Probabilities and the Genesis of Life

_{Gil Dodgen

December 13, 2009

Intelligent Design}

Share: Facebook; Twitter; LinkedIn; Flipboard; Print; Email

The important thing to keep in mind concerning probabilities and the origin of life is that proteins, and everything else in a living cell, are manufactured by machinery which is controlled by an abstract-representation digital coding system. Proteins not only don’t self-assemble, they cannot self-assemble, because basic chemistry drives the process in the opposite direction.

Once this is taken into consideration all arguments that assert, “But it could have happened by chance,” are rendered ludicrous on their face.

By way of analogy, the basic Darwinian argument for the origin of life goes something like this:

1) Clay occurs naturally.
2) Bricks are made of clay.
3) Therefore, there is some (given enough time) probability that houses made of clay bricks came about by stochastic processes and the chemistry of clay.

This is the way I see it, and so do most people with common sense. Apparently, one needs a Ph.D. in Darwinian Speculation (or sufficient indoctrination in this academic, “scientific” specialty) not to recognize the obvious.

Comments

Cabal: Only this morning; I am sorry I can’t remember just where, I read about a number of successful OOL experiments. If there were one such successful experiment, you wouldn't need to remember where you read it. It would be the headline of every newspaper and new site everywhere. But I know what you mean. It's progress in that direction. Sort of like driving a car and saying you're getting closer to Chicago. Except there's no evidence there is or ever was a Chicago, and if there is, no one knows where. You can't say you're getting closer unless you assume it's there and you know where it is. Such assumptions, confidently waiting for evidence to confirm them, are articles of faith. No one is criticizing you for holding fast to your beliefs. You see the world a certain way, and you need to believe that it's true. We all do it. The problem is that your religion includes the self-referential belief that it's not a religion.ScottAndrews_{December 14, 2009
December
12
Dec
14
14
2009
10:33 AM
10
10
33
AM
PDT}

Cabal: George Whitesides is at the cutting edge (if there is one) of OOL chemistry, not "behind the times" as you assume based only on the way overly optimistic appraisals of those who desperately want life-from-chemicals to be true. The difference between Whitesides and the more optimistic Darwinists is that he is brutally honest about what we know and what we don't know. In every area of chemistry, he sets the "we understand this" bar very high, and rightfully so. He is honest enough to not substitute imagination for evidence.Gage_{December 14, 2009
December
12
Dec
14
14
2009
10:29 AM
10
10
29
AM
PDT}

jerry,
The outcome of this is that Darwinist’s outward but false cocksureness is leading many people to believe they actually know something.
That's what you say. I however tend to believe the "Darwinists" really are on to something while cocksureness and letting on knowing something seems to be no less of a virtue in ID circles. I suggest more relevant arguments be used.Cabal_{December 14, 2009
December
12
Dec
14
14
2009
10:15 AM
10
10
15
AM
PDT}

JDH,
Therefore Darwinian evolution must insist on life starting by chance.
Of course not, we have no means of knowing the mind of the designer. Nothing says he couldn't have set it up to look the way it looks. The evidence for evolution is obvious; what went before is not detectable in the same way although abiogenesis as a natural phenomenon seems the most reasonable option. We know no reason why it could not be the result of natural processes. It may be a little premature to write it off yet. As soon as we invoke a designer we open a Pandora's box of possibilities: He may have set it up any way he wants; even to create the world 6000 years ago making it look like it is 4.6 billions.Cabal_{December 14, 2009
December
12
Dec
14
14
2009
10:02 AM
10
10
02
AM
PDT}

vjtorley,
I’ll answer that with a quote from an evolutionary biologist whose academic credentials are impeccable: Natural selection is differential reproduction, organism perpetuation. In order to have natural selection, you have to have self-reproduction or self-replication and at least two distinct self-replicating units or entities. Prebiological natural selection is a contradiction in terms. — T. Dobzhansky, “Synthesis of Nucleosidase and Polynucleotide with Metaphosphate Esters,” in The Origins of Prebiological Systems (1965), pp. 299, 310. (Emphasis mine – VJT.)
A typical response, presenting a forty year old reference as if that had settled some controversy. Am I to believe that was the final and decisive word on that subject?Cabal_{December 14, 2009
December
12
Dec
14
14
2009
09:54 AM
9
09
54
AM
PDT}

