A Critique of Miller-Urey and it's applications
Offline Miller Urey, while appearing to support spontaneous biogenesis, in actuality indicates the reverse. The model of the atmosphere was incorrect, the Oceanic "primordial soup" has never been shown to exist, the experiment itself was rigged for the production of organic molecules, and the published results were skewed by omitting some of the results.
The atmosphere of ancient Earth, according to Miller-Urey, was composed of Methane, Ammonia, and Water (with traces of Hydrogen.) This atmosphere is by no means the actual ancient Earth atmosphere: there are at least two other atmospheres that are considered, but are often discluded because of much lower yield of organic molecules. The atmosphere is also thought to have been Carbon Dioxide and Water, or Carbon Dioxide and Nitrogen, both of which are far less reductive, hence were not put to the Miller-Urey experiment.
R.C. Dowen has said:
"Now, for the first time in 30 years, the widely accepted recipe for the primordial soup is changing from one rich in hydrogen- composed primarily of methane and ammonia- to a Hydrogen-poor atmosphere similar to today's sans (minus) the Oxygen.
"No geological or geochemical evidence collected in the last 30 years favors a strongly reducing atmosphere....Only the success of the laboratory experiments recommends it.
"Scientists are having to rethink some of their assumptions. Chemists liked the old reducing atmosphere, for it was conductive to evolutionary experiments.
Another flaw in the atmosphere is that all exclude oxygen gas. Often Oxygen production is only produced by photosynthesis, but this is really an oversimplification. Oxygen has been known since the 60's to be produced at high altitudes with the effect of ultraviolet light on water in a process known as photolysis. R.T. Brinkman has calculated the bare minimum amount of free oxygen in the atmosphere and has concluded that Earth has always had at least a 5% Oxygen gas atmosphere. Other scientists, who are willing to let uniformitarianism fall by the wayside, compute levels ranging anywhere from 10 to the -1 to 10 to the -15, more or less evenly distributed throughout.
Now what does a disagreement of 14 powers of ten suggest? It suggests that these scientists haven't got a clue what they are talking about.
All this does not consider the various "organic" chemicals that were produced by Miller-Urey that impede life. Among the most prevalent of precursor molecules of monomer synthesis is HCN. While HCN is often attributed with much chemical synthesis, such as the amine of amino acids, its mere presence would be fatal to any precursor metabolisms because of cyanide's overkill reductive powers. In short, the monomers would have to form, then all of the HCN decompose to an extremely low level (parts per trillion at least) while still retaining all of the monomers, then and only then could a primitive life form develop.
Finally, there is doubt as to whether or not the "primordial soup" that Miller-Urey is designed to emulate. Brooks and Shaw in Origin and Development of Living Systems
"If there ever was a primitive soup, then we would expect to find at least somewhere on this planet either massive sediments containing enormous amounts of the various nitrogenous organic compounds, amino acids, purines, pyrimidines, and the like, or alternatively in much-metamorphosed sediments we should find vast amounts of nitrogenous cokes. In fact no such materials have been found anywhere on earth.
In the end, while experiments like Miller-Urey may have interesting results, they prove nothing if not linked to physical evidence from atmospheric studies or geochemistry. Primordial soup producing life is a myth that makes the Biblical Flood look docile and credible in comparison.
All references and most thoughts derived from The Mystery of Life's Origin by Charles Thaxton, Walter Bradley, and Roger Olsen.
"Truth is the cry of all, but the game of the few." George Berkeley
"Truth is always strange — stranger than fiction." Lord Byron
Fixing the world, one dumb idea at a time.
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Nonsense.
From wiki:
During recent years, studies have been made of the amino acid composition of the products of "old" areas in "old" genes, defined as those that are found to be common to organisms from several widely separated species, assumed to share only the last universal ancestor (LUA) of all extant species. These studies found that the products of these areas are enriched in those amino acids that are also most readily produced in the Miller-Urey experiment. This suggests that the original genetic code was based on a smaller number of amino acids -- only those available in prebiotic nature -- than the current one (Brooks et al. 2002).
************
The original experiment is more than half a century old, there's no surprise at all that their estimates have been corrected, updated, ect. This hardly refutes their concept, and its ridiculous to think that it speaks to 'the reverse'.
http://en.wikipedia.org/wiki/Miller-Urey#Earth.27s_early_atmosphere
"Hitler burned people like Anne Frank, for that we call him evil.
"God" burns Anne Frank eternally. For that, theists call him 'good.'
...And forget about all the Oxygen in the atmosphere?
...And forget the lack of evidence for any primordial soup?
...And forget the HCN?
Far from refuting me, selective refutation makes the bigger holes stand out clearer.
Refute me you can, but I would at least like the Oxygen explained, especially in a way that does not arbitrarily ignore uniformitarianism.
"Truth is the cry of all, but the game of the few." George Berkeley
"Truth is always strange — stranger than fiction." Lord Byron
Fixing the world, one dumb idea at a time.
There's a sizeable difference between:
"There are still gaps/mysteries that need explaining" and "the experiments are evidence against spontaneous abiogenesis"
Any biologist (including Mr Dawkins) will happily admit that abiogenesis is a mystery that still has scientists boggled. The question relevent to atheist vs theist is "is science's current failure to explain abiogenesis in natural conditions evidence in favour of a supernatural intervention?"
We have philosophical reasons to answer this question as a 'no'.
As far as I'm aware, all we know about supernatural is that it's not natural. We don't know anything about what it is. So to say that an event like abiogenesis was supernatural is to simply say that it has no natural cause. So significant evidence towards supernaturalism would be to:
1) Have considered all of the possibilities.
2) To have eliminated every last one of these possibilities.
I'm not sure if condition 1 will ever be satisfied as it requires some kind of omniscience. (the difficulty in proving a negative)
Normally we don't have to prove an absolute negative. Sometimes we just have to have an explanation that is more favourable, that has better evidence and/or less problems. However, supernatural explanations aren't favourable. If you say that abiogenesis was caused by a supernatural event then you need to explain what a supernatural event is. As far as I know, (perhaps you can correct me) we have no idea of what supernaturalism is, rather we just know what it isn't - we know that it isn't natural. It's like saying:
"It must've happened by magic"
"Really? What's magic?"
"Dunno... it can't be explained..."
So we can't appeal to supernatural explanations as better explanations because they aren't explanations at all. They are more of a resignation to the fact that no explanation is possible. So the only way to establish supernaturalism would be to absolutely prove a negative which I think is impossible in this case.
What's more, we have reason to believe that there is a physical cause, even if we don't know what this cause is exactly. There is an argument that all physical events require a physical cause. A physical event involves a transfer in energy. For a physical event to have no physical cause then the energy must've appeared spontaneously. This would contradict the laws of nature. So to deny physical closure (that all physical events have physical causes) is to deny the most fundamental laws of nature that all current science depends upon.
So although we admit that there plenty of holes in evolutionary theory that are yet to be explained, that isn't a problem for the theory as it is still our best explanation. And even if the theory of evolution was found to be false (which would be extremely surprising as it ties up and is supported by the whole of biology) it still wouldn't be evidence against naturalism/physicalism/materialism because of arguments like the one involving physical closure. Evolution vs Creationism is a political issue, not an intellectual one. The intellectual issue is Naturalism vs Supernaturalism.
Last time I checked the philosophical implications, derrivations, and sublties of the scientific method are not in the slightest related to the science of the Miller-Urey experiment. That may be true, but it is off topic, especially as that I never invoked any deity in my argument.
The problem is not that abiogenesis is not unexplained, but rather that it is closer to inexplicable. It ammounts to a deus ex machina saving grace for evolution as a theory of origins. The field of abiogenesis has made virtually no progress in the last thirty years and the few examples of what is said to be progress (most noteably self-replicating molecules) have been shown to prove nothing (of course when you put a fragment of any genetic convoy in a soup of its own components with specific enzymes for code replication, it is going to replicate. It is just a variant of PCR.)
