Jesse, thanks for your response, and I'm sorry I didn't see it a few days ago.
First, going back to look at your essay again, I was struck by the first paragraph. My essay makes a similar point, with the opposite emphasis - that is, though the principles and predictive precision of physics are unmatched, we have no clarity at all as to why physics works the way it does; in fact this question hardly seems approachable. In biology, while principles are not exact or highly predictive, there's a very clear understanding of why things happen the way they do, all the way down to the molecular level.
So we have two complementary descriptions of the "great divergence." I emphasize the way things are understood in biology, because the goal of my essay is to show that in principle it should be possible to understand physics, and also the emergence of the human mind, at a similar depth.
I also noted the question you mention in passing, in your essay - "to what extent do these emergent structures have the same reality as their building blocks?" Thankfully there are a number of essays here, particularly the one by George Ellis, that give a clear answer. Without doubting that everything in the world obeys the principles of physics, evidently other kinds of principles are equally important at higher levels, and don't just reflect our need for simplified descriptions. I'm sure you agree, since you note above the importance of qualitative features that emerge in phase transitions, even in physics. I like the way you put it - that there are "different ways of processing information" at different levels, that enable different levels of response.
As to natural language, I fully agree that "natural language may have the same informational importance for human intelligence as genetics has for life." I would say that language was certainly necessary for the emergence of reflective thought in any form, and was definitely the key factor in bringing about "qualitatively distinct behavior" in our early human ancestors.
On the other hand, the RNA code very likely evolved sometime after self-replicating proto-organisms had reached a high level of evolved complexity, though so little is known about how all this happened. Similarly, spoken language must have evolved when proto-humans were already operating in a new dimension of interpersonal connectedness. Though the emergence of language is also still hard to understand, it's recapitulated to some extent by each new one-year-old. The book by Reddy (in my essay's references) gives a good account of the unique kind of pre-verbal contact between kids and moms out of which language emerges.
Anyway, thanks again for your efforts in pulling together so many different viewpoints on the evolution of meaningful information. Your essay certainly deserves a much higher rating!
Conrad