Why creatives carry notebooks all the time

Notebooks, late-night thoughts, and Hideki Yukawa's prediction of the meson

During interviews, I often get asked how people can start putting the lessons of Rest in their everyday lives. The biographical details are interesting and the science is cool, but you really want to know how to put it into practice.

One of the most important lessons from Rest is that highly creative people actually don’t work all the time— by which I mean doing things that a boss or LinkedIn would recognize as “work.” They think intensively about problems, and work hard at them for a few hours a day, but they also recognize that long breaks and sleep give their subconscious minds time to explore approaches to ideas that they might never think up while at the keyboard of whiteboard.

But in addition to giving your subconscious time to do its thing, you need to be ready to catch those ideas when they suddenly appear. That’s why almost everyone I wrote about in Rest carried a notebook with them. (There were a few variations: the mathematician David Hilbert had a student haul a blackboard into his garden, and Lewis Carroll invented a device— the nyctograph— that let him jot down notes in the dark.)

This weekend I came across another account illustrating the importance of keeping notebooks close at hand: Japanese physicist Hideki Yukawa, who in 1934 predicted the existence of mesons (a kind of subatomic particle) based on the work of Heisenberg and Fermi.

Yukawa wrote about this insight— which won him a Nobel prize in 1949— a couple times. The first was a more compressed account given at a talk at the University of Michigan in 1948, and transcribed by Michigan physicist Chihiro Kikuchi:

In the fall of 1934, when my second son was born, I became so engrossed in thinking about nuclear forces, that I began to find it difficult to fall asleep at nights. My mind would become clearer and clearer, and one idea after another would race through my mind. And so not to forget them, I kept a note pad at my bedside and jotted down the ideas as they came to me. But the next morning when I went over the notes, I had the strange experience of not being able to make sense of the ideas that seemed so clear to me the night before. Anyway after repeated attempts of this kind, my ideas of nuclear force field began to crystallize and so was able in October to present my ideas at a seminar.

He gave a second, more detailed account in his autobiography, The Traveler:

I was unable to produce creative ideas during the day, getting lost in the various equations written on pieces of paper. On the other hand, when I lay down in bed at night, interesting ideas entered my head. They seemed to grow, unhampered by the rows of equations. Then I became tired, and eventually fell off to sleep.

When I thought about those ideas the next morning, I found that they were all worthless. My hopes disappeared with the morning light, as if by the hand of the devil. I don’t know how many times that experience was repeated!

That fall, his second son was born. “I was trying to sleep in a small room in the back of the house,” he recalled in his autobiography The Traveler,

but as usual, I was thinking; my insomnia was back again. Beside my bed lay a notebook, so that if I had an idea, I could write it down. That went on for several days.

The crucial point came to me one night in October. The nuclear force is effective at extremely small distances, on the order of 0.02 trillionth of a centimeter. That much I knew already. My new insight was the realization that this distance and the mass of the new particle that I was seeking are inversely related to each other. Why had I not noticed that before? The next morning, I tackled the problem of the mass of the new particle and found it to be about two hundred times that of the electron. It also had to have the charge of plus or minus that of the electron. Such a particle had not, of course, been found, so I asked myself, “Why not?” The answer was simple: an energy of 100 million electron volts would be needed to create such a particle, and there was no accelerator, at that time, with that much energy available.

He got some feedback from colleagues that fall (most notably, one of them pointed out that cosmic ray detectors should be able to find such energetic particles), wrote up an article that predicted the existence of mesons, and published it in 1935. It was not until 1947 that cosmic ray physicists confirmed their existence. In 1949, they were first produced in a cyclotron, and Yukawa was awarded the Nobel prize.

These two accounts differ a bit around exactly when he started keeping a notebook or note pad by his bedside, but they both illustrate the importance of developing the habit of keeping a notebook close by to catch these ideas. They might turn out the next morning to be terrible, and they might take years to validate. But if you don’t take the first steps— of giving your subconscious time to do its thing, and getting in the habit of keeping a notebook so you can catch new ideas quickly— you’re not going to get very far.