Though referring to catalogs and office literature, in 1908 it was known that using decimals would allow one to distinguish between slightly different versions of indexable items without running out of "space" for new additions.

Interesting to see a mix of numbers and letters in the indexing system here from 1908.

Numbers for companies and dates and letters as tags for a variety of business purposes as well as for month indicators.

I've sketched it out elsewhere but let's memorialize the broad strokes here because we're inspired at the moment... come back later and add in quotes from Luhmann and other sources (@Heyde1931).

Luhmann was balancing the differences between topically arranged commonplaces and the topical nature of the Dewey Decimal System (a standardized version across thousands of collections) and building neighborhoods of related ideas.

One of the issues with commonplace books, is planning them out in advance. How might you split up a notebook for long term use to create easy categories when you don't know how much room to give each in advance? (If you don't believe me, stop by r/commonplacebooks where you're likely to see this question pop up several times this year.) This issue is remedied when John Locke suggests keeping commonplaces in chronological order of their appearance and cross-indexing them.

This creates a new problem of a lot of indexing and increased searching over time as the commonplace book scales. Translating to index cards complicates things because they're unattached and can potentially move about, so they don't have the anchor effectuated by their being bound up in a notebook. But being on slips allows them to be more easily shuffled, rearranged, and even put into outlines, which are all fantastic affordances when looking for creativity or scaffolding things out into an article or book for creation.

As a result, numbering slips creates a solid anchor by which the cards can be placed and always returned for later finding and use. But how should we number them? Should it be with integers and done chronologically? (1, 2, 3, ..., n) This is nice, but makes a mish-mash of things and doesn't assist much in indexing or finding.

Why not go back to Dewey, which has been so popular? But not Dewey in the broadest sense of using numbers to tie ideas to concrete categories. An individual's notes are idiosyncratic and it would be increasingly rare for people to have the same note, much less need a standardized number for it (and if they were standardized, who does that work and how is it distributed so everyone could use it?) No, instead, let's just borrow the decimal structure of Dewey's system. One of the benefits of his decimal structure is that an infinity of new books can be placed on ever-expanding bookshelves without needing to restructure the numbering system. Just keep adding decimal places onto the end when necessary. This allows for immense density when necessary. But, importantly, it also provides some fantastic level of serendipity.

Let's say you go to learn about geometry, so you look up the topic in your trusty library card catalog. Do you really need to look at the hundreds of records returned? Probably not. You only need the the Dewey Decimal Number 516. Once you're at the shelves, you can browse through that section to see what's there and interesting in the space. You might also find things on the shelves above or below 516 and find the delights of topology and number theory or abstract algebra and real analysis. Subjects you might not necessarily have had in mind will suddenly present themselves for your consideration. Even if your initial interest may have been in Zhongmin Shen's Lectures on Finsler geometry (516.375), you might also profitably walk away with James E. Humphreys' Introduction to Lie Algebras and Representation Theory (512.55).

So what happens if we use these decimal numbers for our notes? First we will have the ability to file things between and amongst each other to infinity. By filing things closest to things which seem related to each other, we'll create neighborhoods of ideas which can easily grow over time. Related ideas will stay together while seemingly related ideas on first blush may slowly grow away from each other over time as even more closely related ideas move into the neighborhood between them. With time and careful work, you'll have not only a breadth of ideas, but a massive depth of them too.

The use of decimal numbering provides us with a few additional affordances:

1 (Neighborhoods of ideas) 1.1 combinatorial creativity Neighborhoods of ideas can help to fuel combinatorial creativity and forge new connections as well as insight over time. 1.2 writing One might take advantage of these growing neighborhoods to create new things. Perhaps you've been working for a while and you see you have a large number of cards in a particular area. You can, to some extent, put your hand into your box and grab a tranche of notes. By force of filing, these notes are going to be reasonably related, which means you should be able to use them to write a blog post, an article, a magazine piece, a chapter, or even an entire book (which may require a few fistfuls, as necessary.)

2 (Sparse indexing) We don't need to index each and every single topic or concept into our index. Because we've filed things nearby, if a new card about Finsler geometry relates to another and we've already indexed the first under that topic, then we don't need to index the second, because our future selves can easily rely on the fact that if we're interested in Finsler geometry in the future, we can look that up in the index, and go to that number where we're likely to see other cards related to the topic as well as additional serendipitous ideas related to them in that same neighborhood.

