It all depends on how evolutionary theory goes from here. If they find that non organic materials can quite easily (geological time scales speaking) form organic compounds that become RNA self replicating to what we are today, there must be life out there. If they find it is very very very remote even by galactic distances for it to happen probability wise, then perhaps we are alone.

For me, the recent space telescope findings showing that in just a few years of looking they have found thousands of extra terrestrial solar systems and quite a few of those planets fall within the goldilocks ranges for advanced life... Well I think in a billion billion galaxies around us there must be at least ONE other form of life. Perhaps we will find out we will never meet due to the constraints of distance. I don't think we have ever been visited, if you had the ability to go across space to wherever you wanted there must be much more interesting things to see than mankind.