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Real_Solitude -> RE: IC does not support ID (4/30/2008 6:27:59 AM)
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ORIGINAL: Jhud
Again, you apparently have no idea what the word ‘possible’ means. As there is no observed incidence of either, they are equally ‘possible’ – and incidentally, as equally impossible. Indeed, not knowing how life can come from non-life, how can you say the process wasn’t rapid? You are attempting to argue by ignorance!
Not only that, but you have no idea how science works; it never seeks to prove anything ‘impossible’, because that would require knowing every possible case, it can only falsify what is said to be impossible. Spontaneous generation has never been shown to be impossible, only extremely improbable, and a less suitable explanation for the propagation of organisms.
I've always operated under the definition of "That may or can be, exist, happen, be done, be used, etc." As in, that which can, however improbable, actually happen.
I can't say that the development of life wasn't rapid. It indeed may have been. However, the main tenant of classical spontaneous generation "complex, living organisms are generated by decaying organic substances" is patently impossible as our knowledge of physics stands. Nothing but disorder can come from a closed system. Unless SG adds some proposed mechanism by which significant amounts of energy are added to the system, it remains impossible in light of all we know. It is especially unsatisfying as it doesn't explain the origin of life at all, but merely the origin of current life. If it requires organic material to happen, it could not have been the cause of organic material.
I suppose it's my fault for using possible and impossible differently. By possible, I generally mean actually possible. By impossible, I am using it as "not to be done, endured, etc., with any degree of reason or propriety." It is a valid definition, but I suppose it does require clarification when used so close to 'possible.' Apologies. I use possible as "actually possible" and impossible as "vastly improbable."
In this way, this is the puropse of the 'testing' phase of hypothesis. To see if the hypothesis fits all relevant data while being contradicted by none. If the hypothesis is contradicted, it requires revision. This doesn't mean that, this is in no circumstance actually impossible. But rather 'according to what we know, this is not actually possible.'
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The two problems of course is that life is now known to have never been ‘simple’, and as much as abiogenesis has never shown a single possible demonstrable mechanism in over 50 years of research, it doesn’t even rise to the level of a hypothesis, but mere wish fulfillment.
I'm going to copy-paste a description that I find compelling. Paste to word and expand as necessary.
"
Step 1: Formation of basic organic molecules from appropriate precursor materials (for which we have evidence) ... for example, experiments have demonstrated that it is possible for amino acids such as glycine to form even within interstellar clouds via ultraviolet photolysis of ammonia, carbon dioxide and water ices in cometary material, as a paper by Bernstein, Dworkin et al in 2002 demonstrated, where the appropriate conditions were replicated in the laboratory and the requisite synthesis performed. Another paper by Pizzarello and Weber (2004) demonstrates that prebiotic amino acids would act as asymmetric catalysts enhancing homochirality (the 'handedness' that is observed in today's amino acids in living systems). and of course, the Miller-Urey experiments, refined over the years, continue to provide repeatable tests of the ease with which the basic organic molecules seen in today's extant life forms can be synthesised from non-life precursor material with the input of energy from lightning and UV light.
Step 2 : Formation of more complex organic molecules from the simpler ones. Again, a paper by Orgel et al demonstrates that formation of polypeptides from a substrate of amino acids in aqueous solution takes place rapidly with yields of up to 80% in 24 hours or so, if the reactions are catalysed by a compound known as carbonyl sulphide. Carbonyl sulphide, COS, is produced in quantity naturally by volcanoes and is readily water soluble.
Step 3: Formation of the first segments of RNA. Again, this has been demonstrated to be possible experimentally, and even better still, a paper dating as far back as 1996 by Joyce describes the formation of nucleoside triphosphates catalysed by RNA molecules (nucleoside triphosphates are essential molecules in extant living systems - adenosine triphosphate powers muscle activity, for example). More recently, Johnson, Unrau et al in 2001 generated in the laboratory an RNA ribozyme that catalysed the formation of other RNA molecules, and in one experimental run, 1,088 out of 1,100 sequenced nucleotides matched the original template.
Step 4: Self-Replicating RNA molecules. Once autocatalytic RNA molecules are in existence, the first self-catalytic ones, that catalyse formation of identical copies of themselves, becomes possible. Patzke and Kiedrowski (2007) published a paper on this very topic, complete with example systems for synthesis, reaction rate calculations and other relevant data.
Step 5: RNA to other replicating molecules. Other classes of replicating molecules are known, including PNAs (peptide nucleic acids) which in turn could catalyse the formation of the first DNA molecules. Nelson, Levy and Miller (2000) published a paper to this effect and described synthesis pathways for these molecules. Again, these synthesis pathways are concordant with what is known about conditions on the early Earth, and again, appropriate reactions to form the component building blocks of PNAs are known to produce excellent yields even at high dilution in periods of around 24 to 48 hours.
