“An expert is a person who has made all the mistakes that can be made in a very narrow field.”
“An expert is a man who has made all the mistakes which can be made in a very narrow field.”
“An expert is someone who knows some of the worst mistakes that can be made in his subject, and how to avoid them.”
“Show me a person who has never made a mistake and I'll show you someone who has never achieved much.”
“Jenny Fields felt undone, the way only a person who has been careful can feel when confronted by a mistake.”
“Anyone who has never made a mistake has never tried anything new.”