Enjoy this lecture, as it echoes many of the points i have made on this blog:
When it comes to the topic of abiogenesis, I am neither a denier nor a cheerleader. That is, I don’t deny the earth spawned life and argue it is so improbable that it did not occur. I don’t think we know enough to make such negative claims. But neither do I buy into the notion that abiogenesis research has been making great progress over the years and solutions are right around the corner. I’ve heard that unfulfilled promise for too long now not be to be jaded. Personally, I think scientists are about as baffled about the origin as life as they were in 1953. What does this all mean? I don’t know.
Nevertheless, periodically you will come across cheerleaders who will hold up this study or that study as something that is supposed to be ground-breaking or as something that demonstrates the progress that is being made. My response is not to criticize, but to withhold judgment and wait to see if anything comes out of this study or that study. So I’ve been doing a lot of waiting. Anyway, if you don’t have the expertise to judge such claims, simply step back and survey the big picture. Go back to 1953 and again contrast a known field of scientific success (akin to using a positive control) with abiogenesis research over the years.
Since both dramatic findings were laid in the lap of the scientific community at the same time, it would be instructive to compare their respective track records of success.
An easy way to compare them is to take advantage of the fact that 2003 was the 50th anniversary of both papers, as human beings love to celebrate milestones.
Posted in origin of life
Stanley Miller published his original paper that isolated amino acids from an electrical discharge in one of the most widely read scientific journals called Science. It was published on May 15, 1953. What is most uncanny about this date is that another famous scientific paper was published just three weeks earlier in the other most widely read journal in the scientific community, Nature. This was Watson and Crick’s revolutionary paper that first outlined the double helix model of DNA. Since both dramatic findings were laid in the lap of the scientific community at the same time, it would be instructive to compare their respective track records of success.
Posted in origin of life
The Earth’s rock record begins around 3.8 billion years ago with a period that is known as the Archaean. The Archean can be split into different eras, where the early Archaean extends from 3.8 to 3.6 billion years ago, the Paleoarchaean extends from 3.6 to 3.2 billion years ago, the Mesoarchaean extends from 3.2 to 2.8 billion years ago, and the Neoarchaean extends from 2.8 to 2.5 billion years ago. At this point, a new period known as the Proterzoic begins and it will extend all the way until about 550 million years ago, the time of the Precambrian.
I have long assumed that life appeared on this planet approximately 3.5 billion years ago. But lately, the evidence for such ancient life seems to be evaporating. The crown jewel among the ancient microbial fossils has been the filamentous cyanobacteria from 3.5-billion-old Australian chert that were first described by William Schopf from UCLA. Yet in 2002, Martin Brasier and colleagues made a strong case that those fossils are not remnants of living things, but represent the activity of ancient and exotic geochemical processes . And a recent study has just confirmed these are not fossils (HT to Joe):
Posted in origin of life
Life on Earth was unlikely to have emerged from volcanic springs or hydrothermal vents, according to a leading US researcher.
Experiments carried out in volcanic pools suggest they do not provide the right conditions to spawn life.
Posted in origin of life
Jonah Lehrer has some more thoughts on the Decline Effect:
The first letter, like many of the e-mails, tweets, and comments I’ve received directly, argues that the decline effect is ultimately a minor worry, since “in the long run, science prevails over human bias.”
Lehrer then quotes Feynman who discusses the famous 1909 oil-drop experiment and explains why it took so long for scientists to zero on the correct measure for the charge of the electron:
Why didn’t they discover that the new number was higher right away? It’s a thing that scientists are ashamed of—this history—because it’s apparent that people did things like this: When they got a number that was too high above Millikan’s, they thought something must be wrong—and they would look for and find a reason why something might be wrong. When they got a number closer to Millikan’s value they didn’t look so hard.
As Lehrer notes, this is yet another example of the “selective reporting in science.” But Feynmann was trying to make another point:
he warned the Caltech undergrads to be rigorous scientists, because their lack of rigor would be quickly exposed by the scientific process. “Other experimenters will repeat your experiment and find out whether you were wrong or right,” Feynman said. “Nature’s phenomena will agree or they’ll disagree with your theory.”
But Lehrer is quick to puncture the obvious naivety associated with this claim:
You have probably heard this story by now:
But now researchers have discovered a bacterium that appears to have replaced that life-enabling phosphorus with its toxic cousin arsenic, raising new and provocative questions about the origins and nature of life.
News of the discovery caused a scientific commotion this week, including calls to NASA from the White House asking whether a second line of earthly life has been found.
