I refuse to answer this question on the grounds that doing so should count as my Ph.D thesis but won't.

I was thinking of sending the Eid signal for this... I'm glad to see you! Why not talk? We won't tell.

He's afraid that someone will publish his brilliant thoughts on the subject... other than on the webs.

Sleeping keeps us from falling asleep involuntarily, that's all. It's a drive greater than eating, greater than clothing, shelter, sex, even chocolate. If we need sleep, it will take precedence over whatever else we need to survive. If we don't sleep on purpose, we will sleep accidentally.

Sleep is a consciousness-creation factory. You actually have a finite amount of self-awareness, and it's manufactured in sleep, and used up during waking hours. Dreams are the side-effect of consciousness being reassembled.

(I'm only half-kidding -- I really do believe something sorta like this).

I'll tell you one thing; sleep is advantageous. The more a species can sleep, the more it will.

You'd never guess it, but one of the main functions of sleep is homeostatic temperature regulation. In sleep deprived rats, you get chills, then fever, then death. Pretty wacky, but the body loses the ability to control its own temp. without sleep. Personally, I think sleep lengthens the lifespan of an organism, which is why species that can will. I know folks who wish they didn't have to sleep and could work/play during that time, but I'd rather portion my time out over a longer span of time with intervening bouts of unconsciousness. But hey, some people who win the lottery take the lump-sum option, or they wouldn't offer it.