Mr ScottAndrews, You are conflating two of my comments which had different subjects.Nakashima_{December 14, 2009
December
12
Dec
14
14
2009
09:50 AM
9
09
50
AM
PDT}

Mr Jerry, Thank you for criticising my beliefs and expectations, rather than my citations. Now I know I'm on the right track.Nakashima_{December 14, 2009
December
12
Dec
14
14
2009
09:48 AM
9
09
48
AM
PDT}

Be patient, this debate will soon be filed away as another myth debunked. Only this morning; I am sorry I can't remember just where, I read about a number of successful OOL experiments. It seems to me that George M. Whitesides may be somewhat behind the times WRT the current standing of OOL research.Cabal_{December 14, 2009
December
12
Dec
14
14
2009
09:41 AM
9
09
41
AM
PDT}

Gage:
While its true that Darwin’s text dealt with the origin of species (not life), the atheistic worldview his theory so strongly supported requires an abiotic OOL.
What's atheism got to do with it? Atheism doesn't need anything beside itself; rejection of supernature is all it takes. But as soon as the inability of supernature to explain anything in this world is recognized, it is of course easily understood that science does.Cabal_{December 14, 2009
December
12
Dec
14
14
2009
09:34 AM
9
09
34
AM
PDT}

Nakashima, I don't believe you have even began to dent to mass probabilities needed to form the proteins/polymers necessary for a working cell. How did a ribosome or ATP synthase come about?jerry_{December 14, 2009
December
12
Dec
14
14
2009
09:06 AM
9
09
06
AM
PDT}

Nakashima's behavior is an example of the faith based beliefs of Darwinists. Like members of most religions they are hoping for something to some day appear to validate their commitment to their beliefs. Unlike those who profess belief in God and a particular religion, those who search for a naturalistic approach to OOL and evolution and the universe will not admit the faith they hold. They will not admit what weird untruth they believe in. It would be a shame at the end of the day, Nakashima learned that all these properties were part of the fine tuning which he denies. Just tweak one or two variables a hair either way and maybe the stereochemistry would not work. I believe Mike Gene has brought up that evidence for design is in the properties of amino acids. They are an amazing triumph of design. The outcome of this is that Darwinist's outward but false cocksureness is leading many people to believe they actually know something.jerry_{December 14, 2009
December
12
Dec
14
14
2009
09:03 AM
9
09
03
AM
PDT}

