A small metal zettelkasten with a clear plastic lid sitting on a wooden table with a fountain pen and index card in front of it

The Two Definitions of Zettelkasten

What do we mean when we say Zettelkasten? There’s a specific set of objects (cards and boxes or their digital equivalents), but there’s also a spectrum of methods or practices which can be split into two broad categories.


Historically, Zettelkasten as used to describe both Luhmann’s notes and his method is patently in the minority compared to the vast prior Zettelkasten tradition, dating back at least to Konrad Gessner in 1548, which could be broadly framed as a commonplace book kept on index cards, usually organized by topic or subject headings and kept in a card index.

If you’ve been watching the tools for thought space, the note taking space, or the productivity spaces over the past several years, you’ve run across the seemingly foreign idea of Zettelkasten if not possibly tried it out for yourself. Surely by now there are several hundred short one page blog posts that make cursory, but excited attempts to describe what a zettelkasten is, how it works, and why you might want one. Aside from the excitement they all share, nearly all of them will mention the now famous example of Nicholas Luhmann’s collection of over 90,000 notes, and his prolific writing output of hundreds of papers and scores of books. Almost all of them will also inevitably make the error, courtesy of the availability heuristic compounded by the lack of appropriate history and context, of stating that Niklas Luhmann invented the idea of Zettelkasten.

However, in the growing amounts of literature about zettelkasten online there is a massive swath of history and knowledge often missing from what could and should be a broader discussion. The so-called “Zettelkasten Method” you hear about in 99% of the cases is specifically the variation of that method practiced by Niklas Luhmann. Historically, however, the idea of a zettelkasten (or slip box) as practiced by the vast majority of people—and there have assuredly been many—from the mid 1500s to now—is really that of the idea of a commonplace book kept using index cards. Some will be organized by subject headings while others won’t. Some of these will have indexes and some won’t. Some, surprisingly, aren’t even kept in boxes.

The “old” definition of Zettelkasten

So what was a Zettelkasten before we were overwhelmed with all the conversation about Niklas Luhmann’s instantiation?

Since antiquity, writers and thinkers have used what has come to be called the commonplace book tradition. They typically collected quotes (sententiae), thoughts, and ideas in books and notebooks for later review and potential reuse in their own writing. From the 8th to the 12th centuries there was a closely related practice of keeping florilegium that was used in Christian settings and particularly popular within the mendicant orders of the Catholic church. These were focused more on religious topics and ideas and were often used for creating sermons as their ultimate output.

In the 16th century, Swiss physician Konrad Gessner (1516 – 1565), building on the commonplace tradition, realized that one’s notes or excerpts might be easier to use if they were cut out of their places on the page and re-arrangeable. Gessner’s method in brief:

  1. When reading, everything of importance and whatever appears useful should be copied onto a good sheet of paper.
  2. A new line should be used for every idea.
  3. “Finally, cut out everything you have copied with a pair of scissors; arrange the slips as you desire, first into larger clusters which can then be subdivided again as often as necessary.”
  4. As soon as the desired order is produced, arranged, and sorted on tables or in small boxes, it should be fixed or copied directly.

—Gessner, Konrad. Pandectarum sive Partitionum Universalium. 1548. Zurich: Christoph Froschauer. Fol. 19-20 (Tr. Markus Krajewski via Paper Machines) 1

Subsequent note takers and composers eventually realized that, while useful, Gessner’s method could be improved by using “slips of equal size” (thus making it easier to flip through and prevent smaller slips from getting lost) and by indexing them or cross referencing them internally. Because note taking was frequently done on scraps of paper which were often kept in piles by topic, if one didn’t file or properly manage them, they came to be known as “scrap heaps”, a phrase which has linguistically gained the meaning of “trash”, as lack of indexing or coherence made them useless to anyone but their originator.

Indexing of commonplace books became much more common with the publication of John Locke’s Méthode nouvelle de dresser des recueils in Le Clerc’s Bibliothèque universelle vol. 2 (1685) (cf. Catalogue générale des livres imprimés (Paris, Bibliothéque nationale. Département des imprimés) v. 99, col. 192-195) which was translated with Le Clerc’s Observations (Lond., 1697, Lowdnes. v.4, p. 1379-1380) and was posthumously published as the stand alone text A new method of making common-place-books (1706).2

Using cards of equal size became more common following the “invention” of the index card by Carl Linnaeus (1707-1778) who hand cut his own cards used and reused his research materials throughout his career.3 Of course, taking notes on index cards was far easier in the early 20th century with the rise of library card catalogs, the Dewey Decimal System, and Melvil Dewey’s Boston-based company Library Bureau. Mass manufacturing of these cards improved both quality and pricing making it much easier to source one’s own cards. Dewey’s push for profits included expanding his library wares into the business sector, a practice which became more common after his own company adopted a card file-based system for its own office work.

