Noticing is masochistic and disgusting, and the scientific Victorian and pre-Victorian request to pay attention was a lever that could be used to pry Victorianism itself off the wall. Powys is as conscientious with "the red-brown heap" as he has been, in the past, with a dog. His character Porius is aware of it for nearly a hundred pages. Even though Porius' mother is here when she is usually elsewhere, even though Gog and Magog are mentioned, and prisoners brought in, and his soul mate has been killed, and his male relatives are being killed by people who want to overrun the forest kingdom, corpses are desecrated and the horses are speared, he still notices the heap, "neither discouraging the flies nor obliterating the disgust."
New component of his thought machine, it conducts him to ideas that he would not have had without it there; in other words it will lead Powys to sentences, and then those sentences will abandon him (being finished and full stopp'd) and he will go on to other sentences. (The notion of the heap must have come first and then the sentences must have occurred to him afterwards, the author setting himself up for his own surprise, or lighting his own firecrackers with a long fuse.) Porius wonders if thought itself could have some properties of excrement. "What if to certain avidly greedy insects certain thoughts in certain minds possessed the same sort of attractive taste as this shining heap of excrement? Why shouldn't certain thoughts which could be as vivid and palpable as mine of that Uriconian flask, possess enough of the substance of matter to be actually nibbled at by greedy flies?"
And Powys is not following the train of ideas that might seem obvious when a character in a book is comparing thoughts to excrement -- he doesn't say, Life is excrement, this is all pointless, thinking is stupid, a shit is as good as a think -- making it storybook-symbolical-meaningful in that direction -- he is demanding a different aspect of the heap, which is its tangible solidness. The flies' senses respond to the "vivid and palpable" object, the response is proof that the object exists. One of the male relatives is dying. Porius is discriminating between the insects that will be attracted to the thoughts. He imagines that his father and mother will have their thoughts nibbled by less interesting insects, "bronze-coloured dung-flies and blue-bottle blow-flies," while his own thoughts will be nibbled by "languid brown moths."
The heap, the flies, and his estrangement from his parents, are all inside the same machinery of thought. The integrity of that machinery must be important to the author because he spends so much time following it.
(He starts by measuring the immeasurable again, and again with an if -- if such a measurement could be made ... which means that, since it has come to occupy the same world of prose now as everything else, it genuinely has been made:
There is no doubt, however, that had the servant of the late Druid, who was soon to be established in Ty Cerrig, used all the thought-reading power he possessed he would have been in a position to show that instead of Euronwy's and Einion's thoughts being fit food for lively dung-flies, while the uncle's and the nephew's were worthy of languid moths, it was, in the judgement of higher beings, just the other way round. Both Porius and Brochvael were at that moment projecting thought-clouds into the autumnal sunshine by no means marked by any superiority over those of the wounded man or his wife.)
He imagines thought made solid, but the solidness is unwieldy, it is not static, and not controlled: Porius is not concentrating on the gradual death of the male relative in front of him, and if you asked the question, "What would be one of the irrelevant and unlikely things you could think about during one of the most dramatic moments of your life?" then "I would think about my mental processes as if they were a heap of dung and brown moths were eating them," would be one of the answers. I believe in the integrity of thought, says Powys: therefore I need to believe in the integrity of waywardness. I will not only acknowledge it but mine it.