Genius_ The Life and Science of Richard Feynman - James Gleick [221]
His motivation was to discover a new theory, not to reinvent the old one… . His purpose was to explore as widely as possible the universe of particle dynamics. He wanted to make as few assumptions as he could.
A theorist who can juggle different theories in his mind has a creative advantage, Feynman argued, when it comes time to change the theories. The path-integral formulation of quantum mechanics might be empirically equivalent to other formulations and yet—given less-than-omniscient human physicists—find more natural-seeming application to realms of science not yet explored. Different theories tended to give a physicist “different ideas for guessing,” Feynman said. And the century’s history had shown that when even so elegant and pure a theory as Newton’s had to be replaced, slight modifications could not suffice.
To get something that would produce a slightly different result it had to be completely different. In stating a new law you cannot make imperfections on a perfect thing; you have to have another perfect thing.
He understood explanations as a surgeon understands knives. He had a set of practical tests, heuristics, that he applied when reaching a judgment about a new idea in physics: for example, did it explain something unrelated to the original problem. He would challenge a young theorist: What can you explain that you didn’t set out to explain? He knew that why? is a question without an end and that our knowledge of things is inextricable from the language we use. The words and analogies from which we build our explanations are culpably linked with the things explained. Explanans and explanandum are inextricable after all. An interviewer for the British Broadcasting Corporation, Christopher Sykes, once asked him to explain magnets: “If you get hold of two magnets and you push them you can feel this pushing between them… . Now what is it, the feeling between those two magnets?”
“What do you mean, what’s the feeling?” Feynman growled. His hair, swept back in dramatic gray waves, had receded high atop his head, leaving a statue’s high brow above a pair of heavy eyebrows that curled more impishly than ever. His pale blue shirt was open at the collar. A pen and eyeglass case rested in his front pocket, as always. Off camera, a defensive note entered the interviewer’s voice.
“Well, there’s something there, isn’t there? The sensation is that there’s something there when you push these two magnets together.”
“Listen to my question,” Feynman said. “What is the meaning when you say there’s a feeling? Of course you feel it. Now what is it you want to know?”
“What I want to know is what’s going on between these two bits of metal.”
“The magnets repel each other.”
“But what does that mean? Or why are they doing that? Or how are they doing that?” Feynman shifted in his easy chair, and the interviewer added, “I must say I think that’s a perfectly reasonable question to ask.”
“Of course it’s a reasonable—it’s an excellent question, okay?” Reluctantly, Feynman now stepped into metaphysics. Particle theorists were toying with a “bootstrap” model, in which no particle lies at a deepest level, but all are interdependent composites. The name bootstrap paid homage to the paradoxical circularity of having to build each fundamental particle from all the others. Feynman, as he now made clear, believed in a kind of bootstrap model of explanation itself.
You see, when you ask why something happens, how does a person answer why something happens?
For example, Aunt Minnie is in the hospital. Why? Because she went out on the ice and slipped and broke her hip. That satisfies people. But it wouldn’t satisfy someone who came from another planet and knew nothing