" 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 Pelorat, " 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 by allowed to overcome planetary concerns. "