vjtorley, I'm afraid I have to concur with Nakashima's assessment of John Walton's remarks, especially this:
Intense laboratory research has failed to produce even one nucleotide (RNA component) under geologically plausible conditions.
I suggest this paper (to which I indirectly referred to earlier): Powner MW, BG Gerland & JD Sutherland (2009). Synthesis of activated pyrimidine ribonucleotides in prebiotically plausible conditions. Nature 459:239-242
Here we show that activated pyrimidine ribonucleotides can be formed in a short sequence thatbypasses free ribose and the nucleobases, and instead proceeds through arabinose amino-oxazoline and anhydronucleoside intermediates.The starting materials for the synthesis—cyanamide,cyanoacetylene, glycolaldehyde, glyceraldehyde and inorganicphosphate—are plausible prebiotic feedstock molecules12–15, and the conditions of the synthesis are consistent with potential early-Earth geochemical models. Although inorganic phosphateis only incorporated into the nucleotides at a late stage of the sequence, its presence fromthe start is essential as it controls three reactions in the earlier stages by acting as a general acid/base catalyst, a nucleophilic catalyst, a pH buffer and a chemical buffer. For prebiotic reaction sequences, our results highlight the importance of working with mixed chemical systems in which reactants for a particular reaction step can also control other steps.
Jack Szostak, in his summary of this paper in the same issue of Nature, writes:
One of the goals of those developing theories of prebiotic chemistry is to identify geochemically plausible means of purifying key intermediates away from contaminants that might cause trouble in later reactions. The remarkable volatility of 2-aminooxazole suggests that it could be purified by sublimation, as it undergoes cycles of gentle warming from the sun, cooling at night (or at higher altitudes) and subsequent condensation. The compound would thus behave as a kind of organic snow, which could accumulate as a reservoir of material ready for the next step in RNA synthesis. Phosphate continues to have several essential roles in the remaining steps of Powner and colleagues’ pathway, in one case causing depletion of an undesired by-product, and in another saving a critical intermediate from degradation. The penultimate reaction of the sequence, in which the phosphate is attached to the nucleoside, is another beautiful example of the influence of systems chemistry in this set2 of interlinked reactions. The phosphorylation is facilitated by the presence of urea4; the urea comes from the phosphate-catalysed hydrolysis of a by-product from an earlier reaction in the sequence. The authors wrap up their synthetic tour de force by using ultraviolet light to clean up the reaction mixture. They report that ultraviolet irradiation destroys side products while simultaneously converting some of the desired ribocytidine product to ribouridine (the second pyrimidine component of RNA). The development of this complex photochemistry required remarkable mechanistic insight from Powner and colleagues, who not only correctly predicted that ultraviolet irradiation would destroy the majority of the by-products, but also that the desired ribonucleotides would withstand such treatment. The authors’ careful study2 of every potentially relevant reaction and side reaction in their sequence is a model of how to develop the fundamental chemical understanding required for a reasoned approach to prebiotic chemistry. By working out a sequence of efficient reactions, they have set the stage for a more fruitful investigation of geochemical scenarios compatible with the origin of life.
Dave Wisker_{December 14, 2009
December
12
Dec
14
14
2009
08:53 AM
8
08
53
AM
PDT}

Nakashima: If we didn’t know that templates to assist protein self assembly existed in nature, your point that proteins can’t self assemble would have more force. This is quite an optimistic statement in reference to Miller-Urey. Were any proteins self-assembled? You're crediting the experiment with an outcome that it didn't produce, based only on your personal conviction that one day some evidence will justify your extrapolation. Not that it matters. If, if you could solve the problem of "protein self-assembly," that only leads to the next question - what templates cause proteins to assemble into even the simplest living organisms? I don't have a problem with all the research to determine if this is possible, although I'm sure there are better uses of public funding. What irks me is the blatantly non-scientific assumption of the outcome. Every experiment is spoken of as progress toward determining how abiogenesis occurred, which presumes that it did. There's nothing wrong with faith and hope. But they're as far from science as the sunrise is from the sunset.ScottAndrews_{December 14, 2009
December
12
Dec
14
14
2009
08:07 AM
8
08
07
AM
PDT}

Mr Vjtorley, How felicitous that as you were thinking how to respond, you came across a letter on the exact subject, containing the exact phrase you had Googled earlier. The world is a remarkable place. Dr Walton's letter glosses over exactly the same issues as Dr Meyer does in his paper. When he says: As for the chains of nucleotides required for the RNA world, there are insuperable problems associated with their information content, as well as the chemical selectivity needed for their assembly. He is merely repeating Dr Meyer's mistake of ignoring direct templating and the stereochemical theory. When he insists that natural selection only occur based on genetics, he is overstepping the bounds of Dobzhansky's quote. As a chemist he should know that if two reactions are going on in the same flask, using the same feedstocks, there will be a natural selection of the faster reaction, and the faster reaction's end products will dominate over the reaction products of the slower reacton. This is all that is meant by chemical or molecular evolution.Nakashima_{December 14, 2009
December
12
Dec
14
14
2009
07:49 AM
7
07
49
AM
PDT}

Nakashima-san, Had they actually produced a living organism it would refute Gil.Joseph_{December 14, 2009
December
12
Dec
14
14
2009
07:49 AM
7
07
49
AM
PDT}

