Consider "Planet Without Laughter" (note this from the site of Knuth-- that Knuth --and presumably he hosts it there for a reason, so pay attention kids!)
https://www-cs-faculty.stanford.edu/~knuth/smullyan.html
Also he looks like Gandalf! :)
In any event, I don't think the piece is meant as a "ha ha" comedy. It's more of a contemplation or a work of philosophy.
Did it make you smile at any point?
The moral I extracted was that free will is fake and humor is all that matters. If that's the case I'd have hoped he'd have thrown a few more jokes in ;)
If not, um... retroactive spoiler warning? Sorry.
Say, have you heard of that book, The Three Knuths of Ypsilanti?
https://en.wikipedia.org/wiki/Far_Rockaway,_Queens#Notable_p...
It seems Smullyan moved to Manhattan and went to high school in the Bronx, so they would not have been at Far Rockaway High School together.