Predictive processing (or predictive coding, or the "Bayesian brain") is a potentially-unifying theory of cognition, first seriously considered in the 1990s. According to the more extreme versions, all experience is controlled hallucination, guided by sensory inputs, adjusted so as to minimise prediction error. (For a more detailed overview, see SlateStarCodex's description or anything by Karl Friston or Andy Clark in the last ten years.)
So we might summarise what most of the brain does as follows:
From The Oldwood, a friend's unpublished philosophical novella:
I once learned a method of living where you have to go about the following steps:
I called it estuar, because it's an s-two-r's.
There's a resemblance to be noticed here. Estuar looks like a casual description of the thought process thru which every sufficiently humanlike brain goes. It is not so much a method of living as a type of mind.
More from The Oldwood.
Every so often I conduct myself with such ignorance that I forget about estuar. Usually I'm shocked back into estuar by, ironically, sensing it, remembering it, and realizing that it is, in fact, estuar.
A human (brain) may stop thinking about estaur/predictive processing, but it would never stop using it, as The Oldwood seems to lament. Even in dreams, the method still runs, just temporarily ignoring sensory inputs.
But that's perfectly consistent with what happens with The Oldwood. He's not a human mind, but a radically different kind of mind, arising, it seems, from elaborate computations in the dreams of Evan. Or perhaps someone else — read The Oldwood to figure it out.
And in that case, impurities in Evan's (or whoever's) dreaming embeds The Oldwood's thoughts more closely to the native mechanism of a human. Hence, he's "shocked back into estaur" by doing it.
I suppose that just goes to show how effective my system is.
No, that just goes to show how pervasive "your" system is in your mind's substrate.