It is about fundamental basis for consciousness. Stephen Hawking had sensory apparatus and a method to react to inputs. Alas, I would say he is no longer conscious. If he had no method to react, like locked-in patients, we could argue about whether they are conscious, but we are currently trying to measure consciousness in those people too by measuring brain waves (look, something changes predictably when he hears us). We don't see any evidence that sun has any sensory input or output. It's like you arguing whether 0.9999 or 0.99999 is bigger when I argue whether 0 or 1 is bigger.
> A pure observer with no deliberate actions or impulse reactions sounds like it can most definitely be conscious.
Yes, but how can we know about the existence of such observer? There can be infinite number of such observers filling every cubic millimeter of our space, but does it change anything for us? Existence of such observer is as meaningless as orbital teapots [0].
