With regard to your recollection of past conversations about everyone having Buddha nature: “…then we get into these weird conversations where one participant asserts that there isn’t any change in the mind that one might wish for.”
My contention would be that the mind moves right before we fall asleep, if we are able to hold to consciousness long enough to observe it. That’s a big “if”; I personally played with hypnosis a lot in high school, I starved myself as a vegan for awhile which I believe affects consciousness of the in-between state, and I slept sitting up for six months and worked the grave shift for years. Even so when I noticed that staying with the shifts in my consciousness led to waking up or falling asleep, I was surprised. So easy and something everybody has experienced.
I have written about this, and three other people have now succeeded in using something in my description to catch sight of their consciousness shifting around before sleep, and to likewise experience a connection between staying with the sense of location and falling asleep (one of the three was able to catch sight in the daytime as well, not sure about the others).
The technical description would be that consciousness takes place because of contact between a sense organ and a sense object, and that the continuity of consciousness is an illusion; that’s the classical teaching of Gautama the Buddha. Gautama also taught that there is an impact associated with the occurrence of consciousness, and there is feeling. Here is his summation of staying with this kind of experience as it occurs:
(Anyone)… knowing and seeing eye as it really is, knowing and seeing material shapes- visual consciousness- impact on the eye as it really is, and knowing, seeing as it really is the experience, whether pleasant, painful, or neither painful nor pleasant, that arises conditioned by impact on the eye, is not attached to the eye nor to material shapes nor to visual consciousness nor to impact on the eye; and that experience, whether pleasant, painful, or neither painful nor pleasant, that arises conditioned by impact on the eye- neither to that is (such a one) attached. …(Such a one’s) physical anxieties decrease, and mental anxieties decrease, and bodily torments… and mental torments… and bodily fevers decrease, and mental fevers decrease. (Such a one) experiences happiness of body and happiness of mind. (repeated for ear, nose, tongue, body, and mind).
Whatever is the view of what really is, that for (such a one) is right view; whatever is aspiration for what really is, that for (such a one) is right aspiration; whatever is endeavour for what really is, that is for (such a one) right endeavour; whatever is mindfulness of what really is, that is for (such a one) right mindfulness; whatever is concentration on what really is, that is for (such a one) right concentration. And (such a one’s) past acts of body, acts of speech, and mode of livelihood have been well purified.
(Majjhima-Nikaya III 287-288, Pali Text Society volume 3 pg 337-338, ©Pali Text Society)
I’m only saying that this is a description of something that most people experience as they are drifting off to sleep, except that it’s more like shifting than drifting because there really is no continuity. The mind is now here, now there.
Oddly enough, this freedom of mind with the associated impact and feeling is sufficient to sit, and the knowledge I need from one moment to the next seems to be intimately associated with the free occurrence of consciousness. Attachment concludes a hypnogogic state, the place of mind of attachment induces a hynogogic state.
The bottom falls out of the bucket, god help us.