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  #21  
Unread August 2nd, 2006, 05:44 PM
Margaret McGhee Margaret McGhee is offline
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Default Re: Selling Evolution

Fred - You keep referring to "top down" natural selection. I can't imagine what that means - unless maybe you're trying to slip some ID in under the door.

Then you say,
Quote:
. . then natural selection itself, a product of blind natural forces operating in environments that “themselves are effectively random,” would also, ultimately, be “effectively random
That's like saying that water at room temperature and pressure, being a product of the gas oxygen and the gas hydrogen - is therefore effectively a gas.

For someone who complains about rigor in others' arguments, you should understand that your saying that something is true is not enough to establish its validity. You need to have some logical connection in the equation to get from one to the other. Or, is that too rigorous for you?

Margaret

Last edited by Margaret McGhee; August 2nd, 2006 at 06:02 PM.
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  #22  
Unread August 2nd, 2006, 06:44 PM
Carey N Carey N is offline
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Default Re: Selling Evolution

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If, as MM asserts, “environments themselves are effectively random,” which is how I think most Darwinians would generally see things
Absolutely false. This is a ludicrous notion. [To Margaret: I was planning to write a gentle response to your post, but Fred has pushed me into a more aggressive state of mind]

Stop and think for a second . . . if the environment changed randomly, then how could a population evolve to tolerate it? Say, for example, that suddenly a random number generator were used to determine the temperature each day in the range of 0 to 100 Degrees Celsius. One day, it would be, say, 75 degrees, which is well beyond the temperature at which most proteins dissociate. At best, a few bacterial species adapted to life around thermal vents would survive. Then, the next day, the temperature drops to 1 degree, and the only remaining organisms (i.e. the ones adapted to very high temperatures), now have trouble getting on . . . within a few days or weeks, at most, there would be very little or nothing left of life on earth if the environment were "random".

Why do you think that it was only AFTER the earth's atmosphere stabilized that life first got going on this planet?

The features of the environment to which life adapts are the regularities, which exert consistent selection pressures that aren't so powerful that they eliminate every member of the population, rather than just some of them. The more extreme and unpredictable an environmental factor, the more likely it is to wipe out species that were previously adapted to a specific set of environmental conditions. Environmental regularity, not randomness, allows evolution to proceed. The very term "environment" in biology only makes sense with reference to a particular set of conditions and patterns that recur from day to day and year to year. There may be stochastic elements of an environment (e.g. food is randomly distributed in habitat A), but they are generally part of a larger regularity (there is food to be found in habitat A) to which populations can adapt. The greater the degree random facotrs play in a population's evolution, generally, the more likely that population is to crash.

Two extreme illustrative examples:
1)
A cactus plant can live in the desert because it possesses a large suite of desert-specific adaptations, including: water storage structures, deep root systems, thick waxy outer skin, and highly altered, water-efficient photosynthetic biochemical mechanisms. These adaptations are costly and would not be favored if the annual rainfall changed randomly from year to year . . .

2)
Consider the meteor that hit this planet and prompted the end-Cretaceous extinction event (the one that killed the dinosaurs, except for birds). This was a highly irregular, extreme environmental event, and it annihilated a large fraction of metazoan life on earth.

Adaptive evolution proceeds because natural selection non-randomly preserves elements of the variation generated by random mutation. Without environmental regularity, natural selection would be so immensely strong that populations would not be able to respond to it, biological evolution would halt, and life would cease to exist.

The point on which Margaret was heading in the right direction is that the variation generated by random mutation is definitely what gives a population its "evolvability" . . . without varitation from which to select, natural selection cannot mold a population in a changing (or static) environment.

Last edited by Carey N; August 5th, 2006 at 09:38 PM.
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  #23  
Unread August 2nd, 2006, 07:49 PM
Margaret McGhee Margaret McGhee is offline
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Default Re: Selling Evolution

Carey, Thanks for the clarification. As I was writing that I thought it seemed a bit squishy. I said,
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Since environments themselves are effectively random at the level of the organism (volcanoes, hurricanes, CO2 concentrations, migration of predators, disease organisms, etc.) what better way could be devised for species to adapt than for each generation to be able to select the best possibilities from a random set.
I think what I was trying to say was that . .
Quote:
Since the changes in their environments that species must adapt to are effectively random at the level of the organism - like the changes caused by the meteor that hit this planet and prompted the end-Cretaceous extinction event - what better way could be devised for species to adapt to those changes than for each generation to be able to select the best possibilities from a random set.
I should maybe add that by saying that the changes in their environments . . . are effectively random at the level of the organism - I mean that that meteor was not a random event. It was a mass in the universe that was obeying all the laws of physics. But for the organisms that had to adapt to the changes it caused - it was not something that they could have evolved an ability adapt to - it was a non cyclic, non repeating event - therefore effectively random.

