[Thatcherite]

What are the probabilities of a nucleic acid molecule self assembling?

I don't know. How big are they, and how big are the components of them that might be expected to exist in a primordial pool? And how many potential ones are there? (I take it we aren't talking about a particular nucleic acid, any one will do, right?)

[general_re]

And how many potential ones are there?

Well, there's the rub - not only do we not know what this presumed "prime organism" was supposed to have looked like, we haven't got a clue how big the solution space is. Nevertheless, despite the fact that I doubt your interlocutor has actually gone into the lab to figure out how many possible genomes of length n result in viable self-replicators, I predict that a firm number will be presented regardless. Or the (currently) implicit assumption that one and only one solution exists will be made explicit. Take your pick.

[animoveritas]

I am proposing that assembly of a chain to some reasonable length would reach a point of relative efficiency where it could replicate, methodically assemble, and become an organism.

To characterize this proposal, I considered a population of sugars and phosphates large enough to ensure no starving, densities facilitating bond trials averaging every second, no external interdiction, and energy sources sufficient for any of the biochemical and biophysical actions.