When we have an "open task" or "open loop", it tends to stay atop our mind, causing our mind to involuntarily bring these up again and again. Zeigarnik effect.

Writing them down can convince our brain to let the matter rest. With all tasks written down (or loops closed) in a way that convinces us that they will be taken care of, we achieve David Allen's "mind like water". Get all the little stuff out of our short-term memory.

We can weaponize the Zeigarnik effect for knowledge work. Many mathematicians are familiar with the effect where if they think hard about a math problem and then do something else, the solution can come to them during the day.

As of [2022-08-09 Tue], the stuff atop my mind tends to be "there's something I have to do", which is not very useful to dwell on. What could I load it with that's an unsolved problem?

• Coding or other engineering challenge
• A current relationship question
• Something to do with work

Ahrens says we may divide notes into three kinds:

1. Fleeting notes
2. Book notes
3. Permanent notes

Fleeting notes can be taken on any medium, even a napkin, and should be processed within a day or two. When in doubt, everything's a fleeting note: even underlined sentences in books or copy-pasted book excerpts count as fleeting notes. Only if you write something in your own words can it be permanent.

Flyvbjerg 2001. Had videos on paramedics doing CPR, some of them beginners (i.e. had just finished their training), and some of them experienced. When you show these videos to experienced paramedics, they can guess correctly that the person in the video was experienced (90% correct rate), whereas if you show them to beginners, they're just guessing (50-50 correctness rate). The interesting part is when you show the videos to teachers of paramedics. These did worse than guessing, systematically mistaking the experts for beginners and beginners for experts. This is because beginners go by-the-book, exactly the methodology the teachers taught, and the experts know when to diverge from the book, which looks like doing it wrong.

Hubert and Stuart Dreyfus have a five-grade expert scale, and completed training puts you on grade 3, a "performer", and many teachers cannot detect where you are beyond grade 3.

Charles Darwin (1809–1882) wrote down arguments against his theories.

I had […] during many years followed a golden rule, namely, that whenever a published fact, a new observation or thought came across me, which was opposed to my general results, to make a memorandum of it without fail and at once; for I had found by experience that such facts and thoughts were far more apt to escape from the memory than favorable ones. Owing to this habit, very few objections were raised against my views, which I had not at least noticed and attempted to answer.

Darwin's technique is good but primarily mental. A slipbox helps make it natural to do this. It changes the writer's incentives from finding confirming facts (as when you write an article with an argument already in mind) to an indiscriminate gathering of any relevant information regardless of what argument it will support. Developing ideas bottom-up instead of top-down lets us focus on the most insightful ideas we encounter and welcome the most surprising turns of events.

We're still selective, but no longer filter by for/against but by relevant/irrelevant. The criterion is whether something adds to a discussion in the slipbox: "an addition as well as a contradiction, the questioning of a seemingly obvious idea as well as the differentation of an argument." In fact, "dis-confirming data becomes suddenly very attractive, because it opens up more possible connections", and "the experience of how one piece of information can change the whole perspective on a problem is exciting".