exactly ^. The first central question is "how is it possible that we have any experience at all?"
That leads naturally to the other important question "who is the observer that's aware" i.e. who is the "we"/I that is aware.
It's telling that science has made incredible progress (e.g. in the last 100 years) but on questions such as these above, we know little more than people knew then. Although we do know a lot more about the mechanics of what and how we experiences things.
Let's try to replace "who" with "computer". Who is the computer that observes itself? all of them. A computer is not passive, a brain is not passive. It can observe itself. In other words, the parts communicate.
Maybe it is. It's a self replicator, a culture and technology preserver, a competitor in the race for resources.
I think much of what we think is human intelligence is actually crystalized intelligence in the form of language and tools. We got them by default, as citizens of our city.
Personally, I think that "who" is somewhat beside the point. "What" and "how" are the more interesting questions.
The answer to "who" just becomes "a specific instance of X" that perhaps has some low probability combination of minor characteristics compared to other Xs.
It's telling that science has made incredible progress (e.g. in the last 100 years) but on questions such as these above, we know little more than people knew then. Although we do know a lot more about the mechanics of what and how we experiences things.