You may have heard that as Luhmann progressed on his decades long project, broadly on society and within the area of sociology, he managed to amass 90,000 index cards. How many do you suppose he indexed under the topic of sociology? Certainly he had 10s of thousands relating to his favorite subject, no? Of course he did, but what would happen over time as a collection grows? Having 20,000 indexed entries about sociology doesn't scale well for your search needs. Even 10 indexed entries may be a bit overwhelming as once you find a top level card, hundreds to thousands around it are going to be related. 10 x 100 = 1,000 cards to flip through. So if you're indexing, be conservative. In the roughly 45 years of creating 90,000 slips, Luhmann only indexed two cards with the topic of "sociology". If you look through his index, you'll find that most of his topical entries only have pointers to one or two cards, which provide an entryway into those topics which are backed up with dozens to hundreds of cards on related topics. In rarer, instances you might find three or four, but it's incredibly rare to find more than that.

Over time, one will find that, for the topics one is most interested in, the number of ideas and cards will grown without bound. Here it makes sense to use more and more specific topics (tags, categories, taxonomies) all of which are each also sparsely indexed. Ultimately one finds that in the limit, the categories get so fractionalized that the closest category one idea has with another is the fact that they're juxtaposed closely by number. The of the decimal expansion might say something about the depth or breadth of the relationship between ideas.

Something else arises here. At first one may have the tendency to associate their numbers with topical categories. This is only natural as it's a function at which humans all excel. But are those numbers really categories after a few weeks? Probably not. Treat them only as address numbers or GPS coordinates to be able to find your way. Your sociology section may quickly find itself with invasive species of ideas from anthropology and archaeology as well as history. If you treat all your ideas only at the topical level, they'll be miles away from where you need them to be as the smallest level atomic ideas collide with each other to generate new ideas for you. Naturally you can place them further away if you wish and attempt to bridge the distance with links to numbers in other locations, but I suspect you'll find this becomes pretty tedious over time and antithetical when it comes time to pull out a handful and write something. It's fantastically easier to pull out a several dozen and begin than it is to go through and need to pull out linked cards in a onesy-twosies manner or double check with your index to make sure you've gotten the most interesting bits. This becomes even more important as your collection scales.

In the early 1950s, Luhmann spent a year at the Lüneburg Higher Administrative Court organizing a reference system for the administrative court decisions to enable researchers to see what decisions had been made in the higher courts.

Though he had begun his zettelkasten during his studies, this referencing system may have influenced the structure of his own note taking system.

Can we pin the dates on these practices down more closely?

—Georg Christoph Lichtenberg, Notebook E, #46, 1775–1776

In this single paragraph quote Lichtenberg, using the model of Italian bookkeepers of the 18th century, broadly outlines almost all of the note taking technique suggested by Sönke Ahrens in How to Take Smart Notes. He's got writing down and keeping fleeting notes as well as literature notes. (Keeping academic references would have been commonplace by this time.) He follows up with rewriting and expanding on the original note to create additional "explanations" and even "connections" (links) to create what Ahrens describes as permanent notes or which some would call evergreen notes.

Lichtenberg's version calls for the permanent notes to be "separated and ordered" and while he may have kept them in book format himself, it's easy to see from Konrad Gessner's suggestion at the use of slips centuries before, that one could easily put their permanent notes on index cards ("separated") and then number and index or categorize them ("ordered"). The only serious missing piece of Luhmann's version of a zettelkasten then are the ideas of placing related ideas nearby each other, though the idea of creating connections between notes is immediately adjacent to this, and his numbering system, which was broadly based on the popularity of Melvil Dewey's decimal system.

It may bear noticing that John Locke's indexing system for commonplace books was suggested, originally in French in 1685, and later in English in 1706. Given it's popularity, it's not unlikely that Lichtenberg would have been aware of it.

