The Great Tags vs. Folders Debate
In Obsidian, Tags and Folders are complementary organization devices that are much similar than they first may seem.
TLDR;
Tags
faceted (+hierarchical)
can overlap
represent virtual folders
Folders
enumerative (+hierarchical)
mutually exclusive
represent virtual tags
## Information Has a Thousand Names
"What we call things and where we draw the line between one class of things and another depend upon the interests we have and the purposes [goals] of the classification (pg.106)." 1
Well because any item can be described/classified in multiple ways. Classification is a notoriously difficult/slippery task. As a quick example, consider the different ways you might classify a book. You could classify a book by its: subject, author, title, release date, Dewey Decimal Category, publisher, etc. - or even by its format: book. Which one of these is most appropriate will depend on your personal preferences, use case, situation, etc. Every one of these are valid classification criteria, it's just that one (or some) may be more appropriate than others.
Without tags - just using filesystem folders - you're forced to choose a single location, and thus a single dimension to classify. With tags, you can use as many dimensions as you think appropriate. In other words, tags allow for non-mutually exclusive labeling/categorization.
For example, suppose I'm a big media buff. And I like to take notes on all the Film and TV I watch. I might setup a classification scheme that sorts first my Format (Film or TV), then by Genre (Comedy, Horror, Action, Drama, etc.). So a movie like Scream I can file in Film > Horror. And a show like The Crown I can file in TV > Drama. But where would I file a movie like *Shaun of the Dead*? Is it an action movie, a comedy movie, or horror movie?
Relying only on Folders will result in a classification scheme with mutually exclusive categories. This is known as an enumerative classification 2. (More specifically, because the filesystem is also hierarchical, this is an enumerative, hierarchical classification.)
Information can only be understood when examined from multiple perspectives
In contrast, tags allow for categories to overlap. This is known as a faceted classification scheme 3. (Furthermore, because the Obsidian allows hierarchical tags, this can be a faceted, hierarchical classification.)
Know When to Fold 'Em
Folders are still very helpful, as the contemporary Desktop paradigm of computing is heavily oriented around visuo-spatial Folders as the dominant organizing device. And there are several very good reasons why. First, Folders are about as close to a culturally-universal metaphor as you can get. Second, as they are deeply spatial in nature, they intuitively draw upon our innate capacity for spatial reasoning: serving as cues for navigation and to collocate related items. And third, folders excel at information hiding, keeping irrelevant information from cluttering our view, distracting our attention, or disrupting our focus.
Tags, on the other hand, draw upon a different kind of intelligence, our semantic/language-based intelligence.
"Potato, Pohtahto"
But here's the thing: Tags and Folders, at their core, really aren't that different. You can think of every file as having an implicit tag of it's filesystem path. For example. A file in your "Tasks" folder on your Desktop has an (implicit or virtual) tag of "/Desktop/Tasks". And conversely, You can think of every tag as representing a virtual folder. Tags and folders are duals of each other.
Every classification scheme embodies a different way of representing a domain. A different perspective. No single representation is perfect. Rather, for a particular situation, one representation may be more or less appropriate than another. Which representation is most appropriate is context-dependent. This choice requires negotiating between different tradeoffs. Ultimately, pick the one that makes the most sense for you and your unique situation.
Hayakawa, S. I., and Alan R. Hayakawa. Language in Thought and Action. 5th [rev.] ed. San Diego: Harcourt Brace Jovanovich, 1990.
Glushko, Robert J., ed. _The Discipline of Organizing_. Cambridge, MA: The MIT Press, 2013.
ibid.