Kind of crazy how little is known about sleep in the scientific community. The answer right now to "why" we need to sleep doesn't go much deeper than "because we get tired"
As a general rule, when somebody says "nobody knows X", they are almost certainly wrong. There are 7+ billion people on this planet. Someone probably knows something you don't, for just about any common language X you could form. (They just haven't told you about it!)
I've heard of both of these theories (cleanse and consolidation) but it's kind of strange how the first sentence of the abstract is "The purpose of sleep remains mysterious." If the researchers have any confidence in their work, why are they using this language? Why not "sleep is not as mysterious" or "sleep is no longer mysterious"?
I thought it was generally accepted that the brain needs time to recover and assimilate all the input it received during the day, and that process is likely a major factor in dreams. Supporting this is the fact that smarter animals need more sleep than simpler ones and younger brains need more sleep than older ones. Any actual brain scientists can confirm whether I'm just regurgitating folk knowledge or not?
