Who said anything about the probabilities being the same? The evidence for life that is not on Earth is zero at the moment as is the evidence for ghosts. How can that not be clear? I think life is abundant in the universe. I don't think there are ghosts. However, the evidence for both is the same. Yes, there is "evidence" for life here on Earth (do you think I don't realize that?) but that isn't what we were discussing. It is possible for there to be life on every planet in the universe and unless it is able to communicate electromagnetically we will most likely not detect it unless/until we are able to go to other solar systems and since the closest one is over 4 light years away it is quite possible that humans will never get there. Of course it is possible that they will but the odds are probably less than 50/50 IMO.