Margaret

Last edited by Margaret McGhee; August 2nd, 2006 at 10:04 PM.
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  #24  
Unread August 2nd, 2006, 11:25 PM
Fred H. Fred H. is offline
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Default Re: Selling Evolution

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Carey: The features of the environment to which life adapts are the regularities, which exert consistent selection pressures that aren't so powerful that they eliminate every member of the population, rather than just some of them.
OK Carey, so apparently you’re talking Darwinian top-down natural selection, i.e. the selection imposed by the environment, an environment that must have your so-called “Environmental REGULARITY,” that we see only here on Earth (so far anyway), along with, I suppose, all the various (known and unknown) natural forces, that may or may not directly impact the “Environmental REGULARITY” itself.

However, I suspect that most Darwinians would consider the fact that there’s an Earth at all with the requisite “Environmental REGULARITY,” to be the result, ultimately, of random or “effectively random” things. So that while you may decree that “natural selection is a NON-random force,” this so-called “force” seems to require, in addition to effectively random mutations to select from, an “Environmental REGULARITY” that is itself the result of “effectively random” things that have occurred over the last 14 billion years—ultimately, eventually, your so-called “NON-random force” of Darwinian “natural selection” ends up being the result of random or effectively random things.

Be that as it may, let me repeat the more interesting point made in my last post to you regarding your misunderstanding/misinterpretation regarding Penrose.

As you, Carey, have acknowledged at http://www.behavior.net/bolforums/s...990&postcount=4 — “Mutation is the ultimate source of all variation present within a population . . . without mutation, there would eventually be nothing for natural selection to select, and evolution would halt.”

IOW, whether selection be top down, bottom up, “natural,” “artificial,” blind, mindless, whatever, it can only select from what is already available; from, in a sense, what already has blindly, directionlessly, “effectively randomly,” changed/mutated/evolved; at least according to current Darwinian dogma.

So I doubt Penrose is saying, as you opine, that he "can't possibly believe that natural selection, lacking any foresight, produced biological complexity." Rather I think he’s saying exactly what he said: "To my way of thinking, there is still something mysterious about evolution, with its apparent 'groping' towards some future purpose. Things at least seem to organize themselves somewhat better than they 'ought' to, just on the basis of blind-chance evolution and natural selection."

And I’d add that while Penrose indicates that he himself is a strong believer in “natural selection,” I suspect that he, like I, fully realizes that “natural selection,” whether it be a top down or bottom up selection, is ultimately little more than a circular account that really doesn’t explain or predict all that much.
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  #25  
Unread August 3rd, 2006, 03:49 AM
Carey N Carey N is offline
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Default Re: Selling Evolution

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However, I suspect that most Darwinians would consider the fact that there’s an Earth at all with the requisite “Environmental REGULARITY,” to be the result, ultimately, of random or “effectively random” things. So that while you may decree that “natural selection is a NON-random force,” this so-called “force” seems to require, in addition to effectively random mutations to select from, an “Environmental REGULARITY” that is itself the result of “effectively random” things that have occurred over the last 14 billion years—ultimately, eventually, your so-called “NON-random force” of Darwinian “natural selection” ends up being the result of random or effectively random things.
According to this logic, everything is ultimately the result of random things . . . a quick glance at the adaptive complexity of any biological entity, or the complexity of other non-biological phenomena (earth or non-earth-bound), pretty conclusively reveals that your statement above is an absurdity.

"If you atheists think that the universe wasn't made by a Designer, then it must have been made randomly [this is false], which means that everything in the universe is also random [also false]". Seriously, Fred, that's what you sound like.


Quote:
whether selection be top down, bottom up, “natural,” “artificial,” blind, mindless, whatever, it can only select from what is already available; from, in a sense, what already has blindly, directionlessly, “effectively randomly,” changed/mutated/evolved; at least according to current Darwinian dogma.
It can only select from what is available, yes . . . but what evolves is a product not only of what was available due to mutation, but also of what natural selection did with the variation at its disposal. Natural selection is the one and only force that leads to adaptive evolution. Without selection, there would be no elegant fit between form and function we see in the biological world - that kind of complexity doesn't just pop into existence due to mutation alone.


Quote:
And I’d add that while Penrose indicates that he himself is a strong believer in “natural selection,” I suspect that he, like I, fully realizes that “natural selection,” whether it be a top down or bottom up selection, is ultimately little more than a circular account that really doesn’t explain or predict all that much.
Too bad you're not as good at openly reading other peoples' posts as you are at repeating yourself.