A recent culmination of research provided the following paper: Self-Sustained Replication of an RNA Enzyme by Tracey A. Lincoln and Gerald F. Joyce. It was touted as evidence for self-replicating RNA and "evolution in a bottle" (SciAm). The research is leading edge stuff and should give us a glimpse at the reducibility of living organisms. If this paper is any indication, origin of life research isn't looking so good. I say that because all the synthesized RNA did was make- catalyze- ONE connection. It took two pre-synthesized sections and joined them together. The "evolution" came with variance of sequence but the new sequences still performed the same function (the original sequence "died out"). This is a start and I hope they continue to see how far they can go- Sooner or later the "mainstream" will come to realize what IDists have been telling them- living organisms are not reducible to matter, energy, chance and necessity.Joseph_{December 14, 2009
December
12
Dec
14
14
2009
07:45 AM
7
07
45
AM
PDT}

Would it be possible to focus on Gil's OP and (try to) list what is required for the origin of living organisms? For example: 1- Parts- as in what parts are required and how can they be produced: a b c d e 2- Localization (getting the parts in one area) 3- Configuration 4- Cross reactions 5- ? This is just the basic DCO (discrete combinatorial object) stuff discussed in "No Free Lunch".Joseph_{December 14, 2009
December
12
Dec
14
14
2009
07:44 AM
7
07
44
AM
PDT}

Mr Joseph, Their experiment did not match any primordial Earth and the results show that toxins were also produced. Indeed, but as a refutation of Mr Dodgen's position that basic chemistry defeats abiogenesis, that is acceptable.Nakashima_{December 14, 2009
December
12
Dec
14
14
2009
07:36 AM
7
07
36
AM
PDT}

Mr Jerry, Thank you for the reference to the full text. They still have to overcome those nasty probabilities. I think they already have shown the path forward on that. Of the original 10^-164, 45 orders of magnitude was from producing only peptide bonds, and templating on RNA supports that. Another 74 orders of magnitude was functional specificity, and the RNA was functionally specific for arginine-arginine sequences while the polypeptide showed enzymatic activity for the associated RNA. (The remaining 45 orders of magnitude were chirality, which this experiment does not address.) Also, the length of RNA and AA polypeptide are much smaller than 150 AAs, and yet they still have some function. The presence of a metal ion also catalyzes the reaction, a factor not considered in the original improbability calculation.Nakashima_{December 14, 2009
December
12
Dec
14
14
2009
07:35 AM
7
07
35
AM
PDT}

