The basic methodology for concept acquisition employed in the Mikrokosmos project involves a fine-grained cycle of requests for concepts from the lexicon acquisition team and the resulting responses which may involve pointing out an existing concept, adding a new concept, enhancing the internal structure of one or more concepts, or suggesting a different lexical mapping for the word in question. If it is determined that a word sense requires a new concept in the ontology, the ``algorithm'' applied for adding the new concept hinges on viewing the ontology as a discrimination tree. The acquirer discriminates from the top down until at some point there is no child that subsumes the meaning in question. A new concept is added as a child at that point. In the Mikrokosmos project, sets of guidelines have emerged for making various kinds of decisions in ontology acquisition. These guidelines collectively define the methodology for ontology building.
Given the above theoretical foundation, we now attempt to list a set of guidelines and sketch a methodology for each of the subtasks in ontology acquisition. The following is an evolving set of guidelines and is largely derived by generalizing from the problems we have faced in our experience.