Three Logicians Walk Into A Bar...

The waitress asks, “Do you all want a beer?”

First logician: “I don’t know.”

Second logician: “I don’t know.”

Third logician: “Yes!.”

How did the third Logician know they all wanted beer?

(answer below)


The waitress has asked, “Do you all want beer?” In saying “I don’t know,” each of the first two logicians is saying, “I want beer, and at this moment it does appear possible that all three of us do, but we don’t yet have enough information to say so definitively.”


The third logician wants beer, so he’s able to say for certain that everyone in the group does. So the waitress serves beer to all three logicians.

(and much merriment ensued)