Whether or not the bacteria actually replace phosphorus with arsenic is something that will eventually be sorted out. But for now, we can be confident that no “second line of earthly life has been found.”
“This is different from anything we’ve seen before,” said Mary Voytek, senior scientist for NASA’s program in astrobiology, the arm of the agency involved specifically in the search for life beyond Earth and for how life began here.
“These bugs haven’t just replaced one useful element with another; they have the arsenic in the basic building blocks of their makeup,” she said. “We don’t know if the arsenic replaced phosphorus or if it was there from the very beginning – in which case it would strongly suggest the existence of a shadow biosphere.”
Yes, we do know it wasn’t there from the beginning. How?
What is life? Biologists have long understood that life is very hard to nail down with any precise definition. Daniel Koshland, from the Department of Molecular and Cell Biology at the University of California, recounts the following story that nicely illustrates this:
What is the definition of life? I remember a conference of the scientific elite that sought to answer that question. Is an enzyme alive? Is a virus alive? Is a cell alive? After many hours of launching promising balloons that defined life in a sentence, followed by equally conclusive punctures of these balloons, a solution seemed at hand: “The ability to reproduce—that is the essential characteristic of life,” said one statesman of science. Everyone nodded in agreement that the essential of a life was the ability to reproduce, until one small voice was heard. “Then one rabbit is dead. Two rabbits— a male and female— are alive but either one alone is dead.” At that point, we all became convinced that although everyone knows what life is there is no simple definition of life. [Koshland, DE. 2002. The Seven Pillars of Life. Science 295: 2215-2216.]
Moving away from a reductionist definition, Koshland instead identifies seven universal principles inherent in all living things. He calls these the “pillars” of life. Since such pillars are features of life itself, and LUCA (the last universal common ancestor) would also be considered an expression of life (otherwise, it could not evolve into the three basic cell types), it seems quite reasonable to suppose that the same seven pillars would apply to LUCA. So what are they?
Bradley Monton is a philosopher at the University of Colorado at Boulder. He has a new book coming out entitled, Seeking God in Science: An Atheist Defends Intelligent Design and recently blogged about an interesting private exchange with another atheist philosopher:
Also, the atheist-minded philosophers are unhappy with how some intelligent design opponents seem more focused on emotion and rhetoric than argument — they expect better of people (especially philosophers) who are engaging in this debate. For example, I recently got an email from a philosopher of science at a top philosophy program, which read in part:
“I’m also an atheist who thinks that the arguments for ID are far more interesting than philosophers tend to appreciate. I think it’s lamentable that the climate now is such that you can’t seriously discuss such things without attracting ill will from well-meaning opponents of the religious right. … Writing a book like yours is a brave thing to do and it might make the world a better place.”
What is interesting to me is how sociological pressures can impose a form of self-censorship in Academia, which is supposed to represent the heart and soul of free thinking and inquiry.
I’m reminded of a quote from Paul Davies (in his book, The Fifth Miracle): “Many investigators feel uneasy stating in public that the origin of life is a mystery, even though behind closed doors they admit they are baffled.”
So why do such investigators only admit this behind closed doors? Consider the follow-up sentences offered by Davies:
There seem to be two reasons for their unease. First, they feel it opens the door to religious fundamentalists and their god-of-the-gaps pseudo-explanations. Second, they worry that a frank admission of ignorance will undermine funding, especially for the search for life in space.
It’s easy to skip by these statements, but in reality, Davies is making a truly radical claim. He is saying that there is a community of scientists who are not being totally sincere in public about the state of their research for sociological reasons. Can it be that the general public is kept in the dark about things that might open the door to “religious fundamentalists” or undermine the ability to obtain money? I don’t know the answer to that question, but thanks to the internet, there is some recent support for the notion that some researchers are very concerned about opening the door to “god-of-the-gaps pseudo-explanations.”
Aha! I had a couple of essays saved from a few weeks back……
Most arguments about the origin of life are sucked into the domain of the Traditional Template. In other words, we are once again treated to the old arguments whereby people dispute whether or not it was possible for geochemical processes to spawn biological processes. But I think it is more interesting to approach this topic while looking for clues – facts about the world we might expect to find if a given hypothesis is true.
The Seeding Story and Spawning Story have a different story to tell. One begins with a consortium of sophisticated, complex cells while the other begins with a simple self-replicating molecule able to co-opt from a huge assortment of potentially useful chemicals in the thick prebiotic broth. Does it really make sense to think such two radically different starting points cannot leave any traces that would help us distinguish between the two?