An expert is a person who has made all the mistakes that can be made but in a very narrow field.

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

Failure is essential. Trial and error is necessary.

It is common sense to take a method and try it. If it fails, admit it frankly and try another. But above all, try something.

Trial and error are usually the prime means of solving life’s problems. Yet many people are afraid to undertake the trial because they’re too afraid of experiencing the mistake. They make the mistake of believing that all error is wrong and harmful, when most of it is both helpful and necessary.

Error provides the feedback that points the way to success. Only error pushes people to put together a new and better trial, leading through yet more errors and trials until they can ultimately find a viable and creative solution.