joe & bill met on a street corner. when joe said he was sure glad to see his friend, bill said, "how can you see me when i'm not here"? "& i'll bet you $10 i can prove it. "you're going to bet me $10 you're not here, okay, it's a bet. go ahead & prove it". "am i in chicago?. "nope". "am i in new york"? "nope". "well if i'm not in chicago & not in new york, that means i'm in some other place, right"? 'that's right". "well if i'm in some other place, i can't be here, i'll take the $10". "how can i give you the $10 if you're not here"?