I beleive purely based on chance (we orbit ONE of billions of stars in ONE of countless galaxies) that somewhere out there aliens do exist. But if you had the ability to travel the universe, go anywhere you want, would you really come to this war struck, polluted dump of a planet and meet the primitive, aggressive freaks that are destroying it?
Just like to add; as i said before my belief in the exsistance of alien life is down purely to numbers there are infinate chances that life exists or may come into existance at any given point in spacetime. To believe in a god relies on trusting what you have been told