“It can scarcely be denied that the supreme goal of all theory is to make the irreducible basic elements as simple and as few as possible without having to surrender the adequate representation of a single datum of experience.”
— Albert Einstein,  On the Method of Theoretical Physics

When I whined to Professor Rosenthal that my camera wouldn’t accept a white balance from something that was out of focus, what a pain it was to have to set the gray card down, and shoot from further than arm’s reach,  he deftly pulled out a sharpie, drew a black “X” from corner to corner of a gray card, presented it to me and said,
“There.  Now it will focus.”

Experience.  Genius.  Wisdom.

Thanks.