Is Intelligent Life Inevitable?

Imagine if the genetic deck had been shuffled slightly differently as some of the earliest life forms began their evolutionary paths. Might a creature just as smart as us — or even smarter — have emerged? By the same token, perhaps human intelligence is an evolutionary fluke. Perhaps, without some fortuitous mix-up on the genetic assembly line long ago, human intelligence might never have emerged. What do you think? Is intelligent life inevitable? More specifically, is intelligent life an inevitable result of evolution?

Produced by WGBH/Evolution.