One of the naturalistic theories for the origin of biological information in the origin of life is Stuart Kauffman’s “self-organization” theory. The theory attempts to account for the functional sequences of information in living systems by arguing that the information emerges automatically from a sufficiently diverse pre-biotic soup.
In his book, “At Home in the Universe”, Kauffman writes:
I hope to persuade you that life is a natural property of complex chemical systems, that when the number of different kinds of molecules in a chemical soup passes a certain threshold, a self-sustaining network of reactions—an autocatalytic metabolism—will suddenly appear. Life emerged, I suggest, not simple, but complex and whole, and has remained complex and whole ever since… The secret of life, the wellspring of reproduction, is not to be found in the beauty of Watson-Crick pairing, but in the achievement of catalytic closure.
When chemicals react, they produce different chemicals. So the idea here—call it Kauffman’s conjecture—was that mixtures with a sufficient number of different chemicals are bound to give rise to local compositions that continually replenish themselves through a self-catalyzed network of chemical reactions. Those special compositions would typically differ from the original mixture, but since they make more of themselves, they should be able to ‘grow’ by establishing themselves repeatedly in local pockets. The ability to propagate in this way, if proven, would be something like reproduction, only at the low level of chemical composition rather than at the high level of organismal form.
It was clear enough to me why Kauffman and others liked this idea. If some kind of reproduction and inheritance could conceivably be achieved in systems that are much, much simpler than anything we think of as living, then maybe scientists were making the problem of explaining life much, much harder than it really needed to be.
But now a new peer-reviewed research paper has cast doubt on this naturalistic theory.
The paper’s title is a diplomatic statement of its main conclusion: Lack of evolvability in self-sustaining autocatalytic networks constrains metabolism-first scenarios for the origin of life. It becomes clear on reading the paper that the word constrains is here being used euphemistically. After testing the effect of fitness on the evolution of their model compositional assemblies, they report that “some slight relative increases and decreases in their replication-mutation equilibrium frequencies are detected, but the effects are so minor that it is hard to think of any evolutionary relevance.” The problem is that the behavior of the whole system is almost completely determined by the inherent chemistry, leaving no room for selection to do anything interesting.
The citation is “Lack of evolvability in self-sustaining autocatalytic networks constraints metabolism-first scenarios for the origin of life”, Proceedings of the National Academy of Sciences USA, vol. 107, no. 4, pp. 1470-1475.