Step 6: First DNA molecules. This is one step for which I do not have extant scientific literature on my hard drive, but there are several papers that cite the existence of known catalytic formation of DNA when certain clay substrates such as montmorillonite are available to stabilise and catalyse the syntheses. Franchi, Ferris and Galliori (2003) is one such paper dealing with this. An alternative hypothesis is advanced by Laczano, Guerrero and Margulis (1998), in which the first proto-cells rely upon RNA at first, and make an evolutionary shift to DNA once those cells exist. But I'm jumping ahead a little here. Robertson & Miller (1995) propose yet more mechanisms for migrating from RNA to DNA, while Gartner and Liu (2001) cover the utility of DNA with respect to the directed synthesis of molecules other than proteins and the experimentally observed reactions relevant thereto. We now move on to:
Step 7: Formation of enclosures within which replicating nucleic acids can reside. This involves the formation of lipid bilayers, which again are supported in the scientific literature. Furhop, Schneider et al began work on this as far back as 1988, whilst a more recent paper covering this is Segré, Ben-Eli et al (1999). Lipid bilayers are known to be capable of invaginating and forming vesicles around other molecules, and nucleic acids are prime candidates for such enclosure. Once enclosure in semi-permeable lipid bilayers takes place, we are part of the way toward the first proto-cells.
Step 8: Formation of additional structures. Once enclosed nucleic acids are able to engage in controlled catalytic reactions in a protected vesicle, the possibility of extension of nucleic acid strands to form other structures facilitating becomes possible. Now at the moment I haven't reviewed the scientific literature with respect to this step, but once this step is in place, we're a whisker away from the first cells.
So, apart from Step 8 above, the scientific literature on the subject is replete with documentation on the appropriate mechanisms, and I suspect that if I knew what papers to look for with respect to step 8 (as it's not my precise technical speciality, I'll have to rely on someone else to find the relevant papers), that gap would be filled neatly as well. So, it's not as if there isn't evidence supporting abiogenetic theory. Far from it."
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No,no, no, it has never been ‘disproved’ – you can’t ‘disprove’ it accept to show that it is impossible for any mechanisms to produce life naturally – and you have already said this is possible. It’s like you are talking in circles.
I was arguing the difference between the apparition of a complex organism and the gradual accumulation of a simply chemical replicator. To say "life can naturally arise." is different from saying, "It's possible for complex life to arise without due process."
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You are offering a strawman version here; the later SGs didn’t say this.
However, my statements still apply to classical SG, which is what most people are familiar with. The strawman is a real argument, just not the most current. There's a difference between attacking what's not there, and what is no longer held to be true. I can attack flat earth theory without attacking a straw man, because it was an actually held belief. Shall I label it "Aristotle to Redi Spontaneous Generation." for ease of reading?
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But this is beside the point; spontaneous generationists didn’t deal only in rats and rags – the more sophisticated ones offered nutrient rich broths; and abiogenisists simply extend that to other scenarios. But I agree I think even in 13.7 billion years the odds of life occurring are so incredibly small that it is essentially impossible.
For 1500+ years it did, forgive me for attacking the most prevalent form of the dead theory. From what I can find, SG stopped being a theory around Pasteur, and abiogenesis took over the 'how life began' field at the time of Oparin. There doesn't seem to be a smooth transition between the two, and the only 'chemical soup' theories I can find start with Oparin.
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t’s rather easy to say it is ‘unobservable’, as it has never been observed – to prove me wrong would require observing it.
But I never said it was unobservable; just that every observation indicates otherwise.
It is easy to say that my body is inedible, as it has never been eaten. To prove me wrong would require eating me.
Obviously this is false. We know bodies are edible because they have been eaten. It does not require observation to know that my body is edible.
I'm using "unobservable" in the same way I was using "possible" up above.
That comment was really more directed at Monkey's original comment than at you anyways.
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Well, technically, no assemblage of parts (Computers, books, skyscrapers, etc) violate a ‘known law’ when considering their unguided assembly, because our imaginations can always come up with a scenario whereby such a thing could occur – however, this doesn’t make such an assertion reasonable, probable, or worth considering.
Again, there are people smarter than me who have provided reasons as to why they think it is worth considering. The generation via montmorillonite seems the most plausible to my feeble mind, but apparently there are others.
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In short, you are saying abiogenesis is an attempt to provide a rational for spontaneous generation within the known laws of physics according to imagined mechanisms; but this doesn’t make it any less spontaneous generation.
In short, I'm saying that abiogenesis is an attempt to provide a rational for natural causes of life arising within the known laws of physics, according to actual mechanisms. This is why there are numerous hypothesis' that fall under the umbrella of abiogensis. It, unlike SG, is a field of research, not a single proposed idea.
And from what I've seen, none of the theories involve anything "spontaneous." They work within the natural bounds, and generally take quite a bit of time.
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