July 14, 2006
The origin of life
Darwin's theory of evolution by natural selection deals with the question of how life evolves and does not directly address the question of the origin of life itself. The fields of cosmology and physics and chemistry have provided models of how the universe evolved and created the solar system, among other things. But those theories do not explain how organic molecules, the basic building blocks of life, came about.
An article by Gareth Cook in the August 14, 2005 issue of the Boston Globe examined this question in the light of an initiative (known as the ''Origins of Life in the Universe Initiative") by then Harvard president Lawrence Summers to invest millions to investigate this important question, partly in an effort to have Harvard try and catch up the leaders in this field at the University of Arizona, the California Institute of Technology, and the Scripps Research Institute in La Jolla, Calif..
Cook says that the questions to be addressed are: "How can life arise from nonlife? How easy is it for this to happen? And does the universe teem with life, or is Earth a solitary island?"
Scientists generally work on the assumption that the laws of physics and chemistry that we work with on Earth should also apply everywhere in the universe. But those laws need not result in the same environment being created on different planets and since it is the environment that will determine the nature of the life forms that come into being, the laws of biology could be, and in fact would likely be, quite different from planet to planet, depending on the environment that was in existence at the time that living organisms came into being there.
Of course, we have no evidence right now that life forms exist on other planets. But "biologists have been finding that life can survive in much more hostile environments than thought possible -- such as microbes that live deep in rock or in searingly acidic water -- meaning that planets with more extreme environments might support life", lending support to the idea that life is likely to be found elsewhere.
Hence an important related question would be studying how different environments came into existence in the different planets and how the nature of life is related to the environment that produced it.
Cook's article summarizes some theories for the origins of life. The first is the famous 1953 Miller-Urey experiment: "A flask, containing elements of the early Earth's atmosphere, was jolted with electricity, like bolts of lightening. This simple setup created a wealth of organic molecules, but since [then], the prevailing view of the makeup of the early atmosphere has changed, and the experiment doesn't work well with the new recipe."
Others have suggested that "organic molecules could have been carried to Earth in the icy core of comets" (which presupposes the existence of life elsewhere and does not really answer the question of how life began, only how it began on Earth), or that "life began near the intense heat of deep sea vents, an environment that drives unusual reactions."
Yet other possibilities exist, such as the idea of chemist Scot Martin, who
"believes that ultraviolet light from the sun, shining down on tiny mineral crystals floating near the surface of the early ocean, may have generated organic compounds.
In his flask, he has shown that molecules of bicarbonate, common in the early ocean, attach themselves to a mineral called sphalerite. When the ultraviolet light hits the sphalerite, it sets off a chain of events that makes the bicarbonate more reactive, and that leads to a wide range of organic compounds in Martin's flask."
I find reports of this kind of research exciting because of the deep questions they address. It is undoubtedly challenging work, and finding answers will require intense effort by many dedicated scientists over many years. What will keep them going, apart from funding, is the belief that scientists have in methodological naturalism, the idea that the only thing that stands between them and answers to these important questions is their ingenuity.
As David R. Liu, a professor of chemistry and chemical biology at Harvard, says: ''We start with a mutual acknowledgment of the profound complexity of living systems" and he continues ''my expectation is that we will be able to reduce this to a very simple series of logical events that could have taken place with no divine intervention."
Of course not everyone is happy with that last thought. Those who seek to preserve a role for god are hoping that this effort fails, as their claim for the inexplicability of the origin of life is almost their last refuge, perhaps behind only consciousness and the mind. Cook reports:
Michael Behe, a biologist at Lehigh University in Pennsylvania and one of the leading proponents of intelligent design, said he was glad that Harvard was going to try to address the issue.
''If, as I suspect will happen," Behe said, ''they fail to find a plausible answer without invoking intelligence, then maybe science will be less hostile to folks who see intelligent direction in the history of life," he said.
To my mind, this sentiment captures perfectly the anti-science view of the intelligent design creationism (IDC) people, and shows very clearly why IDC should never be part of science. When Behe says he "suspects" that answers won't be found, he really means "hopes," since he has no basis for his suspicions except his faith that god created life. The IDC people actually want to see science fail to answer an important question in order to preserve their religious beliefs.
People with such attitudes can never do really good science because they will willingly and happily give up at the first sign of difficulty and let god do the explanatory heavy lifting. To do science at the frontiers requires one to be willing to work very hard, overcoming setback after setback, spurred on by your belief that an answer exists and is discoverable. The IDC people, always eager to pull god out of their hip pockets to answer tough questions, just do not have what it takes.
We can let Richard Dawkins have the last word on this (thanks to MachineLikeUS.com):
You see, if you say something positive like the whole of life – all living things – is descended from a single common ancestor which lived about 4,000 million years ago and that we are all cousins, well that is an exceedingly important and true thing to say and that is what I want to say. Somebody who is religious sees that as threatening and so I am represented as attacking religion, and I am forced into responding to their reaction. But you do not have to see my main purpose as attacking religion. Certainly I see the scientific view of the world as incompatible with religion, but that is not what is interesting about it. It is also incompatible with magic, but that also is not worth stressing. What is interesting about the scientific world view is that it is true, inspiring, remarkable and that it unites a whole lot of phenomena under a single heading. And that is what is so exciting for me.
POST SCRIPT: No Joementum!
The indispensable Stephen Colbert looks at democracy and the Democratic senatorial primary in Connecticut.