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old6598 wrote:Maybe the most that we can achieve is that we may know some general conditions where molecules polymerize, we can see some evolution or some portions, we can see some reactions and some primitive organisms evolve slightly, but past that we won't see
Ganapati wrote:Would you be happy with 'highly probable'? Sounds technical enough for me. Of course, it is still a fading out definition. I suppose different people would be satisfied with different quantitative values. Has anybody quantified the probability so far?
Size matters in that the probability of one of a random combination is much higher if the size is small than if the size is large. Stability is certainly a function of the environment. I never talked about stability in the present environment. If we can guess intermediate molecules, guess and demonstrate the environment was stable in and if the progression of such enviroments is what we would expect from the laws of physics, we would have a credible case for abiogenesis. As for presence of molecular oxygen in today's environment, I am not aware of that being a constraint in our ability to simulate environments that were drastically different from what exists today. Can you direct me to information that presents this to be the limitation in our ability to simulate pe-life environments in the laboratory?
I am not aware of any experiment where a self-replicating molecule was formed without deciding a-priori what its structure was going to be, something that is a must for abiogenesis. That anyone can arrange pebbles on a beach into a long sentence in English, does not prove that such a pattern could emerge by physical forces. I would be glad to know of any such successful experiment.
rasava wrote:It is difficult to determine the probability of life occurring in the universe without knowing for sure what really can be defined as life and what kinds of life are out there already in the universe.
Scientists in the United States have made a phenomenal breakthrough after they found a bacteria that thrives on Arsenic in Mono Lake, California. The most shocking discovery in this bacteria is that it is living with another element in its DNA and it is basically Arsenic. Every living organism on earth are built of six basic elements which constitute in the DNA they are – Carbon, Oxygen, Nitrogen, Hydrogen, Sulfur, and Phosphorus.
Now here is the twist, if such sort of bacteria is freely living on earth, in an unimaginable environment which lacks most of the building blocks or elements of a DNA, then there is also a huge possibility that there could be life outside planet earth.
The questions that have been pondering scientists for many years has been finally answered, and yes life can also exists without the basic elements that are found suitable on earth. This means that there can be a massive window of opportunity that life can exist in many parts of our universe, if the surrounding atmosphere and environment helps them to exist. Life can adapt to its environment around it, the environment does not adapt to life.
Xunzian wrote:Ganapati wrote:Would you be happy with 'highly probable'? Sounds technical enough for me. Of course, it is still a fading out definition. I suppose different people would be satisfied with different quantitative values. Has anybody quantified the probability so far?
What are the variables you would use to calculate such a probability? There are too many variables and we are (at present) too ignorant to begin a proper calculation of them.
We can create anoxic environments in laboratories, it happens all the time. The Miller–Urey and Jose Oro experiments are pretty classic examples of trying to recreate the reducing environment of the early Earth atmosphere and plenty of compounds involved in present life are formed there. While there is some controversy surrounding the specifics of these experiments, other variations accounting for those controversies still produce materials that would be sufficient for early "life" in significant quantities.
Ganapati wrote:I am not aware of any experiment where a self-replicating molecule was formed without deciding a-priori what its structure was going to be, something that is a must for abiogenesis. That anyone can arrange pebbles on a beach into a long sentence in English, does not prove that such a pattern could emerge by physical forces. I would be glad to know of any such successful experiment.
Actually, most of the self-replicating RNA demons were not designed a priori but rather through a selective process starting with Q beta. Randomly messing around with Q beta to see what happens is hardly an a priori approach, it is an experimental one where selection is at play.
rasava wrote:I basically echo one of Xunzian's points - It is difficult to determine the probability of life occurring in the universe without knowing for sure what really can be defined as life and what kinds of life are out there already in the universe. It's a pretty wild extrapolation from the perspective of the entire universe to say that our life is the only type there can be, given that we're currently locked on one planet out of quadrillions without any larger perspective on what the universe outside of us really contains.
But let's define life first at least.
