I've also been wondering whether the kestrel in Kes is a reference to Gerard Manley Hopkins' windhover. And looking into that led me to discover Hopkins' idea of inscape. According to The Victorian Web, Hopkins wrote: "Each mortal thing does one thing and the same:/ . . myself it speaks and spells,/ Crying Whát I dó is me: for that I came." Tolkein expressed Hopkins' idea by saying that, "Each being in the universe 'selves,' that is, enacts its identity." This is not exactly "The Nothing noths," but it isn't a million miles away from "The World worlds," it seems to me.
Apparently the idea comes from Duns Scotus, and I don't have much to say except that I like it. Here's Hopkins on a tree:
There is one notable dead tree . . . the inscape markedly holding its most simple and beautiful oneness up from the ground through a graceful swerve below (I think) the spring of the branches up to the tops of the timber. I saw the inscape freshly, as if my mind were still growing, though with a companion the eye and the ear are for the most part shut and instress cannot come.This is quite different from Sartre. If Anthony Rudd ever wanted to write about more people looking at a tree he might do well to include Hopkins.