Given Lichtenberg's very popular waste books were known to have influenced Leo Tolstoy, Albert Einstein, Andre Breton, Friedrich Nietzsche, and Ludwig Wittgenstein. (Reference: Lichtenberg, Georg Christoph (2000). The Waste Books. New York: New York Review Books Classics. ISBN 978-0940322509.) It would not be hard to imagine that Niklas Luhmann would have also been aware of them.

Open questions: <br /> - did Lichtenberg number the entries in his own waste books? This would be early evidence toward the practice of numbering notes for future reference. Based on this text, it's obvious that the editor numbered the translated notes for this edition, were they Lichtenberg's numbering? - Is there evidence that Lichtenberg knew of Locke's indexing system? Did his waste books have an index?

The problem here is equating the "top level" number with category in the first place. It's just an idea and the number is a location. Start by separating the two.

https://www.youtube.com/watch?v=Lp818Ml3C2w&list=PLuJbg6eLC7Y2nU_KhrWZX8zGg-yl_L-_T

At the opening of the video he describes his numbering system: 7.106.1 is shorthand for 7th year, 106th day, video number 1. This is a chronological numbering for tracking things and not a relational sort of numbering often seen in zettelkasten contexts.

https://en.wikipedia.org/wiki/Stephanus_pagination

Stephanus pagination is a system of reference numbers used in editions of Plato based on the three volume 1578 edition of Plato's complete works published by Henricus Stephanus (Henri Estienne) and translated by Joannes Serranus (Jean de Serres).

See also: - Bekker numbering (for Aristotle) - Diels-Kranz numbering (for early pre-Socratics)

While Heyde spends a significant amount of time on encouraging one to index and file their ideas under one or more subject headings, he address the objection:

“Doesn’t this neglect the importance of sequentiality, context and development, i.e. doesn’t this completely make away with the well-thought out unity of thoughts that the original author created, when ideas are put on individual sheets, particularly when creating excerpts of longer scientific works?"

He suggests that one file such ideas under the same heading and then numbers them sequentially to keep the original author's intention. This might be useful advice for a classroom setting, but perhaps isn't as useful in other contexts.

But for Luhmann's use case for writing and academic research, this advice may actually be counter productive. While one might occasionally care about another author's train of thought, one is generally focusing on generating their own train of thought. So why not take this advice to advance their own work instead of simply repeating the ideas of another? Take the ideas of others along with your own and chain them together using sequential numbers for your own purposes (publishing)!!

So while taking Heyde's advice and expand upon it for his own uses and purposes, Luhmann is encouraged to chain ideas together and number them. Again he does this numbering in a way such that new ideas can be interspersed as necessary.

Heyde indicates how "valuable notes and chains of thought are" but also points out "how uncontrollable and irretrievable" they are.

This statement is strong evidence along with others in this chapter which may have inspired Niklas Luhmann to invent his iteration of the zettelkasten method of excerpting and making notes.

(link to: Clemens /Heyde and Luhmann timeline: https://hypothes.is/a/4wxHdDqeEe2OKGMHXDKezA)

Presumably he may have either heard or seen others talking about or using these general methods either during his undergraduate or law school experiences. Even with some scant experience, this line may have struck him significantly as an organization barrier of earlier methods.

Why have notes strewn about in a box or notebook as Heyde says? Why spend the time indexing everything and then needing to search for it later? Why not take the time to actively place new ideas into one's box as close as possibly to ideas they directly relate to?

But how do we manage this in a findable way? Since we can't index ideas based on tabs in a notebook or even notebook page numbers, we need to have some sort of handle on where ideas are in slips within our box. The development of European card catalog systems had started in the late 1700s, and further refinements of Melvil Dewey as well as standardization had come about by the early to mid 1900s. One could have used the Dewey Decimal System to index their notes using smaller decimals to infinitely intersperse cards on a growing basis.

But Niklas Luhmann had gone to law school and spent time in civil administration. He would have been aware of aktenzeichen file numbers used in German law/court settings and public administration. He seems to have used a simplified version of this sort of filing system as the base of his numbering system. And why not? He would have likely been intimately familiar with its use and application, so why not adopt it or a simplified version of it for his use? Because it's extensible in a a branching tree fashion, one can add an infinite number of cards or files into the midst of a preexisting collection. And isn't this just the function aktenzeichen file numbers served within the German court system? Incidentally these file numbers began use around 1932, but were likely heavily influenced by the Austrian conscription numbers and house numbers of the late 1770s which also influenced library card cataloging numbers, so the whole system comes right back around. (Ref Krajewski here).