So where does this leave us? Sure religion may never be "scientifically provable" but neither will evolution if 30 years of silence says anything. This reminds me of what one scientist said about artificial intelligence, that it should be dubbed "artificial optimism."
"Truth is the cry of all, but the game of the few." George Berkeley
"Truth is always strange — stranger than fiction." Lord Byron
Fixing the world, one dumb idea at a time.
At least according to the sources that I have run across, adjusting for better estimates of early earth atmosphere decreases the amount of amino acids produced, but does not eliminate them. I can provide some links if you wish.
www.caseagainstfaith.com
Yes, but we both know why this topic appeared in the "atheist vs theist" forum. The context of this criticism was to weaken naturalistic explanations of the origins of life to make a supernatural alternative more appealing. My point was that even if your best case scenario happened, that a natural abiogenesis was found to be an unsolvable mystery, it still wouldn't be evidence for a non-natural cause. It would be a case that the natural cause responsible for 'first life' would be beyond our knowledge because our knowledge of what the world was like a billion years ago is too incomplete for us to have access to such specific details.
Not quite. Firstly, the theory of evolution is that life has evolved gradually and abiogenesis is a seperate issue. Secondly, I've given you the reason why we have judged that whatever caused life, it had to be a natural event. That's all scientists are assuming here - that it's a natural event.
30 years is a small amount of time in the process of scientific discovery.
That abiogenesis was a natural event is metaphysical necessity. It's as proven as the closure of physical causes and that, as I understand it, is backed by the most fundamental laws of physics. (energy conservation and the uniformity of space-time)
Another thing I should point out is that our criticisms of religion aren't down to a lack of scientific proof. There are clearly things we all believe in without scientific proof. Our concerns on religious belief go a lot deeper. I think that a quote from kmisho sums things up nicely.
The problem is not that abiogenesis is not unexplained, but rather that it is closer to inexplicable. It ammounts to a deus ex machina saving grace for evolution as a theory of origins.
Evolutionary theory explains how life evolved from proto-cellular organisms, and that every living thing has a common descent lineage to a primordial cell/genome. Where that cell/genome came from is another matter entirely.
"Physical reality” isn’t some arbitrary demarcation. It is defined in terms of what we can systematically investigate, directly or not, by means of our senses. It is preposterous to assert that the process of systematic scientific reasoning arbitrarily excludes “non-physical explanations” because the very notion of “non-physical explanation” is contradictory.
-Me
Books about atheism
The Miller-Urey experiment has been repeated numerous times under different conditions and the results have still produced amino acids. So unless you'll actually present something that refutes it then there isn't much to talk about is there?
Here's one article from an actual university (not the joke of facility called the Discovery Institute) that refutes your claim.
http://news-info.wustl.edu/news/page/normal/5513.html
There's nothing in any update on the original experiment that speaks to the 'opposite' conclusion, and seeing as this was your claim, you don't have any facts to stand on....
Yes. I am glad everyone here immediately sees the dishonesty in his post.... So much for his claim...
"Hitler burned people like Anne Frank, for that we call him evil.
"God" burns Anne Frank eternally. For that, theists call him 'good.'
And what do you base this claim on? Your own awareness of the situation.
And so the next question that should be asked is: what are your credentials?
So far, all you have here is an argument from ignorance.
I hope you're able to work out the irony here in your own statement..... You're actually projecting the very flaw of theistic answers, onto naturalism.
It is theism that can says "We don't know, ergo goddidit' This is precisely what a deux ex machina is.
Big statement, but no reference.
So, what are your credentials?
1) abiogenesis is not evolution
2) You've not demonstrated that there has been 30 years of silence regarding abiogenesis.
3) You've not demonstrated that a current lack of a satisfying answer grants you any epistemic grounds for rejecting naturalism for supernaturalism.
4) You've not even attempted to deal with the incoherence of supernatural claims.
I could go on... but why?
"Hitler burned people like Anne Frank, for that we call him evil.
"God" burns Anne Frank eternally. For that, theists call him 'good.'
I doubt that anyone who cites the Discovery Institute is interested in learning all the facts.... C S Lewis? Come on, even other apologists crank on Lewis...
"Hitler burned people like Anne Frank, for that we call him evil.
"God" burns Anne Frank eternally. For that, theists call him 'good.'
The case for oxygen interfering with abiogenesis in the Miller-Urey model.
I had thought I had properly explained this,but I appear to really suck at conveying problems. Miller-Urey cannot be used to account for abiogenesis in any way as that it does not properly model the atmosphere.
Oxygen production is usually attributed to photosynthesis, but in the 60's it was discovered that UV light in the stratosphere breaks down water to produce Hydrogen and Oxygen in a process now called "photolysis." In other words, any water-vapor content in an atmosphere exposed to UV light (a fairly easy to see combination) will inevitably yeild Oxygen.
As cited earlier, using uniformitarianism a scientist computed a minimum constant Oxygen content of Earth at 5% (actually 5.25, but who cares?)
Miller-Urey did not include Oxygen (or constant exposure to it, as would be the case if Oxygen was an atmospheric gas) and none of the other replication experiments have either for a very basic reason: Oxygen is so electronegative that any decent presence will prevent any molecule synthesis at all, especially if it is in the form of the diatomic Oxygen gas formed by photolysis.
In other words, rather than the atmosphere Miller-Urey used of Ammonia, Methane, and Water, the atmosphere should have been Nitrogen (N2), Oxygen, and some traces of other gases with a salt-water base.
Miller and Urey were not stupid, they knew that a spark under conditions like this will not yeild organic molecules - perhaps some Nitrogen Dioxides, some Carbon Monoxide, but nothing useful for life.
Miller-Urey isn't a model of Earth's early atmosphere, it is a rigged experiment to produce pseudo-organic molecules.
"Truth is the cry of all, but the game of the few." George Berkeley
"Truth is always strange — stranger than fiction." Lord Byron
Fixing the world, one dumb idea at a time.
I'm not the best on chemistry here, but I was under the impression that oxygen was actually a part of many amino acids, nucleotides and polypeptides.
Can someone point me to a resource that shows how the presence of oxygen prevents the formation of organic molecules? Certainly oxygen is electronegative, but this just means that electrons will attract to it, this doesn't seem to imply the immediate destruction of chemical formation, but seems to imply that it would drive chemical reaction.
The Regular Expressions of Humanistic Jones: Where one software Engineer will show the world that God is nothing more than an undefined pointer.
Actually, your suckage comes in when you attempt to properly understand the 'problem'. Why don't you stop citing a christian apologist site and actually read into what scientists say?
"Hitler burned people like Anne Frank, for that we call him evil.
"God" burns Anne Frank eternally. For that, theists call him 'good.'
First off, there is no room for ad hominems in any kind of debate. I do not appreciate that, and I am hopeful that in the future a moderator such as yourself will not utilize such question begging epithets.
Furthermore, in case you are not aware, Charels Thaxton, the person who I am getting most of this argument from (and whom I have met in person) is a PhD in Chemistry, so I am quoting a scientist and not some random website that says something I like in some manner that sounds somewhat educated. My initial post was fully cited to boot, so I take it that you have already forgotten that.
PS: What about that Oxygen?
"Truth is the cry of all, but the game of the few." George Berkeley
"Truth is always strange — stranger than fiction." Lord Byron
Fixing the world, one dumb idea at a time.
What about the Oxygen?
Being that I don't have alot of paleogeological periodicals and books around, I have to rely on wikipedia and its information. By what is there, the earth has gone through three primary atmospheric phases.
First Atmosphere: Hydrogen, Helium and Dust from the residue of the planetary nebula.
