I don't think that's the case where this question is concerned. I'm pretty sure 'life' has already been discovered on other planets so that's not really an issue. I think the main question is intelligent life.
Even where science is concerned on the subject they will conceed that it is very likely that intelligent life exists on other planets. That's not to say that it does or doesn't, just that the likelyhood of it being the case is overwhelming in the odds department.
If life on earth is a billion to 1, then the criteria for 2 billion to 2 exists. The same can be said for a trillion to 1. No matter what the chances are of there being life on earth given the complex nature of our being, there are enough "chances" in the universe for it to happen again.
I doubt very much we will prove intelligent life exists elsewhere in the universe, certainly not in our lifetime, but it would be nice if we got lucky