 Representational formal ontologies, somewhat paradoxically, are independent of any strictly ontological issues. Their success or failure is independent of what there is. Descriptive formal ontologies are just like representational ones, except with the ambition of describing a domain of entities. Systematic formal ontologies go further in not only describing one domain, but in relating all entities (of a certain kind) to each other, often with particular notions of reduction. These theories seem to be the most ambitious. Their motivation comes from an attempt to find a simple and systematic theory of all, say, abstract entities, and they can rely on the paradigm of aiming for simplicity in the physical sciences as a guide. They, just like descriptive theories, will have to have as their starting point a reasonable degree of certainty that we indeed are ontologically committed to the entities they aim to capture. Without that these enterprises seem to have little attraction. But even if the latter philosophical ambitions fail, a formal ontology can still be a most useful representational tool.