Second Atmosphere: About 4.4 billion years ago, the surface had cooled enough to form a crust, still heavily populated with volcanoes which released steam, carbon dioxide, and ammonia. This led to the early "second atmosphere", which was primarily carbon dioxide and water vapor, with some nitrogen but virtually no oxygen. This second atmosphere had approximately 100 times as much gas as the current atmosphere. (this would be the atmosphere abiogenisis would occur under. So really the question is, what oxygen to worry about?)
Third Atmosphere: You are breathing it now.
So I guess I have to wonder why there is a concern for there not being enough oxygen in the simulation.
The Regular Expressions of Humanistic Jones: Where one software Engineer will show the world that God is nothing more than an undefined pointer.
From http://www.talkorigins.org/faqs/wells/iconob.html#Prebiotic-Oxygen
which is a critique of Jonathan Wells' book, _Icons of Evolution_, which gives the same argument as you are giving about the Miller-Ulrey experiments:
Prebiotic Oxygen. A key question in origin-of-life research is the oxidation state of the prebiotic atmosphere (the current best guess is that the origin of life occurred somewhere around 4.0-3.7 bya (billion years ago)). Wells wants you to think that there is good evidence for significant amounts free oxygen in the prebiotic atmosphere (significant amounts of free oxygen make the atmosphere oxidizing and make Miller-Urey-type experiments fail). He spends several pages (14-19) on a pseudo-discussion of the oxygen issue, citing sources from the 1970's and writing that (p. 17) "the controversy has never been resolved", that "Evidence from early rocks has been inconclusive," and concluding that the current geological consensus -- that oxygen was merely a trace gas before approximately 2.5 bya and only began rising after this point -- was due to "Dogma [taking] the place of empirical evidence" (p. 18). None of this is true (see e.g. Copley, 2001).
Certain minerals, such as uraninite, cannot form under significant exposure to oxygen. Thick deposits of these rocks are found in rocks older than 2.5 bya years ago, indicating that essentially no oxygen (only trace amounts) was present. On page 17 Wells notes that uraninite deposits have been found in more recent rocks, but neglects to mention to his readers that these only occur under rapid-burial conditions, whereas ancient deposits of uraninite occur in slow deposition conditions, for example in sediments laid down by rivers, so that the minerals were exposed to atmospheric gases for significant periods of time before burial.
'Red beds' are geologic features containing highly oxidized iron (rust) indicative of high amounts of oxygen. Wells (p. 17) notes that red beds are found before 2 bya, but fails to mention that the temporal limit of red beds is just a few hundred million years before 2 bya.
Wells doesn't even mention the evidence that banded iron formations (incompletely oxidized iron indicative of ultralow-oxygen conditions) are very common prior to 2.3 bya and very rare afterwards.
Wells also doesn't mention that early paleosols (fossil soils) from about ~2.5 bya contain unoxidized cerium, impossible in an oxygenic atmosphere (e.g., Murakami et al., 2001).
Finally, Wells doesn't mention to his readers that pyrite, a mineral even more vulnerable to oxidation than uraninite, is found unoxidized in pre-2.5 bya rocks, and with significant evidence of long surface exposure (i.e. grains weathered by water erosion; e.g. Rasmussen and Buick, 1999).
Why does Wells leave out the converging independent lines of geological evidence pointing to an anoxic early (pre ~2.5 bya) atmosphere?
Was the prebiotic atmosphere reducing? Are the Miller-Urey experiments "irrelevant"? The famous Miller-Urey experiments used a strongly reducing atmosphere to produce amino acids. It is important to realize that the original experiment is famous not so much for the exact mixture used, but for the unexpected discovery that such a simple experiment could indeed produce crucial biological compounds; this discovery instigated a huge amount of related research that continues today.
Now, current geochemical opinion is that the prebiotic atmosphere was not so strongly reducing as the original Miller-Urey atmosphere, but opinion varies widely from moderately reducing to neutral. Completely neutral atmospheres would be bad for Miller-Urey-type experiments, but even a weakly reducing atmosphere will produce lower but significant amounts of amino acids. In the approximately two pages of text where Wells actually discusses the reducing atmosphere question (p. 20-22), Wells cites some more 1970's sources and then asserts that the irrelevance of the Miller-Urey experiment has become a "near-consensus among geochemists" (p. 21).
This statement is misleading. What geochemists agree on is that if the early earth's mantle was of the same composition as the modern mantle and if only terrestrial volcanic sources are considered as contributing to the atmosphere, and if the temperature profile of the early atmosphere was the same as modern earth (this is relevant to rates of hydrogen escape) then there will be much less hydrogen compared to Miller's first atmosphere (20% total atm.). Even if this worst-case scenario is accepted, hydrogen will not be completely absent, in fact there is a long list of geochemists that consider hydrogen to have been present (although in lower amounts, roughly 0.1-1% of the total atmosphere). At these levels of H2 there is still significant (although much lower) amino acid production.
Also, many geochemists think that these conditions do not represent the early earth, contrary to the impression given by Wells. For example, on p. 20, Wells mentions terrestrial volcanos emitting neutral gases (H2O, CO2, N2, and only trace H2), but he fails to mention that mid-ocean ridge vents could have been significant sources of reduced gases -- they are important sources of reduced atmospheric gases even today, emitting about 1% methane (Kasting and Brown, 1998) and producing reduced hydrogen and hydrogen sulfide (e.g. Kelley et al., 2001; Perkins, 2001; Von Damm, 2001) and potentially ammonia prebiotically (Brandes et al., 1998; Chyba, 1998). Why does Wells exclude oceanic vents from consideration?
Another strange omission is that Wells completely fails to mention the extraterrestrial evidence, which is the only direct evidence we have of the kinds of chemical reactions that might have occurred in the early solar system. For example he neglects to mention the famous Murchison meteorite, which contains mixtures of organic compounds much like those produced in Miller-Urey style experiments, and which constitutes direct evidence that just the right kind of prebiotic chemistry was occurring at least somewhere in the early solar system, and that some of those products found their way to earth (see e.g. Engel and Macko, 2001 for a recent review).
Wells asserts that since the 1970's, non-reducing atmospheres have become the "near-consensus." The latest article that Wells cites supporting this view, however, is a 1995 nontechnical news article in Science (Cohen, 1995). Why doesn't he quote Kral et al. (1998), who write,
None of this is meant to convey the impression that no controversies exist (both Cohen (1995) and the Davis and McKay (1996) article cited by the above-quoted Kral et al. (1998) are about the various competing hypotheses about the origin of life). But textbooks generally mention some of these hypotheses (briefly of course, as there is only space for a page or two on this topic in an introductory textbook), and furthermore generally mention that the original atmosphere was likely more weakly reducing than the original Miller-Urey experiment hypothesized, but that many variations with mildly reducing conditions still produce satisfactory results. This is exactly what is written in the most popular college biology textbook, Campbell et al.'s (1999) Biology, for instance. In other words, the textbooks basically summarize what the recent literature is saying. The original Miller-Urey experiment, despite its limitations, is also repeatedly cited in modern scientific literature as a landmark experiment. So why does Wells have a problem with the textbooks following the literature? Wells wants textbooks to follow the experts, and it appears that they are.
www.caseagainstfaith.com
This is from another critique of Wells':
http://www.ncseweb.org/icons/icon1millerurey.html
The experiment itself
The understanding of the origin of life was largely speculative until the 1920s, when Oparin and Haldane, working independently, proposed a theoretical model for "chemical evolution." The Oparin-Haldane model suggested that under the strongly reducing conditions theorized to have been present in the atmosphere of the early earth (between 4.0 and 3.5 billion years ago), inorganic molecules would spontaneously form organic molecules (simple sugars and amino acids). In 1953, Stanley Miller, along with his graduate advisor Harold Urey, tested this hypothesis by constructing an apparatus that simulated the Oparin-Haldane "early earth." When a gas mixture based on predictions of the early atmosphere was heated and given an electrical charge, organic compounds were formed (Miller, 1953; Miller and Urey, 1959). Thus, the Miller-Urey experiment demonstrated how some biological molecules, such as simple amino acids, could have arisen abiotically, that is through non-biological processes, under conditions thought to be similar to those of the early earth. This experiment provided the structure for later research into the origin of life. Despite many revisions and additions, the Oparin-Haldane scenario remains part of the model in use today. The Miller-Urey experiment is simply a part of the experimental program produced by this paradigm.
