Phi. It’s a fascinating notion: Imagine being able to quantify consciousness of a system by a single number and call it Phi? Those below are not conscious; those above are conscious.
It’s a fascinating notion and it’s on my long list of, “Boy, I would love this to be true… but” – right alongside m-brane, superimposed dimensions and other fun flights of mental fancy.
I think consciousness is probably a common features of many systems because I think intelligence is a common feature of many systems — and there is some kind of link between the two , although I can’t say I know what that is at the moment.
This has a nice overview of the history of Phi as well and some criticisms.