The Metaphysics of Jokes

The joke is either still funny or not funny and because of that we have either some reason for or against a particular theory of humor. So imagine the same joke but instead of the punchline being his name is Ralph the punchline is now that's a washing machine. It seems that sort of response to the question is incongruous but it doesn't actually make the joke funny. That isn't to say that questions about the metaphysics of jokes aren't important. I think that there should be more attention paid to what makes one joke the same laugh.