Wells boils off
Wells says that the Miller-Urey experiment should not be taught because the experiment used an atmospheric composition that is now known to be incorrect. Wells contends that textbooks don't discuss how the early atmosphere was probably different from the atmosphere hypothesized in the original experiment. Wells then claims that the actual atmosphere of the early earth makes the Miller-Urey type of chemical synthesis impossible, and asserts that the experiment does not work when an updated atmosphere is used. Therefore, textbooks should either discuss the experiment as an historically interesting yet flawed exercise or not discuss it at all. Wells concludes by saying that textbooks should replace their discussions of the Miller-Urey experiment with an "extensive discussion" of all the problems facing research into the origin of life.
These allegations might seem serious; however, Wells's knowledge of prebiotic chemistry is seriously flawed. First, Wells's claim that researchers are ignoring the new atmospheric data, and that experiments like the Miller-Urey experiment fail when the atmospheric composition reflects current theories, is simply false. The current literature shows that scientists working on the origin and early evolution of life are well aware of the current theories of the earth's early atmosphere and have found that the revisions have little effect on the results of various experiments in biochemical synthesis. Despite Wells's claims to the contrary, new experiments since the Miller-Urey ones have achieved similar results using various corrected atmospheric compositions (Figure 1; Rode, 1999; Hanic et al., 2000). Further, although some authors have argued that electrical energy might not have efficiently produced organic molecules in the earth's early atmosphere, other energy sources such as cosmic radiation (e.g., Kobayashi et al., 1998), high temperature impact events (e.g., Miyakawa et al., 2000), and even the action of waves on a beach (Commeyras, et al., 2002) would have been quite effective.
Even if Wells had been correct about the Miller-Urey experiment, he does not explain that our theories about the origin of organic "building blocks" do not depend on that experiment alone (Orgel, 1998a). There are other sources for organic "building blocks," such as meteorites, comets, and hydrothermal vents. All of these alternate sources for organic materials and their synthesis are extensively discussed in the literature about the origin of life, a literature that Wells does not acknowledge. In fact, what is most striking about Wells's extensive reference list is the literature that he has left out. Wells does not mention extraterrestrial sources of organic molecules, which have been widely discussed in the literature since 1961 (see Oró, 1961; Whittet, 1997; Irvine, 1998). Wells apparently missed the vast body of literature on organic compounds in comets (e.g. Oró, 1961; Anders, 1989; Irvine, 1998), carbonaceous meteorites (e.g. Kaplan et al., 1963; Hayes, 1967; Chang, 1994; Maurette, 1998; Cooper et al., 2001), and conditions conducive to the formation of organic compounds that exist in interstellar dust clouds ( Whittet, 1997).
Wells also fails to cite the scientific literature on other terrestrial conditions under which organic compounds could have formed. These non-atmospheric sources include the synthesis of organic compounds in a reducing ocean (e.g., Chang, 1994), at hydrothermal vents (e.g., Andersson, 1999; Ogata et al., 2000), and in volcanic aquifers (Washington, 2000). A cursory review of the literature finds more than 40 papers on terrestrial prebiotic chemical synthesis published since 1997 in the journal Origins of life and the evolution of the biosphere alone. Contrary to Wells's presentation, there appears to be no shortage of potential sources for organic "building blocks" on the early earth.
Instead of discussing this literature, Wells raises a false "controversy" about the low amount of free oxygen in the early atmosphere. Claiming that this precludes the spontaneous origin of life, he concludes that "[d]ogma had taken the place of empirical science" (Wells 2000:18). In truth, nearly all researchers who work on the early atmosphere hold that oxygen was essentially absent during the period in which life originated (Copley, 2001) and therefore oxygen could not have played a role in preventing chemical synthesis. This conclusion is based on many sources of data, not "dogma." Sources of data include fluvial uraninite sand deposits (Rasmussen and Buick, 1999) and banded iron formations (Nunn, 1998; Copley, 2001), which could not have been deposited under oxidizing conditions. Wells also neglects the data from paleosols (ancient soils) which, because they form at the atmosphere-ground interface, are an excellent source to determine atmospheric composition (Holland, 1994). Reduced paleosols suggest that oxygen levels were very low before 2.1 billion years ago (Rye and Holland, 1998). There are also data from mantle chemistry that suggest that oxygen was essentially absent from the earliest atmosphere (Kump et al. 2001). Wells misrepresents the debate as over whether oxygen levels were 5/100 of 1%, which Wells calls "low," or 45/100 of 1%, which Wells calls "significant." But the controversy is really over why it took so long for oxygen levels to start to rise. Current data show that oxygen levels did not start to rise significantly until nearly 1.5 billion years after life originated (Rye and Holland, 1998; Copley, 2001). Wells strategically fails to clarify what he means by "early" when he discusses the amount of oxygen in the "early" atmosphere. In his discussion he cites research about the chemistry of the atmosphere without distinguishing whether the authors are referring to times before, during, or after the period when life is thought to have originated. Nearly all of the papers he cites deal with oxygen levels after 3.0 billion years ago. They are irrelevant, as chemical data suggest that life arose 3.8 billion years ago (Chang, 1994; Orgel, 1998b), well before there was enough free oxygen in the earth's atmosphere to prevent Miller-Urey-type chemical synthesis.
Finally, the Miller-Urey experiment tells us nothing about the other stages in the origin of life, including the formation of a simple genetic code (PNA or "peptide"-based codes and RNA-based codes) or the origin of cellular membranes (liposomes), some of which are discussed in all the textbooks that Wells reviewed. The Miller-Urey experiment only showed one possible route by which the basic components necessary for the origin of life could have been created, not how life came to be. Other theories have been proposed to bridge the gap between the organic "building blocks" and life. The "liposome" theory deals with the origin of cellular membranes, the RNA-world hypothesis deals with the origin of a simple genetic code, and the PNA (peptide-based genetics) theory proposes an even simpler potential genetic code (Rode, 1999). Wells doesn't really mention any of this except to suggest that the "RNA world" hypothesis was proposed to "rescue" the Miller-Urey experiment. No one familiar with the field or the evidence could make such a fatuous and inaccurate statement. The Miller-Urey experiment is not relevant to the RNA world, because RNA was constructed from organic "building blocks" irrespective of how those compounds came into existence (Zubay and Mui, 2001). The evolution of RNA is a wholly different chapter in the story of the origin of life, one to which the validity of the Miller-Urey experiment is irrelevant.
What the textbooks say
All of the textbooks reviewed contain a section on the Miller-Urey experiment. This is not surprising given the experiment's historic role in the understanding of the origin of life. The experiment is usually discussed over a couple of paragraphs (see Figure 2), a small proportion (roughly 20%) of the total discussion of the origin and early evolution of life. Commonly, the first paragraph discusses the Oparin-Haldane scenario, and then a second outlines the Miller-Urey test of that scenario. All textbooks contain either a drawing or a picture of the experimental apparatus and state that it was used to demonstrate that some complex organic molecules (e.g., simple sugars and amino acids, frequently called "building blocks"
could have formed spontaneously in the atmosphere of the early earth. Textbooks vary in their descriptions of the atmospheric composition of the early earth. Five books present the strongly reducing atmosphere of the Miller-Urey experiment, whereas the other five mention that the current geochemical evidence points to a slightly reducing atmosphere. All textbooks state that oxygen was essentially absent during the period in which life arose. Four textbooks mention that the experiment has been repeated successfully under updated conditions. Three textbooks also mention the possibility of organic molecules arriving from space or forming at deep-sea hydrothermal vents (Figure 2). No textbook claims that these experiments conclusively show how life originated; and all textbooks state that the results of these experiments are tentative.
