Even with a uniform language, there may still be incompatible assumptions in the conceptualization. For example, in [Hayes 96] it is shown that two representations for time, one based on time intervals and another based on time points, are fundamentally incompatible. That is, an agent whose time ontology is based on time points can never incorporate the axioms of another agent whose ontology for time is based on time intervals. From a logic perspective, the two representations are like oil and water.