1. A method, in a data processing system, for exploring knowledge, the method comprising: receiving, by the data processing system, a set of known facts; traversing, by the data processing system, paths in an ontology for a domain of knowledge from known facts in the set of known facts to one or more hypotheses, wherein the ontology includes a plurality of entity types and a plurality of relationships between the entity types; and presenting, by the data processing system, the one or more hypotheses.