Two sides of the irreducible complexity argument: dhw Pt1 (Introduction)

by xeno6696 , Sonoran Desert, Tuesday, September 22, 2009, 14:19 (5540 days ago) @ dhw

Matt writes: According to conventional evolutionary theory [...] the appearance of new organisms only arrives through "need", or in other words, some environmental attribute outside the organism's control starts putting pressure on it, either through predation or through destruction of its habitat by means of any natural phenomenon. [..] So that's what I mean that evolution only seems to happen when it has to. It is this particular segment of evolution that David (and you?) seem to be at odds with.
> 
> I can only speak for myself, but this is not the segment that I am at odds with. Allowing for the fact that those original self-replicating molecules possessed the astonishing potential for all this adaptation (George objects, but if that's how life started, there could have been no evolution without it), I have no problem with that principle, which is what both you and David have referred to as passive evolution, i.e. organisms reacting to changing conditions. -[EDIT]
Not even that according to evolutionary theory: The organisms must already have *a* trait (or behavior) that allows them to survive in the new environment. Chances are low for them to develop one in time if the pressure is lethal. -After the problem of the origin of life itself, the evolutionary stumbling block for me is not adaptation but innovation.
> -> t they were also able ... over a vast period of time and in stages from rudimentary (though functioning) to complex ... to bring all the above from non-existence to existence. For instance, what need was there for the first light-sensitive nerve? Come to that, what need was there for light-sensitive nerves to develop into the hitherto non-existent sense of sight? The advantages are clear, but those came after the event.
>-Widen your scope. The same incredulity can be applied to our galaxy, yet physics had done a pretty damn good job of putting together how galaxies and stars formed: and for all we know those systems are more complex than we are. There is still much to discover!
 
> Your account of evolution seems to begin at a point where the basic structures already exist. Once the mechanism (apologies to George) for adaptation is in place, evolution follows, and natural selection ensures a degree of improvement. -Firstly: Evolution does not need to explain the origin of life in order to be an explanation that applies to life. Evolution says absolutely nothing about origins. Evolution makes no supposition about abiogenesis. Newton's theory of gravity didn't have to account for the big bang or biblical creation, yet it is still a perfectly valid theory. (Newton's equations are what we use to send objects into space.) Evolution only explains life after life got here. How does a theory that describes life describe nonlife?-Secondly, I will quote myself: "even though mutations happen at all times in all organisms..." How is that not figuring in chance mutations? And this plugs into my very first question to the site: What definition of chance are you talking about? I can read two possibilities from you here. 
1. that something beneficial happens through random changes. 
2. That an organism is selected against. -My answer to 1 would be: So nothing good ever happens by chance?-Mutations happen at all times in all organisms for a combination of inner and outer reasons. Standard theory predicts that only when environmental conditions change to favor some trait will you see a population shift in terms of those that have that trait. If you add environmental stress to the situation, you start stacking the deck towards more change, faster. Of course, this also increases the error rate, but the way chance works, if you increase the number of iterators, you increase the likelihood of a good outcome. This is why "The house always wins" in Vegas. -My answer to 2 would be: There is no tails in a game of coins? Flippancy aside, the greater part of interest to standard theory is actually on THIS question, not the first. The first is generally assumed, and in general evidence supports that mutations happen from millions of internal reasons alone. David and you are focused on the first question, but the standard model essentially considers that question to be answered. When an environment changes, either the population has a trait, or stress helps the population find a genetically transmissible solution. My point of contention with David on this issue is on being able to determine whether the mutations are random or not. I don't think you can.

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\"Why is it, Master, that ascetics fight with ascetics?\"

\"It is, brahmin, because of attachment to views, adherence to views, fixation on views, addiction to views, obsession with views, holding firmly to views that ascetics fight with ascetics.\"