In my last post, I drove home the point that intelligent design and theistic evolution, in the most generic sense of the two, should be welcome bedfellows. This is not to say that intelligent design of the kind that says "the bacterial flagellum is too complex and thus evolution cannot be true" should be wedded to theistic evolution; instead I am saying that evolution or no, God is sovereign, and He designed this universe and all life at some level.
However, if we accept that, we are denying what many people (in academia and elsewhere) equate with the theory of biological evolution: a naturalistic worldview. We should have no problem with the idea that all life on earth is related, but we should have a problem with the idea that, since we descended from an ape-like ancestor that also gave rise to chimpanzees (in common vernacular: we came from monkeys), we do not have inherent moral value. Or that we have the same moral value as chimpanzees. Or that we are different in degree only, not in kind. Folks, we were made in the image of God! Tarnished now, but that is true for no other creature (including the angels). And none other has the chance for redemption that we do.
What's more, as Christians we are in a unique position. We can affirm evolution, but we deny the naturalistic worldview. However, the proponent of naturalism (i.e., the atheist) must affirm evolution, because he/she denies the theistic worldview. (I hope I am not simplifying too much here, but I feel I am more or less correct.) And thus, the veracity of biological evolution carries too much weight; the atheist's worldview depends on it. And perhaps this is why evolution is considered sacred to biologists (as I mentioned in an earlier post).
I understand that most biologists would say that evolution has such high regard in biology because the entire field hinges upon it; it is the foundation for all biological research. I say hogwash to that. The field only hinges upon it if you have a naturalistic worldview.
Anyway, back to my main point. The naturalist's worldview hinges on the veracity of evolution. In contrast, the Christian worldview hinges on the veracity of the resurrection, and not on any "intelligent design" argument. We can go into the evidence for the resurrection later, but my point is that as Christians and as scientists (ok, some of us are scientists), we can take or leave biological evolution.
And so my question is: are we bold enough to test it?
God has spoken through both Nature and the Bible, and thus these two "books" are in harmony. Whether you are a Christian or a skeptic, we hope you will see the reasonable faith of Christianity.
Friday, November 20, 2009
Thursday, November 19, 2009
Theistic evolution and intelligent design (part 4): "Will you marry me?"
Hearkening back to my original post in this series, I mentioned that I thought neither the "Theistic evolutionists" nor the proponents of the Intelligent Design Movement (IDM) have it right. I pointed out in part two that theistic evolutionists should, at their very heart, be proponents of intelligent design. In parts 3a and 3b, I spent most of the time talking about the IDM, but did mention that all Christians should be intelligent design (notice the lowercase letters) proponents of some sort.
Why can't then these two positions (theistic evolution and intelligent design) be married together in some way?
Sure, the natural mechanisms of biological evolution (that is, descent with modification, natural selection operating on variations caused by mutations) can promote diversification and speciation. But how does that detract from the fact that this universe and everything in it was part of the Designer's grand plan? Isaiah 45:18 says that God "did not create it [the earth] to be empty, / but formed it to be inhabited." It was God's plan in the beginning that earth should be filled with life. And if I may be so bold: human life was part of His plan as well. In other words, things may have evolved, but life was still designed.
Look at it this way. There are a lot of quotes from famous scientists that tread the edge of intelligent design, while at the same time vehemently denying it. For example, Francis Crick (in his book "What Mad Pursuit") says the following: "Biologists must constantly keep in mind that what they see was not designed, but rather evolved." Uhm, excuse me, but why not both? No, seriously, one would correctly infer from this quote that biological entities, at the very least, appear designed. They do. The common evolutionist answer to that is the appearance of design is what we would expect given the mechanisms of evolution.
I have two things to say to that. First, how do we know? I think that's coming pretty close to putting the cart before the horse. Although I would tend to agree with that statement, I am still disgruntled that we take that at face value and don't test it.
Second, that statement (as well as the quote by Dr. Crick) relies on a false dichotomy. It's either designed, or it evolved. Theistic evolutionists and IDM proponents (and most people in general) play into that game, perhaps unknowningly. Most theistic evolutionists I know are uncomfortable with the idea that life is designed, even though I believe that's a natural consequence of their philosophical position. But we don't have to fall into that trap! Even though God may work through the natural laws and processes that He created, there is no reason to believe that life didn't evolve with a purpose, with a design!
