Feynman, normally as quick and lively as they come, went silent. It was the only time I’ve ever seen him look wistful. Finally he said dreamily, “I once thought I had that one figured out. It was beautiful.” And then, excited, he began an explanation that crescendoed in a near shout: “The reason space doesn’t weigh anything, I thought, is because there’s nothing there!”
Picture Source: Feynman Diagram
Click here for more detail: How Feynman Diagrams Almost Saved Space By: Frank Wilczek