Current thinking is that all life requires water, but in the end that too is limited to what we know on Earth. This then leads us to something akin to old-school metaphysics - a worthy exercise but it is nonetheless important to recognize it at the outset. Our body of Natural Science is far too limited to be of much use in narrowing this question down.
Humpty wrote:rasava wrote:It is difficult to determine the probability of life occurring in the universe without knowing for sure what really can be defined as life and what kinds of life are out there already in the universe.
This sentiment is completely correct. It was in the news recently: a kind of bacteria completely unlike any other lifeform previously discovered. Apparently, it uses different building blocks than every other known life form. It uses Arsenic.
http://www.thatsfamous.com/6832-nasa-sc ... alifornia/Scientists in the United States have made a phenomenal breakthrough after they found a bacteria that thrives on Arsenic in Mono Lake, California. The most shocking discovery in this bacteria is that it is living with another element in its DNA and it is basically Arsenic. Every living organism on earth are built of six basic elements which constitute in the DNA they are – Carbon, Oxygen, Nitrogen, Hydrogen, Sulfur, and Phosphorus.
Now here is the twist, if such sort of bacteria is freely living on earth, in an unimaginable environment which lacks most of the building blocks or elements of a DNA, then there is also a huge possibility that there could be life outside planet earth.
The questions that have been pondering scientists for many years has been finally answered, and yes life can also exists without the basic elements that are found suitable on earth. This means that there can be a massive window of opportunity that life can exist in many parts of our universe, if the surrounding atmosphere and environment helps them to exist. Life can adapt to its environment around it, the environment does not adapt to life.
But Redfield disagreed, writing that the paper "doesn't present ANY convincing evidence that arsenic has been incorporated into DNA (or any other biological molecule).
In an interview Monday, Redfield said the methods used by the researchers were so crude that any arsenic they detected was likely from contamination. There is no indication that the researchers purified the DNA to remove arsenic that might have been sticking to the outside of the DNA or the gel the DNA was embedded in, she added. Normally, purifying the DNA is a standard step, Redfield said: "It's a kit, it costs $2, it takes 10 minutes."
She also questioned why the researchers analyzed the DNA while it was still in the gel, making the results more difficult to interpret: "No molecular biologist would ever do that."
Redfield also disagreed with the paper's conclusion that the bacteria had to rely on arsenic to build molecules such as DNA because there wasn't enough phosphate (a form of phosphorus) available in the samples with the lowest levels. Her arithmetic showed that in fact, there was enough phosphate to account for the amount of bacteria that grew.
"That shocked me," she said.
Redfield added that there was actually very little arsenic in the DNA of bacteria grown in an environment high in arsenic and low in phosphorus. In fact, the amount was only twice that of the cells grown without arsenic: "That's a level of difference that could be easily explained by very minor contamination."
Humpty wrote:even if the results of the study i linked are incorrect, that doesn't preclude the possibility that life can arise under drastically different conditions than Earth's.
rasava wrote:Hello Ganapati:
The point is that we don't have a sufficient domain of knowledge on life to even know if our probability estimates of life, whether as we know it or as we don't know it. Calculating the probability of whether a quarter will land heads or tails starts with the knowledge of the set of alternatives for the facing of the coin, the domain of possibilities. Life as we know it on Earth may be not exist anywhere else, but any planet that sustains life has a different form. The principle of life may be a generation of self-motive bodies using the chemicals available on the planet provided certain solar characteristics exist. In such a definition, life made of silicon that floats through a gas giant and which drinks liquid methane instead of water would not be life as we know it, and the standard or definition of life would be so out of touch with our probability characterizations that they would be useless. Heck, life may originate from persistent sound waves on a planet - how would our probability calculations or your definition account for that? These are speculations on other types of life to be sure, but our very narrow frame of reference in a universe with quadrillions of planets makes any calcuations on our part equally speculative or purely in the realm of metaphysics, not natural science.
As to your argument that our knowledge of life's current forms will "have to do", I would ask "have to do for what?" What good will they serve as a scientific foundation when we do not have sufficient observations and data to draw a conclusion under the Scientific Method?