Mr. Nakashima and Dave Wisker: Thank you both for your posts. As you are both aware, I make no claim to any expertise in biochemistry, so it is difficult for me to respond to your arguments in favor of the RNA world. As luck would have it, I came across this letter to The Times (December 9, 2009) while I was pondering how I would reply. The author is John Walton, a chemist and professor at the University of St Andrews. He wrote a letter in defense of philosopher Thomas Nagel, who was lambasted by another chemist, Dr. Stephen Fletcher, of Loughborough University, for recommending Dr. Stephen Meyer’s Signature in the Cell in The Times's Books of the Year. Here is Dr. Walton's letter, complete and unabridged:
Sir, – The resilience of the “prebiotic soup” myth, in spite of torrents of counter-evidence, is truly astonishing. Even professionals such as Stephen Fletcher (Letters, December 4), criticizing Thomas Nagel’s recommendation of Signature in the Cell by Stephen C. Meyer (Books of the Year, November 27), apparently still believe in it. Fletcher asserts that “Natural selection is in fact a chemical process as well as a biological process, and it was operating for about half a billion years before the earliest cellular life forms appear in the fossil record”. Actually the operation of neoDarwinian natural selection depends on the prior existence of entities capable of self-replication. Variants are produced in their genetic material by mutations, the variants are copied by the organism’s biochemical machinery, and then natural selection ensures the most “fit” survive. Before the arrival of organisms capable of reproduction, this process could not operate. In the words of the renowned evolutionist Theodosius Dobzhansky: “Prebiological natural selection is a contradiction in terms”. It follows that, even in principle, some quite different explanation is required to account for the origin of life. Fletcher is pinning his hopes on a supposed RNA world. He tells us: “Indeed, before DNA there was another hereditary system at work, less biologically fit than DNA, most likely RNA (ribonucleic acid)”. It is an amusing irony that while castigating students of religion for believing in the supernatural, he offers in its place an entirely imaginary “RNA world” the only support for which is speculation! Intense laboratory research has failed to produce even one nucleotide (RNA component) under geologically plausible conditions. As for the chains of nucleotides required for the RNA world, there are insuperable problems associated with their information content, as well as the chemical selectivity needed for their assembly. Furthermore, the earth’s oldest Precambrian rocks show very good evidence that life was present from the start, so the half-billion years Fletcher counts on were actually not available for chemical evolution. Rather than just kowtowing to the creaky naturalist “prebiotic soup” scenario, Meyer engages with the whole range of origin of life problems. Anyone interested in discovering where the evidence leads will find this a fascinating book. JOHN C. WALTON School of Chemistry, University of St Andrews, North Haugh, St Andrews.
Well, that's what a chemistry professor says. If he likes Dr. Stephen Meyer's book, then I think his arguments deserve careful scrutiny. Mr. Nakashima: I'm greatly heartened to hear that you're reading Dr. Meyer's book. I'm sure his arguments against the RNA world in his book are a lot more sophisticated than those in the brief two-page critique he wrote, as part of his 2007 paper, DNA and the Origin of Life: Information, Specification and Explanation, which I recommended to you earlier. By the way, my tactical preference for an eternal universe is a hypothetical one. If I were an atheist (which, as you know, I'm not), that's the argumentative strategy I'd adopt. At the present time, the scientific arguments that the universe had a beginning are highly suggestive but not compelling, whereas the probabilistic argument that life could not have evolved in the space of a few hundred million (or even a few billion) years is much more mathematically rigorous. Another attraction of the "eternal universe" scenario is that it leaves open the possibility of top-down explanations; there's no need to boil everything down to physics and chemistry. (If, hypothetically speaking, I were an atheist, I'd definitely want to retain my belief in libertarian freedom. For to seriously suppose that my reasons for acting persuade me by virtue of the chemical processes occurring in my brain while I cogitate, is to undermine the validity of rational thought itself. A chemical process may be efficacious, but that doesn't make it rational.) As you point out, given the infinite probabilistic resources of an eternal universe, one might argue that life could have originated from non-living matter, but why bother? Wouldn't it be simpler to just say it was always there? (By the way, there are some philosophers who would dispute your implicit assumption that anything can happen, given enough time.) You may be wondering why I proposed the eternal universe scenario. Well, you might say I was fishing: I was curious as to whether any of the atheists would bite. None did. That tells me something. What it suggests to me is that dyed-in-the-wool atheists are not content to have a self-sufficient universe, where God is absent; rather, what they want is a bottom-up, reductionist, materialistic universe, which precludes the very possibility of a theological explanation of anything, on principle. In other words, they want a universe in which God is an "un-thought," a meaningless concept. I am not accusing skeptics of having a hostile, anti-theistic motivation, you understand. The underlying motivation is not to exclude God, but to exclude certain ways of explaining reality: top-down explanations are a no-no, and teleological explanations are an even bigger no-no. It seems to me that many scientifically-minded atheists are hooked on "bottom-up" explanations, to the extent that they cannot conceive of any other kind. That kind of tunnel vision strikes me as dangerous. After all, does the world have to be bottom-up? And if so, why? Might it not be a brute fact that there are different levels of explanation in the universe, with no possibility of reducing one level to another? Faced with these arguments, atheists typically fall back on two lines of defense: (i) "Scientific reductionism has worked well so far; why shouldn't it explain the origin of life too?" and (ii) a bottom-up explanation is the only kind of explanation that really explains anything. Neither line of defense works. Statement (i) is an inductive argument. Now, the inductive approach is quite appropriate when one has reason to believe that there may be an underlying law which grounds the regularity that one observes. If falling objects on Earth accelerate at 9.8 meters per second per second (unless buffeted by air currents), you might well think there's a law that covers all these falling objects. But a grand master law covering all scientific explanations? (As in: It is a law that all explanations have to be reductive explanations.) That doesn't even make sense. Laws cover classes of events, not explanations. Statement (ii) is sadly revealing. What it boils down to is: "I can't get my head around non-reductive explanations, so I'll stick to formulating reductive ones, and carry on in the hope that the universe conforms to my cognitive limitations." Well, why should it? The universe doesn't care a fig about us and what our minds can do, if it's godless. Dave Wisker: Thanks for your comments. I just came across The Alfred Russel Wallace Page , and of course I was already aware of The Complete Work of Charles Darwin Online . What do you think of the idea of creating similar pages for 20th century evolutionary biologists? Just a thought. (Copyright might be a problem, but even if some of their older works could be made available online, that would be a useful resource.) On top of that, you'd need a master page linking to all of them, for ease of reference.vjtorley_{December 14, 2009
December
12
Dec
14
14
2009
06:48 AM
6
06
48
AM
PDT}

