


Re: So: 'If it was designed intelligently then it is the product of intelligent design.'
Yes, meant 'not a marker for INTELLIGENT design'.

In the latter case that you mentioned, where a phenotype change does not alter fitness -- but selective pressure still applies ... that seems a contradiction.

If selective pressures are placed upon the new phenotype, then natural selection is at play, but does not favor the new phenotype over the pre-existining one (relevant to the mutation).

Bu in respect of THAT genetic mutation selection remains a factor.


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Peter
Member (Idle past 2310 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 27 of 138 (615753)
05-16-2011 11:49 AM
Reply to: Message 26 by PaulK
05-16-2011 11:32 AM


Re: So: 'If it was designed intelligently then it is the product of intelligent design.'
But how does that make drift a part of the environment?

Drift isn't an event.

Drift is a kind-of hap-hazard fixing of a genetic change within a population for no specific reason.

Changes in behaviour may have an impact on subsequent changes ... so it may result in different types of event in the subsequent 'round', but that doesn't make it an event.

If we were to view natural selection (as I do) as a process which acts iteratively on a set of environmental effects & a set of genetic mutations (within a population of interest) then that process must be deterministic, else it is not a process at all.

It's like a computer function that takes a rand() as one of it's arguments ... seed your random number system the same each step and all your results will be the same -- change the seed ro something else (like date) and your results will be different.

The variability in the inputs doesn't make the function non-deterministic.


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Peter
Member (Idle past 2310 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 31 of 138 (615810)
05-17-2011 4:36 AM
Reply to: Message 29 by Taq
05-16-2011 5:52 PM


Re: So: 'If it was designed intelligently then it is the product of intelligent design.'
Taq writes:

In the latter case that you mentioned, where a phenotype change does not alter fitness -- but selective pressure still applies ... that seems a contradiction.

You need to carefully parse what I said. I stated that the environment determines which changes are under selective pressure. The environment determines which mutations are under negative, positive, or neutral selection. I am relating all of this back to a previous post where you stated:

"Drift is not a function of the environment (if I understand the term correctly) since the prevalence of that 'trait' is not dependent on environment (if it were it would be bound up in the natural selection)."

The environment does determine which mutations are neutral, and therefore determines the probability of that trait being passed on to the next generation.

Nuetrality is not determined by the environment, it is the position when the environment has no relationship to the mutation in question.

It is the absence of a dependency.


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