The answer is to forget grounding such discussions in science and instead put it where it belongs - as a metaphysical inquiry. That's not such a bad thing.
Ganapati wrote:Until we can demonstrate the path and quantify the probability, abiogenesis will remain a faith position.
Well, having the components and demonstrating the path are entirely different things. Demonstrating that amino acids could form in an abiotic environment is a step closer to proving abiogenesis, but doesn't constitute proof by itself.
If this is an experiment where self-replicating RNA molecules were formed starting from molecules that have been demonstrated to have been capable of forming in an abiotic environment, please link me to it. I am not aware of Q beta replicase being formed in abiotic environments.
Xunzian wrote:Ganapati wrote:Until we can demonstrate the path and quantify the probability, abiogenesis will remain a faith position.
What I think you mean to say here is that until that time abiogenesis will remain hypothetical.
I don't think anyone (and certainly not myself) is claiming that abiogenesis is more than a hypothesis, though as a hypothesis it does have a fair deal of evidence supporting it as well as a great degree of explanatory power.
I'm not sure what you are trying to establish with this point, though.
If this is an experiment where self-replicating RNA molecules were formed starting from molecules that have been demonstrated to have been capable of forming in an abiotic environment, please link me to it. I am not aware of Q beta replicase being formed in abiotic environments.
I've noticed a series of moving goalposts within this discussion, this being the latest of them. It went from, "We have nothing" to, "Well, show me this very specific experiment". This lends your entire argument a "god-of-the-gaps" feel to it, which is very weak ground to stand on both rhetorically and philosophically. Simply because unknowns do exist does not mean that the entire structure is unknown, unknowable, or that we are unable to understand it. But if you want a demonstration of possibility, these self-replicating RNA contains nucleotides that could be created under the abiotic conditions described and the shortest of them, 165 nucleotides, is significantly shorter than other nucleotides which have been created under simulated pre-biotic environments (some of which have reached around 400 nucleotides in length). While not a rigorous proof by any means, that does serve as a proof of concept.
Ganapati wrote:Beg to differ. I find the evidence supporting it to be quite slim and its explanatory power being extremely limited.
I was trying to establish the point, not something else with it. Frankly I find it very uncomfortable when an unproven scientific hypothesis, like abiogenesis, and a valid scientific theory, like evolution, are mentioned in the same context with the same degree of conviction. When discussing abiogenesis, we can leave evolution completely out, since evolution comes into play only after the first self-replicating forms appear.
I am sorry you find that goalposts are being moved. When you mention something specific in response to a claim of nothing exists, why would you find it uncomfortable to show that the specific you mentioned meets the criteria?
But if all the components, nucleotides and the enzymes piecing them together to form the self-replicating RNA molecule are themselves known to be formed in pre-biotic environment and the only things controlled in the experiment were abiotic parameters, it would have demonstrated abiogenesis of some kind of life if not the one as we know it. If any of them is not known to have formed in a pre-biotic environment, it would have demonstrated little to someone who is not already assuming the validity of abiogenesis.
Xunzian wrote:Ganapati wrote:Beg to differ. I find the evidence supporting it to be quite slim and its explanatory power being extremely limited.
May I ask on what grounds you base that conclusion off of?
I am sorry you find that goalposts are being moved. When you mention something specific in response to a claim of nothing exists, why would you find it uncomfortable to show that the specific you mentioned meets the criteria?
I don't have a problem providing the information -- clearly, as I did provide the information. I merely wanted to point out the regression being employed in your argument before it gets out of hand.
But if all the components, nucleotides and the enzymes piecing them together to form the self-replicating RNA molecule are themselves known to be formed in pre-biotic environment and the only things controlled in the experiment were abiotic parameters, it would have demonstrated abiogenesis of some kind of life if not the one as we know it. If any of them is not known to have formed in a pre-biotic environment, it would have demonstrated little to someone who is not already assuming the validity of abiogenesis.
