[jacobolus]

This is a semantic quibble as much as a substantive one. “Asleep” vs. “awake” isn’t really a binary distinction. Both sleepwalking (which isn’t a single well-defined thing) and the kind of awake-but-then-suffer-amnesia states you are talking about (can be caused by extreme tiredness, too much alcohol, dementia, etc.) fall somewhere in between full alertness and deep sleep.

[civilian]

I think sleepwalking _is_ a defined thing. https://en.wikipedia.org/wiki/Sleepwalking What Zaphar is describing is not true sleepwalking, it's just that he was awake such a short time that he didn't form memories about it. In much the same way that I can't remember how I walked to work this morning.

[tamana]

The difference between sleepwalking and not remembering your wakeup is in how alert and responsive you are during the up time.