It is true that some textbooks do not mention that our knowledge of the composition of the atmosphere has changed. However, this does not mean that textbooks are "misleading" students, because there is more to the origin of life than just the Miller-Urey experiment. Most textbooks already discuss this fact. The textbooks reviewed treat the origin of life with varying levels of detail and length in "Origin of life" or "History of life" chapters. These chapters are from 6 to 24 pages in length. In this relatively short space, it is hard for a textbook, particularly for an introductory class like high school biology, to address all of the details and intricacies of origin-of-life research that Wells seems to demand. Nearly all texts begin their origin of life sections with a brief description of the origin of the universe and the solar system; a couple of books use a discussion of Pasteur and spontaneous generation instead (and one discusses both). Two textbooks discuss how life might be defined. Nearly all textbooks open their discussion of the origin of life with qualifications about how the study of the origin of life is largely hypothetical and that there is much about it that we do not know.
Wells's evaluation
As we will see in his treatment of the other "icons," Wells's criteria for judging textbooks stack the deck against them, ensuring failure. No textbook receives better than a D for this "icon" in Wells's evaluation, and 6 of the 10 receive an F. This is largely a result of the construction of the grading criteria. Under Wells's criteria (Wells 2000:251-252), any textbook containing a picture of the Miller-Urey apparatus could receive no better than a C, unless the caption of the picture explicitly says that the experiment is irrelevant, in which case the book would receive a B. Therefore, the use of a picture is the major deciding factor on which Wells evaluated the books, for it decides the grade irrespective of the information contained in the text! A grade of D is given even if the text explicitly points out that the experiment used an incorrect atmosphere, as long as it shows a picture. Wells pillories Miller and Levine for exactly that, complaining that they bury the correction in the text. This is absurd: almost all textbooks contain pictures of experimental apparatus for any experiment they discuss. It is the text that is important pedagogically, not the pictures. Wells's criteria would require that even the intelligent design "textbook" Of Pandas and People would receive a C for its treatment of the Miller-Urey experiment.
In order to receive an A, a textbook must first omit the picture of the Miller-Urey apparatus (or state explicitly in the caption that it was a failure), discuss the experiment, but then state that it is irrelevant to the origin of life. This type of textbook would be not only scientifically inaccurate but pedagogically deficient.
Why we should still teach Miller-Urey
The Miller-Urey experiment represents one of the research programs spawned by the Oparin-Haldane hypothesis. Even though details of our model for the origin of life have changed, this has not affected the basic scenario of Oparin-Haldane. The first stage in the origin of life was chemical evolution. This involves the formation of organic compounds from inorganic molecules already present in the atmosphere and in the water of the early earth. This spontaneous organization of chemicals was spawned by some external energy source. Lightning (as Oparin and Haldane thought), proton radiation, ultraviolet radiation, and geothermal or impact-generated heat are all possibilities.
The Miller-Urey experiment represents a major advance in the study of the origin of life. In fact, it marks the beginning of experimental research into the origin of life. Before Miller-Urey, the study of the origin of life was merely theoretical. With the advent of "spark experiments" such as Miller conducted, our understanding of the origin of life gained its first experimental program. Therefore, the Miller-Urey experiment is important from an historical perspective alone. Presenting history is good pedagogy because students understand scientific theories better through narratives. The importance of the experiment is more than just historical, however. The apparatus Miller and Urey designed became the basis for many subsequent "spark experiments" and laid a groundwork that is still in use today. Thus it is also a good teaching example because it shows how experimental science works. It teaches students how scientists use experiments to test ideas about prehistoric, unobserved events such as the origin of life. It is also an interesting experiment that is simple enough for most students to grasp. It tested a hypothesis, was reproduced by other researchers, and provided new information that led to the advancement of scientific understanding of the origin of life. This is the kind of "good science" that we want to teach students.
Finally, the Miller-Urey experiment should still be taught because the basic results are still valid. The experiments show that organic molecules can form under abiotic conditions. Later experiments have used more accurate atmospheric compositions and achieved similar results. Even though origin-of-life research has moved beyond Miller and Urey, their experiments should be taught. We still teach Newton even though we have moved beyond his work in our knowledge of planetary mechanics. Regardless of whether any of our current theories about the origin of life turn out to be completely accurate, we currently have models for the processes and a research program that works at testing the models.
How textbooks could improve their presentations of the origin of life
Textbooks can always improve discussions of their topics with more up-to-date information. Textbooks that have not already done so should explicitly correct the estimate of atmospheric composition, and accompany the Miller-Urey experiment with a clarification of the fact that the corrected atmospheres yield similar results. Further, the wealth of new data on extraterrestrial and hydrothermal sources of biological material should be discussed. Finally, textbooks ideally should expand their discussions of other stages in the origin of life to include PNA and some of the newer research on self-replicating proteins. Wells, however, does not suggest that textbooks should correct the presentation of the origin of life. Rather, he wants textbooks to present this "icon" and then denigrate it, in order to reduce the confidence of students in the possibility that scientific research can ever establish a plausible explanation for the origin of life or anything else for that matter. If Wells's recommendations are followed, students will be taught that because one experiment is not completely accurate (albeit in hindsight), everything else is wrong as well. This is not good science or science teaching.
www.caseagainstfaith.com
Okay, I've given two sources that argue against the claims of this thread. It is true that I'm not a scientist. And therefore, as a layman, I cannot personally testify as to whether Wells is more accurate, or his critics. That said, I have reasons to believe my sources are more reliable. Some are, indeed bias. I generally find Creationists dishonest.
But, not all my reasons are bias. For example, if these other articles were off base, and Wells is really right, then it should be fairly easy for Wells to demonstrate this, and send his critics packing. The fact is, I never see any exchange by Creationists, meaning, if a counter-argument to a Creationist claim is made, the Creationist seems to never adjust their argument to explain why the counter-argument fails; they just keep repeating their original argument ignoring the counter-claims. At least that is my experience.
Additionally, even if Wells is right, and the Miller-Ulrey experiments are a complete flop, evolution, a separate topic, is beyond debate. Even Dr. Behe, author of _Darwin's Black Box_, accepts evolution and just denies abiogenesis. But Behe's "God" is very peculiar, creating first life forms and letting everything evolve from there. Such a diety isn't theoretically impossible, just merely preposterous.
www.caseagainstfaith.com
??? I never quoted or even cited Wells, so whatever makes you think that a refutation of him will have the slightest influence on my argument?
Even if there is an Oxygen rich atmosphere, there are plenty of anerobic environments, but most require either geologic activity to force the air out of the area, or areobic respiration to use it all up, niether of which are particularly conducive to the Miller-Urey situation for abiogenesis.
As that you haven't even touched on photolysis, I will assume that there is Oxygen to show why it is impossible to synthesize anything.
Miller-Urey has a highly reductive atmosphere, so when exposed to energy the molecules will tend to form larger molecules as that there is no real potential for lowering energy potential. Introduce an oxidizer (like Oxygen) and that changes. When an energy spike (ie lightning, etc) causes a reaction, it will take whatever large molecules there are and produce smaller waste molecules like carbon dioxide and water from methane, and a very stable diatomic Nitrogen and water from ammonia. Such conditions are not coducive for life forming, it is almost identical to the modern atmosphere of Nitrogen ans Oxygen, which requires Nitrogen fixing bacteria or a plant with very high osmotic pressure to gather any significant ammount of nitrates.
"Truth is the cry of all, but the game of the few." George Berkeley
"Truth is always strange — stranger than fiction." Lord Byron
Fixing the world, one dumb idea at a time.
Because Wells uses the same argument, that's why.
Per the articles, prebiotic atmosphere was virtually oxygen free.
