The Scarcity of Life Bearing Planets

Rick Sobie wrote:

I give up. There is no intelligent life on this planet. So how
do you expect to find it elsewhere?

How would we perceive intelligence in a species that is physically alien
to us? We can't even decide whether dolphins or apes are intelligent (I
think they are) and these critters are made of pretty much the same DNA
as we are. If we can't make a conclusive decision in these cases, how
would we manage in a truly alien context?

Bob Kolker