I've never really heard a satisfying explanation for what human consciousness is. Many scientists who study it say, "it's an illusion". But that remains an unsatisfying answer. It's like the childhood thought of, "how do I know you see the same 'blue' as I do?" Consciousness is something I subjectively experience, but I have no idea how I would measure it or validate its existence.
That gets you into some 'eastern' type thinking. Because if you practice any kind of deep meditation, or emptiness meditation, it gets you wondering – where does my sense of 'self' come from. And, am I really separate from everything else?
Which kind of brings things, in my shower-thought mind, to the idea that – perhaps we're being too 'western' about these questions; perhaps the whole universe is conscious? Perhaps things like multiplication matrices can be just as conscious as our chemically triggered neurons?
Anyway, no, none of this is 'scientific' – but, like I said, shower thoughts ...