I believe Feynman did not even use a sarcastic tone of voice. Feynman stole the door, and when everyone was arguing about it, Feynman said he knew how to solve it: Have everyone swear on their honor not to lie, and then ask them point blank whether or not they took it. So the head of the house went through each member, asking them to swear, and then asking if they took the door. When they reached Feynman, he swore, and then said that yes, he did take the door in a deadpan serious voice. They told Feynman to stop joking around, and then just went on to the next member in line, asking them to swear and whether or not they took the door, etc.
And like you said, when they later found out that Feynman had indeed taken the door, nobody remembered that he had actually said “yes” when asked.
Feynman didn’t want to set himself up for the NTaL; his idea wasn’t the honor pledge but a plea for the anonymous thief to return the door as secretly as it was taken, with a heaping of praise for the thief’s ingenuity. (Feynman was honest, but nobody ever accused him of humility.)
But when someone else came up with the honor-pledge solution, he did the only thing that comported with his ethic of literal honesty.
“Jack, did you take the door?”
“No, sir, I did not take the door.”
“Tim: Did you take the door?”
“No, sir! I did not take the door!”
“Maurice. Did you take the door?”
“No, I did not take the door, sir.”
“Feynman, did you take the door?”
“Yeah, I took the door.”
“Cut it out, Feynman, this is serious! Sam! Did you take the door...”— it went all the way around. Everyone was shocked. There must be some real rat in the fraternity who didn’t respect the fraternity word of honor!
. . .
Sometime later I finally admitted to taking the other door, and I was accused by everybody of lying. They couldn’t remember what I had said. All they could remember was their conclusion after the president of the fraternity had gone around the table and asked everybody, that nobody admitted taking the door. The idea they remembered, but not the words.
I believe Feynman did not even use a sarcastic tone of voice. Feynman stole the door, and when everyone was arguing about it, Feynman said he knew how to solve it: Have everyone swear on their honor not to lie, and then ask them point blank whether or not they took it. So the head of the house went through each member, asking them to swear, and then asking if they took the door. When they reached Feynman, he swore, and then said that yes, he did take the door in a deadpan serious voice. They told Feynman to stop joking around, and then just went on to the next member in line, asking them to swear and whether or not they took the door, etc.
And like you said, when they later found out that Feynman had indeed taken the door, nobody remembered that he had actually said “yes” when asked.
Feynman didn’t want to set himself up for the NTaL; his idea wasn’t the honor pledge but a plea for the anonymous thief to return the door as secretly as it was taken, with a heaping of praise for the thief’s ingenuity. (Feynman was honest, but nobody ever accused him of humility.)
But when someone else came up with the honor-pledge solution, he did the only thing that comported with his ethic of literal honesty.
. . .