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.
ADDENDUM 10/4/2024: An old math joke comes back to undeadness.
My friend Roz, in an email, raises a fair objection: It’s pretty obnoxious for 100 logicians to walk into a bar and not order anything. (Though maybe, he points out, “they were all going into the bar to accommodate suspected drinkers, which is a nice gesture, albeit very dorky.”)
Anyway, as usually told, the joke has them all ordering a beer. But Roz proposes an even better alternative:
Tony, fleeing a zombie apocalypse, takes refuge in a conference hall. He ducks under a half-collapsed banner that says “Logicianpalooza 2028.” In the shadows, it seems safe.
Then, suddenly, he hears shuffling steps. A figure is silhouetted in the low light.
“Who’s that?!” shouts Tony. He lights one of his flares and holds it up. One rumpled academic is squinting in the sudden light — no, there are six of them — no, oh no, he pans around revealing maybe 100 in total. Some have ominous sores on their faces. None are overly aggressive, but he’s completely surrounded.
“Hello,” Tony says, cautiously. “Have we all avoided the infection?”
“I don’t know,” says the first logician.
“I don’t know,” says another one.
It goes like this, until the final logician, who says: “No.”
It is the last thing Tony ever hears.
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