Are you talking about this rare earth hypothesis? http://en.wikipedia.org/wiki/Rare_Earth_hypothesis http://en.wikipedia.org/wiki/Rare_Earth_hypothesis It's be

Are you talking about this rare earth hypothesis? http://en.wikipedia.org/wiki/Rare_Earth_hypothesis http://en.wikipedia.org/wiki/Rare_Earth_hypothesis It's been a decade since I read the book but IIRC very little of it had to do with whether lots of planets exist. In fact they assume microbial life is abundant but argue against complex multi-cellular life being very common. It's a fascinating book ("Rare Earth") but even without their arguments, I'm curious: why would one assume that planets equal civilizations?