An old math joke comes to life.

Perhaps you’ve heard the old gag:

A hundred logicians walk into a bar. “Does anyone want a beer?” asks the bartender.

“I don’t know,” says the first logician.

“I don’t know,” says the second logician.

This repeats until the 100th logician, who concludes: “No, no beers for us.”

The joke is that each logician is operating with bizarre literalness. It’s not “Do you want a beer?” (to which each person could easily answer “yes” or “no”). It’s “Does anyone want a beer?” So if you personally want a beer, you can just say “yes,” because someone wants one (namely, you). But if you don’t want a beer, you can’t yet answer “no.” Someone else may want one. All you can say is “I don’t know.”

But by this reasoning, 99 “I don’t knows” is enough information for the 100th logician to conclude ,at long last, that no one wants a beer.

This kind of logical absurdity can give mathematics a bad name. (That name: “mathematics.”) Why not act like a human being, and say, “Not for me” or “I’ll pass” instead of the weirdly literal “I don’t know”? Are you an alien? An NPC? Or just opposed on principle to normal social interactions?

Anyway, I retell this joke because I recently lived it.

I was in a conference session when the speaker asked, “Is my mouse visible on the screen?”

There was a momentary pause.

Then, as a chorus, everyone in the room–a room of perfect logicians, each aware that they personally could not see the mouse, but needing the moment’s silence to affirm that no one else could see it either–answered, “No.”

Suddenly the joke didn’t seem so wild. In fact, I don’t think you even need proper logicians to get this behavior. It’s surprisingly natural in the context. “I can’t see it,” you think, “but maybe it’s just me?” Then, when no one else speaks up, you feel emboldened: “Okay, it’s not just me.”

Maybe the joke–and the logicians, living or dead, to whom the joke bears more than a coincidental resemblance–ain’t so illogical after all.