Manuals on note taking and early Zettelkasten

In addition to early popular handbooks on commonplace book methods by Desiderius Erasmus, Rudolph Agricola, and Phillip Melanchthon, which were written for both teachers and students, one can find a growing number of texts which are either dedicated to note taking practices which heavily feature slips of paper or index cards or give them significant discussion. Some of these include:

  • Bernheim, Ernst. Lehrbuch der historischen Methode und der Geschichtsphilosophie : mit Nachweis der wichtigsten Quellen und Hilfsmittelzum Studium der Geschichte … völlig neu bearbeitete und vermehrte Auflage. 1889. Reprint, Leipzig : Duncker, 1903. http://archive.org/details/lehrbuchderhisto00bernuoft.
    • This book, in German, is an influential handbook on historical method which influenced the early science of history and historical method and helped to reinvigorate card-based note taking methods in a short section discussing such methods. I’m unaware of any translations in English.
  • Langlois, Charles Victor, and Charles Seignobos. Introduction to the Study of History. Translated by George Godfrey Berry. First. New York: Henry Holt and company, 1898. http://archive.org/details/cu31924027810286.
    • Influenced by Bernheim, but going further, this text, originally in French, has a section outlining a commonplace-esque zettlekasten method.
  • Seward, Samuel Swayze. Note-Taking. Boston, Allyn and Bacon, 1910. http://archive.org/details/cu31924012997627.
    • Popular text in the early 1900’s written by the brother of William Henry Seward.
  • Sertillanges, Antonin Gilbert, and Mary Ryan. The Intellectual Life: Its Spirit, Conditions, Methods. First English Edition, Fifth printing. 1921. Reprint, Westminster, MD: The Newman Press, 1960. http://archive.org/details/a.d.sertillangestheintellectuallife.
    • Has a fascinating chapter on note taking with some rich philosophy not often seen in such treatises including encouraging making active links between ideas and numbering one’s notes using a decimal system.
  • Dow, Earle Wilbur. Principles of a Note-System for Historical Studies. New York: Century Company, 1924.
  • Webb, Beatrice Potter. My Apprenticeship. First Edition. New York: Longmans, Green & Co., 1926.
    • While the book is a fascinating autobiography of one of the founders of the London School of Economics, The Fabians, and The New Statesman with broad experience in sociology and economics, of most interest here is Appendix C which she writes on note taking. She describes a zettelkasten based system which she describes as “scientific note taking” and which many are sure to recognize as a an early structured database or spreadsheet functionality which would find its way into edge notched cards, early computer programming, and computer science.
  • Heyde, Johannes Erich. Technik des wissenschaftlichen Arbeitens: zeitgemässe Mittel und Verfahrungsweisen. Junker und Dünnhaupt, 1931.
    • In German, though there is an English translation of a portion making it’s way around. This is the handbook which Niklas Luhmann apparently read and heavily influenced his own method. If true, I’m a developing theory on how he may have devised his method, presuming that he didn’t learn it or parts of it from colleagues or friends while in school.
  • Mills, C. Wright. “On Intellectual Craftsmanship (1952).” Society 17, no. 2 (January 1, 1980): 63–70. https://doi.org/10.1007/BF02700062.
    • A spectacular essay which later made it into Wright’s influential book The Sociological Imagination (1959), it goes far beyond basic note taking to some more serious substance and is closer in line to Luhmann’s Communicating with Slip Boxes (1981).
  • Eco, Umberto. How to Write a Thesis. Translated by Caterina Mongiat Farina and Geoff Farina. 1977. Reprint, Cambridge, MA, USA: MIT Press, 2015. https://mitpress.mit.edu/books/how-write-thesis.
    • While written for an academic audience of students focusing on writing for a particular purpose (the thesis), he does suggest that one could use the method as a lifelong practice.
  • Goutor, Jacques. The Card-File System of Note-Taking. Approaching Ontario’s Past 3. Toronto: Ontario Historical Society, 1980. http://archive.org/details/cardfilesystemof0000gout.
    • Just as commonplace books and zettelkasten are taking their last gasps in the 21st century, Goutor revives some of the ideas for helping out a local historical society by framing things as if the traditions had never existed in force within intellectual history.
  • Weinberg, Gerald M. Weinberg on Writing: The Fieldstone Method. New York, N.Y: Dorset House, 2005.
    • Written for the writers who want to be productive, Weinberg analogizes research and note taking to collecting the most useful and fascinating fieldstones that one might find to use to build a wall, a building, or other useful structure.

This brief, but limited collection, shows that there was certainly a long and illustrious note taking tradition using slips or index cards. It doesn’t highlight the fact that often these methods were also handed down from teacher to student, which was also a major mode of transmission and somewhat similar to current messy person-to-person transmission on the internet using examples and conversation on various fora and social platforms.

Resurgence of the old Zettelkasten in the new Millennium

Of course, the most recent resurgence of these commonplace and older zettelkasten ideas comes to us courtesy of a handful of interesting practitioners who have kept the memory alive as well as helped to push some of them into digital form. A limited selection of some of these include:

  • technologist Ward Cunningham, inventor of the wiki, which he based in part on Hypercard functionality. He also created the Smallest Federated Wiki (aka FedWiki) at an early IndieWebCamp in 2011 which features a card-like user interface which encourages small, atomic-sized notes.
  • writer, scientist, and engineer Mark Bernstein who created Tinderbox in 2002 as a note taking tool, outliner, and publishing software that along with DevonThink is an early precursor of tools like Evernote, Obsidian, and Roam Research. He’s also the author of the influential hypertext essay Hypertext Gardens: Delightful Vistas (1998).
  • TiddlyWiki, first released on September 20, 2004, is a card-based user interface software built by Jeremy Ruston who was inspired by Ward Cunningham’s wiki and focused on small chunks of interlinked information. 4
  • author Steven B. Johnson who wrote frequently about his experiences with note taking, commonplaces, and DevonThink in the early 2000s in The New York Times as well as his blog. 5
  • authors Robert Green and his former assistant Ryan Holiday who have talked at reasonable length about their commonplace methods using index cards in videos and blog posts over the last decade.

