Surely some people-like animals have evolved elsewhere. Surely we are not, in this crowded reality of countless other similar planets, the only thinking beings to have turned up. Most unlikely! So why isn't life out there contacting us? Why aren't the intergalactic phones ringing?Here is one sobering possibility for our isolation: maybe life has often evolved to intelligence on other planets with biospheres and every time that intelligence, when it became able to alter its environment, did so with catastrophic consequences. Maybe we have had many predecessors in the Cosmos but all have brought about their own downfall.That's why they are not communicating with Earth. They have extincted themselves. They have come and gone. And now it's our turn.