Your definition in #312 was fine by me:
[to VadeRetro:] In your own words, the building blocks of our universe consisted of “certifiably mindless” material, a non-uniform gas. There was neither an actuality nor a potential for self-awareness in any of those particles. Nothing even close, I am confident in saying. And yet, the very definition of consciousness is self-awareness, the ability not just to have a mind, but to “step out” of it.
Scientifically speaking, it does not exist, because it is not observable - it cannot be located anywhere or as the result of the combinations of anything
Of course consciousness is observable. We see that other species show some signs of abstract thought, and (most) others show no evidence of such at all. We see that a person with a brain that's damaged in certain ways doesn't show signs of consciousness. We see certain parts of the brain are active while the person is engaging in different components of conscious thought.
[continuing with #312:] The problem is that you can’t get here from there. Those dots do not connect. Materially speaking, as long as the building blocks of the cosmos are mindless, unconscious atoms, then piling on block after block only gives you more mindless, unconscious atoms, but it categorically cannot give you consciousness.
Speaking of what's observable & what's not, what's not observable is the Ideal vitalism liquid or magic pixie dust that God pours/sprinkles into the atoms inside the brain that makes them "conscious atoms" so that the brain as a whole can achieve consciousness.
Incidentally, one of the productive areas of research in recent years has been the differences in genes between humans & the other primates, and what their subtle effects have been on development of the brain, ears, eyes, vocal systems, etc. It's another line of inquiry to answer the question of what structural differences, exactly, give humans the capacity for abstract self-contemplation & why others don't have it. Again, this has everything to do with how the components of the brain work together to achieve a synergistic result beyond a simple addition of qualities of its components. Exactly like water's fire-suppression capability being nowhere near a simple addition of the fire-suppression capabilities of its component atoms, because that capability comes from how those flammable component atoms interact.