Foundation and Earth (Foundation, #5)

by Isaac Asimov

Common belief, even universal belief, is not, in itself, evidence.”

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.”