by intelligent life does that mean human level intelligence ?<br><br>I feel like once human level intelligence has evolved that reaching communication ability would be close to 100% even for pessimistic, because what you're really trying to calculate is what are the chances an extinction level  event happening between that period which was like a million years for us?  I feel like the chances of an extinction would be low meaning the chance of reaching communication is high. <br>If by intelligent life you mean animals, then yes maybe not so high.