Unfortunately, he could have proven that he did or did not have a baseball. Which is why God should never be compared to a baseball.
Actually he would only be able to prove that he did. If he didn't there would be no baseball to show, which is the point of the image and how it compares to God.
It is obvious that I am God - after all, every single atom of my being has been drawn from other things to create me from virtually nothing. Being an Atheist would also make sense - who am I supposed to believe in when I'm God?
Prove that I'm not - I assert that I am God, merely in human form. My powers are locked away in a different dimension and so I can't prove any of this but it's true!
Actually, false. There is a book called "A Case For Christ" thats out. It's about a man who was a journalist and a lawyer who, after his wife got saved, sought out to find all the flaws of The Bible and Christianity. After the end of many years to find the flaws... there were none. He could not find a single piece of evidence that God didn't exist. There is also a movie about this. But of course, why did I ever take the time to type a reply? When arrogant people like you will probably never watch the movie?