In other words, I'm saying that if you're a Christian, and you believe that evolution correctly describes the history of life on earth and the diveristy of life we see today, you should still believe that it has been designed for the benefit of humanity. And that's just based on a philosophical/theological position. It doesn't even take into account the scientific evidence in favor of that position. (Perhaps I'll describe that evidence at a later date.)
Why can't then these two positions (theistic evolution and intelligent design) be married together in some way?
Sure, the natural mechanisms of biological evolution (that is, descent with modification, natural selection operating on variations caused by mutations) can promote diversification and speciation. But how does that detract from the fact that this universe and everything in it was part of the Designer's grand plan? Isaiah 45:18 says that God "did not create it [the earth] to be empty, / but formed it to be inhabited." It was God's plan in the beginning that earth should be filled with life. And if I may be so bold: human life was part of His plan as well. In other words, things may have evolved, but life was still designed.
Look at it this way. There are a lot of quotes from famous scientists that tread the edge of intelligent design, while at the same time vehemently denying it. For example, Francis Crick (in his book "What Mad Pursuit") says the following: "Biologists must constantly keep in mind that what they see was not designed, but rather evolved." Uhm, excuse me, but why not both? No, seriously, one would correctly infer from this quote that biological entities, at the very least, appear designed. They do. The common evolutionist answer to that is the appearance of design is what we would expect given the mechanisms of evolution.
I have two things to say to that. First, how do we know? I think that's coming pretty close to putting the cart before the horse. Although I would tend to agree with that statement, I am still disgruntled that we take that at face value and don't test it.
Second, that statement (as well as the quote by Dr. Crick) relies on a false dichotomy. It's either designed, or it evolved. Theistic evolutionists and IDM proponents (and most people in general) play into that game, perhaps unknowningly. Most theistic evolutionists I know are uncomfortable with the idea that life is designed, even though I believe that's a natural consequence of their philosophical position. But we don't have to fall into that trap! Even though God may work through the natural laws and processes that He created, there is no reason to believe that life didn't evolve with a purpose, with a design!
In other words, I'm saying that if you're a Christian, and you believe that evolution correctly describes the history of life on earth and the diveristy of life we see today, you should still believe that it has been designed for the benefit of humanity. And that's just based on a philosophical/theological position. It doesn't even take into account the scientific evidence in favor of that position. (Perhaps I'll describe that evidence at a later date.)
Labels:
intelligent design,
theistic evolution
Sunday, November 15, 2009
Theistic evolution and intelligent design (part 3b): what is Intelligent Design?
Last time, I introduced the generic idea of intelligent design, contrasting it with the higly political Intelligent Design Movement (IDM). To be perfectly up front, I have problems with the IDM, mostly because they offer no testable/falsifiable hypotheses, yet they want their "theories" taught in high school biology courses. This is a no-no.
But what should the IDM do differently if it wants to get into the classroom? (As I said in my previous post, I personally have no problem with ideas of intelligent design being taught at the high-school level, but only if these ideas have been shown worthy of scientific merit.)
First, stop focusing so much negative evidence. At this point, you cannot overturn naturalistic evolution as an explanatory hypothesis by saying that it can't do something. I'm not saying that negative evidence never overturns hypotheses, but it won't overturn evolution. Evolution is not quantitative enough, and itself isn't testable/falsifiable enough to be challenged in this way. If the IDM wants to go up against evolution, it needs to show that it has more testable/falsifiable explanatory power than evolution does.
Here's an example. The bacterial flagellum (a whip-like structure attached to bacteria that allows them to swim) is an "icon" of intelligent design. The basic IDM argument is that the flagellum is so complex, there's no way that evolution can produce that. It's beyond the limits of what evolution can do. Evolutionists respond with, "no, that's not true, and we can imagine ways in which evolution can do this." Notice that neither of those assertions are actually testing anything; in essence they are just hand-waving arguments. It is extremely difficult to overthrow a scientific paradigm using hand-waving arguments, even if that's all that the other side is doing.
Second, the IDM really should try to move to another field (ie, besides biology/biochemistry). I don't know why, but for whatever reason, biological evolution is different from other scientific theories. Most disciplines (such as astronomy, physics, geology, chemistry, etc) tolerate or even welcome challenges to long-standing scientific theories. This is not true in biology; challenging the veracity of naturalistic evolution meets you with ridicule and disdain. Evolution is somewhat sacred to biologists, and to go up against it is sort of like going up against the premise that the bible can be trusted. Weird, but true. Perhaps this is a direct outgrowth from the whole "Scopes monkey trial" fiasco...and now anyone who disbelieves evolution is perceived as being either ignorant or brainwashed.
