For some reason, something that's always stuck with me is my grandfather asking the priest at my school (it was a church school) "Do you think aliens exist?" an

For some reason, something that's always stuck with me is my grandfather asking the priest at my school (it was a church school) "Do you think aliens exist?" and him replying "I'd be naïve to think they don't". The sheer number of stars seems to make it likely we aren't alone. Whether we're practically alone, and will remain forever separated from our nearest intelligent neighbours, is a more interesting question IMO (though somehow discovering we are completely alone would be fascinating in its own right and raise further questions).