...in the book I'm looking at right now, "Greek Myths", I couldn't help but look it up :-). It says, and I quote: "At last the stream slacked, and
Pandora, who had been paralyzed with fear and horror, found strength to shut her box. The only thing left it it now, however, was the one good gift the gods had put in among so many evil ones. This was hope, and since that time the hope that is in a man's heart is the only thing which has made him able to bear the sorrows that
Pandora brought upon him."
I guess you can interpret this to say hope could have been unleased as well if
Pandora hadn't shut it in, but also that it already resided in the hearts of men. But if they didn't have that hope they weren't gettin any any where else. :-) But, who really knows anyway?