The other motivation IDM proponents should have in focusing on other scientific disciplines is that almost all other theories are infinitely more quantitative than biological evolution, and thus are also more testable/falsifiable. One problem with the theory of evolution is that we have no idea what the limits are to its explanatory power (if any). Because of this, we can attribute almost anything to evolution. (By the way, this is an interesting twist on the God-of-the-gaps fallacy, which I have written about several times.) In addition, using negative evidence to demonstrate that God created (ie, showing that naturalistic forces could not account for some phenomenon) is actually possible in a quantitative field, such as cosmology. In that case, the classical arguments coming from the IDM camp become less like hand-waving arguments and more like testable hypotheses.
Finally, the IDM should drop the facade about being religiously neutral. They see the past failures to get religious ideas taught in science classrooms (such as young-earth creation) as stemming from the religious content. So, IDM proponents make the claim that the movement is completely secular. They refuse to identify the intelligent Designer, and thus say that they have no religious affiliation. Note that this tactic is not working. No one in the scientific community buys that; most have linked the IDM to conservative Christianity, and rightly so in my opinion. After all, where else has the opposition to biological evolution come from? This has the unintended consequence of galvanizing the opposition to Christianity and has given intelligent design (note the lowercase letters) a bad name. At the beginning of my last post, I said that affirming "intelligent design" in the most generic sense should not subject one to ridicule. I didn't say does not. Now nearly any discussion about any kind of intelligent design links you to the IDM, which links you to a political agenda of anti-science and ignorance, which brings you ridicule. Maybe I'm exaggerating a bit, but the IDM has given Christianity an uphill battle.
At any rate, the proponents of the IDM have had a fallacy in their political thinking. It wasn't actually the religious content of creationist ideas that blocked their introduction into science classrooms, it was the scientific merit. The rulings of the courts in the mid-to-late 20th century regarding the teaching of young earth creationism rested on academic merit, not religious content. Furthermore, if the IDM were following the "proper route" into classrooms, rather than try to force their way in via court rulings, there wouldn't be any issue anyway. Secularists and atheists might be upset about the fact that scientific theories promote a Designer, but what we would prefer shouldn't matter anyway. In summary, instead of trying to be fake and subversive in their agenda, why doesn't the IDM simply come clean? At this point, the IDM gives most people an untrustworthy vibe.
But there are some good things about the IDM. Some of their arguments, such as regarding the bacterial flagellum, I find to be intellectually compelling, just not scientifically defensible. (Notice a trend? I'm saying that a lot these days.) What Christians need are good scientific minds developing Christian apologetic arguments (or even better: research plans) that are both compelling and testable/falsifiable.
But what should the IDM do differently if it wants to get into the classroom? (As I said in my previous post, I personally have no problem with ideas of intelligent design being taught at the high-school level, but only if these ideas have been shown worthy of scientific merit.)
First, stop focusing so much negative evidence. At this point, you cannot overturn naturalistic evolution as an explanatory hypothesis by saying that it can't do something. I'm not saying that negative evidence never overturns hypotheses, but it won't overturn evolution. Evolution is not quantitative enough, and itself isn't testable/falsifiable enough to be challenged in this way. If the IDM wants to go up against evolution, it needs to show that it has more testable/falsifiable explanatory power than evolution does.
Here's an example. The bacterial flagellum (a whip-like structure attached to bacteria that allows them to swim) is an "icon" of intelligent design. The basic IDM argument is that the flagellum is so complex, there's no way that evolution can produce that. It's beyond the limits of what evolution can do. Evolutionists respond with, "no, that's not true, and we can imagine ways in which evolution can do this." Notice that neither of those assertions are actually testing anything; in essence they are just hand-waving arguments. It is extremely difficult to overthrow a scientific paradigm using hand-waving arguments, even if that's all that the other side is doing.
