"So evolving intelligence seems likely, given a propitious habitat..." I would argue the opposite. Human level intelligence isn't necessary for survival, so wh

"So evolving intelligence seems likely, given a propitious habitat..." I would argue the opposite. Human level intelligence isn't necessary for survival, so why should one assume that it's bound to be common when its not even the case on Earth now or in it's history? What percentage of life that has ever existed on earth could you consider to have an intelligence on par or better than ours? Obviously less that a hundredth of 1%. If evolution is the law of life, then I doubt that intelligent life in the universe is as common as is assumed