(Cross reference/ see: https://hypothes.is/a/CqGhGvchEey6heekrEJ9WA

Other pieces he may have been attempting to get around include the excessive work of additional copying involved in this piece as well as a lot of the additional work of indexing.

One will note that Luhmann's index was much more sparse than without his methods. Often in books, a reader will find a reference or two in an index and then go right to the spot they need and read around it. Luhmann did exactly this in his sequence of cards. An index entry or two would send him to the general local and sifting through a handful of cards would place him in the correct vicinity. This results in a slight increase in time for some searches, but it pays off in massive savings of time of not needing to cross index everything onto cards as one goes, and it also dramatically increases the probability that one will serendipitously review over related cards and potentially generate new insights and links for new ideas going into one's slip box.

While Heyde outlines using keywords/subject headings and dates on the bottom of cards with multiple copies using carbon paper, we're left with the question of where Luhmann pulled his particular non-topical ordering as well as his numbering scheme.

While it's highly likely that Luhmann would have been familiar with the German practice of Aktenzeichen ("file numbers") and may have gotten some interesting ideas about organization from the closing sections of the "Die Kartei" section 1.2 of the book, which discusses library organization and the Dewey Decimal system, we're still left with the bigger question of organization.

It's obvious that Luhmann didn't follow the heavy use of subject headings nor the advice about multiple copies of cards in various portions of an alphabetical index.

While the Dewey Decimal System set up described is indicative of some of the numbering practices, it doesn't get us the entirety of his numbering system and practice.

One need only take a look at the Inhalt (table of contents) of Heyde's book! The outline portion of the contents displays a very traditional branching tree structure of ideas. Further, the outline is very specifically and similarly numbered to that of Luhmann's zettelkasten. This structure and numbering system is highly suggestive of branching ideas where each branch builds on the ideas immediately above it or on the ideas at the next section above that level.

Just as one can add an infinite number of books into the Dewey Decimal system in a way that similar ideas are relatively close together to provide serendipity for both search and idea development, one can continue adding ideas to this branching structure so they're near their colleagues.

Thus it's highly possible that the confluence of descriptions with the book and the outline of the table of contents itself suggested a better method of note keeping to Luhmann. Doing this solves the issue of needing to create multiple copies of note cards as well as trying to find cards in various places throughout the overall collection, not to mention slimming down the collection immensely. Searching for and finding a place to put new cards ensures not only that one places one's ideas into a growing logical structure, but it also ensures that one doesn't duplicate information that may already exist within one's over-arching outline. From an indexing perspective, it also solves the problem of cross referencing information along the axes of the source author, source title, and a large variety of potential subject headings.

And of course if we add even a soupcon of domain expertise in systems theory to the mix...

While thinking about Aktenzeichen, keep in mind that it was used in German public administration since at least 1934, only a few years following Heyde's first edition, but would have been more heavily used by the late 1940's when Luhmann would have begun his law studies.

https://hypothes.is/a/CqGhGvchEey6heekrEJ9WA

When thinking about taking notes for creating output, one can follow one thought with another logically both within one's card index not only to write an actual paper, but the collection and development happens the same way one is filling in an invisible outline which builds itself over time.

Linking different ideas to other ideas separate from one chain of thought also provides the ability to create multiple of these invisible, but organically growing outlines.

This alternating patter also has the appearance of Luhmann's numbering system and may have made him think, why use the other system(s)? Why not just file everything based on this method from the start?

https://www.reddit.com/r/antinet/comments/w7ytto/we_could_literally_go_nuts_with_our_personal/

No new insight here...

If it's continuing on 15a, then 15b would make most sense to me. Perhaps this example description helps? https://sociologica.unibo.it/article/view/8350/8270#the-system-of-numbering Try not to think "between" as it indicates links forwards and backwards, but what does this thought "continue on" or "follow"?

https://lis653.wordpress.com/2022/04/06/license-plates-and-war-crimes/

The court file number is used to identify a document and goes back to the file regulations (AktO) of November 28, 1934 and its predecessors.

