Hypothesis: consciousness is what a physical interaction feels like from the inside.

Importantly, it is a property of the interacting system, which can have various degrees of coherence - a different concept than quantum coherence, which I am still developing: something along the lines of negative-entropic complexity. There is therefore a deep correlation between negentropy and consciousness. Random thermodynamic motion in a gas is about as minimum-conscious as you can get (lots of random interactions, but all short lived and decoherent). A rock is slightly more conscious due to its crystalline structure, but probably leads a rather boring existence (by our standards, at least). And so on, all the way up to the very negentropic primate brain which experiences a high degree of coherent experience that we call “consciousness” or “self.”

I know this sounds like making thinking an ontologically basic concept. It's rather the reverse - I am building the experience of thinking up from physical phenomenon: consciousness is the experience of organized physical interactions. But I'm not yet convinced of it either. If you throw out the concept of coherent interaction (what I have been calling computation continuity), then it does reduce to causal continuity. But causal continuity does have it's problems which make me suspect it as not being the final, ultimate answer...