Second, the IDM really should try to move to another field (ie, besides biology/biochemistry). I don't know why, but for whatever reason, biological evolution is different from other scientific theories. Most disciplines (such as astronomy, physics, geology, chemistry, etc) tolerate or even welcome challenges to long-standing scientific theories. This is not true in biology; challenging the veracity of naturalistic evolution meets you with ridicule and disdain. Evolution is somewhat sacred to biologists, and to go up against it is sort of like going up against the premise that the bible can be trusted. Weird, but true. Perhaps this is a direct outgrowth from the whole "Scopes monkey trial" fiasco...and now anyone who disbelieves evolution is perceived as being either ignorant or brainwashed.
The other motivation IDM proponents should have in focusing on other scientific disciplines is that almost all other theories are infinitely more quantitative than biological evolution, and thus are also more testable/falsifiable. One problem with the theory of evolution is that we have no idea what the limits are to its explanatory power (if any). Because of this, we can attribute almost anything to evolution. (By the way, this is an interesting twist on the God-of-the-gaps fallacy, which I have written about several times.) In addition, using negative evidence to demonstrate that God created (ie, showing that naturalistic forces could not account for some phenomenon) is actually possible in a quantitative field, such as cosmology. In that case, the classical arguments coming from the IDM camp become less like hand-waving arguments and more like testable hypotheses.
Finally, the IDM should drop the facade about being religiously neutral. They see the past failures to get religious ideas taught in science classrooms (such as young-earth creation) as stemming from the religious content. So, IDM proponents make the claim that the movement is completely secular. They refuse to identify the intelligent Designer, and thus say that they have no religious affiliation. Note that this tactic is not working. No one in the scientific community buys that; most have linked the IDM to conservative Christianity, and rightly so in my opinion. After all, where else has the opposition to biological evolution come from? This has the unintended consequence of galvanizing the opposition to Christianity and has given intelligent design (note the lowercase letters) a bad name. At the beginning of my last post, I said that affirming "intelligent design" in the most generic sense should not subject one to ridicule. I didn't say does not. Now nearly any discussion about any kind of intelligent design links you to the IDM, which links you to a political agenda of anti-science and ignorance, which brings you ridicule. Maybe I'm exaggerating a bit, but the IDM has given Christianity an uphill battle.
At any rate, the proponents of the IDM have had a fallacy in their political thinking. It wasn't actually the religious content of creationist ideas that blocked their introduction into science classrooms, it was the scientific merit. The rulings of the courts in the mid-to-late 20th century regarding the teaching of young earth creationism rested on academic merit, not religious content. Furthermore, if the IDM were following the "proper route" into classrooms, rather than try to force their way in via court rulings, there wouldn't be any issue anyway. Secularists and atheists might be upset about the fact that scientific theories promote a Designer, but what we would prefer shouldn't matter anyway. In summary, instead of trying to be fake and subversive in their agenda, why doesn't the IDM simply come clean? At this point, the IDM gives most people an untrustworthy vibe.
But there are some good things about the IDM. Some of their arguments, such as regarding the bacterial flagellum, I find to be intellectually compelling, just not scientifically defensible. (Notice a trend? I'm saying that a lot these days.) What Christians need are good scientific minds developing Christian apologetic arguments (or even better: research plans) that are both compelling and testable/falsifiable.
Theistic evolution and intelligent design (part 3a): what is Intelligent Design?
First of all, I have to apologize to everyone. I've been out of town for a week, and haven't been too frequent with my postings. Note that it took me about three weeks just to finish up a summary of our last meeting about the origin of life.
Now, where to begin when talking about Intelligent Design? First, we have to differentiate between intelligent design and the Intelligent Design Movement.
To me, the words "intelligent design" simply mean that a supernatural, causal, intelligent agent created this universe, and perhaps has a hand on the unfolding of history. This is seemingly uncontroversial, as most Christians should agree with this, and most anyone who truly believes in God likely does as well. In addition, even most atheists respect the fact that many people believe in God, and thus do not find fault with belief in an intelligent agent. In other words, believing in "intelligent design" in the most generic sense should not be a big deal, nor should it subject you to ridicule.
The "Intelligent Design Movement" (IDM) on the other hand is a completely different animal. This appears to be a group of people (mostly scientists, I suppose; the most prominent of whom is Dr. Michael Behe, professor of biochemistry at Lehigh University) that has a political agenda. Maybe that's going a bit too far, but it does explain why intelligent design has faced major opposition. Simply put, the IDM wants to force the teaching of creationism in high school biology classes.
