While I've defended abiogenesis as more likely common than not, what I am not so clear on is if intelligence isn't far more rare. To our knowledge, there were no highly intelligent tool-makers among the dinosaurs, in spite of all the survival pressures, changing ecological niches, millions of years and so on. I am not aware of arguments showing intelligence to be preferentially selected for in the broadest sense; ie, no overarching evolutionary imperative for its emergence (like to hear an argument if someone has one).
The pace of natural extinction events may also be high enough in most systems to reduce long-term chances for intelligence even further. In my understanding, extinction events bathe the galactic core, making the outer rim the goldilocks area for intelligence, no? I wonder if it is indeed valid to suggest that if there is life elsewhere in our galaxy it must have had time to expand. That assumes an early starting date in galactic evolution, while it could be generally true that stable life-supporting systems are later rather than early developments. Is there a reason that cannot be so? Perhaps you kind astronomers can fill me in.
We may very well be the first in our galaxy, or even part of the first fledgling batch, I reckon.
For each man, according to the measure of his intelligence, must speak what he can speak, and do what he can do. - Alfred, King of Wessex
Calm down, have some dip. -George Carlin