a) I agree with several posters that the "you are what you eat" theory is by far the most morally/philosophically interesting candidate for the inhumi secret, and also the most consistent with what I would expect from Wolfe. But it doesn't seem to fit with Horn's description of the secret, as has also been pointed out. (And let's assume that this isn't just because Horn is far from the brightest bulb in the chandelier, and is also a somewhat incoherent and inconsistent narrator). A much more boring variation, but one which might fit the known facts better, is a bit more physical/literal. Suppose that it's particular chemicals - e.g. adrenaline - which make the inhumi more intelligent/humanlike. So if the humans organise themselves to stay a bit calmer and be a little less afraid of the inhumi, the latter would become gradually less intelligent (and maybe eventually even our heroic narrator would be able to outsmart them ;-). I know this sounds like an old Star Trek script, and I rather hope it's
not the secret, but it seems to work a little better with respect to Horn's description of the secret. It allows the humans to continue to be intrinsically sinful creatures, but encourages them to try not to act out their sins, because this would fill their bloodstreams with inhumi-stimulating chemicals. Hmmm...
b) How many Silks? I've always liked the much-debated theory that the "special embryos" of which Silk is one (and Hyacinth is another? My memory fails me on this point) were designed as receptacles for the Mainframe Gods to download into as part of the Plan of Pas. (The main sticking point being whether Mainframe is required to engineer/maintain a theophany). If the embryos are designed for this, you would expect there to be a degree of redundancy. So maybe there's more than one Silk running around on the Whorl and/or on Green/Blue? There's no evidence for this that I can recall, but it seems an interesting possibility. Maybe there's an alternate reading of BOTLS in which different "Silks" take part in different parts of the story without Horn noticing :-).
auld newt
*This is WHORL, for discussion of Gene Wolfe's Book of the Long Sun.