David Chalmers formulated the hard problem of consciousness.

Thomas Nagel's essay on bats.

why didn't evolution create zombies (intelligent organisms without consciousness)? so much of our mental processes are unconscious (e.g. vision grammar, movement) — couldn't it all just happen without any consciousness at all?

is consciousness an epiphenomenon? i.e. its existence doesn't actually change anything. perhaps it's just a byproduct rather than a cause of anything. but a zombie, in theory, would have no reason to discuss the implications of consciousness, so doesn't that mean consciousness has had a causal impact on reality, in that we are discussing it?

Giulio Tononi: mathematical formulation of consciousness. perhaps the earth as a system could be a conscious entity on a longer timescale.

what makes consciousness hard: you can't describe it in terms of any observable behavior.

the problem of other minds: Harris claims it's actually more of a leap to believe that other minds are not conscious than to believe that they are. there's a deep analogy between how I became conscious and how any other human became conscious. it's not parsimonious to be a solipsist.

Chalmers' three possibilities for consciousness — (i) it is an epiphenomenon; (ii) it exists outside of physical processes (i.e. dualism); or (iii) it is fundamental to the universe.

some phenomena are taken as a primitive (e.g. space), and we build scientific laws around them. the same could happen with consciousness.

maybe the hardness of the problem is just an illusion, or a chance failure of our intuition. just like how the spelling of the word "boat" becomes unintuitive if you stare at it long enough.

"it from bit" hypothesis. the world as a simulation, all of physics underpinned by computation. simulation theology: postulating about the potential creator of this simulation.

reductionism: explaining a phenomenon in terms other than itself.

we have a perfect map of the neural system of the C. elegans worm, but we don't know how to simulate it because we don't understand the behavior of the underlying components.

see this wiki page:

Research has successfully constructed the full connectome of one animal: the roundworm Caenorhabditis elegans.