Huh, the fact that we have not discovered (or they discover us) any advanced civilizations or even evidence of any in our galaxy makes me believe it extremely l

Huh, the fact that we have not discovered (or they discover us) any advanced civilizations or even evidence of any in our galaxy makes me believe it extremely likely that civilizations wipe themselves out before very long. Right now, Global Thermonuclear War and Climate Destruction top my list as likely causes.