I have no problem with that. Except for the fact that the ideas of the IDM are not scientifically defensible. At this point. A commenter from my last post asked me what I meant by "scientifically defensible". This was in response to my saying a couple times that my discussion of the origin of life was intellectually compelling but not scientifically defensible (see here and here), and I likened that to the IDM.
So here's what I meant. The hypotheses held by the IDM are mostly negative explanations regarding the veracity of biological evolution. They offer no way to test their hypotheses, and thus it boils down to "some biological features found in nature look so complex, there's no way naturalistic evolution could have resulted in that; it must have been God creating it." They offer no counter explanations that can be tested, and thus, it is quite difficult to publish in peer-reviewed, scientific journals (much less overthrow a scientific paradigm) if you have no hope of testing/falsifying your hypotheses. In summary, they don't offer an alternative model!
And here's the kicker. If you can't publish in the peer-reviewed scientific journals, then you cannot get into high school curricula. The proper way to make your way into the textbooks is to publish in the peer-reviewed journals, then get into cutting-edge graduate level classes, and then finally trickle down through the undergraduate levels to the high school level. The IDM is trying to circumnavigate this whole process and make their way straight into high school biology classrooms. That's not how science is done. They're playing at politics, and they're losing. What's worse, they're losing for the rest of us (more on this later). Scientific theories must be peer-reviewed, must be testable/falsifiable, and must stand the test of time.
This post is getting quite long, so I'll stop here. Next time, I'll go into more detail about what the IDM proponents should do to be taken seriously.
Now, where to begin when talking about Intelligent Design? First, we have to differentiate between intelligent design and the Intelligent Design Movement.
To me, the words "intelligent design" simply mean that a supernatural, causal, intelligent agent created this universe, and perhaps has a hand on the unfolding of history. This is seemingly uncontroversial, as most Christians should agree with this, and most anyone who truly believes in God likely does as well. In addition, even most atheists respect the fact that many people believe in God, and thus do not find fault with belief in an intelligent agent. In other words, believing in "intelligent design" in the most generic sense should not be a big deal, nor should it subject you to ridicule.
The "Intelligent Design Movement" (IDM) on the other hand is a completely different animal. This appears to be a group of people (mostly scientists, I suppose; the most prominent of whom is Dr. Michael Behe, professor of biochemistry at Lehigh University) that has a political agenda. Maybe that's going a bit too far, but it does explain why intelligent design has faced major opposition. Simply put, the IDM wants to force the teaching of creationism in high school biology classes.
I have no problem with that. Except for the fact that the ideas of the IDM are not scientifically defensible. At this point. A commenter from my last post asked me what I meant by "scientifically defensible". This was in response to my saying a couple times that my discussion of the origin of life was intellectually compelling but not scientifically defensible (see here and here), and I likened that to the IDM.
So here's what I meant. The hypotheses held by the IDM are mostly negative explanations regarding the veracity of biological evolution. They offer no way to test their hypotheses, and thus it boils down to "some biological features found in nature look so complex, there's no way naturalistic evolution could have resulted in that; it must have been God creating it." They offer no counter explanations that can be tested, and thus, it is quite difficult to publish in peer-reviewed, scientific journals (much less overthrow a scientific paradigm) if you have no hope of testing/falsifying your hypotheses. In summary, they don't offer an alternative model!
And here's the kicker. If you can't publish in the peer-reviewed scientific journals, then you cannot get into high school curricula. The proper way to make your way into the textbooks is to publish in the peer-reviewed journals, then get into cutting-edge graduate level classes, and then finally trickle down through the undergraduate levels to the high school level. The IDM is trying to circumnavigate this whole process and make their way straight into high school biology classrooms. That's not how science is done. They're playing at politics, and they're losing. What's worse, they're losing for the rest of us (more on this later). Scientific theories must be peer-reviewed, must be testable/falsifiable, and must stand the test of time.
This post is getting quite long, so I'll stop here. Next time, I'll go into more detail about what the IDM proponents should do to be taken seriously.
Thursday, November 5, 2009
Summary of meeting on 10/24 (part 6)
I'm going to try to finish up the summary of our last meeting here in this post, because the excessive number of sub-parts is getting kind of ridiculous.
I still have one more point to cover here: are there chemical pathways, relevant to the conditions on the early earth, by which life's precursor molecules could have been made? If so, we should be able to deduce these pathways through conducting laboratory experiments.
