The fluid dynamics of increased velocity, deepening and bank erosion on the outside of bends, along with slowing, silt deposition (shallowing) and bank building on the inside of stream bends is very well understood. So much so, in fact, that, given the daily flow volume, that meandering action can be modeled, predicted and drawn with high precision.
No "intelligence" or "purpose" on the part of the river is required (or, indeed, exists.)
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The function of a river is to transport water from its source/inflow points to the sea. IF there were any "selection" at work to "evolve" the river to a higher functional state, we would see rivers inexorably straightening their courses over time.
Never happened. Never will.
At one point in your .GIF, you can see the inevitable effect of a "cutoff", wherein the river "punches through" a narrowed meander -- leaving the course temporarily "evolved upward" (straighter at that point).
But, then the second law of thermodynamics takes its inevitable effect -- and the course of the river "DEVOLVES" back to its sluggish, meandering state.
Always has. Always will.
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"Upward evolution" is a no-win game. The Second Law makes it so.
Between cut-and paste from the old Crevo wars and misstatements of science and scholasticism this discussion has become pretty pointless.
But many can come and warm their hands on the straw men afire.
Lurkers: I assure you many of us Conservatives do understand science, stochastic processes, the realty of TToE and what a Scientific Theory is (the real definition, not the straw man definitions posited).
Please, dear lurker, know that.
Do you have a link for that? I thought that predicting the exact course of a meandering river was an extremely inexact science at best.
No "intelligence" or "purpose" on the part of the river is required (or, indeed, exists.)
Yes, I know. That was why I used the analogy.
The function of a river is to transport water from its source/inflow points to the sea. IF there were any "selection" at work to "evolve" the river to a higher functional state, we would see rivers inexorably straightening their courses over time.
That seems to me like an odd way to describe a river. If by "function" you just mean what it does, then I agree with you. But if you mean what it's for, then you're introducing a standard for judgment that I don't think you've justified. The fact that you then go on to describe a straight river as having a "higher functional state" than a meandering one makes me think you are using the value-laden definition, and that illustrates how groundless it is. A river has a lot more functions than just getting water from A to B, some of which a meandering river does better than a straight one--providing riparian habitat, for example.
But, then the second law of thermodynamics takes its inevitable effect -- and the course of the river "DEVOLVES" back to its sluggish, meandering state.
If you're claiming that a meandering river is somehow less ordered than a straight one--a claim I'm not sure is justified--then at least you're acknowledging that natural processes can result in a temporary local decrease in entropy, 2nd Law notwithstanding.
Those who tout the theory of (unobserved) "upward evolution" very conveniently ignore the more powerful (observable) opposing effects of Entropy (aka "devolution or downward evolution").
We're not saying it's permanent and eternal. But "temporary and local" can mean "for millions of years on our planet."
Well and truly said, dear brother in Christ!