Practitioners of the older Zettelkasten method

While there are thousands upon thousands of practitioners of the commonplace book tradition using the notebook format, there is a smaller less well known set who have used these methods with index cards or other slip-like formats. I’ll present just a handful of some that I’m aware of, but I’m sure that there are thousands upon thousands more.

  • Vladimir Nabokov (author) famously wrote many of his books on including Lolita on index cards which he filed in boxes 6
  • Phyllis Diller (comedienne) with 52,000 3×5-inch index cards
  • Joan Rivers (comedienne) over a million 3×5-inch index cards
  • Bob Hope (comedian) 85,000 pages in files
  • George Carlin (comedian) paper notes in folders
  • Ronald Reagan (actor, President), unlike the majority, Reagan kept his note cards in a photo album-like binder which allowed him to flip through it like a book while still retaining the ability to move cards or add pages as necessary.
  • Robert Greene (author)
  • Ryan Holiday (author)
  • Eminem Yes! Even Slim Shady himself has the most basic version of the OG practice I’ve ever seen: he literally had “just” slips and a box in a practice he aptly called “Stacking Ammo”, but which Anderson Cooper analogized as the scrawlings of a crazy person. The scare quotes on the word just here underline the fact that his practice contained no organization at all other than his potential internal mental recognition of his handwriting and variations in the papers sizes, types, and letterheads when available. It worked, because it worked for him and his needs.
  • Roland Barthes (French philosopher and writer) called his collection of about 12,250 cards by the traditional French name fichier boîte; he also kept a form of diary using a card index which his biographer called a fichierjournal
  • Hans Blumenberg (German philosopher and intellectual historian)
  • Mortimer J. Adler’s team which created The Syntopicon as part of the Great Books of the Western World (1952), used a shared card index to create it. 7
  • Michael Ende (German writer, possibly best known for his book The Never Ending Story which became a movie with the same title) kept a Zettelkasten, and in 1994, a year prior to his death, he published Michael Endes Zettelkasten: Skizzen und Notizen (translation: Michael Ende’s File-card Box: Drafts and Notes), an anthology of some of his writing as well as observations and aphorisms
  • Frederic L. Paxson (historian)
  • Walter Benjamin (German philosopher and cultural critic)
  • Gotthard Deutsch (history professor) had a card index of 70,000 cards, mostly focused on Jewish history. 8

The “new” definition of Zettelkasten

Niklas Luhmann has, for the last several years, almost entirely defined much of popular culture’s conceptualization of the idea of what a zettelkasten is, when, in fact, he represents only the tiniest tip of the iceberg of a much broader tradition.

Why the new definition

Rather than spend our time on rehashing what is already a massive and still growing volume of words, work, and available research on Luhmann’s particular practice, perhaps a more productive question is how his version manages to capture so much mind share? In large part, I attribute it to the fact that the prior tradition has significantly waned from cultural consciousness, making it seem like the idea is new while pitches for Luhmann’s system simultaneously tout it as being almost wholly responsible for Niklas Luhmann’s outsized productivity.

To some extent, our “new” definition (at least in the English language) of a Zettelkasten is driven by a several factors:

Lack of a broader history of the older methods

Given some of the basic discussion above outlining some of this history will point out a fraction of some of we’ve all been missing. I’ll leave the aphorism “Those who cannot remember the past are condemned to repeat it” here to gild this lily. Hopefully those in the space will look more closely at the well-worn cow paths of analog history in deciding how to pave our (digital) futures. Students looking to improve upon their own practices will hopefully have more examples to examine and use as models.

It bears mention that Vannevar’s influential essay “As We May Think” in the July 1945 issue of The Atlantic is entirely underpinned by the commonplace book and zettelkasten traditions pervading Western thought and culture. Rather than acknowledge this tradition explicitly, he creates the neologism “Memex” which stands in for a networked and connected zettelkasten. Given that his essay appears at the cusp of the waning of these older traditions and that following technologists would not have been as knowledgeable of them, Bush did a massive disservice to the computing field by specifically leaving the earlier words out of his essay. Had he mentioned them, designers and programmers would have had them as more explicit examples to emulate in their work.

Lack of an “official” name or branded method

Many of our note taking traditions were explicitly taught and learned from either handbooks, transmitted from teacher to student, or from practitioner to practitioner. (We definitely see a lot of this mode online now via blogposts, Twitter, YouTube, and fora (including https://zettelkasten.de, r/zettelkasten, and r/antinet, amongst a slew of productivity writers and influencers who make a living promoting variations of these ideas.) But historically, outside of older phrases like florilegia and commonplace books, there weren’t concrete names or brands for these practices.

