Nick Matzke at Panda's Thumb has a piece addressing the article in The Scientist, which I blogged about here
He writes, among other things:
I consider both Slack and his critics friends and colleagues, and both sides make some valid points. But I think many of the arguments that both Slack and his critics make in this particular instance don’t work.
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Slack lists a “few worthy points” creationists make. Here is the first:
First, I have to agree with the ID crowd that there are some very big (and frankly exciting) questions that should keep evolutionists humble. While there is important work going on in the area of biogenesis, for instance, I think it’s fair to say that science is still in the dark about this fundamental question.
My take: It is high time all of these statements be discarded or highly modified. They are basically lazy, all-too-easy responses relying on hair-splitting technicalities or nearly philosophical assertions of the “even if the creationists were empirically correct on this point, which they aren’t but I’m too busy to back it up right now, it wouldn’t matter” variety. And the worst part is that these sorts of statements mis-describe the actual state of the science among the people who work in the field. It is simply not true that we, the scientific community, know almost nothing about the OOL (what an individual who spent a career working on fossils or fruit flies or speciation might know personally is a different question).
t is simply not true that we, the scientific community, know almost nothing about the OOL (what an individual who spent a career working on fossils or fruit flies or speciation might know personally is a different question).
Here is a short list of things we have discovered or confirmed in the last 50 years or so pertaining to the origin of life. In my opinion all of these points have reached high enough confidence that they are unlikely to change much with future discoveries, and our confidence in them does not depend in uncertainties in the remaining unanswered questions.
Here is a short list of things we have discovered or confirmed in the last 50 years or so pertaining to the origin of life. In my opinion all of these points have reached high enough confidence that they are unlikely to change much with future discoveries, and our confidence in them does not depend in uncertainties in the remaining unanswered questions.
OOL Discovery #1. All known life can be traced back to a single common ancestor which, compared to what most people think of as present-day life (i.e. plants and animals), was relatively simple – microscopic, single-celled, perhaps as complex as an average bacterium or perhaps somewhat less so.
OOL Discovery #2. The Last Common Ancestor itself was the product of evolution from an even simpler ancestor. The simplest piece of evidence for this is that a number of the genes found in the Last Common Ancestor are homologous, thus derived from a single common ancestor by duplication and modification.
OOL Discovery #3. DNA/RNA/protein-based life was preceded by something even simpler, an RNA world or at least an RNA-heavy world.
OOL Discovery #4. The increasingly simple ancestors of modern life weren’t made out of just anything, they were made out of chemicals that just happen to be generated by plausible abiotic mechanisms found in early solar systems.
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What is actually being worked on. The above should convince you that the idea that we know nothing or very little about the OOL is just uninformed foolishness. The field has made major progress. There are some famous puzzles remaining, but they do not add up to “we know nothing about the origin of life.” Furthermore, some of the puzzles that creationists, and sometimes others, consider to be major hangups, are not necessarily so. For example:
* The origin of chirality (the left-handedness of amino acids). This is a major puzzle if you make the extremely foolish and unthinking assume (like creationists do, but sometimes others) that the first use of amino acids in early life was supposed to be in long amino acid chains made up of 100+ amino acids randomly assembled from an even mixture of 20+ different amino acids with an even mixture of right- and left-handed amino acids. But over here in the real world, where the origin of the genetic code has been reconstructed in some detail, we know the following: the first primitive genetic code used just one or a few amino acids, and one of the first was glycine, which is the simplest amino acid, the most common amino acid produced in prebiotic experiments, and which is achiral (no left-hand/right-hand difference) to boot.
* The origin of the first replicator. This really is the big cahuna of the OOL discussion, and where the big and contentious debates are still occurring within science, but again I find that many discussants operate with very crude and naive assumptions about what early replicators “should” have been like and what prebiotic experiments “should” be able to produce to “solve” this problem.
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The Main Point
Is it really true that “science is still in the dark” on the OOL, as Slack said? Not a chance. If we lived in a world where it actually looked like the first living things were as complex or more complex than life today, or where the last common ancestor contained absolutely no evidence of an evolutionary history, or where big obvious puzzles like the interdependency of DNA/RNA/protein had no hint of solution, or where the building blocks of life were completely unrelated to those produced in prebiotic experiments – all of these things would be true, say, on a robotic planet without microscopic life, where robots were replicated by macroscopic assembly performed by other robots, and powered by hooking up to a grid of fusion-fueled power plants – then we could say “science is still in the dark” on the origin of this robotic biosphere. But instead, we have numerous lines of evidence all pointing towards the notion that current life descends from a relatively simple ancestor, and that ancestor descends from a series of even simpler ancestors. Why should any of this evidence exist, if life was poofed into existence all in one step, which is what the creationists/IDers think happened even when they won’t admit it, because they are not brave enough to defend what they actually think?
Slack’s second point: the cell is more complex than Darwin could have imagined Slack highlights another area where he suggests that creationists/IDists might have a point:
“Second, IDers also argue that the cell is far more complex than Darwin could have imagined 149 years ago when he published On the Origin of Species.”
Shallit responds with a “Darwin got some things wrong 150 years ago, so what?”-type of response, and PZ says that “Scientists say” that cells are more complex than they seemed to Darwin and that creationists have just copied them. However, both of them do point to some evidence that Darwin’s understanding of the cell was not as primitive as the talking point suggests.
....Like various dubious statement about the OOL which I discussed above, the “Darwin thought the cell was simple” statement became an unquestioned factoid merely through creationist repetition and flawed assumptions from the critics of creationists – it seemed reasonable, nothing crucial hung on it for scientists so they didn’t bother to double check in a serious way, and besides it is a lot easier to agree with your opponent and declare on other grounds that their point is irrelevant to the fundamental issues, than to do a serious analysis.
The moral of the story is, as Wes Elsberry once told me, when a creationist says the sky is blue, go outside and check.
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