How Richard Feynman Thought

Photo: Jupiterimages, Brand X Pictures

I am fascinated by how we can improve our thinking and problem solving and enjoy learning about and from masters of those arts. My interest was therefore caught by the advice on thinking given in a review of Quantum Man: Richard Feynman’s Life in Science. The reviewer, George Johnson, writes:

This triumph came early in his [Feynman’s] career. His later thinking (about solid-state physics, for example, or quantum cosmology) was just as original. Maybe sometimes too original, Krauss suggests. Science usually proceeds by building on what came before. The maverick in Feynman kept him from accepting even the most established ideas until he had torn them apart and reassembled the pieces. That led to a deeper understanding, but his time might have been better spent at the cutting edge…“He continued to push physics forward as few modern scientists have,” Krauss [the biographer] writes, “but he tended to lead from the rear or, at best, from a side flank.”

To simplify my discussion, I will conflate the reviewer and biographer (Lawrence Krauss), because they seem to agree that Feynman should have worked differently, that he should have spent his effort at the “cutting edge.”
The advice is interesting but I think fundamentally flawed. Had Feynman followed it, it may have killed the magical spark of his originality. The reviewer says that Feynman could not accept “even the most established ideas until he had torn them apart and reassembled the pieces.” As a graduate student at Caltech, where I was a student of two of Feynman’s collaborators, I absorbed many stories and lore about Feynman.
It’s not quite true that Feynman could not accept an idea until he had torn it apart. Rather, the idea could not yet be part of his way of thinking and looking at the world. Before an idea could contribute to that worldview, Feynman wanted to turn over the idea, to see why it was true, from any angle that he could find. (I like to think that Feynman would have enjoyed my book on Street-Fighting Mathematics.) In other words, he wanted to connect a new idea to what he already understood and thereby extend his understanding.
Feynman’s approach is a wonderful recipe for becoming more intelligent. I believe that intelligence is not a fixed quality; rather, it is a process of growth. The best explanation of and support for this view is Carol Dweck’s research, wonderfully described in her book Mindset: The New Psychology of Success. Feynman’s approach to new ideas is a fantastic example of the growth mindset.
(This approach, when combined with Feynman’s aversion to publishing, often disconcerted others. At Caltech, there were stories of Feynman’s younger colleagues who had worked on an idea and then showed the result to Feynman, who said, “Oh, right, I’ve thought about that,” and pulled out his notes where he had already derived that result — often with extensive generalizations.)
Spending time “at the cutting edge” may have killed the creative goose. When Feynman was developing his approach to quantum mechanics, the work for which he eventually won a Nobel Prize, the cutting edge was a very difficult version of Heisenberg’s original quantum mechanics, extended to handle the complexity of how radiation (such as radio waves, light, or gamma rays) interacts with matter. But the subject was stymied by infinities in every calculation. The answer was to start with minus infinity so that adding positive infinity resulted in a reasonable value. Through great efforts, brilliant physicists made this crazy idea usable and practical. But it required heroic mathematical efforts.
Instead of working at the cutting edge by improving those methods, Feynman found an entirely new way: his famous method of path integrals.
If we were perfect reasoning machines, it would not harm us to first work at the cutting edge and then develop our own ways of thinking. But we are imperfect. As economists might say, there’s a huge path dependence in our thinking: Once you know something, it’s hard to unknow it. Once you learn a way of thinking, it’s hard not to keep falling into that way of thinking at the expense of finding new ways of thinking. I think Feynman had a healthy respect for how our minds actually work — as opposed to how they might work if they were ideal reasoning machines. That humility, a word infrequently associated with Feynman, made him wary of digging those mental paths before he had explored his own ways and had made his own, perhaps different, paths. That’s how he reached or, rather, created the cutting edge.