You're comparing Apples and Oranges a bit. OWL is formal framework that can be used to describe ontologies. Cyc is an attempt to create an ontology that describ

You're comparing Apples and Oranges a bit. OWL is formal framework that can be used to describe ontologies. Cyc is an attempt to create an ontology that describes the world. You are right that a lot of these "glob everything together" ontologies inevitably get too unwieldy to actually use. And wouldn't be so far off saying that OWL itself is a bit hard to grok. But it is important to see what the difference is. What is important about something like OWL, OWL-DL, or OWL Light is that they specify the types of axioms you are allowed to use. For example, the following statements are very different: - Humans have exactly two biological parents - Humans must have biological parents - Humans must have biological parent(s) - Humans can have parent(s) OWL, and its subsets, are attempts to carve out logical axioms that allow you to specify the nature of conceptual classes and their properties. You need a framework such as OWL to spell out what you are allowed to state about concepts like this because different types of logical relationships have algorithmic complexity implications. What you are allowed to state is incredibly important to people who want to perform logical inference, for example, because certain types of axioms will take a dataset on which inference would otherwise be O(P) time, and turn it to O(NP) time.