It is surely important that the differences between coma, deep sleep, being under anesthesia, on the one hand, and being alert on the other, all involve changes in the brain.

Eventually I realized that for contemporary philosophers conceptual analysis per se was an end in itself. For some, it was somehow supposed to lead to the truth about these phenomena, not just to tidy things up a bit.

Humility bids us to take ourselves as we are; we do not have to be cosmically significant to be genuinely significant.

It seems that the brain has a "small world" architecture - or at least the cortex does. Everything can connect to everything else in a few synaptic steps.

Early studies of sleep and dreaming were crucially dependent on waking subjects up during sleep to find out whether they are dreaming or not. Using that strategy, it was found that when the eyes are rapidly moving (REM sleep) people are usually dreaming; when the eyes are not moving, there may be some mentation, but little in the way of visually rich dreams.

In all probability, mental states are processes and activities of the brain. Exactly what activities, and exactly at what level of description, remains to be seen.

I made the assumption, wrong of course, that conceptual analysis was a brief preliminary on the road to finding out about the nature of free will, consciousness, the self, the origin of values, and so forth.