Comment by hwayne | Hacker News Reader

Comment by hwayne | Hacker News Reader

This is an argument against taxonomic classification, not categories per se. In Wikipedia, pages can belong to multiple categories, and categories can have multiple parent categories. It's more complex than single hierarchical taxonomies, but it's also a lot more expressive.

That expressiveness is something I find is missing from a lot of tag systems. Most have no structure at all, when even a little structure makes things a lot more convenient. At the very least, I want hierarchical tags. Let things I tag "physics" show up in a search for "science!"

(I think most systems don't have structured tags because it raises a lot of implementation and UI questions. How do you prevent cycles? Do searches go one layer deep or are they fully transitive?)

See also the first comment in TFA:

> I maintained the largest collection of dishes served by restaurants for more than 10 years. [...] 70% of the metadata was captured via tags, manually added or automatically extracted from plain text. Our clients notified us that some of the entries were of poor quality: for instance some dishes were tagged with "vegan" and "beef" at the same time.

#vegan and #beef is an interesting example which I didn't get.

Either a dish is vegan, or it has beef. So a dish tagged #vegan and #beef is either wrong about the #vegan tag, or has... vegan beef, which ontology aside, exists in the sense that there are foods with this name.

Hierarchies can't fix misclassification, a beef-containing dish doesn't belong in the #Vegan: namespace either.

As for organizing tags, something I'd like to see (pending a reasonable UX) is just being able to tag tags. #physics could be tagged #science, and #science could be tagged #physics, cycles aren't a problem for set union.

A dish tagged #vegan and #beef would imply vegan meat version

Or a vegan dish that is also good if you add meat.

That would only exist in an alternate universe.

One universe of vegan dishes and non-vegan dishes.

Another universe where the tag is generated by meat chefs for vegans— this vegan dish would be great if only you added some meat…or something like that.

I like to go to the restaurant chain called Wagamama. They have vegan dishes where you can optionally add different kinds of meat.

> "I like to go to the restaurant chain called Wagamama."

The Wagamama-universe. haha.

I don't know this chain, but your example poses an interesting problem. Is a Caesar salad, add chicken, a new dish? I would argue it's not a new recipe, but a manifestation of how the restaurant caters to patrons' desire. Or, a manifestation of how salads can be minimally altered with grilled chicken to turn a side dish into a main dish for lunch. So maybe there are better, less confusing, tags for restaurants who permit these alterations? `add-meat-optional`. And that's where I find this to be an interesting example.

So now... You're in your sandbox classifying "important things", you might think to add an `add-meat` tag (or whatever). But what if you're just wasting time with your phone standing in a queue just adding bookmarks in Firefox (does the phone app have tags--i don't know)? So now...you might not recall the rules of your ontology. Instead you're drawn into the _alternate universe_ created by the website's design, or it's branding. Branding intended to tweak your perception and you start adding strange tag combinations, without thinking how this will goof up your search algorithm. Tag salad--haha.

A dish with an option could legitimately be both — as, eg, burritos at my local Mexican place allow a variety of meat and non-meat fillings. For a single item on the menu.

If they didn’t separate, eg, burrito options into different entries, then you’d get a burrito entry with both “vegan” and “beef” correctly.

The music site RateYourMusic has a hierarchical genre tree. They might organize it like this:

- beef [meta]

- - beef (co-parent: meat)

- - vegan beef (co-parent: vegetarian faux meat)

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