Compare the traditional zettelkasten to the ideas of a “card catalog” or a “rolodex”. The card catalog has an immediate definition as a physical object consisting of wooden filing cabinets specifically for index cards containing information about the subjects, titles, and authors of books. The rolodex is now a generic term (like Kleenex is for tissues or Xerox for photocopies) stemming from the company product Rolodex for a previously ubiquitous piece of office furniture. Having both explicit terms for their physical instantiations and their specific uses helped to drive the ubiquity of both compared to the humble, generic card index, which while ubiquitous in physical form in early 20th century offices was never defined explicitly with respect to a specific form of note taking practice. Just as academics in English speaking countries referred to their generic card indexes, those in Germany and France talked about their Zettelkasten and fichier boîte, respectively. The linguistic shift occurs broadly with the transmission of zettelkasten from German into English spheres around the time of the German exhibition “Zettelkästen. Machines of Fantasy” at the Museum of Modern Literature, Marbach am Neckar in 2013 where we begin to equate the physical objects with a particular method. It bears noting that the Marbach exhibition featured a number of very similar Zettelkasten (the physical item consisting of boxes and slips), but with a variety of zettelkasten methods, the majority of which were more similar to each other than the “different” one represented by Luhmann’s.

One can’t help but notice the proliferation of specific method names for slightly different practices within the now growing space. These specific names for practices literally give both a name and power to the space and help to make it grow. Some of these names include: Zettelkasten itself as a name for Luhmann’s method; Smart Notes (Sönke Ahrens’ delineation of Luhmann’s method, Linking Your Thinking (aka LYT, Nick Milo’s method); Building a Second Brain (BaSB, Tiago Forte’s method); ANTInet (Scott P. Scheper’s analog branded version of Luhmann’s method); and even Pile of Index Cards (PoIC, Hawk Sugano’s productivity-based method from 2006). The naming tends to expand here as many of these examples have a commercial need to differentiate these practices to make them sellable to a larger audience. Should one really consider it a coincidence that Obsidian is so heavily used by those in Tiago Forte’s Building a Second Brain camp when Obsidian’s tag line on their home page boldly declares “A second brain, for you, forever.”?

This naming craze even extends to a proliferation of names for note types within each system including fleeting notes, permanent notes, literature notes, atomic notes, evergreen notes, source notes, point notes, concept notes, claim notes, etc. Of course the power of naming begins to wane here as the over-proliferation of names causes semantic collisions and worries when these systems and their adherents talk about related ideas online in broader overlapping publics. One would presume that over time this list of names will settle down and roughly standardize around a much smaller (dare I say atomic?), possibly mutually exclusive set.

The lack of a specific name to distinguish the methods and uses of card indexes from each other in the early 20th century further muddles the picture of their use. How does one specifically differentiate the use of a card index for business versus note taking versus a library card catalogue? The library card catalogue has a both a named object and a method (verb) and is much more easily distinguished than the card index being used for either business or note taking use, and in fact there may have been reasonable overlap of business and note taking use making their distinct uses less clear. As an example, in The Crown season 1 episode 4 “Act of God” (Netflix, 2016) there is a scene portraying former British Prime Minister Clement Atlee in his office in which he is prominently bookended in the background by two four drawer card indexes: one 3 x 5″ and the other 4 x 6″. Are these for general business filing use and document tracking or were they full of ideas from his reading and thinking?

Screen grab from The Crown showing an actor playing a bald and bespectacled Atlee at his desk in his office. Behind him on a credenza are a variety of files including two card index boxes each with four drawers.

Tangential names exist for practices in the German part of the tradition. For example there is the phrase Wissenschaftliches Arbeiten which translates as “scientific work”. This phrase arises out of Ernst Bernheim’s framing of the zettelkasten practice within his formulation of historical method, or how a professional historian might scientifically approach their work. The phrase not only pops up in the title of the book which likely inspired Niklas Luhmann’s practice, but curiously and even surprisingly, searching on the term within the Internet Archive reveals 106 works, predominantly textbooks in the English language, about research methods, note taking, and writing geared toward masters and Ph.D. students.

The lack of a named method, generally makes finding written examples of these practices in the historical record more difficult as one must search for generic words (index cards, slips, notes) used within the practice rather than specific method words with dramatically higher signal-to-noise ratios.

Relegation of the practice to academia

Knowledge about these note taking practices has almost always been geared toward academic settings and even there it has been primarily geared toward masters and Ph.D. level students who would more profitably use them over extended time horizons for not only their thesis work, but their extended careers. While early manuals on commonplace methods were written for broader student audiences, it’s exceedingly rare to find works written for non-specialist or popular audiences. It’s only within the last decade or so that one finds general note taking advice or practices for knowledge workers or those interested in greater productivity in their work. Advice of the sort and form given by Twyla Tharp or Anne Lamott is the exception rather than the rule.

Hidden transmission and unclear value proposition

Beyond the modes of written transmission of these practices and methods which have been geared toward academics, the primary mode of transmission is from either teacher to student or from practitioner to practitioner. This transmission mode is often much “quieter” and ostensibly hidden from historical view without significant work. There are media studies and history scholars who look at the notebooks and records of students and teachers to follow some of these methods, so some of these specific practices may surface over time.

