The following is a conversation I recently had with an internet acquaintance. As a side note, this is how I remember the conversation and it may not be 100% accurate.
Presup: You are an atheist? You don't believe in God?
Me: Nope, I do not believe believe in God.
Presup: You don't believe in god or you deny the existence of god?
Me: Ah, you are trying to shift the burden of proof to me, I am cool with that. I'll make this easy for you, I deny the existence of god.
Presup: How did you come to that conclusion?
Me: I read the Bible, the Quran and various other religious texts and I have found none of them convincing. I have also had many many many conversations with theists over the years and none of them has ever produced a shred of evidence that any sort of god exists.
Presup: Yes but how have you proven that god does not exist?
Me: The same way you have proven fairies don't exist.
Presup: That does not answer the question, if you are going to make the claim that God does not exist you have to prove it.
Me: So you have to prove fairies don't exit before you can make the claim that fairies don't exist?
Presup: We are not talking about fairies, we are talking about God.
Me: Now who is not answering questions. Do you believe in fairies?
Presup: No of course not, but there have been no divine revelations about fairies, God has been revealed through divine revelation.
Me: Okay, provide me with evidence of this divine revelation.
Presup: I don't think you understand the position you are in, you have made a claim that you need to provide evidence for.
Me: This is what I call the "Nigerian Prince Fallacy", see I don't have to automatically believe everything anyone tells me, just because I have no evidence to the contrary, my default position is to not accept anything without evidence. If I receive an email from someone claiming to be a Nigerian Prince, who says if I send them $10,000, he will give me $10,000,000, should I believe him and send him $10,000 or should my default position be disbelief?
Presup: Your analogy does not hold up, there is evidence for God, because he has revealed himself through divine revelation.
Me: You keep saying that, but so far I have seen no evidence of god or divine revelation.
Presup: But you have not provided any evidence that God does not exist.
Me: So what?
Presup: Your position is unreasonable, you can't deny the existence of god if you have no evidence that he does not exist.
Me: Sure I can watch "I deny the existence of god because I have seen no evidence to prove his existence.", there I just did it. If you think that requiring evidence before belief is unreasonable, then I have a Nigerian Prince I'd like to introduce you to.
Presup: I don't think you understand burden of proof, you are making a claim that God does not exist, now you have to prove your claim. Lack of evidence is not in and of itself evidence. Give me an example other than God where lack of evidence is evidence for something?
Me: Sure, fairies, unicorns, leprechauns, dragons, do you want me to go on? I have the D&D Monster Manual on my bookshelf, so I can go on.
Presup: You don't understand what I am saying. You can't be 100% sure there is no God if you don't have any evidence that God doesn't exist, it is unreasonable to think otherwise.
Me: I understand you perfectly and I disagree, I think accepting any premise on face value without evidence is the unreasonable stance, not vice versa.
Presup: I don't think you are as smart as you think you are. You are not getting it, you have the burden of proof here, you have to provide evidence.
Me: My wife would certainly agree that I am not as smart as I think I am, but I do know one thing, I have never fallen for the Nigerian Prince scam, I have also never tithed 10% of my income to a church so they could build yet another church nor have I been required to sacrifice any animals.
Presup: I think your worldview leaves a lot to be desired and you still haven't proved God does not exist.
Me: I would also point out that you have done nothing to convince me that God or any god exists. I think this is where the problem is. See, I have no desire to prove anything to you, I am not trying to convert you to my viewpoint, if you want to continue believing in your god, go for it, The only reason we are having this conversation is because you challenged my belief that no god exists, had you not brought it up, I would have never challenged your belief in god, because I simply don't care if you believe in god or not. I am not and I never have been an activist atheist.
Presup: When you told me you were an atheist, wasn't that a challenge to my belief?
Me: Only if you took it that way, you told me you were a Christian weeks ago, did I ever say a word about it? In fact you did not even know I was an atheist until you asked me if I went to church. I am happy to continue this conversation, but I really think if we do you should take a different approach with me, you will never convince me like this.
Presup: Well what I am trying to do is show you that your worldview is flawed and you should at least consider the possibility that God exists and you keep refusing to provide evidence for your claim that God does not exist and you keep saying lack of evidence is evidence and that is not true.
Me: Except you are trying to overcome my very reasonable default position of not accepting things at face value. I would suggest trying a different line of questioning, because you are getting nowhere with this one.
Presup: Only because you are not thinking this through logically.
Me: Maybe that is because you have not given me anything to work with, you say god exists, but you have not defined god, the word god means a lot of different things to a lot of different people. To me, the Christian God is no different that Zeus or Allah or Yahweh. Maybe next time we can pick up with you being more specific about god and what your worldview actually is and then I can be more specific about why that god does not exist.