Taxonomies are taxonomies, whether they’re used for physical or digital files. With physical files, unless you photocopy and place an item in multiple folders, there is only one location – one folder – one taxonomy label – to which it belongs. Even if an item is conceptually “about” more than one thing, it only “is” in one place. There is a tension here between aboutness and isness, then, that is mitigated by adhering to, as much as possible, a single organizing principle and a simple taxonomy.
Some time ago I created a taxonomy for some ephemera files in the philatelic library.
Here is a sample of folder labels that demonstrated the existing hierarchy (folder system):
- Civil War
- Money
- History – Arizona – Ghost Towns.
- Philately – Societies, etc. – American Philatelic Society.
- Postage stamps – Aspects – Postmarks.
- Postal Service – Airmail – Katherine Stinson.
- Transportation – Airplanes.
As you can see, not everything in this collection is related to stamps or stamp collecting. Some, like Money, are tangentially related (stamps can be used as money, some stamp collectors also collect money); others support stamp/philately research (Transportation-Airplanes would give information on the types of airplanes used to deliver mail). Having philatelic and non-philatelic concepts blended together was messy.
In order to keep categories clean and separate, the first thing I did was create four top-level concepts (categories): Philately, Arizona, Civil War, Ancillary.
This division does a few things. First, it logically separates the concepts represented in the material. This simplifies both the taxonomy and the physical labels on the folders. No more “Philately – Societies, etc. – American Philatelic Society. Now, under the category Philately Ephemera, it’s just Societies, etc. – American Philatelic Society. That may not seem like a big deal, but when you’ve got hundreds of subconcepts/folders, it adds up, especially the more levels that are required. The cleaner the term (and folder label, in the case of these physical files), the easier it is to file and retrieve items.
It also makes clear the types of items collected, and the purpose for collecting them. Philately is our main focus and materials in this category should be collected in support of the mission. Civil War items are retained due to a promise to generous benefactors. Arizona materials are retained because a large portion of them are philatelic (post office documents) and because we already own them and still have space for them. Ancillary items that support the stamp collectors’ research are also retained because they are helpful, and we still have room.
The categories are also prioritized. Philately is clearly the most important. This is reflected in the fact that it’s the largest of the four collections. If space is ever an issue, items from the other categories would be weeded first. As well, it’s not as important to actively collect from the other three categories as it is Philately.
The guiding principles of this taxonomy are a modified product attribution taxonomy. Product attribution taxonomy concepts are mutually exclusive. A product can only be in one “slot” or have one unique identifier for it. For example Tools –> Hammers –> Claw hammers –> Model #1234. There is only one object that is Model #1234 (there may be multiple instances of this hammer in stock, but that is outside the scope of this point). No other hammer or any other type of tool is Model #1234. This example demonstrates what the object/product/concept is, or its isness. Similarly, the ephemera item can only be in one place (folder) at the same time. However, unlike products, an ephemera item such as a newspaper clipping is not filed solely by its isness, it’s also filed by its aboutness. Its subject matter. That’s why the taxonomy I created is akin, but not exactly like, a product attribution taxonomy.
[Edited for clarity 10-23-23.]