Per the articles, there are many possible sources of environments capable of Miller-Urey style creation of amino acids. And, the discovered meteor with those types of compounds prove that such conditions exist at least SOMEWHERE, and do make it to the earth.
True, the articles I posted did not address this argument of yours. Then again, your posts do not address the counter-evidence: If your source is correct, that there must have always been at least a fair amount of oxygen in the atmosphere, what explains the evidences that indicate there was no oxygen in the very early period of the earth? And, again, even if you are right, the meteor found shows that conditions existed SOMEWHERE.
www.caseagainstfaith.com
SVT, how can you argue that the atmosphere at the time of the origin of life was similar to today's when most of the oxygen in today's atmosphere comes from plants? I understand that there are other mechanisms that create oxygen, but the fact is that plants are belching oxygen into the atmosphere all the time and you have to account for where all that oxygen would come from in an era before green plants.
Lazy is a word we use when someone isn't doing what we want them to do.
- Dr. Joy Brown
To be accurate, SVT didn't say the atmosphere was similar to today, just that it had more O2 than Miller-Ulrey experiments would allow for. Here was the argument:
I don't at this moment have any counterarguments directly related to Brinkman's claim, other than the evidence that I already posted which seems to indicate that prebiotic earth atmosphere was oxygen free.
www.caseagainstfaith.com
There was no ad hominem. You're confused. You brought up 'sucking' and hypothesized one reason for it. I proposed another: its not that you are not explaining yourself well, its that you are totally unprepared to discuss this topic as you've not even done a cursory exploration of what mainstream science (your opposition) has to say.
I'd appreciate it if you learned what an ad hominem is before attemtping to accuse someone of committing it.... There was no ad hominem. It was merely pointed out to you that you ought to consider what mainstream science has to say.
Your problem is that you are selectively reading only one source. That's not critical thinking. You have not actually read what mainstream science has to say. This is the point being made to you. This is not an ad hominem argument. It is a request that you actually broaden your understanding of the topic you wish to 'debate'.
Again, if you actually read a mainstream scientist concering the actual reality of the situation, you'd already have your answer. In fact, you yourself ought to be able to already tell me how mainstream science answers this question. You shouldn't be learning the answer, for the first time, during your 'debate'.
By the way, your own, singular source for this debate comes from 1984 (why didn't you cite the year?) Any reason why you are relying on decades old information concerning such a speculative science? How can we interpret your '30 years' comment correctly if it was written 23 years ago?
"Hitler burned people like Anne Frank, for that we call him evil.
"God" burns Anne Frank eternally. For that, theists call him 'good.'
Because the same argument is being used....
Case, thanks for your post. Our friend can read what mainstream science actually has to say, for the <I>very first time </I> which is something a debater never, ever, EVER ought to be doing in the midst of a 'debate'....
"Hitler burned people like Anne Frank, for that we call him evil.
"God" burns Anne Frank eternally. For that, theists call him 'good.'
I wonder how that fact escaped SVT?
But, par for the course in a theist debate...
www.caseagainstfaith.com
Like I said, though, all of your argument points are minerals (Iron oxide, Pyrite, Iron Beds, and Uraniumites) Mineral formation does not have to occur on earth's surface, it is far more common in submerged magma chambers where Oxygen presence even on a planet with an Oxygen rich atmosphere would be a surprise.
On a similar note, if we can infer things about a planet's past atmosphere by looking at the rocks, why does Mars have Iron Oxide dust all over the place when the present theories all say that it never had free Oxygen gas?
I know that that kinda leans in your favor, but it illustrates my point that mineral formation and atmosphere are probably not corrolatable.
So...any other evidences for an Oxygen poor atmosphere?
"Truth is the cry of all, but the game of the few." George Berkeley
"Truth is always strange — stranger than fiction." Lord Byron
Fixing the world, one dumb idea at a time.
It didn't. If you read his comment without bothering to critically examine it, it sounds like he's countered your point, and that's all he really seems interested in...
I've also now seen that his sole source for this 'debate' comes from a work written in 1984 - no doubt its been 'updated' but I don't see how anyone can enter into a debate concerning a speculative science with a decades old source written by someone with a extreme bias: creationism.
"Hitler burned people like Anne Frank, for that we call him evil.
"God" burns Anne Frank eternally. For that, theists call him 'good.'
"R.C. Dowen has said:
"Now, for the first time in 30 years, the widely accepted recipe for the primordial soup is changing from one rich in hydrogen- composed primarily of methane and ammonia- to a Hydrogen-poor atmosphere similar to today's sans (minus) the Oxygen.
"No geological or geochemical evidence collected in the last 30 years favors a strongly reducing atmosphere....Only the success of the laboratory experiments recommends it."
I was trying to qualify this one and can't seem to find anything on R.C. Dowens. As a matter of fact, when I googled him this thread was the 1st to come up. Speling eror?
The quote is a mystery as well. Sir Vailant, could you tell us more about R.C. Dowen? I hope you're not quoting the paper boy.
Yeah. Amazon lists the hardback published in '84, and the paperback in '92. It doesn't indicate the paperback is a revised edition, but even if it was a revised edition, that's still 15 years ago. And given that the book doesn't seem to get much press from even Creationists -- SVT is the first I've heard of it -- makes it all the more suspicious.
Of course I accept that scientists can make mistakes, and that minority opinions do, at times, overturn majority opinions. But the theist penchant for latching onto one minority opinion as "gospel", no matter how old or obscure, and hold it up like they have the real scoop and everybody else is "clueless" (SVT's word) well, its just annoying.
www.caseagainstfaith.com
I have no idea. Why don't you ask a scientist? You've been refuted. Deal with it.
www.caseagainstfaith.com
...I have no idea = you refuted me? ??? OK, even though I think it is pretty darn clear that that isn't a refutation, I will assume that, because you are one of the inteligencia atheist and I am a superstitious theist that you are right and I'll move onto point 2.
What needs to be said is that, unless evolution adresses the issue of abiogenesis, it is nothing more than a mechanism without a beginning (this is true of panspermia theory, too. Without acknowledging how life came into being, how it changes and moves is irrelevent if it is to be used as the "complete theory of origins" that it is paraded around as.
Life in general only uses left handed molecules. Miller-Urey produdes an even distribution of right and left handed molecules. How did lifecome into being if half of the complex molecules produced are not even life related or how for no reason did life become all left-handed, ought we not to have at least some hangover right-handed molecules?
"Truth is the cry of all, but the game of the few." George Berkeley
"Truth is always strange — stranger than fiction." Lord Byron
Fixing the world, one dumb idea at a time.
I'm sure there is direct evidence for the early earth having a low-oxygen atmosphere, but I can deduce that this must have been the fact even without it.
1. Plants produce massive amounts of oxygen
2. The time frame we are discussing lies before the evolution of green plants
3. There is no mechanism we are aware of that could have produced an equivalent amount of oxygen at that time, then suddenly stop for no reason once plants came along.
Therefore the early earth had lower oxygen levels than we do now.
Lazy is a word we use when someone isn't doing what we want them to do.
- Dr. Joy Brown
That's a good position for you to take. Stick with it and you may learn something.
It doesn't matter that there's unanswered questions about the beginnings of evolution. If you see a car in the street to do you need to know where it was manufactured in order to support the theory that it is a car? Do you even need to know everything about how it works? No. You creationists apply a false, overly demanding standard of knowledge when you insist that a scientific theory must explain everything before it can explain anything. No one is parading evolution as a theory of origins except theists. The fact is, evolution explains what we see in nature and has made predictions that have been backed by subsequent discovery. It is fact.
One word: evolution.
SVT I double dog dare you to actually read a book on evolution that was not published by a religious or creationist group. I triple dog dare you.
Lazy is a word we use when someone isn't doing what we want them to do.
