Introducing David Berlinski:
Having with indignation rejected the assumption that the creation of life required an intelligent design, Mr Fletcher has persuaded himself that it has proceeded instead by means of various chemical scenarios.
These scenarios all require intelligent intervention. In his animadversions, Mr Fletcher suggests nothing so much as a man disposed to denounce alcohol while sipping sherry.
Heh, heh. Vintage Berlinski.
If experiments conducted in the here and now are to shed light on the there and then, they must meet two conditions: They must demonstrate in the first place the existence of a detailed chemical pathway between RNA precursors and a form of self-replicating RNA; and they must provide in the second place a demonstration that the spontaneous appearance of this pathway is plausible under pre-biotic conditions.
There's a third condition bearing on the plausibility of RNA world scenarios. There is a need to show that self-replication evolves into systems of interacting components which replicate as systems. System replication characterizes life.
The existence of a synthetic pathway has now been established. (Matthew W. Powner et al, “The Synthesis of activated pyrimidine ribonucleotides in prebiotically plausible conditions," Nature 459, 239–242, 2009).
Questions of pre-biotic plausibility remain. Can the results of Powner et al be reproduced without Powner et al?
It is a question that Powner raises himself: "My ultimate goal," he has remarked, "is to get a living system (RNA) emerging from a one-pot experiment."
The ultimate goal- a living system from a single pot of soup. But, getting to the heart of the matter:
If the steps leading to the appearance of the pyridimines in a pre-biotic environment are not yet plausible, then neither is the appearance of a self-replicating form of RNA. Experiments conducted by Tracey Lincoln and Gerald Joyce at the Scripps Institute have demonstrated the existence of self-replicating RNA by a process of in vitro evolution. They began with what they needed and purified what they got until they got what they wanted.
Although an invigorating piece of chemistry, what is missing from their demonstration is what is missing from Powner's and that is any clear indication of pre-biotic plausibility.
And closing with Berlinski's trademark wit:
Mr Nagel is correct in remarking that Mr Fletcher is insufferable. Mr Walton is correct in observing that the RNA world is imaginary. And Mr Fletcher is correct in finding the hypothesis of intelligent design unacceptable.
He should give it up himself and see what happens.