So, what is the current state of biochemical pathways pertaining to the origin of life? Let's start with a history lesson. Most biology textbooks these days discuss seminal work by Stanley Miller in the 1950's (called the Miller-Urey experiment) in which he bubbled water vapor into a chamber filled with ammonia and methane (hydrogen-rich gases thought to comprise the primordial atmosphere). After simulating lightning with electric discharges for a long period of time, he found that some simple amino acids had formed in the reaction chamber! Subsequently, the origin of life research community had great optimism that the solution to the origin of life problem was just around the corner.
Fast forward 50+ years to today. Now we know the primordial atmosphere did not have the composition that Miller thought it to have. (Instead of reducing gases, such as ammonia and methane -- which have lots of hydrogen atoms -- it contained oxidizing gases, such as carbon dioxide and oxygen.) Most origin of life researchers today consider the Miller-Urey experiment to be irrelevant to the origin of life.
Most scientists today consider something called the "RNA world hypothesis" to be central to the origin of life question. Today, we live in a DNA-protein world, where DNA stores genetic information, and proteins catalyze the biochemical reactions. It would be difficult to envision that life could originate that way, since you would have to get two extremely rare events happening simultaneously: the chemical origins of DNA and of proteins. On the other hand, RNA can fulfill both roles, albeit slightly less efficiently. RNA can store information in the same way DNA can (but is less stable), and some RNA molecules can catalyze reactions similar to what proteins do (but not as well). So if the first life-form was RNA-based, instead of DNA/protein-based, then this would eliminate a major barrier to the likelihood that life arose naturalistically. Later, DNA and proteins could have slowly replaced RNA in its roles as information carrier and reaction catalyst. (This replacement would have been more or less permanent because DNA and proteins are better at their respective jobs than the RNA was.)
Now the question comes down to identifying a reasonable way in which RNA could have formed on the early earth. However, efforts to do this have been met with uninspiring results. In 2002, at an origin of life conference, here is how one leading origin of life researcher (Leslie Orgel) put it: "It would be a miracle if a strand of RNA ever appeared on the early Earth."
However, perhaps he was too quick to pronounce the miraculous-seeming nature of life's origin. Research published this year on the synthesis of nucleotides (the building blocks of RNA) demonstrated that perhaps it would be less-than-miraculous if a strand of RNA appeared on early Earth. On the other hand, some in the scientific community are skeptical. Leading origin of life researcher Robert Shapiro (and by the way, if I had to identify the three leading origin of life researchers of the 20th century, I would have said Miller, Orgel, and Shapiro) had this to say of the recent work: "The flaw with this kind of research is not in the chemistry. The flaw is in the logic -- that this experimental control by researchers in a modern laboratory could have been available on the early Earth."
In other words, even our best efforts to determine the chemical pathways to life's precursors suffer from one thing: the hallmarks of intelligent design.
Ugh. My entire summary suffered from the hallmark of intelligent design. Like I've said in previous posts, we don't want to construct an argument from a negative point of view, saying, "Look how crazy-complex this is...it must have been an intelligent designer." However, I do find these arguments regarding the origin of life to be intellectually compelling, just not scientifically defensible.
Until next time...
I still have one more point to cover here: are there chemical pathways, relevant to the conditions on the early earth, by which life's precursor molecules could have been made? If so, we should be able to deduce these pathways through conducting laboratory experiments.
So, what is the current state of biochemical pathways pertaining to the origin of life? Let's start with a history lesson. Most biology textbooks these days discuss seminal work by Stanley Miller in the 1950's (called the Miller-Urey experiment) in which he bubbled water vapor into a chamber filled with ammonia and methane (hydrogen-rich gases thought to comprise the primordial atmosphere). After simulating lightning with electric discharges for a long period of time, he found that some simple amino acids had formed in the reaction chamber! Subsequently, the origin of life research community had great optimism that the solution to the origin of life problem was just around the corner.
Fast forward 50+ years to today. Now we know the primordial atmosphere did not have the composition that Miller thought it to have. (Instead of reducing gases, such as ammonia and methane -- which have lots of hydrogen atoms -- it contained oxidizing gases, such as carbon dioxide and oxygen.) Most origin of life researchers today consider the Miller-Urey experiment to be irrelevant to the origin of life.