- Dr. Joy Brown
Selective reading, I see. I said "I have no idea" to your question: "why does Mars have Iron Oxide dust all over the place?" I don't have to know everything about everything to have refuted your primary claims of this thread, about Miller-Ulrey experiments. Meteors and comets with organic compounds, as I've said several times, proves that proper environment for Miller-Ulrey type creation of organic compounds exist SOMEWHERE, and make it to earth. This, in itself, is sufficient refutation of your claims, even if your source about 5% oxygen was correct.
Abiogenesis IS separate from evolution; and evolution -- by itself -- IS "a mechanism without a beginning."
That's like saying Quantum Mechanics and The Theory of Relativity are "irrelevant" until some unifying theory has been found. The fact that we don't have all answers to all questions doesn't make the answers to the questions we do have "irrelevent".
Evolution is not a "complete theory of origins", just like QM or relativity are not, by themselves, a complete theory of physics.
But, that said, if it IS true that evolution explains life after the first life, is it REALLY that hard to imagine that the first life also has a natural origin? I suppose Dr. Behe would disagree, as he argues that evolution is true, the "Intellegent Designer" just created the first cells and let evolution take over from there. Even if Behe was right, I have no idea who/what this "Intellegent Designer" is.
You don't think I've heard this all before? Is it that hard for you to research a claim just a little bit before posting your throw-down, old-hat argument? Most every claim you've posted is refuted on TalkOrigins. Here is their response about left-handed molecules:
http://www.talkorigins.org/indexcc/CB/CB040.html
Claim CB040:
The twenty amino acids used by life are all the left-handed variety. This is very unlikely to have occurred by chance.Response:
Links:
Jacoby, Mitch. 2003. Serine flavors the primordial soup. Chemical and Engineering News 81(32): 5. http://pubs.acs.org/cen/topstory/8132/8132notw1.htmlReferences:
Further Reading:
Clark, Stuart. 1999. Polarized starlight and the handedness of life. American Scientist 87(4) (Jul/Aug): 336-343.Guterman, Lila. 1998. Why life on Earth leans to the left. New Scientist, 160(2164): 16.
www.caseagainstfaith.com
Oh, and, of course, you've been refuted again.
Its a true statement that I'm not an organic chemist, so I don't personally know whether TalkOrigins is right or wrong. Yet, if that was all BS and really wrong, I'm pretty sure every Creationist site in the world would be ridiculing it. As I said before, whenever I hear a Creationist claim that, at least to my layman's perspective, looks like it has some validity, I always find a scientific site with an answer. To the scientific answers, all I ever get from Creationists is the same original argument, as if there was never any scientific response. And then I get people like you that just regurgitate them without bothering to do the slightest bit of checking the facts first. So, who has credibility?
www.caseagainstfaith.com
Next time would you be so kind as to NOT DOUBLE POST because it makes quoting that much more difficult for no reason.
What you say my argument is:
It is pretty clear that it isn't me doing the selective reading because my original argument should be properly paraphrased:
It seems that you have forgotten that I am a focused individual and am ONLY attacking Miller-Urey. It would also seem that you have forgotten that in citing scientists, you are also inheriting their biases, making your own writing more credible and accepted, but not nessecarily more accurate. I know that theist scientists are often used as an example of bias in science, but did Carl Sagan have a bias against God? Count on it.
Also, the self-replicating molecules you cited are bunk. First off, the molecules themselves are, like viruses, not alive because of no metabolism. Secondly, the means of replication that the molecule uses involves being in a soup of pure reactants. (Citation needed, I'll get to that.) Not to burst your bubble, but the molecules were designed to boot, so this really reinforces my position and not yours.
Finally,if life emerged from a 50/50 soup of molecules (as all Miller-Urey type experiments would suggest, why do we not have 40 amino acids (20 L, 20 D)? This would provide much more flexibility of the genetic code and with a codon capacity of 64, there is plenty of room in the genome?
Almost all of life (except for the very few known bacteria you cited) uses L amino acids. Why? Evolutionarily speaking the D molecules are no worse, so the best possible evolutionary standpoint is that we ought to have a mix.
Unless you can point to a diffinitive reason why only L molecules are superior, either in evolution or in abiogenesis, you are forced by the nature of your argument and beg the question by arguing that "what we see is the result of the surviviors, therefore must be somehow better."
Also, think twice before spitting out evidence. Evidence is dumb and can be manipulated to say anything the speaker want's it to, so even though the right handed aminos sound like they reeinforce your position, I can actually spin this on it's head and ask you "If D isn't inherently bad, why don't we see more of it, either in the form of a mixed structure, or D life-forms (D lifeforms must have a fully independent metabolism, so they are insulated from competition with L life as far as evolution is concerned.)
Why should I bother citing when I can flip your arguments around? (I know...your going to come up with some silly reason why I am wrong, but I will probably continue to use your own cites because, frankly, it is far easier to show that you aren't proving anything either and you just might be proving yourself wrong than to try to prove something myself. Atheists, like theists, have a bias and will ignore evidence, so I find it far more effort efficient to do this.
EDIT: Tiberian: I have read books on evolution. Several in fact, namely my AP Bio text, which had a whole #$%! unit on evolution, and The Dinosaur Heresies by Robert Bakker (among other things too small and numerous to list.)
The thing you seem to be reacting to is that I, like Galeleo, have no qualms in questioning what is now presented as "knowledge" because I know what he knew: scientific progress has been most hindered by assumed knowledge (in Galeleo's case, that of the Greeks.)
"Truth is the cry of all, but the game of the few." George Berkeley
"Truth is always strange — stranger than fiction." Lord Byron
Fixing the world, one dumb idea at a time.
Since there has been plenty of science provided and the prevailing view from the scientific community is consistent from the findings you refuse to accept the conclusion. On the other hand you go and follow some fringe group's rantings despite their lack of scientific study. You've proven that your entire agenda is not to argue science but to promote your religious beliefs. Do you care to be honest about that?
"Truth is the cry of all, but the game of the few." George Berkeley
"Truth is always strange — stranger than fiction." Lord Byron
Fixing the world, one dumb idea at a time.
When I end a post with a long quotation, I will often put my commentary in a separate post so as to make clear the separation of the quoted material and my commentary. However, in this post, I have no long quotation, so it will be one post.
Actually, you just proved your inability to read once again. That summarization of the handedness argument was from the article that I quoted, and identified as such. You may not precisely agree with their wording of the argument, but the point is moot, TalkOrigin's response is equally applicable to your wording of the argument.
That's not true, you've attacked abiogenesis in general. You said in part: "making abiogenesis more difficult to occur because ..." You see, I can actually read what you write.
Actually, I specifically addressed that possibility in my follow-up to the quote. That was the whole purpose of that follow-up post! Do I really have to spoon feed this to you??? I acknowledge that I am a layman in most fields of science, and therefore, I readily acknowledge that it is at least technically possible that the scientific answers that I have posted are wrong. But, when I look at Creationst arguments that look at first glace to possibly have some merit, I find scientific responses that sound reasonable. And the Creationist response to the scientific response is invariably: "repeat original argument"
Everybody is biased. You will never hear me say otherwise.
I don't remember citing any self-replicating molecules. I've read something about some proposed possible self-replicating molecules, but I don't believe that I have cited any of that in this discussion here.
Agreed but irrelevant. Nobody says that the first self-replicating molecules, assuming that is how life started, themselves deserve to be termed "alive". There isn't any real sharp dividing line between alive and not, per your virus example.
The article I posted last time gave some possible answers. If you're not going to fucking read what I post, why should I bother? Now, if you say those possible answers aren't sufficient "proof" for you, okay. So what? Science never says it has the "proof" of all answers, it simply attempts to give the best answer given the evidence. That's it.
EDIT: Going back to the TalkOrigins page I cite, I notice that there is a reference to the first self-replicator being single-handed could be purely by chance and not that improbable. But that citation wasn't intended to be a complete discussion of self-replicating molecules, just stating that if you assume such a thing once existed, and if it was single-handed by pure chance, its not that improbable.
www.caseagainstfaith.com
This is a separate post since I'm responding to what was a separate post by you. It was addressed to D-cubed, but I'll provide my own response:
Actually, it is arbitrarily determined -- it is determined that you will only disagree with science when you or whomever you quoted feels that the science encroaches on your religion. Anything that is a prevailing view among scientists, if you don't perceive it as a threat, you don't object to it at all.
