minyardt:

Humans were so circular; they lived the same slow cycles of joy and misery over and over, never learning. Every lesson in the universe had to be taught billions of times, and it never stuck.
Maybe it was good that the world forgot every lesson, every good and bad memory, every triumph and failure, all of it dying with each generation. Perhaps this cultural amnesia spared them all. Perhaps if they remembered everything, hope would die instead.