Keep this life skill for later
Sign in to save
← All life skills

Learning & thinking · a life skill

Advanced Reading Notes

a box that talks back

The sociologist Niklas Luhmann read with a pen for over forty years and kept what he took from it on about 90,000 small cards, one idea each, filed behind the card it continued and linked to others. He called the box a partner he could have a conversation with. You don't need 90,000. You need the habit of turning what you read into cards you'd understand in five years.

  • Fleetinga quick line, caught anywhere, thrown away within a day or two
  • Literaturewhat a source says, short, in your words, with the page
  • Permanentone idea of your own, written for a stranger, filed and linked
  • Challenging to start
  • Life-Changing impact
  • Learn it in 30 days
  • A few cards a day
from a note on the bus to a draft
A slip-box: notes from reading become numbered cards in a branching tree, linked, indexed, and drafted A fleeting note asks whether rereading only feels like work. A literature note records Roediger and Karpicke's 2006 finding in the reader's own words. Below them, six permanent cards branch by number: 1, Rereading feels like learning; 1a, Ease gets mistaken for knowing; 1a1, Highlights only add to the ease; 1b, A week on, recalling wins; 2, One card holds one idea; 2a, Title a card with its claim. A dashed link runs from card 1a1 to card 2a, because a highlight isn't a claim. An index card lists entry points: rereading at 1, highlights at 1a1, note-making at 2. At the bottom, a draft called “Why rereading fails” is built from the chain 1, 1a, 1a1, 1b. on the bus rereading feels like work. is it? Roediger & Karpicke 2006 · Exp. 2 read four times: best at 5 minutes, worst a week on (40% vs 61% for read once, recalled three times) the slip-box Rereading feels like learning Ease gets mistaken for knowing Highlights only add to the ease A week on, recalling wins One card holds one idea Title a card with its claim 1 1a 1a1 1b 2 2a a highlight isn't a claim index rereading 1 highlights 1a1 note-making 2 a draft, from one branch Why rereading fails 1 → 1a → 1a1 → 1b

Nothing in the box is filed by topic. A card goes behind the one it continues, so a line of thought stays together, and the links and the index are how you get across.

Over the next thirty days

Try it now.

Paper slips in a box or a notes app with links both work. The three kinds of note are Sönke Ahrens's names for it, in How to Take Smart Notes; the numbering is Luhmann's.

  1. Catch fleeting notes, then clear them

    Any thought, anywhere, in a few words. They're reminders, not notes. Within a day or two, turn each into something better or throw it away.

  2. Write literature notes as you read

    Short, in your own words, with the source and the page. Not quotes: if you can't put it in your words, you haven't understood it yet, and that's worth knowing now.

  3. Turn them into permanent notes

    One idea per card, written so a stranger could follow it without the book. Give it a title that says the claim, not the topic: “Ease gets mistaken for knowing”, not “Fluency”.

    A few cards a day for thirty days, not a weekend's binge.

  4. File each behind the card it continues, and link it

    A card that follows 1a becomes 1b; one that branches off 1a becomes 1a1. Then add a link to any card it speaks to, with a few words on why.

  5. Keep a short index of ways in

    A keyword and the one or two cards where a line of thought starts. Not every card: the links do the rest.

  6. Write from the branches

    When a branch has grown long, lay its cards out in order. That's the outline of a draft, already in your own words, and you never start from a blank page.

Not writing a book? The box still works for decisions, talks and teaching. A report on why a project slipped is a branch: the cards from three post-mortems, read in order.

Try it on yours

Write one card, and file it.

Write a permanent note from something you've read. The checks look for the four things a card needs to still make sense in five years, and the helper gives it a number.

Give it a number

Which card does it continue? Add any numbers already taken nearby, and the helper skips them.

no number

    Nothing you type is saved or sent anywhere. Copy the card into your box before you leave the page.

    What the method rests on

    Ninety thousand cards, and one man.

    Luhmann kept two boxes. The first, about 23,000 cards, he started in the early 1950s; the second, about 67,000, he kept from the early 1960s until 1997. From them came dozens of books and hundreds of articles. In a 1981 essay, “Communicating with Slip Boxes”, he described the box as a partner that surprised him: follow the links, and it gave back connections he had forgotten making.

    Both boxes are now at Bielefeld University, scanned and online at the Niklas Luhmann-Archiv, so you can read the cards and follow the numbers yourself.

    Be clear about what this is: one remarkable man's archive, not a trial. No study shows a slip-box makes you write more. What it builds on is studied. Writing an idea in your own words is remembered better than reading it, the generation effect (Slamecka & Graf, 1978). And asking how a new idea fits what you already know, which is what every link asks, is close to a technique, elaborative interrogation, that the 2013 review by Dunlosky and colleagues rated of moderate use.

    Slip-box I: about 23,000 cards, the 1950s to about 1962; Slip-box II: about 67,000 cards, about 1963 to 1997. One line stands for a thousand cards. Slip-box I the 1950s to about 1962 ≈ 23,000 Slip-box II about 1963 to 1997 ≈ 67,000
    Each white line stands for about a thousand cards. Counts and years are approximate, from the Niklas Luhmann-Archiv, Bielefeld University.

    The idea

    Why it works.

    Most notes are filed by topic and die there, because a topic is a drawer you have to remember to open. A card filed behind the one it continues sits inside a line of thought, and a link with a reason is a thought about two ideas at once. The box gets more useful as it grows, which a pile of highlights never does.

    The real work is the rewriting. Every card forces the question a reader skips: what do I think this means, and where does it fit? That's slow at first. After thirty days, it's how you read.

    Keep it alive

    Habits that help.

    • Write for a stranger. In five years you are one, and the book won't be beside you.
    • Link before you file. A card with no links is one you'll never meet again.
    • Don't import highlights. A thousand copied lines is a second library, not a box that answers.
    • Small and daily. Three cards a day is a thousand a year.

    Go deeper

    Keep going.

    Practise this in HourLife.

    In Learning: Captures. Track the books, courses, podcasts, videos and articles you are working through, log where you are, and keep what you take from them.

    Download on the App Store Download on the Mac App Store How Learning works in HourLife