In other words, they're saying "we don't know yet", which most of us kinda already knew.
...they argue that the life here on Earth could be common, or it could be extremely rare...
I'm a cynical optimist. I think the only way out is through, but once we get through it'll be better. Very different, but better. Howard Tayler
It is not the strongest of the species that survive, nor the most intelligent, but the one most responsive to change. Charles Darwin
"It is the duty of the writers to seduce me into suspending my disbelief!" Paul Beardsley
Power, Lord Acton says, corrupts. Not always. What power always does is reveal. Robert A. Caro