These “manual” transmission modes are “high touch” (requiring a lot of work) and as a result are very slow to diffuse. Quite often they fail to adequately inspire or communicate their immense long term value. In a zettel in his second zettelkasten entitled “Does Spirit hide in the filing cabinet” (literally, though one could translate it as “Is there a Ghost in the machine?”), Niklas Luhmann wrote a note about people disappointed in seeing his system in person: “People come, they see everything [his boxes, slips, and notes] and nothing more than that, just like in porn movies; consequently, they leave disappointed.” 9

In Appendix C of her autobiography, Beatrice Webb found difficulty in explaining the massive value she found in her note taking practice and resorted to telling the reader to trust her experience:

“What is the use of this pedantic method of note-taking, involving masses of paper and a lot of hard thinking, not to mention the shuffling and reshuffling, which is apparently the final cause of this intolerable elaboration?” will be asked by the post-graduate student eager to publish an epoch-making treatise on the History of Government, or, perchance, on the History of Freedom, within the two years he has allotted to the taking of his doctorate. The only answer I can give is to cite our own experience.

My own anecdotal experience of research and note taking with index cards dates to 1985 when, in sixth grade, I was admonished to take my notes on index cards so that I could later string them together in outline form to create a narrative. While this was done with good intentions, there was no indication of doing this as a life-long practice nor was there any discussion of potential long term uses or potential beneficial affordances or effects. To make matters worse, my natural memory for storing ideas for a 3 page essay with only a handful of sources was strong enough that note taking seemed a waste of time. Never anticipating the need to be able to think and write over a lifetime, I filed the idea into the proverbial circular bin. I suspect this is the case for the vast majority students in the latter half of the twentieth century.

These historically hidden transmission modes can be contrasted directly with a more public facing and readily visible transmission mode of these practices which now occurs online. Social media, blogs, online fora and video platforms makes it dramatically easier for individual users to write about and pass along their particular experiences and affordances they find in specific methods, tools, and modes of use.

The hidden value proposition of the older methods can be contrasted with the incessant drumbeat of the value and productivity inherently “promised” by those describing Niklas Luhmann’s system. Look at all the books and papers he wrote in his lifetime! The system explains it all! It’s so simple. You can do this too! Reframed, one could almost visualize Ron Popeil pitching the idea of Luhmann’s zettelkasten and having his audience chant “Set it and forget it!”

The rise of the new Zettelkasten

The rise of the Zettelkasten as a name for both a specific object and a specific practice (Luhmann’s) in English started roughly in 2007. The first instances come from the work of Manfred Kuehn on note taking with his blog Taking Note starting in 2007 and ending in 2018, though large portions are still fortunately archived on the Internet Archive. He was definitely aware of Niklas Luhmann’s note taking practices and even translated Luhmann’s 1981 article “Kommunikation mit Zettelkästen” into English. This is supplemented on March 4, 2013 with the opening of the Marbach exhibition followed closely by the launch on June 20, 2013 and subsequent growth of the website https://zettelkasten.de begun by Christian Tietze and featuring both a blog as well as a forum for questions and further discussion of the practice. While these started a low brew of Luhmann’s method within the productivity and writing communities in the mid 2010s, things continued to heat up with the release of Sönke Ahrens’ English language book How to Take Smart Notes in 2017. Full boil was reached after 2018 and during the COVID-19 pandemic as a massive swath of note taking applications like Roam Research, Obsidian, and Notion came to the forefront of internet culture which was ostensibly idle enough to need ideas and tools like these to fill their new found free time and distract them from their pandemic worries.

In addition to all these applications, which could be used to implement digital versions of Luhmann’s method, a lot of the hype behind the idea of this particular Zettelkasten Method (again, the one specifically practiced by Luhmann) is driven by the often quoted prolific writing output of Luhmann. It’s as if no one prior to him had been creative or productive within the history of ideas. Surely his output is notable for its size, but he also had more freedom and flexibility by being employed full time as a research professor at a German University where it was both his life-long vocation and avocation to produce this output. Certainly his modification of earlier commonplacing techniques helped him along, but if one looks at the historical record, nearly every famous writer or researcher in the Western tradition had some sort of note taking or commonplace book practice upon which to build. In a handful of cases, we see well known intellectuals of their day writing down some of these ideas and influential methods in handbooks, addenda to other works, or in autobiographies including Erasmus, Agricola, Melanchthon, John Locke, Beatrice Webb, Jacques Barzun, and Umberto Eco.

Other definitions of zettelkasten

Of course, there are surely other uses of the term zettelkasten in various places and languages—this is a well known feature of ever-evolving words in active use. One which comes quickly from my old word horde is the current use of zettelkasten within German speaking countries of an office product consisting of a stack of slips of note paper held in a box. There are a variety of these available for sale within the German version of Amazon.

It also bears pointing out that card indexes were used in the early 1900s for a variety of business use functionalities including for accounting, general back office management and file maintenance, as indexes for larger filing systems, as early proto-rolodexes, and what would now be known as customer relationship management purposes.

Differences in the traditions

I’ve made some presumptions about the level of familiarity readers may have with the commonplace book tradition and that of Niklas Luhmann’s practice. It may be helpful for those missing parts of one or both to have some quick resources to fall back on as well as to describe the broad differences.

Commonplace Books and Early Zettelkasten

For the commonplace tradition, I can heartily recommend Earle Havens’ Commonplace Books: A History of Manuscripts and Printed Books from Antiquity to the Twentieth Century (Yale, 2001) short but reasonably wide ranging text as a crash course on the topic. Additionally Colleen Kennedy has an excellent 12 page primer she developed for classroom use on how to actively implement and create one’s own commonplace book which takes into account some of the historical practices seen in the literature.

