There are plenty of irrefutable arguments:
first cause argument
atheists believing in things that can't be empirically proven, but denying God exists by claiming it's not empirically proven.
skeptic54768, I will happily debate you, one on one, on ANY of those topics, to allow you to demonstrate the irrefutable proof of your particular god. Let me know which one you want to do, and I'll get a debate room set up.
Make sure you do the moral argument first. Here is the formula:
(1) Invite Christian to define what the law against killing means, and let him map out all the exceptions (re punishment, war, self defence, euthanasia, abortion) , til his heart is content
(2) Invite Christian to comment on whether he agrees, alongside God, with all the anti-killing law that he just defined (he will say, yes, he agrees with God in all cases)
(3) Ask if it's a coincidence that he agrees with all the law he just mapped out, himself
(4) Ask him to justify all the law he just defined, (and agreed with), to check that he knows why all the law exists
(5) Point out that if he knows, logically, why all the law and exceptions exists, then he doesn't need God to invent them, and neither did any other civilization.
Repeat process for law against theft and false testament.
After that, point out that all other other "morals", involving polygamy, sex before marriage, homosexuality, sleeping with your mother, sacrificing beef, worship on Saturday, can't actually be decided logically, and that's why God changes his mind between the old testament and new, and there is not really any cross cultural agreement.
The basic process is to get the Christian to admit that he can defend all the laws of God. Only the laws that he can't defend
, come from God, and those laws do not constitute any morality.
Q: Why is it not OK to rape your mother?
Christian: I don't know. God just says so, but I can't think of any reason why I shouldn't rape my mother.
Q: Why is it not OK to eat your brother?
Christian: I don't know why I shouldn't eat my brother. It seems like he would taste good. Yum yum. But God says not to, so I guess I shouldn't.