You are displaying an ignorance of biochemistry here. Enzymes are protein catalysts. The RNA world hypothesis doesn't involve enzymes, it involves ribozymes, which are nucleotide catalysts.
In this case, the ribozyme in question is an RNA polymerase which can replicate itself. What the paper describes is a self-replicating RNA molecule that is built from nucleotides which could have been present in the pre-biotic world and is short enough that it could have been generated in the pre-biotic world. As I said before, that seems a rather strong proof of concept in terms of the RNA world hypothesis within abiogenesis.
Ganapati wrote:May I ask on what grounds you believe abiogenesis has "a fair deal of evidence supporting it as well as a great degree of explanatory power"? In the end, until something is proven (and I don't think you are claiming abiogenesis to have been proven), whether the evidence supporting it is "fair deal" or "slim" and the explanatory power "great" or "limited" is a judgment call. If I wanted to convert you to my judgment, I may make such an attempt. Since I am not interested in whether you, or anyone else, believe(s) abiogensis is true or not, I don't see much point in discussing what are clearly subjective judgments on the same objective basis.
I am sorry you find that goalposts are being moved. When you mention something specific in response to a claim of nothing exists, why would you find it uncomfortable to show that the specific you mentioned meets the criteria?
I don't have a problem providing the information -- clearly, as I did provide the information. I merely wanted to point out the regression being employed in your argument before it gets out of hand.
There isn't any regression being employed. Abiogenesis will remain hypothetical until either a living cell is created in a simulated but exclusively pre-biotic environment or its probability of happening computed rigorously and shown to be close to 1 over geological time.
OK. So replace enzymes in what I said above with catalysts.
Are you referring to the higher probability of this self-replicating molecule being formed as one of the many possible random combinations of the nucleotides which were themselves capable of forming in a pre-biotic environment as opposed to a longer chain as "strong proof"?
Xunzian wrote:Ganapati wrote:May I ask on what grounds you believe abiogenesis has "a fair deal of evidence supporting it as well as a great degree of explanatory power"? In the end, until something is proven (and I don't think you are claiming abiogenesis to have been proven), whether the evidence supporting it is "fair deal" or "slim" and the explanatory power "great" or "limited" is a judgment call. If I wanted to convert you to my judgment, I may make such an attempt. Since I am not interested in whether you, or anyone else, believe(s) abiogensis is true or not, I don't see much point in discussing what are clearly subjective judgments on the same objective basis.
I mentioned this earlier and you've been avoiding it ever since. Your rhetoric is really, really shoddy. Bringing up spurious points which have already been addressed isn't just poor philosophy, it is weak rhetoric. Not hacking it philosophically and rhetorically is a sad thing indeed.
But since you've asked, I've provided some of the evidence supporting abiogenesis in this thread. This is in contrast to other hypotheses regarding the origin of life where the evidence is scant if existent at all. As for the explanatory power, the origin of life remains a mystery. However, abiogenesis takes what we do know about pre-biotic conditions on Earth, what we know about life as it presently exists on Earth, and basic chemistry and manages to synthesize those elements into a coherent narrative.
If that doesn't convince you, I'd be curious to know why.
I am sorry you find that goalposts are being moved. When you mention something specific in response to a claim of nothing exists, why would you find it uncomfortable to show that the specific you mentioned meets the criteria?
I don't have a problem providing the information -- clearly, as I did provide the information. I merely wanted to point out the regression being employed in your argument before it gets out of hand.There isn't any regression being employed. Abiogenesis will remain hypothetical until either a living cell is created in a simulated but exclusively pre-biotic environment or its probability of happening computed rigorously and shown to be close to 1 over geological time.
Kicking the goal-post once again, with the addition of a strawman! Really?
Are you referring to the higher probability of this self-replicating molecule being formed as one of the many possible random combinations of the nucleotides which were themselves capable of forming in a pre-biotic environment as opposed to a longer chain as "strong proof"?
Since you seem unable to synthesize the evidence on your own:
Under pre-biotic conditions:
1) RNA components are formed.
