Computer systems that have similar upper ontologies will have much lower integration costs. If upper ontologies are stable then people will develop trust in the systems. They are the anchors of your semantics and the foundation of your building. Change them frequently and you will quickly lose the trust of your stakeholders. [..] An upper ontology is like a high-level sieve. Data elements come pouring out of requirements like little grains of sand and need to be sorted correctly by the "uppers." Even a novice that is unfamiliar with your ontology should have the ability to guess how the data elements are sorted.