There are various flavors of pan-psychism (and the "consciousness-first" idealists, who think that Mind is a substrate below Matter). There are some who claim t

There are various flavors of pan-psychism (and the "consciousness-first" idealists, who think that Mind is a substrate below Matter). There are some who claim that it goes all the way down, that even subatomic particles experience a micro-consciousness (and we can't rule it out, even as I share your skepticism). One common confusion (IMO among critics and supporters alike) is to say something like "a rock experiences rock-ness". But this suffers from a compositional dilemma: does half of the rock experience half-rock-ness? If we flipped a coin for every atom, do the heads-flip rock atoms have their own experience? If we pick two rocks at random, are they experiencing two-rock-ness? It gets silly fast. This is one thing that fascinates me about "ontology", simultaneously an inquiry into categories, and Being. It bewildered me at first, that it seemed to be doing double-duty on two distinct subjects, but I now see that the two are inseparable, that Being is in part defined negatively (apophatically), by the boundary that separates the Being from its not-Being. My intuition on the nature of consciousness, is that it's something akin to a field which permeates the Universe, and that biological systems adapted to leverage that field, acting like a gravity well that concentrates subjectivity in one place, drawing a boundary (event horizon?) around experience, in a way that a rock doesn't. My ancestors could have avoided fire with "-X utility points", and sought food with "+X utility points", but it turned out to be more efficient to adapt with "fire ouch, food yum". And in zero-sum competition (predator/prey dynamics), each organism has an incentive to avoid leaking its subjectivity into another's. It's far from a full theory, but it's the best I've got. :)