The following is an oldish logic joke. I used it to explain a conclusion I’d come to, and I got just a blank stare and a confused giggle, so here goes:

Three logicians walk into a bar. The barman asks: “Do all of you want the daily special?” The first logician says, “I don’t know.” The second says, “I don’t know.” The third says, “yes.”

The point of the joke was that, in several situations, depending on who you ask, “I don’t know” can be a very meaningful answer. Similarly, “I’m not sure.”  While I’m at it, here’s an engineering education joke, it’s based on the same logic, here applied:

A team of student engineers builds an airplane and wheel it out before the faculty. “We’ve designed this plane”, they explain, “based on the principles and methods you taught us. “We’ve checked our calculations rigorously, and we’re sure we’ve missed nothing. “Now. it would be a great honor to us if you would join us on its maiden flight.”

At this point, some of the professors turn white, and all of them provide various excuses for why they can’t go just now. But there is one exception, the dean of engineering smiles broadly, compliments the students, and says he’ll be happy to fly. He gets onboard the plane seating himself in the front of the plane, right behind the pilot. After strapping himself in, a reporter from the student paper comes along and asks why he alone is willing to take this ride; “Why you and no one else?” The engineering dean explains, “You see, son, I have an advantage over the other professors: Not only did I teach many of you, fine students, but I taught many of them as well.” “I know this plane is safe: There is no way it will leave the ground.”

Robert Buxbaum, November 2i, 2018.  And one last. I used to teach at Michigan State University. They are fine students.