A planet might deteriorate even if human beings existed upon it, if the society were itself abnormal and did not understand the importance of preserving the environment."" Surely," said Elora, "such a society would quickly be destroyed. I don't think it would be possible for human beings to fail to understand the importance of retaining the very factors that are keeping them alive." Bliss said, "I don't have your pleasant faith in human reason, PEL. It seems to me to be quite conceivable that when a planetary society consists of Isolates, local and even individual concerns might easily buy allowed to overcome planetary concerns.

Foundation and Earth