Regarding a prediction about life in the galaxy.

I'm convinced that these studies inevitably overestimate the likelihood of intelligence emerging. Yes we only have a sample size of one planet, extrapolating from which the chance of intelligence emerging from life appears near unity. Yet looked at another way, there are millions of different species on earth all of which have been evolving for the same length of time and only 1 of those millions has achieved written language. So are the odds 1/1 or 1/1,000,000 that once life forms that language level intelligence will follow?

I think we would do better to assume that we are pretty freaking special and therefore we shouldn't squander what we've achieved by assuming that it can happen again easily.