> fair reason to doubt that advanced life is common
Emphasis mine. This is an enormously different and stronger claim than just "life is common". Personally I think it's most likely that cells are relatively common (given a habitable planet anyway), but anything as complex as a fish is very rare.
I think it's reasonably likely (but not certain) that simple forms of life are plentiful, and it is even possible that life more advanced than us exists out there. What I absolutely reject is the notion that I should feel quite certain of the latter because "so many stars!"
Emphasis mine. This is an enormously different and stronger claim than just "life is common". Personally I think it's most likely that cells are relatively common (given a habitable planet anyway), but anything as complex as a fish is very rare.