Most scientists today consider something called the "RNA world hypothesis" to be central to the origin of life question. Today, we live in a DNA-protein world, where DNA stores genetic information, and proteins catalyze the biochemical reactions. It would be difficult to envision that life could originate that way, since you would have to get two extremely rare events happening simultaneously: the chemical origins of DNA and of proteins. On the other hand, RNA can fulfill both roles, albeit slightly less efficiently. RNA can store information in the same way DNA can (but is less stable), and some RNA molecules can catalyze reactions similar to what proteins do (but not as well). So if the first life-form was RNA-based, instead of DNA/protein-based, then this would eliminate a major barrier to the likelihood that life arose naturalistically. Later, DNA and proteins could have slowly replaced RNA in its roles as information carrier and reaction catalyst. (This replacement would have been more or less permanent because DNA and proteins are better at their respective jobs than the RNA was.)
Now the question comes down to identifying a reasonable way in which RNA could have formed on the early earth. However, efforts to do this have been met with uninspiring results. In 2002, at an origin of life conference, here is how one leading origin of life researcher (Leslie Orgel) put it: "It would be a miracle if a strand of RNA ever appeared on the early Earth."
However, perhaps he was too quick to pronounce the miraculous-seeming nature of life's origin. Research published this year on the synthesis of nucleotides (the building blocks of RNA) demonstrated that perhaps it would be less-than-miraculous if a strand of RNA appeared on early Earth. On the other hand, some in the scientific community are skeptical. Leading origin of life researcher Robert Shapiro (and by the way, if I had to identify the three leading origin of life researchers of the 20th century, I would have said Miller, Orgel, and Shapiro) had this to say of the recent work: "The flaw with this kind of research is not in the chemistry. The flaw is in the logic -- that this experimental control by researchers in a modern laboratory could have been available on the early Earth."
In other words, even our best efforts to determine the chemical pathways to life's precursors suffer from one thing: the hallmarks of intelligent design.
Ugh. My entire summary suffered from the hallmark of intelligent design. Like I've said in previous posts, we don't want to construct an argument from a negative point of view, saying, "Look how crazy-complex this is...it must have been an intelligent designer." However, I do find these arguments regarding the origin of life to be intellectually compelling, just not scientifically defensible.
Until next time...
Labels:
origin of life,
prebiotic soup
Monday, November 2, 2009
Summary of meeting on 10/24 (part 5!!)
I'm really sorry to have dragged this summary out like this. There's just so much to talk about!
Back to our discussion of the origin of life: one of the main predictions (or, more like expectations) of our naturalistic scenario is that the first life was initially simple, and only later evolved to become complex. This was expectation was seemingly borne out in the early days of microbiology: the simplest known life forms at that time, bacteria, when viewed under the microscope seemed to simply be "bags" of jelly, with very little structure or organization. If these life forms are really that simple, there is a possibility that the earth's first life was also that simple, or perhaps even simpler. This would fit well into a naturalistic paradigm.
On the other hand, as we have grown to understand microbiology more, we now realize that the internal and surface structure and organization of prokaryotes such as bacteria are incredibly complex; it's just that this organization couldn't be seen under a simple light microscope. By itself, this doesn't rule out the possibility that the first life was simple. However, further research into the minimum complexity of life has shown that even the simplest life form possible, which could not exist/thrive without constant TLC from intelligent agents (ie, laboratory scientists), requires at minimum roughly 200 genes. That's 200 different sets of instructions to build 200 different complex molecules. If that is indeed life's minimum complexity, then the first life form must have had at least 200 genes. That indeed is an uncomfortable fit into a naturalistic scenario.
Further geobiochemical evidence has supported the notion that earth's first life was complex. As far back as 3.5 billion years ago, an evolutionary instant after the end of the late heavy bombardment (see my previous post), we have evidence of entire ecosystems of microbes in symbiotic relationships.
In addition to that, very early on -- and I must confess, I am not sure about the published date for this -- we have photosynthetic life on earth. Why is that important? The biochemical machinery required to have photosynthesis is quite complex; not something you would expect from the earliest, most simple life forms posited by naturalistic models.
I just realized something. This blog post is supposed to be a summary of the meeting we had two Saturdays ago, but I just rambled on about something we didn't actually talk about. I guess it's bonus material.
And please, if you guys have any comments or questions, criticisms, I welcome them.
