Current research assumes that life’s origin must be a fully natural event, whether it occurs due to an as-yet-unknown law of nature or by chance. The results are not a cause for celebration. “RNA world,” the current best accepted theory, is simply a proposal that in the comparatively simple earliest life forms, RNA might have done DNA’s job. But RNA must then have co-evolved with the proteins whose work it directs. As we saw earlier, the thesis has been called by rival theorists everything from “absurd to imagine” to the equivalent of a gorilla preparing a coherent chili con carne recipe. Rivals indulge in ridicule when they have little to fear from the rejoinder.
University of Chicago cell biologist James Shapiro* offers a different, conceptually more attractive approach, a 21st-century theory of evolution as he terms it. He proposes that life forms can in fact organize themselves. He writes:
Living cells and organisms are cognitive (sentient) entities that act and interact purposefully to ensure survival, growth, and proliferation. They possess corresponding sensory, communication, information-processing, and decision making capabilities …
But can one properly use terms like “cognitive” or “purposefully” apart from demonstrated intelligence? And how does he think living cells and organisms began to exhibit such qualities?
Self-organization theory in general is fuzzy on how a life form gains the intelligence to organize itself. One of the best-known theorists, Stuart Kauffman, has described his work as “alchemy,” a term that famously resists specifics. David H. Koch, wealthy chemist and funder of TV evolution documentaries, tries to help by explaining,
It’s a deeper approach to understanding evolution. They’re not kooky ideas. The concept of self-assembly, for instance, where you put certain chemicals into a beaker or test tube, shake it up and vesicles form.
At times, it happens. Last October, one group of researchers reported that fatty chemicals formed a primitive version of a cell membrane and “got the chemicals close enough to react in a highly specific manner”:
Computer calculations reveal that even by chance, five liposomes in 1,000 could not have trapped all 83 molecules of the assembly. Their calculated probability for even one such liposome to form is essentially zero.
So, they concluded, “self-assembly into simple cells may be an inevitable physical process.”
Now that’s a leap. A 2014 article in Chemical Reviews, surveying the field to date, notes that “Even the simplest microorganisms known on Earth are breathtakingly complex,” with the result that the probability of a random series of events of physics and chemistry leading to a bacterium by spontaneous self-organization of biomolecules “is negligibly low.”
Irritatingly, self-assembly does sometimes happen. But the way it happens is no help. In 2009, one type of “Lazarus” bacterium, accustomed to extreme conditions, astonished researchers (who referred to such processes as “miracles”) by reconstituting itself within hours of its DNA being shattered by desiccation and radiation. The sample organisms proceeded to live normally. Clearly, the bacterium re-self-organizes, so to speak, guided by something that survives the destruction of its DNA.
But have we any reason to believe that this extra layer of interior guidance is an “inevitable physical process”? Far from it, the bacterium had to already exist in a specific form in order to self-reassemble. So it points to new levels of the specified complexity inherent in the life processes for whose origin we cannot account even without such a capacity.
The good news is, self-organization might play a role in life forms if some of the great physicists are right: Mind or intelligence, or at worst information, underlie the universe, not matter. As John Wheeler expressed the idea: “It from bit.” In that case, perhaps we can discover laws by which information “self-assembles” into life. But they would be laws of information, not of physics or chemistry.
And those do not seem to be the laws that origin-of-life theorists want to discover. Admitting that there is no general consensus on what life is, the Chemical Reviews survey article nonetheless declares that it is clear that “all the current biodiversity is the outcome of Darwinian evolution from a primitive cellular species.” Darwinian evolution is, famously, blind. Similarly, Richard Egel et al. tell us that their book, Origins of Life: The Primal Self-Organization (2011), “distances itself from any intelligent design/creationist approach.” If the authors are so sure that blind processes drive the subsequent history of life, it is no wonder that they are thought to drive the prior self-organization too. That confidence has survived nearly a century of research whose main discovery is a host of inventive phrases describing dead ends.
But wait. What if there have been rare times and places where a combination of law and chance click just right? It could be on a comet or in a volcanic vent. And the key ingredient might be an overlooked chemical element. Could a truly unique occurrence shake that bit right out of the it?
* Not to be confused with the late New York University origin-of-life chemist Robert Shapiro.
Editor’s note: Here are links to the whole “Science Fictions Origin of Life” series.
Photo source: Tom Mooring/Flickr.