The German "file number" (aktenzeichen) is a unique identification of a file, commonly used in their court system and predecessors as well as file numbers in public administration since at least 1934.

Niklas Luhmann studied law at the University of Freiburg from 1946 to 1949, when he obtained a law degree, before beginning a career in Lüneburg's public administration where he stayed in civil service until 1962. Given this fact, it's very likely that Luhmann had in-depth experience with these sorts of file numbers as location identifiers for files and documents.

We know these numbering methods in public administration date back to as early as Vienna, Austria in the 1770s.

The missing piece now is who/where did Luhmann learn his note taking and excerpting practice from? Alberto Cevolini argues that Niklas Luhmann was unaware of the prior tradition of excerpting, though note taking on index cards or slips had been commonplace in academic circles for quite some time and would have been reasonably commonplace during his student years.

Are there handbooks, guides, or manuals in the early 1900's that detail these sorts of note taking practices?

Perhaps something along the lines of Antonin Sertillanges’ book The Intellectual Life (1921) or Paul Chavigny's Organisation du travail intellectuel: recettes pratiques à l’usage des étudiants de toutes les facultés et de tous les travailleurs (in French) (Delagrave, 1918)?

Further recall that Bruno Winck has linked some of the note taking using index cards to legal studies to Roland Claude's 1961 text:

I checked Chavigny’s book on the BNF site. He insists on the use of index cards (‘fiches’), how to index them, one idea per card but not how to connect between the cards and allow navigation between them.

Mind that it’s written in 1919, in Strasbourg (my hometown) just one year after it returned to France. So between students who used this book and Luhmann in Freiburg it’s not far away. My mother taught me how to use cards for my studies back in 1977, I still have the book where she learn the method, as Law student in Strasbourg “Comment se documenter”, by Roland Claude, 1961. Page 25 describes a way to build secondary index to receive all cards relatives to a topic by their number. Still Luhmann system seems easier to maintain but very near.

<small><cite class='h-cite via'>ᔥ <span class='p-author h-card'> Scott P. Scheper </span> in Scott P. Scheper on Twitter: "The origins of the Zettelkasten's numeric-alpha card addresses seem to derive from Niklas Luhmann's early work as a legal clerk. The filing scheme used is called "Aktenzeichen" - See https://t.co/4mQklgSG5u. cc @ChrisAldrich" / Twitter (<time class='dt-published'>06/28/2022 11:29:18</time>)</cite></small>

Link to: - https://hypothes.is/a/Jlnn3IfSEey_-3uboxHsOA - https://hypothes.is/a/4jtT0FqsEeyXFzP-AuDIAA

Even the long running (2013) zettelkasten.de website credits Niklas Luhmann as being the "original creator" of the zettelkasten.

sigh

We really need to track down the origin of linking one idea to another. Obviously writers, and especially novelists, would have had some sort of at least linear order in their writing due to narrative needs in using such a system. What does this tradition look like on the non-fiction side?

Certainly some of the puzzle stems from the commonplace book tradition, but this is more likely to have relied on natural memory as well as searching and finding via index methods.

Perhaps looking more closely at Hans Blumenberg's instantiation would be more helpful. Similarly looking at the work of Claude Lévi-Strauss and his predecessors like Marcel Mauss may provide at least an attack on this problem.

My working hypothesis is that given the history of the Viennese numbering system, it may have stemmed from the late 1700s and this certainly wasn't an innovation by Luhmann.

link to: https://hyp.is/hLy7NNtqEeuWQIP1UDkM6g/web.archive.org/web/20130916081433/https://christiantietze.de/posts/2013/06/zettelkasten-improves-thinking-writing/ for evidence of start of zettelkasten.de

https://www.youtube.com/watch?v=MrjUg4toZqw

It's worth look looking into the structure of Walter Benjamin's Arcade Project as the numbering system that he used on his zettels is very similar to that of both Niklas Luhmann's zettelkasten as well as the street numbers of 1770 Vienna.

link to - https://hypothes.is/a/4jtT0FqsEeyXFzP-AuDIAA - https://hypothes.is/a/lvGHJlNHEeyZnV-8psRNrA