I don't want to give the impression that it is meaningless to ask for a definition of God, I think it is a good question if a long discussion is to ensue. However, I think that definitions can benefit and they can hinder discussions. In the case of a general question "Do you think science will prove God's existence?", I think such a question doesn't necessarily require a definition of each and every word. Perhaps 'God' is so ill-defined that it is impossibly vague and that we need definition everytime someone uses the word, but I don't think it falls into that category. True, every word with enough scrutiny falls into that category, but we have to have a cut-off at some point and proceed with the discussion. This requires a little flexibility and a little tolerance.
The question to me is what is a reasonable cut-off according to the context of the question. This is a value judgement that each of us must make (and the person who poses the question must eventually specify).
***If the meaning of the question "does God exist" is so obvious, why is it that people can't agree on an answer? Why is it that people don't waste their time asking each other "does the sun exist", or "does money exist"?***
We have to infer God's existence based on abstract inductive logic, but the inferences to the sun and money is immediately obvious.
Warm regards, Harv