english: But while we know a great deal more about sleep now than when Galen was around, we still haven't understood why it is that sleep, of all of our activities, has this incredible restorative function for the mind.
non_english: Iako se sad zna mnogo više o snu nego u Galenovo vreme, još uvek ne znamo zbog čega od svih aktivnosti, baš san tako uspešno obnavlja um.