The renowned and divisive Hungarian-American physicist Edward Teller would tell this little story about an exchange he had with the great Niels Bohr:

Some of us, including Bohr, were having a discussion about the spectrum and states of molecular oxygen. Bohr had some opinions, the details of which I have now forgotten, but which were in obvious conflict with the facts that were known. In this special detailed case, I knew the situation and tried to explain it. Unfortunately I could not do so to Bohr’s satisfaction.

He began his objection: “Teller, of course, knows a hundred times more about this than I.” With a lack of politeness occasionally seen among twenty-year-olds, I interrupted (with some difficulty): “That is an exaggeration.”

Bohr instantly stopped and stared at me. After a pause, he declared, “Teller says I am exaggerating. Teller does not want me to exaggerate. If I cannot exaggerate, I cannot talk. All right. You are right, Teller. You know only ninety-nine times more than I do.” He then proceeded with his original argument having dispensed with any possibility of further interruption.

I have never forgotten, nor have I often neglected to mention, Bohr’s wisdom: *If you cannot exaggerate, you cannot talk.*

This is one of my favourite stories. (I’m with Bohr, surprise.)

• from Niels Bohr: A Centenary Volume, edited by A. P. French and P. J. Kennedy, Harvard U. Press, 1985.