vjtorley, Even if the current model is mistaken, how do you get around the observations regarding the cosmic microwave background radiation? So perhaps the details aren't ironed out, but why prefer the idea that the universe has always been suitable for life when the data from COBE and others suggests completely the opposite? So what if particular details about the theory are mistaken? You still need to establish that a theory which claims that the universe has always been suitable for life is easier to fit with our observations than not.kevlar_{December 14, 2009
December
12
Dec
14
14
2009
06:32 AM
6
06
32
AM
PDT}

vivid, The empirical data from COBE and other experiments suggests that the belief the universe was always as it is now is extremely untenable. As a matter of fact, the best evidence suggests that the universe used to be extremely hot and dense. Now if you think that requires less mental gymnastics than contemporary biology, I really have nothing to say to you. There is substantial empirical evidence that the universe, (eg, COBE, WMAP, Boomerang) and not just the earth, was at one point in time unsuitable for life.kevlar_{December 14, 2009
December
12
Dec
14
14
2009
06:27 AM
6
06
27
AM
PDT}

Miller-Urey? Their experiment did not match any primordial Earth and the results show that toxins were also produced.Joseph_{December 14, 2009
December
12
Dec
14
14
2009
06:05 AM
6
06
05
AM
PDT}

vjtorley: All in all, it’s entirely reasonable to say that there’s at least a 1% chance that the Big Bang theory is wrong.
We can almost guarantee that any scientific theory will be supplanted by a new theory as more is learned. But in the case of the Big Bang, any new theory would almost certainly incorporate cosmic expansion.
GilDodgen: All of modern Darwinian theory is fundamentally based on the presupposition that the first living cell came about by stochastic chemical processes.
Sorry, though biologists would like to see a unified theory that encompasses the origin of life, such a theory doesn't exist.
Stephen C. Meyer: First, for strands of RNA to perform enzymatic functions (including enzymatically mediated self-replication), they must, like proteins, have very specific arrangements of constituent building blocks (nucleotides in the RNA case). Further, the strands must be long enough to fold into complex three dimensional shapes (to form so called tertiary structures). Thus, any RNA molecule capable of enzymatic function must have the properties of complexity and specificity exhibited by DNA and proteins.
Scientists regularly find ribozymes (catalytic RNA) in random sequence libraries.Zachriel_{December 14, 2009
December
12
Dec
14
14
2009
06:04 AM
6
06
04
AM
PDT}

Nakashima, Here is the full text of the article http://nar.oxfordjournals.org/cgi/content/full/37/8/2574 It is interesting but looks like we have just built a couple screws when it is the space shuttle that is the objective. There is still the information building that is necessary. They still have to overcome those nasty probabilities.jerry_{December 14, 2009
December
12
Dec
14
14
2009
04:24 AM
4
04
24
AM
PDT}

vjtorley, I'm glad the creationist site got the quotation right, though I would have preferred that they had interpreted it correctly. But that would have meant them actually reading the paper by Schramm, in which he talks about the possibility of self-replication of nucleic acids in a prebiological setting, and how selection could ensure the replication of some template sequences over others. If you recall, Dobzhansky says in the complete quote that Schramm correctly used the term natural selection in his paper. This takes the teeth out of the creationist's use of Dobzhansky's remark, it seems to me. I'm not aware of any good online source of scientific quotes. If I use a quote, I usually try to get it from the primary source if at all possible. As for the RNA world, I'm familiar with some of it (the literature on the subject is enormous). One thing I have found, though, is that the most productive work on the plausibility of the RNA world has come by abandoning certain restrictive assumptions. For example, regarding RNA itself, The traditional view is that the ribose sugar and its other components formed separately, and then combined. This assumption led the experimental work down a path of reactions which were ultimately found to be implausible. However, recent work has shown that thsi basic assumption may be incorrect--at least for the pyrimidine bases cytosoine and uracil. Using a set of far more plausible reactions for prebiotic conditions, the building blocks of RNA for pyrimides, at least, have been experimetally assembled via a chemical intermediate. Recent Nobel laureate Jack Szostak wrote a summary of this work in the May 2009 issue of Nature.Dave Wisker_{December 14, 2009
December
12
Dec
14
14
2009
04:12 AM
4
04
12
AM
PDT}

Nakashima, Do you look at the tire and wheel on a car and say they do not necessarily indicate design, given that their shape, size, and construction make them suited to the job they do? To look at the enrirety of the biological system and say that it is not designed because it works! is a measure of utter blindness. Its incredible that we would find that the individual parts within the translation system actually are well-fitted to do the job they do and then turn our heads from the context. The entire body is made of up context-specific reactions and interplay between chemical constituents that have nothing whatsoever to do with each other outside of the context of the system they are coordinated within. cAMP has absolutely nothing to do with glucose. Do we just go from the front bumber to the tailights, examining each part along the way, and ignore it all? You go ahead. Not me.Upright BiPed_{December 13, 2009
December
12
Dec
13
13
2009
11:05 PM
11
11
05
PM
PDT}

Mr Vjtorley, Now, even if I were a scientific and/or philosophical naturalist, I would not argue along those lines. Indeed, I would prefer to argue that life had always existed in an eternal universe, than to argue for the plausibility of abiogenesis. I am surprised that you express this preference, given that an eternal past would overcome the lack of probabilistic resources upon which Dr Meyer's argument against chance is built. Do you hold some other reason for this preference? I understand the distinction of cause and explanation, but I have often found the physical world indifferent, at best, to our ability to explain it. I am in the mddle of Signature in the Cell, but haven't reached the RNA World chapter yet. I am pretty much forcing myself to read the book word for word inthe order Dr Meyer laid it out, and so far I have found that to be rewarding. For the sake of this discussion, I'll make these comments about the Meyer paper you cite, on the pages referring to the RNA World hypothesis. (p 260) Most important for our present considerations, the RNA-world hypothesis presupposes, but does not explain, the origin of sequence specificity or information in the original functional RNA molecules. (p 261) Second, for a single-stranded RNA catalyst to self-replicate (the only function that could be selected in a prebiotic environment)... In passages such as these, Dr Meyer completely ignores the direct templating of amino acids on RNA and the stereochemical theory of the origin of the genetic code. As Dr Meyer points out in Signature of the cell (for DNA), the sequence of bases create a bumpy surface when they are stacked up. This same bumpiness that allows complementary strands of DNA and mRNA to form also creates a situation in which some amino acids have a preference for sticking to some triplets of RNA over others. This affinity for specific amino acids in preference to others can be the source of the information and function that Dr Meyer denies knowing any possible source for. In contradiction to Dr Meyer, it does explain the origin of sequence specificity. The ligated peptide bonds of the templated amino acids are another property upon which natural selection can operate. Dr Meyer here, and I expect in Signature in the Cell also, does not so much refute the RNA world hypothesis as ignore an important part of it. a part developed by many scientists over the years. It is hard to say which implication is worse - that Dr Meyer is ignorant of this literature, or that he simply is refusing to engage directly with the most relevant challenge to his views. With respect to the way the Wikipedia entry is worded, I don't find the use of 'conceptually' to be inapt. Reordering slightly, the conceptual possibility of the (idea of the) hypothesis is grounded in the properties of RNA. I think this reflects the historical flow that scientists realized that RNA could self catalyze, and from the discovery of that property came the OOL hypothesis. Similarly, the knowledge that clays can adsorb nucleotide chains make the clay assisted hypothesis conceptually possible. In contrast, there is no salt hypothesis because there is no property of salt that would make such a hypothesis conceptually possible, even before any experiment was performed. Of course, scientists are not comfortable stopping at conceptual possibility, and have performed experiments to justify continuing to entertain the RNA World hypothesis. Real scientists do indeed like hard numbers, though upper and lower bounds on a probability model are unlikely to be the numbers that get updated first!Nakashima_{December 13, 2009
December
12
Dec
13
13
2009
09:57 PM
9
09
57
PM
PDT}

