I agree to this extent - that I don't like the term "self-generated" or even "self-arising" and I am not suggesting that they are self-generated even under the suggestions I am making. What this text seems to clearly indicate to me is that due to natural movements of particles just like all others the images become enmeshed in ways that were not generated by an actual object in the first place, just like any kind of wave is going to be altered by contact with another wave. It's in our minds that we assemble them and believe them to be actual centaurs. I am not sure I even see the issue here or what would need to be left unexplained? Certainly our greater knowledge gives us greater insight as to what particles and waves are ever-present in the "atmosphere" around us, but the basic insight that our senses are interacting with material things that are "flying through space" seems to me to be pretty reasonable(?)
Cassius , those are two issues:
1) I am saying I do not recommend assuming that the self generated description was about the same thing as where he talks _elsewhere_ about recombinations of images. I can't see any basis for making that assumption-- you'd have to say his self generated language was misleading if he actually meant recombination, and I am not convinced he was being unclear. If he was unclear, it could be a result of failing to distinguish between images and whatever the "seeds" of the images would be-- but it's uncharacteristic for him to leave out something like that. The little section about self generated images sounded pretty intentional. I think we either take it as written or leave it in a suspense file.
2) Yes, he's making (elsewhere) an analogy about images recombining and then our brains misinterpreting the results as an explanation for our imagination of centaurs and such. He apparently didn't conceive of human imagination being a process which does not actually require something entering the brain from the outside, and this was an inaccurate but fascinatingly creative idea! In the same way, he thought images from outer space passing into the brain caused humans to believe in gods-- he did not know our brains could produce their own sensory cortex content. It's like saying the explanation for hallucinations people have in sensory deprivation tanks would be something passing through the tanks into the brain. It's a valiant attempt to explain complicated neurological processes.