Who is a Jew?
--No, Who's on first.
What is a Jew?
How is a Jew?
--Fine, thanks! How are you?
Where is a Jew?
Why is a Jew? Why, oh why, oh why?
--Because, because, because, because. Goodbye, goodbye, goodbye.
(Or, as we used to say in the '70s, "Jew is not a problem to be solved, but a reality to be experienced.")