Broadly, the commonplace book tradition involves excerpting ideas (ars excerpendi), quotes, or writing one’s own ideas into a notebook either pre-broken into topical categories (love, war, civility, productivity, etc.), or indexed after the fact with cross-references to particular pages. In index card or early zettelkasten form, this process is easier as each idea is placed on its own card and placed behind a tabbed card with a single topic heading written on it. As a result, one might have dozens of cards (generally unordered) on the topic of “Hope”, for example, and when writing about that topic, one would ostensibly go to that section of their index, pull out those related cards, sort through them, identify one appropriate for the piece, and insert the relevant idea(s) into their writing. One might thus look at the essays of Montaigne and discern that he’d taken years of reading and excerpting and formed essays around topics in his collection based on his experience and thinking.

Niklas Luhmann’s Zettelkasten

While broadly similar, Luhmann’s practice puts far less emphasis on the index portion of the work, but relies on juxtaposing ideas that are close in thought next to each other. This means that he needs a method for both ordering and finding specific cards. He chose a decimal numbering system, which (mathematically) allows for infinite internal branching and growth and was likely based on Melvil Dewey’s system from half a century prior. One could frame his system as building a book in reverse, so he would take an idea, create a single index entry for it, and then number it and place it in his system. Rather than indexing each further related idea, he would visit the index, find that idea and then find the section of related prior cards. He could then install his new idea behind the most closely related idea already in the system. Repeating this thousands and thousands of times creates a complex branching tree structure of inter-related ideas. Once a particular interesting branch becomes large enough, one can reverse the process and turn it into a paper or book. Traversing one’s tree and its branches of knowledge regularly generates not only reminds one of prior knowledge, but also tends to generate new ideas.

While the method is very simple in form, it can generate a great deal of complexity. One will notice that instead of having a single card index tab labeled “Sociology” with thousands of (unordered) cards behind it, as would be likely in the earlier tradition, Luhmann’s index only contains a few links into the idea of sociology from whence things branch out into multiple directions. Thus his index can focus on the more specific to find what he needs rather than the broad. This also allows for greater levels of inter-disciplinarity across ideas which may have otherwise been split into different topic headings.

In the near future, I expect to write out a theory of how Niklas Luhmann may have evolved his practice from the older zettelkasten practice which will surely point out a number of differences in the practices as well as affordances each provides. While we have some indications of where Luhmann’s practice originated historically, it is presently unknown whether he evolved his own practice from the prior or if someone else did that work and communicated the method to him personally and from which he continued to use and evolve it.

For those interested in more specifics on Luhmann’s practice, I might recommend the Getting Started page at zettelkasten.de, the first seven chapters of Dan Allosso and Salvatore Allosso’s book How to Make Notes and Write, or Sönke Ahrens’ book. Looking directly at the digital archive of Luhmann’s zettelkasten can be of immense value. Similarly the digital archives of Jonathan Edwards’ commonplace book (which are known as “the Miscellanies” rather than the traditional commonplace book) and its surrounding research as well as the digitized hybrid notebook/index card version of H. Ross Ashby’s notes can provide some fabulous insight as to how one might structure or use their own notes.

A Progressive Zettelkasten Practice

Using some of this history, I’ve previously outlined a progressive zettelkasten method with levels of slowly increasing complexity which may be an easier method for people to immediately begin working towards some creative goal without getting bogged down in the weeds. It combines the older traditions with Luhmann’s traditions to provide the practitioner with a potential formula to determine the level of complexity that may be right for them. Different practices and levels of complexity can be used for different end goals. (Why go “full-Luhmann” when “stacking ammo” is useful enough and fits your lifestyle and goals?)

Other variations of these two broadly different traditions might include keeping a traditionally indexed commonplace slip box with quotes, aphorisms, summaries of others’ ideas, and even fleeting notes in one box while maintaining a more densely linked version of a Luhmannian-based zettelkasten of one’s own best thoughts with refinements in a separate box.

Naturally the methods and instantiations one could arrive at are far richer and potentially more useful and practical if one is aware of more of the possibilities involved in the fuller spectrum of historical practices.

Editor’s note: I wrote this essay of approximately 7,000 words in about half a day’s work, including outlining, footnoting, and editing by drawing material directly from my own hybrid commonplace books/Luhmann-based Zettelkasten.


Allosso, Dan, and S. F. Allosso. How to Make Notes and Write. Minnesota State Pressbooks, 2022. https://minnstate.pressbooks.pub/write/.

Ahrens, Sönke. How to Take Smart Notes: One Simple Technique to Boost Writing, Learning and Thinking – for Students, Academics and Nonfiction Book Writers. Create Space, 2017.

Bernstein, Mark. “Hypertext Gardens: Delightful Vistas.” Hypertext essay. Eastgate Systems, 1998. http://www.eastgate.com/garden/Enter.html.

Bush, Vannevar. “As We May Think.” The Atlantic, July 1, 1945. https://www.theatlantic.com/magazine/archive/1945/07/as-we-may-think/303881/.

