there have been many, MANY historical attempts to organize the worlds knowledge hierarchically. They have all failed to achieve their goals spectacularly. some

there have been many, MANY historical attempts to organize the worlds knowledge hierarchically. They have all failed to achieve their goals spectacularly. some of the most common reasons - things exist in multiple categories that aren't in the same branch of the tree - different state of mind during data retrieval means you expect the same item to be in different categories. - different humans think the same thing belongs in different hierarchical locations there's also been a LOT of scientific research around informational organization. It all came to the same conclusion. Hierarchies have interesting promises but fail when it meets the practical reality of the human brain. in the end hierarchical organization of knowledge is a terrible solution expect in VERY restricted cases.