The Physicist And The Chauffeur

How do you know what you know?…

Allegedly, shortly after winning the Nobel Prize in Physics in 1918, Max Planck went on a lecture tour across Germany. Wherever he was invited, he delivered the same lecture on new quantum mechanics before audiences of physics specialists and enthusiasts. Over time, his chauffeur, who accompanied him and attended the lectures, came to know the text by heart. One day, he suggested, “Would you mind, Professor Planck, because it’s so boring to stay in our routine, if I gave the lecture in Munich and you just sat in front wearing my chauffeur’s hat?…”

And the story goes that Planck accepted this amusing idea.

With conviction, the chauffeur recited the text in front of the experienced and attentive physicists, after which a professor stood up, raised his hand and asked a question. The speaker said, “Well I have to say that I’m surprised that in an advanced city like Munich I get such an elementary question. I’m going to ask my chauffeur to reply.”

While the chauffeur knew the text, he was quite incapable of answering specific questions. In his own field of expertise — the chauffeur had a solid knowledge of automobile mechanics — he would have been very comfortable, but in quantum physics, he was outside his field of expertise. He was however able to skillfully avoid an embarrassing moment, with undeniable wit and presence of mind.