> How is this distinct from organizing world information? Any practical classification system starts with corpus at hand, and tries to organize that. Any ideal

> How is this distinct from organizing world information? Any practical classification system starts with corpus at hand, and tries to organize that. Any idealistic classification system that aspires to be "complete" (at least in theory) starts with theoretically possible corpus, and tries to organize that. For example, if you want to classify the pictures you have in your personal photo library, it would make sense to have e.g. a folder named "2020", for the pictures you've made that year. But it would not make sense to have a folder named "1900", as it's unlikely you made any photos then. This is a practical classification. But if you want to classify all of the world's photos, you may need to start with a folder named "1826" to hold the View from the Window at Le Gras[1]. Or maybe earlier, for the paintings. That's a theoretical classification. DDS is a practical classification, and as such, it started with the corpus at hand — whatever public libraries in the USA had at Dewey's time. This is how it's "distinct from organizing world information". ————— [1]: It's not clear if the photo was taken in 1826 or 1827, so our theoretical classification would need to account for that, or for photos where the year is unknown, or estimated, etc.