I'm perfectly willing to admit that I am biased towards naturalism. But, for one, it wasn't always that way -- I tried to be a theist for many years. I'm 45, and only classified myself as an atheist about 5 years ago. And for two, so what? We are all biased. I grant you that it is indeed your right to be biased towards the supernatural. 100% your right. But, if you are going to post what I perceive to be highly innaccurate information, I will respond why I believe it is so.
www.caseagainstfaith.com
Nice work Case.
It is irrational for someone to attempt to 'debate' an issue over which they are fundamentally ignorant. If you are learning about possible refutations of your points for the FIRST time during a debate, the only rational response is to concede ignorance, bow out of the debate, and head over to a library.
The fact that SVT has had this happen to him multiple times in this thread alone speaks to the weakness of his position.
I can't count how many times a 'debate challenge' from a theist ended up involving a theist repeating some nonsense he pulled from the web, without ever actually bothering to learn about the topic, or explore what actual scientists say about the matter.
If you get a chance Case, take a look at my email exchange with Kelly Tripplehorn that I've posted on the site. You see the same thing going on there as well.
"Hitler burned people like Anne Frank, for that we call him evil.
"God" burns Anne Frank eternally. For that, theists call him 'good.'
In other words, you actually take the time to look at what both sides of the 'debate' say, and, if you yourself feel that you aren't able to rely on your own experience and know-how yourself, you tend to favor the expert's analysis of the matter. At the same time, you don't latch onto it dogmatically... you do your best to understand as much of it as you.
I think that's admirable, and pretty much the way I hope I approach such matters myself.
SVT, on the other hand, learns about the expert analysis for the first time during these exchanges.
"Hitler burned people like Anne Frank, for that we call him evil.
"God" burns Anne Frank eternally. For that, theists call him 'good.'
If you were an honest individual, you'd actually read what science has to say on the matter, and not learn about it, for the first time, during a 'debate' over the matter!
1) This is a hollow complaint from a creationist, who begins by begging the question of god's existence! Talk about bias!
Seriously, I have to stop here a moment: Do you even have a conscience? Any self awareness at all? How can you talk about anyone else's bias, particularly the bias of science, a method that is built upon the idea of recognizing human bias and doing whatever it can to control for it?
How can you, a creationist supporter, take a shot at the biases of anyone else? You're like a serial rapist giving advice on dating etiquette!
2) Scientists may be biased, but the scientific method is the least biased method humans possess, when it comes to understanding the natural world.
2a) If you want to rant about how science rules out supernaturalism as if that's a 'bias', then please provide an ontology for supernaturalism, and we'll talk. Science would love to study 'beyond nature'... but they have no means to do so... so please, give us a coherent ontology for supernaturalism and we'll all fold up our shirt sleeves and get to work.
Based on what? Your say so?
Any 'bias against' god is actually immaterial, seeing as 'god' is an incoherent term, it cannot be used a hypothesis, ergo a bias against supernaturalism is utterly moot.
Actualy, virus are neither not totally 'alive' nor totally 'not alive'.. they are at a hazy crossroads between life and non life....
While doing that, why not actually read what a scientist says on the matter?
"Designed' or is it more accurate to say made purposely to fit an earlier, natural state?
See how disengenous your argument is?
You can't be taken seriously.
"Hitler burned people like Anne Frank, for that we call him evil.
"God" burns Anne Frank eternally. For that, theists call him 'good.'
**SIGH**
Wrong again. I have only learned two things in this whole discussion:
1. There are some mineral deposits that, taking their dating into account and assuming direct contact with the atmosphere durring synthesis, indicate Earth once had a low or nonexistant Oxygen.
This is obviously flimsy when the underlying assumptions are shown. I both disagree with the dating system, and have pointed out that almost all mineral synthesis occurs away from the atmosphere.
2. That there are some recorded bacteria that use D amino acids. This was a bit of a surprise, but merely corrected and strengthened my own argument rather than refuting it.
Caseagainstfaith has admitted that he isn't an organic chemist. I assumed as such because, usually, cridentials are put up front along with the name and as that this is about Miller-Urey, an organic chemist would have said so early on.
On a similar note, I have not told you my own cridentials, and, while I have no PhD or Doctorite in organic chemistry either, my education isn't something to be sneezed at either.
As that it is clear that many atheists here assume that theist = ignorant, I feel required to inform them that such is not the case.
I am a theist, but I have taken AP Biology (and got a 3 on the AP exam,) which had one unit devoted to microbiology and another solely to evolution, but all in all, another unit at least was on evolution between the cracks in the book. I am not a biology expert, but I know what I am talking about.
Also, I am proud of my logic schooling. I have had one semester of Logic, and another on informal fallacies (high-school classes).
I am also well schooled in other sciences from either the Teaching Company, Anenburg, or high-school or college classes, including Neurobiology, Astrophyisics, Astronomy, Chemistry, Geology, and Physics.
Anyone else want to call me ignorant?
While I respect the opinions of a PhD holder as educated in that particuar field, I do believe that I know enough (specifics as well as well rounded) to formulate and defend my own position.
"Truth is the cry of all, but the game of the few." George Berkeley
"Truth is always strange — stranger than fiction." Lord Byron
Fixing the world, one dumb idea at a time.
Stand back, everybody! He's got a high school education! If it goes off by accident he might revolutionize geology and biochemistry!
Götter sind für Arten, die sich selbst verraten -- in den Glauben flüchten um sich hinzurichten. Menschen brauchen Götter um sich zu verletzen, um sich zu vernichten -- das sind wir.
Why not? R.T. Bird, one of the best paleontologests of the early 1900s was a high school dropuot.
So are lots of people. Heads up: a lot of high school dropouts never revolutionized anything.
Götter sind für Arten, die sich selbst verraten -- in den Glauben flüchten um sich hinzurichten. Menschen brauchen Götter um sich zu verletzen, um sich zu vernichten -- das sind wir.
And you have proven...?
R.T. Bird proves my point pretty clearly, but as that you have digressed into pure ad hominems and it no longer amuses me to correct you, I won't bother to and will merely await conversation deserving the title of "rational" in RRS, of which you clearly are not...not presently at least.
"Truth is the cry of all, but the game of the few." George Berkeley
"Truth is always strange — stranger than fiction." Lord Byron
Fixing the world, one dumb idea at a time.
Sorry about that. Normally I'd join in with the biochemistry debate and all, but a month or so ago I got into a debate on another forum and made a great big post that was about 41K (including quotes and BBCode, of course) and then the guy didn't even read it and then I kind of got burned out on debates. Now I'm content to sit on the sidelines and make smaller remarks, like "why the hell does a guy with a high school level education in geology and biochemistry think he's just disproved the work of hundreds of people who have performed intense and dedicated studies in these fields for years" and "if he did disprove them why is he sharing his revolutionary insight on an Internet forum instead of submitting it to Nature or something, seriously this is the information age you don't have to be like Mendel and let your discoveries sit around in some dude's library for years".
One might think that it's undignified to sit around like a scavenger, making snide remarks after other posters have done the heavy lifting, so to speak. And it is. Of course, it's more undignified to show up to a debate and having to learn about the topic under discussion during the course of the debate and asserting elsewhere that evidence is stupid. I mean, yeah, I'm a dick, but I'd rather be a dick than an idiot.
(Mods: The other forum is the one where I have to be nice, right?)
Götter sind für Arten, die sich selbst verraten -- in den Glauben flüchten um sich hinzurichten. Menschen brauchen Götter um sich zu verletzen, um sich zu vernichten -- das sind wir.