kevlar, The post by Oramus that you referred to began with his comment "The question is what drove the beginning of life AND early life prior to it breaking some supposed threshold where evolutionary processes could kick in." In his post he went on to question the value of NS in relation to this central question (which was the topic of the OP). You then skipped over that and suggested that to have narural selection operate, one only needs an environment, replication, and heredity. Which, of course, missed the point by a fairly wide margin. Perhaps it couldn't have been wider. You stated "How wasn’t there survival pressure 2.7 billion years ago? There was still an environment, still reproducing organisms with heritable and varying traits… what’s missing?" My question was targeted at what you ignore.Upright BiPed_{December 13, 2009
December
12
Dec
13
13
2009
09:49 PM
9
09
49
PM
PDT}

Kevlar You write:
So what is your explanation for the COBE data? Where do you pull the 1% possibility that the big bang didn't occur from? Are you seriously this ignorant of cosmology?
I've been following trends in cosmology on and off since about 1970. How about you? Three short points in response. 1. The fact that the Big Bang theory makes some singular predictions that alternative scientific theories don't, doesn't make it true. It doesn't make it 99% probable, or even 9% probable. It just makes it a lot more probable than the proposed alternatives. For all we know, there may well be alternative theories that we haven't even thought of, which account for the observed facts just as well or better. 2. This article, which appeared in New Scientist magazine last year, gave me pause: Lithium: The hole in the big bang theory by Matthew Chalmers (7 July 2008). One of the selling points of the Big Bang is that it predicts cosmic abundances of helium-4 and helium-3. However, the observed abundances of lithium-6 and lithium-7 appear to be significantly at odds with the theory. Is this a major problem, or will future observations resolve the difficulty? I don't know. 3. The Big Bang theory requires scientists to make some extravagant assumptions - for instance, the existence of dark matter and dark energy. While there is some indirect observational evidence for the existence of dark matter, no dark matter particles have been observed in laboratories, to date. As for dark energy: yes, I'm well aware of observational evidence that the universe appears to be accelerating. However, I'm sure you're also aware of the spectacular failure (by 100 orders of magnitude!) of scientists' efforts to predict the value of the cosmological constant, which is how the Lambda-Cold Dark Matter Model (the best current Big Bang model) accounts for dark energy. Add up all these uncertainties, and factor in the very real possibility that the true explanation for the evolution of the cosmos may simply not have occurred to us yet. All in all, it's entirely reasonable to say that there's at least a 1% chance that the Big Bang theory is wrong.vjtorley_{December 13, 2009
December
12
Dec
13
13
2009
09:47 PM
9
09
47
PM
PDT}

Prev 1 2 3 4 5 Next

You must be logged in to post a comment.

Leave a Reply