Last edited by Carey N; August 3rd, 2006 at 08:16 AM.
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  #26  
Unread August 3rd, 2006, 08:45 AM
Fred H. Fred H. is offline
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Default Re: Selling Evolution

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Carey: It [natural selection] can only select from what is available, yes….
Good Carey, then it seems we now agree on two things: That selection can only select from what is already available; and that what is available, the so-called mutations, aren’t necessarily intrinsically “random,” but rather, currently anyway, just seem to be unpredictable, at least by us humans based on our current knowledge.

Speaking of selection from only what’s available, I’m reminded of one of my old 4/2002 posts regarding what LeDoux had to say concerning selection vs. instruction as it relates to human “learning”:
Quote:
Selection vs. Instruction — LeDoux (in his Synaptic Self, 2002, pg. 72-79) writes that, “Pretty much everyone agrees that that the transition from uncommitted, immature initial connections of the young brain to the mature and very specific connectivity that characterizes that of the adult requires neural activity, that is, transmission across synapses…. [The issue is whether] activity initiated by environmental stimulation helps create [instruction] the mature connections or just selects [selection] from the initial set of intrinsically established connections those that will be retained… Is the [synaptic] self sculpted from a preexisting set of synaptic choices, or does experience instruct and add to the synaptic basis of the self as we go through early life?”

LeDoux also writes, as Niels Jern has pointed out, “the history of biology is filled with instances of instructional ideas giving way to selectionist ones… [For example, in the field of immunology] it was once thought that the foreign antigens enter cells and instruct them to make antibody molecules…[but now research has shown that] foreign antigens select precursor molecules from a preexisting pool that can be assembled into a large variety of antibodies… Jerne later applied his antibody logic to the topic of learning… [and] suggested that the idea of learning from experience (instruction) be replaced with the concept that experience just selects from preexisting latent knowledge. Paraphrasing Socrates, Jern noted that ‘learning consists of being reminded of what is already in the brain.’”
And so I suppose that’s kind of how I see Darwinian “natural selection” as it relates to biological evolution—Darwinian natural selection in biological evolution is nothing more than a selection, a selection imposed by environmental factors and various (known and unknown) blind natural forces, of the evolution/diversity/ change/mutation that has already taken place. And from that we conclude that whatever traits are selected must be the fittest, b/c otherwise they’d not have been selected . . . I have to admit that the circularity is rather compelling, and I can see why you and others are such strong believers in such a circular notion.
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  #27  
Unread August 3rd, 2006, 09:07 AM
Fred H. Fred H. is offline
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Default Re: Selling Evolution

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Carey: According to this logic, everything is ultimately the result of random things . . . a quick glance at the adaptive complexity of any biological entity, or the complexity of other non-biological phenomena (earth or non-earth-bound), pretty conclusively reveals that your statement above is an absurdity.
Well Carey, if you’re saying that the complexity of life and the universe that we find ourselves in, a universe that began 14 billion years ago with inexplicably low entropy, couldn’t be the result of an accident or chance, which implies that there is indeed, after all, some sort of purpose/meaning/ first cause . . . well, hallelujah bro, and welcome to the fold.
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  #28  
Unread August 3rd, 2006, 09:24 AM
Carey N Carey N is offline
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Default Re: Selling Evolution

You built a straw man of evolutionary biology, I knocked it down, and now you're saying that I agree with you indirectly? Your argument tactics are child's play, Fred. Grow up.

Last edited by Carey N; August 3rd, 2006 at 09:54 AM.
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  #29  
Unread August 3rd, 2006, 09:36 AM
Carey N Carey N is offline
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Default Re: Selling Evolution

Removed by user.

Last edited by Carey N; August 3rd, 2006 at 03:15 PM.
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  #30  
Unread August 3rd, 2006, 09:44 AM
TomJrzk TomJrzk is offline
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Default Re: Selling Evolution

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Originally Posted by Fred H.
a universe that began 14 billion years ago with inexplicably low entropy
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Originally Posted by wiki
The thermodynamic arrow is often linked to the cosmological arrow, as according to the Big Bang theory, the Universe was initially very hot with energy distributed uniformly. As the Universe grows its temperature drops, which leaves less energy available to perform useful work in the future than was available in the past. Thus the Universe itself has a well-defined thermodynamic arrow of time. But this doesn't address the question of why the initial state of the universe was that of low entropy. If cosmic expansion were to halt and reverse due to gravity, the temperature of the Universe would once again increase, but it's expected that entropy would continue to increase.
We know that the early universe was not "with energy distributed uniformly"; there were fluctuations shown by the infrared survey.

Those fluctuations caused energy to clump due to gravity; those clumps cooled to stars; those stars pressed the energy into the different elements; those elements were spread by novae; those elements made your DNA.

We've been living off those fluctuations.
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