He/She exists : But only in people's minds :-) People always needed and need something to believe in in order to explain "unexplainable" things. For most people,life doesn't seem so bad if you know there is an afterlife or a power that makes things meaningful. Try to argue with some people that God/whateveryouwanttocallit DOESN't exists. That is when things get tough.

You can argue that anything exists, but it doesn't mean it does.