Some people, including perhaps most philosophers, believe that the existence of God is a philosophical question, not a scientific one. But is it really? It seems to me that while the existence of a purely deistic God is not a scientific question, the existence of a theistic God, one who can do miracles, is definitely a scientifically testable notion. But what have philosophers said about this issue?
"... the existence of a theistic God, one who can do miracles, > is definitely a scientifically testable notion."
A Popperian would say that science requires all hypotheses to be not only testable but falsifiable. There is no way to show that the existence of a "theistic God" that can do miracles is false, only corroborate it's truth. In which case this question does not fall within the remit of science.