Does a similar analysis apply to the evolution of intelligence?
Here you have a planet burgeoning with life, profoundly changing the physical environment, generating an oxygen atmosphere 2 billion years ago, going through the elegant diversification that Mayr briefly summarized– and not for almost 4 billion years does anything remotely resembling a technical civilization emerge. In the early days of such debates (for example, G.G. Simpson’s “The Non-prevalence of Humanoids”) writers argued that an enormous number of individually unlikely steps were required to produce something very like a human being, a “humanoid”; that the chances of such a precise repetition occurring on another planet were nil; and therefore that the chance of extraterrestrial intelligence was nil. But clearly when we’re talking about extraterrestrial intelligence, we are not talking–despite Star Trek–of humans or humanoids. We are talking about the functional equivalent of humans– say, any creatures able to build and operate radio telescopes. They may live on the land or i