Why is it out of the question that there could be other universes, you know for a fact there is one. Why not two or more? What evidence are you using to think the universe is so unique there couldn't be another?
Why is out of the question there is a Creator? Neither are out of the question for me. In fact one does not even rule out the other. However, this is the logic that is killing the rabid atheists like Stu and FC -- The constants of our universe is so finely tuned - that tuning is evidence of a Tuner. The rebuttal to that conclusion is that if there are infinite other universes you would not be surprised to find one that is finely tuned for life.
Whatever might not be out of the question for you, a 'Creator' is out of any scientifically based question. That's the thing whether you like it or not. A religious so called explanation, is not a scientific one. Before multiverse comes into it, the rebuttal to that false conclusion is, credulity toward the value of constants of the universe does not make them fine tuned.
Which is why this argument is pointless. Not because the other guy can't be convinced, but imo because it's actually two different arguments, i.e. you're arguing past each other.
Many Christians actually believe stories like these; a snake talked, the life span of men used to be hundreds of years, a man lived inside a fish for three days and many more crazy myths. It's impossible to have a reasonable conversation with these people about facts and evidence and probabilities when the answers conflict with their religious beliefs.
I agree with you to a point. Someone stating they want to believe there is a 'Creator' whatever science says or doesn't say, basically I have never had an argument with. If you think it's pointless to argue against misinformation and untrue statements like... "The constants of our universe is so finely tuned...", not withstanding the appalling grammar, well I would wonder why one would bother posting on a message board at all.