All that biology has told us about where life might be is that everywhere on Earth where it can survive, it is. We have oodles of extremophiles in cold places, hot places, deeply buried places, deep ocean vents and so on. But none of them are removed from the other life we have which hangs out in more amenable spots. Even things which use arsenic istead of phosphorus in their DNA still have DNA. We can form the opinion that life could start anywhere under the range of conditions we know, but we can't know for certain that it could start under the extreme conditions we find in places on Earth if that sort of place were the only option. Further, we cannot assume that if that sort of place were the only option then development to intelligence might happen.

While it seems very unlikely that there is NO other life out there, that there is something which could be imagined to be intelligent in some way, which could be in its window of communication, which would have mastered some sort of way of exceeding light speed, and would be interested in us in the rather dilettante way which seems to have been observed, seems extremely lacking in probability.

I have direct contact with SETI, and the search for habitable planets.

Penny