What Is a Practical Joke?

It’s April Fools Day—a day of jokey trickery, of practical jokes.

Unlike in year’s past (2025, 2024, 2023, 2022…) I have no jokey post. Depending on how you feel about that I’d like to say either “I’m sorry” or “You’re welcome.”

I thought about soliciting examples of great practical jokes in philosophy, but of course that raised the question: “What is a practical joke?” or “What is it to make a practical joke?”

It does not appear that much philosophy has been written about practical jokes. One recent exception is “Practical Joking, Lying, and Denying” by Emanuel Viebahn (Hamburg) in The Philosophical Quarterly (ungated version here). While insightful on the relationship between deception and practical joking, it does not offer an answer to our definitional question.

So let’s be good philosophers and define our terms.  Fill in the blank in

X is a practical joke if and only if _______________

or in

A makes a practical joke on B when _______________

(or, if you prefer a different definition structure, go with that).

With luck, we’ll get some good suggestions in the comments, counterexample them into shape, and see which one is the best. If there is a clear winner, I’ll update this post with the definition, giving credit to its author, such that afterwards your name will forever be associated with practical jokes. Is that a prize? (“What is a prize?”…)

Related: “A Parody Issue of Mind… from 118 Years ago“