How to be an Expert: The Difference Between Knowledge and Understanding or What Job Candidates Can Learn from Max Planck’s Chauffeur

Max Planck, who won the 1918 Nobel Prize in Physics, was one of the founders, if not the founder, of quantum mechanics/physics. (Just as an aside, he was involved with the plot to kill Hitler, for which his wife was assassinated.)

Apparently, in his time, it was not common practice for physicists, even prominent ones, to be photographed. As the story goes, he would travel throughout Germany speaking to lay audiences. One day his chauffeur told him that he had heard his presentation so often that he could give it himself. So, at their next stop, they changed hats, and the chauffeur entered the hall where the presentation was to be given wearing the professor’s hat and the professor was wearing the chauffeur’s cap.

The chauffeur perfectly recited the lecture. He was flawless. And then things started to fall apart. Following his remarks, people wanted to ask questions. The chauffeur knew the speech, he had the knowledge, but he lacked the understanding so he could not answer the first question.

Apparently Professor Planck was smart about hiring as well as physics! The chauffeur did not miss a beat. He looked at his questioner and responded, That question is so simple I’ll have my chauffeur answer it!

I’ve read this story a couple of times. I want to believe that it is true. Even if not it is something to keep in mind because the lesson is valid. Repeating what you have heard does not make you anything make than a recorder. To be an expert, you need understanding. So in an interview, if you can’t explain it, don’t say it!


Bruce Hurwitz is an executive recruiter and career counselor. His posts on LinkedIn have been read over 300,000 times and have garnered national and international media attention.  In addition to serving on the Board of Directors of the Manhattan Chamber of Commerce, he chairs their Entrepreneurs Network, hosts their weekly podcast – The Voice of Manhattan Business – and serves as an Ambassador. An advocate for the protection of job seekers, visit the homepage of his website,, to read about questionable offerings of so-called job search assistance companies and to learn about his upcoming speaking engagements.

%d bloggers like this: