[bradleyland]

> Was it necessary to make the point as he did when he did? I don't think so.

Feynman was deliberate in his means of communication. Was it necessary? That's a tough one to answer.

As crazy as it sounds, causing your listener to be frustrated can be a very effective rhetorical device. Feynman's goal was to get the asker to think carefully about the question he had asked. Consider that, in a way, he was relaying his own sense of frustration to the asker.

Sometimes, in order to have someone truly understand you, it is necessary for them to shift their emotional state to one more similar to yours. The beauty of Feynman's explanation is that he hits the listener hard, then walks them back to a place of understanding. I thought it was a brilliant bit of teaching.

Was it necessary? I think that a short period of discomfort is a small exchange for a deeper understanding of not just how the physics of magnets work, but an understanding of how to properly ask questions, and just how deep the physics rabbit hole goes.