Havens, Earle. Commonplace Books: A History of Manuscripts and Printed Books from Antiquity to the Twentieth Century. Beinecke Rare Book and Manuscript Library New Haven, CT, 2001.

Kennedy, Colleen E. “Creating a Commonplace Book (CPB).” Accessed August 31, 2021. https://www.academia.edu/35101285/Creating_a_Commonplace_Book_CPB_.

Lamott, Anne. Bird by Bird: Some Instructions on Writing and Life. 25th Anniversary. 1994. Reprint, Anchor, 1995. https://www.penguinrandomhouse.com/books/97395/bird-by-bird-by-anne-lamott/.

Luhmann, Niklas. “Kommunikation mit Zettelkästen.” In Öffentliche Meinung und sozialer Wandel / Public Opinion and Social Change, edited by Horst Baier, Hans Mathias Kepplinger, and Kurt Reumann, 222–28. Wiesbaden: VS Verlag für Sozialwissenschaften, 1981. https://doi.org/10.1007/978-3-322-87749-9_19. – Luhmann, Niklas. “Communicating with Slip Boxes: An Empirical Account.” Translated by Manfred Keuhn. kuehnm on scriptogr.am, December 6, 2014. https://web.archive.org/web/20150825031821/http://scriptogr.am/kuehnm.

Tharp, Twyla. The Creative Habit: Learn It and Use It for Life. Simon & Schuster, 2006. https://www.simonandschuster.com/books/The-Creative-Habit/Twyla-Tharp/9780743235273.


  1. Krajewski, Markus. Paper Machines: About Cards & Catalogs, 1548-1929. Translated by Peter Krapp. History and Foundations of Information Science. MIT Press, 2011. https://mitpress.mit.edu/books/paper-machines.↩︎
  2. Locke, John, 1632-1704. A New Method of Making Common-Place-Books. 1685. Reprint, London, 1706. https://archive.org/details/gu_newmethodmaki00lock/mode/2up.↩︎
  3. Charmantier, Isabelle, and Staffan Müller-Wille. “Carl Linnaeus’s botanical paper slips (1767–1773).” Intellectual History Review 24, no. 2 (April 3, 2014): 215–38. https://doi.org/10.1080/17496977.2014.914643.↩︎
  4. TiddlyWiki [@TiddlyWiki]. “@WardCunningham The First Demo of TidlyWiki from 2004 Took the Ideas of Wiki and Applied Them to Fragments Rather than Entire Pages. The Hypothesis Was That It Would Be Easier to Write in Small Interlinked Chunks That Could Be Gradually Massaged into a Linear Narrative Https://Classic.Tiddlywiki.Com/Firstversion.Html Https://T.Co/MJO7tyopr2.” Tweet. Twitter, September 20, 2022. https://twitter.com/TiddlyWiki/status/1572288988383248384.↩︎
  5. Johnson, Steven. “Tool for Thought.” The New York Times, January 30, 2005, sec. Books. https://www.nytimes.com/2005/01/30/books/review/tool-for-thought.html.↩︎
  6. Gold, Herbert. “Vladimir Nabokov, The Art of Fiction No. 40.” The Paris Review, 1967. https://www.theparisreview.org/interviews/4310/the-art-of-fiction-no-40-vladimir-nabokov.↩︎
  7. “The 102 Great Ideas: Scholars Complete a Monumental Catalog.” LIFE, January 26, 1948, 92–93.↩︎
  8. Lustig, Jason. “‘Mere Chips from His Workshop’: Gotthard Deutsch’s Monumental Card Index of Jewish History.” History of the Human Sciences 32, no. 3 (July 1, 2019): 49–75. https://doi.org/10.1177/0952695119830900.↩︎
  9. Luhmann, Niklas. “Geist im Kasten?” ZKII 9/8,3. Niklas Luhmann-Archiv. Accessed December 10, 2021. https://niklas-luhmann-archiv.de/bestand/zettelkasten/zettel/ZK_2_NB_9-8-3_V.↩︎

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Chris Aldrich

I'm a biomedical and electrical engineer with interests in information theory, complexity, evolution, genetics, signal processing, IndieWeb, theoretical mathematics, and big history. I'm also a talent manager-producer-publisher in the entertainment industry with expertise in representation, distribution, finance, production, content delivery, and new media.

115 thoughts on “The Two Definitions of Zettelkasten”

  1. We’ve all heard the expression, “standing on the shoulders of giants.”. He’s writing in the context of Chris Aldrich’s essay about “the often actively ignored history of the things that make up the current wave of note making methods and tools.” According to Ton Zijlstra (and I agree), “Every output is the result of processes, and building blocks that go beyond the person making the output. And most of those inputs and earlier practices are of a mundane origin.” The expression should be, he says, “standing on the shoulders of everyone.” I would go even further and note that the selection of ‘giants’ often reflects their status and privilege, rather than their accomplishments. We often read in these pages of a community effort that is suddenly attributed to a star researcher from Stanford, Harvard or MIT.

  2. This is really helpful, thankyou! I first heard of commonplace books ages ago, but ended up with my ammo more scattered than stacked 😀 Lately I’ve been into the Lehmann style zettles, but as you say so much of the teaching is shaped by commercial needs.