2) Reducing conditions result in polymerization
3) RNA molecules can reach a size of around 400nt.
Couple those with:
4) Self-replicating ribozymes as short as 140nt have been observed.
Now, all I've claimed is a proof-of-concept. I'd say that those elements do represent a rather solid proof-of-concept.
Which is substantially more than other hypotheses going for them . . .
tentative wrote:Coming in late on this, but... The ID game of numbers assumes one single instance of the right combination of molecules necessary to form self-replicating life. The numbers look overwhelmingly in favor of ID.
But if you introduce just a tiny bit of reason, the pre-biotic "primordial soup" wouldn't have just one each of the necessary molecules to begin life. The soup would have literally trillions of possible combinations when the correct conditions for life "arrived". The only miracle of life is if it HADN'T happened.
Ganapati wrote:tentative wrote:Coming in late on this, but... The ID game of numbers assumes one single instance of the right combination of molecules necessary to form self-replicating life. The numbers look overwhelmingly in favor of ID.
It is funny that those who believe in abiogenesis think the only reason it can be rejected is because someone is proposing an alternate hypothesis based on Intelligent Design. Any hypothesis can be rejected without proposing an alternate hypothesis either because the proposed hypothesis is not falsifiable and hence not scientific or because there isn't enough evidence to support it.But if you introduce just a tiny bit of reason, the pre-biotic "primordial soup" wouldn't have just one each of the necessary molecules to begin life. The soup would have literally trillions of possible combinations when the correct conditions for life "arrived". The only miracle of life is if it HADN'T happened.
But for some reason we cannot simulate the conditions and make even one such molecule happen in pre-biotic conditions.
tentative wrote:The numbers game used in the OP... What would be the purpose if not to discredit abiogenesis as possible? Gee, I wonder what the agenda behind those numbers might be?But if numbers used "scientifically" is useful, consider the potential opportunities given all the waters in all the oceans on the planet. The possible opportunities for abiogenesis to occur when conditions are right for self replicating life to appear is staggering. Why have all our efforts to replicate those conditions and create life failed? Experiments involving whole oceans and conducted over the period of a million years or so are a bit difficult to put together at this time. But you are right. Abiogenesis is just an unproven hypothesis and will likely remain such given the sheer magnitude of the necessary proofs. Still, failed experiments in a bathtub says nothing about an ocean. Yes, just a hypothesis, but it beats the hell out of anything else offered as explanation.
Ummm, reason alone suggests that the numbers game is bogus regardless the hypothesis. Any competent scientist isn't about to proclaim "rigorous" numbers. At best, the number is "large". the question isn't the numbers, it is the plausibility of the hypothesis matching up with what little we know. If one examines carefully the processes of early evolution of self replicating life forms, it isn't too difficult to suggest that that those processes had earlier precedents in the pre-biotic world. It seems more likely that abiogenesis is a bit more possible than a big guy in the sky.Ganapati wrote:tentative wrote:The numbers game used in the OP... What would be the purpose if not to discredit abiogenesis as possible? Gee, I wonder what the agenda behind those numbers might be?But if numbers used "scientifically" is useful, consider the potential opportunities given all the waters in all the oceans on the planet. The possible opportunities for abiogenesis to occur when conditions are right for self replicating life to appear is staggering. Why have all our efforts to replicate those conditions and create life failed? Experiments involving whole oceans and conducted over the period of a million years or so are a bit difficult to put together at this time. But you are right. Abiogenesis is just an unproven hypothesis and will likely remain such given the sheer magnitude of the necessary proofs. Still, failed experiments in a bathtub says nothing about an ocean. Yes, just a hypothesis, but it beats the hell out of anything else offered as explanation.
I am not so convinced about this "The possible opportunities for abiogenesis to occur when conditions are right for self replicating life to appear is staggering". Until someone rigorously calculates the opportunities to claim one way or the other is meaningless. However the fact that none of the supporters of abiogenesis, including scientists, actually come out with any rigorous numbers is highly suspcicious in itself.
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