Until the computer came along, the only viable way to manage information was in document-sized chunks, arranged in hierarchical categories. Now that the computer is here—and has been for a while—we can afford much richer forms of organizing information, but don't seem to be using them nearly as much as we could. This, I suspect, has is because we lack a simple concept, the thing that makes a category a category. That concept is intension.

Deck

Source cited, at least the books:

I suppose I should also include the 2010 article that kicked this thinking off.