Imagine, somewhere out there, 60 light years ( 352 476 100 400 000 miles ) away someone may be watching first run episodes of The I love Lucy show. We are here waiting patiently for any signal from anyone.
Whether or not someone is watching Lucy or if we will ever hear from anyone is unknown. Since we cannot go star hopping and check out the distant planets first hand we have to rely on the chance there may be a signal. The decision to listen for a signal is based on probabilities or as I affectionately refer to it SWAG (Scientific Wild Ass Guess). There is NO way of knowing if there is life anywhere else unless and until we receive an undeniable signal from them. So to say there IS or that there ISN'T life out there is no more than a guess by ANYONE, scientist, cosmologist, astronomer, or regular Joe. No one's opinion, regardless of how much math they use, is any more valid than the next guys.
One thing to consider is the discovery of so many extremeophiles in places we never thought life could exist.That in itself increases the probabilities that life could exist on many planets even though WE couldn't exist there. "Life as we know it" has taken on a much larger ecosystem than before and that needs to be taken into account when we contemplate life on other planets. Now there is a BIG difference when you specifically qualify "Intelligent" life. That being someone who has discovered Radio and Television or who can receive and transmit electromagnetic waves containing useful information. There you may have a limiting factor.