  3. This morning, I saw that Chris Aldrich has written an excellent overview of zettlekasten-note taking techniques and history. Ton Zijlstra comments that the article is great, and is itself a product of a zettlekasten, so Chris is “practicing what he preaches”. I agree with Ton’s compliment, but I still have one nagging qualm – what does the zettlekasten itself look like? In July 2022, Chris Aldrich called for public examples of zettlekasten output, which he has created a great example in his recent post. But what about the zettlekasten itself? As I state in the title (a play on the classic Wendy’s hamburger commercial) – show us the beef! Show us what was collected and how it was collected so we (humanity) can try to learn from your experiences. Of all my looking through Zettlekasten.de, I have found only one post with semi-specific information about actual zettlekasten cards/notes. Sounds like a 30-day challenge is in order here…

    1. Chris Aldrich says:

      Andy, this is a subtle, but brilliant question. Fortunately I’m a guy who not only happens to have lots of hidden context, but lots of it exists online to point you to “the receipts”. Earlier this morning I commented back to Jeremy and Ton on this very topic. Ton had commented broadly that it was interesting to have been watching my note taking and annotation practice using Hypothes.is and seeing pieces of that work emerge in this piece. I know that he follows my RSS feed to do this.

      I responded:

      I was almost tempted to link to the original notes (as many are available publicly online) instead of doing more traditional footnotes to underline the flow of this practice which is often invisible to most readers.

      Centering it and making it more apparent may be a helpful example for those who don’t otherwise “see” it.

      If you’d like you can look back to large portions of my research and note taking practice by searching through my Hypothes.is account. Though it is digital in form, the careful observer will recognize my notes done this way are closer to the older zettelkasten/commonplace book tradition as my notes are discrete, card-like in nature, and heavily tagged with topical keywords. Because it’s digital and searchable, I don’t need to make multiple copies to place behind each headword the way one might need to in a paper analog method. Some of these digital notes even cross the boundary into Luhmann’s method as there are oftentimes explicit links from one note/idea to another. When linked this way, it’s usually a sign that these notes will also be copied over into my physical/analog (Luhmann-esque) zettelkasten for which I primarily save for material that is entirely my own. I generally refrain from putting synopses of other’s material into my own paper ZK.

      Going back and showing all the receipts here is difficult as some on the commonplace tradition were analog notes were made from analog sources not made online. However, if you search some of the keywords in my Hypothes.is repository, you’ll definitely find direct traces for much of what’s in this long piece. Just to highlight one particular example, in part because of its recent and comes more easily to mind, you’ll notice that I made a note about a zettelkasten that I saw in the Netflix series The Crown: https://hypothes.is/a/Cz7e_lHKEe2Qv79IbEgmNw. This note ended up in the final piece as an example with some additional observations about it: https://hyp.is/iIz2VFMSEe2ZQkuNSzVq6w/boffosocko.com/2022/10/22/the-two-definitions-of-zettelkasten/.

      Of course, not all the ideas and observations in the piece were necessarily in my notes to begin with. Some of them arose as new thinking in stringing things together while composing the larger work. Sometime this week, I’ll go back to my own piece and excerpt it for inclusion back into my own corpus of notes for later potential reuse.

      This may not be the mass of one-to-one correspondence evidence you were expecting, but hopefully it’s close enough. Perhaps on a future piece, I’ll do the extra work to make it all more apparent?

      Syndicated copies:

      1. Chris, thank you very much for your reply. I appreciate your providing the “breadcrumbs” to gain insight into your zettelkasten practice. Again, your post is wonderful, I just saw this as an opportunity to “put in a request” to learn about a practitioner’s techniques.

  4. What a brilliant read that will certainly course-correct the conversations around Zettelkasten for the future.

    I do think the shapeability of digital notes—used often as a form of thinking—opens up new terrain in the conversations around notes

  5. This Article was mentioned on linksfor.dev

  6. This Article was mentioned on linksfor.dev

  7. linksfor.dev says:

    This Article was mentioned on linksfor.dev

  8. Great write up, Chris.

    For the record, I think the biggest problem with the term Zettelkasten is the term Zettelkasten.

  9. Chris Aldrich says:

    There was a kind video mention of this article by Nick Milo in both his newsletter and in a recap video:

  10. This Article was mentioned on arthurperret.fr

  11. Zettelkasten

    Go to this page if you are interested in building a Zettelkasten. Although it is not my aim to take notes and develop ideas in exactly the way the German sociologist Niklas Luhmann did, in the posts on that page, I lay out how to build a Zettelkasten in

  12. Caroline says:

    Thanks for writing this. I always feel like so many articles miss out on the history. Another fascinating historical example of thinking about linked thought and knowledge is Otlet’s Mundaneum -https://daily.jstor.org/internet-before-internet-paul-otlet/

  13. Mikjail says:

    Hello Chris,

    I was re-reading some of your posts on Zettelkasten, and I find myself amazed by how many references you’ve collected.

    With the aim of furthering the research, and make the list of usage examples bigger, did you know that Hannah Arendt kept a Zettelkasten? And it is digitized! She did not only handwritten cards, but also typed ones!


    Here are some examples:



    Have a good time!


    1. Chris Aldrich says:

      Spectacular find Mikjail. Thanks for passing it along. I become less and less amazed at the number of people who kept these, but this one looks like some fun, especially as they’ve digitized it.

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