An expert is a man who has made all the mistakes, which can be made, in a very narrow field.

More from Niels Bohr

• The opposite of a profound truth may well be another profound truth.
• Your theory is crazy--but not crazy enough to be true.
• 24 beers in a case, 24 hours in a day, coincedence? I think not.
• A bank is a place where they lend you an umbrella in fair weather and ask for it back when it begins to rain.
• Above all, do not fail to give good dinners, and to pay attention to the women.
• Abstinence is as easy to me as temperance would be difficult.