Back to our discussion of the origin of life: one of the main predictions (or, more like expectations) of our naturalistic scenario is that the first life was initially simple, and only later evolved to become complex. This was expectation was seemingly borne out in the early days of microbiology: the simplest known life forms at that time, bacteria, when viewed under the microscope seemed to simply be "bags" of jelly, with very little structure or organization. If these life forms are really that simple, there is a possibility that the earth's first life was also that simple, or perhaps even simpler. This would fit well into a naturalistic paradigm.
On the other hand, as we have grown to understand microbiology more, we now realize that the internal and surface structure and organization of prokaryotes such as bacteria are incredibly complex; it's just that this organization couldn't be seen under a simple light microscope. By itself, this doesn't rule out the possibility that the first life was simple. However, further research into the minimum complexity of life has shown that even the simplest life form possible, which could not exist/thrive without constant TLC from intelligent agents (ie, laboratory scientists), requires at minimum roughly 200 genes. That's 200 different sets of instructions to build 200 different complex molecules. If that is indeed life's minimum complexity, then the first life form must have had at least 200 genes. That indeed is an uncomfortable fit into a naturalistic scenario.
Further geobiochemical evidence has supported the notion that earth's first life was complex. As far back as 3.5 billion years ago, an evolutionary instant after the end of the late heavy bombardment (see my previous post), we have evidence of entire ecosystems of microbes in symbiotic relationships.
In addition to that, very early on -- and I must confess, I am not sure about the published date for this -- we have photosynthetic life on earth. Why is that important? The biochemical machinery required to have photosynthesis is quite complex; not something you would expect from the earliest, most simple life forms posited by naturalistic models.
I just realized something. This blog post is supposed to be a summary of the meeting we had two Saturdays ago, but I just rambled on about something we didn't actually talk about. I guess it's bonus material.
And please, if you guys have any comments or questions, criticisms, I welcome them.
Labels:
origin of life
Summary of meeting on 10/24 (part 4)
Last time I left you with the cliffhanger that the oldest rocks known to man show the chemical signatures of life, rather than non-life. In other words, as far back as we can study geological formations, life has been here. Let me put this in perspective.
After the earth was formed roughly 4.5 billion years ago, it was unfit for life (or formless and empty). There were many impactor events that would have melted the earth's crust and vaporized all of its water in this early, "hadaean" period, which lasted from the time of earth's formation until roughly 3.9-3.8 billion years ago. The end of this era was particularly harsh, and was called the "late heavy bombardment", when the intensity and frequency of these impactor events were quite high.
These events are planet-sterilizing, so any life that could have existed was snuffed out. (Interestingly enough, there is recent research that argues that some life, if it existed, may have survived. However, this conclusion is controversial at this point. We'll have to see how that theory shakes out over then next year or so.) In addition to destroying all life, these impactors also melted all of the rocks, such that the oldest known rocks on the planet today (which are in Greenland I believe) date to the end of the late heavy bombardment, roughly 3.85 billion years ago.
In these rocks, the carbonaceous materials that we can find all bear the signature of life! In other words, the oldest known rocks date from a period that is also the earliest possible moment that the earth was habitable, and yet they show signs that life existed then! Not only was there no prebiotic soup (see my previous post), but life arose essentially instantaneously.
Wow. OK, next time we'll get to the third point I brought up in my last post: the initial complexity of life.
After the earth was formed roughly 4.5 billion years ago, it was unfit for life (or formless and empty). There were many impactor events that would have melted the earth's crust and vaporized all of its water in this early, "hadaean" period, which lasted from the time of earth's formation until roughly 3.9-3.8 billion years ago. The end of this era was particularly harsh, and was called the "late heavy bombardment", when the intensity and frequency of these impactor events were quite high.
These events are planet-sterilizing, so any life that could have existed was snuffed out. (Interestingly enough, there is recent research that argues that some life, if it existed, may have survived. However, this conclusion is controversial at this point. We'll have to see how that theory shakes out over then next year or so.) In addition to destroying all life, these impactors also melted all of the rocks, such that the oldest known rocks on the planet today (which are in Greenland I believe) date to the end of the late heavy bombardment, roughly 3.85 billion years ago.
In these rocks, the carbonaceous materials that we can find all bear the signature of life! In other words, the oldest known rocks date from a period that is also the earliest possible moment that the earth was habitable, and yet they show signs that life existed then! Not only was there no prebiotic soup (see my previous post), but life arose essentially instantaneously.
Wow. OK, next time we'll get to the third point I brought up in my last post: the initial complexity of life.
Labels:
late heavy bombardment,
origin of life
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