Of particular importance is the insistence on a dominance relationship inherent in the most popular use of the term, Definition 1. H4 D is antisymmetric and transitive. Simon deduced his concept of hierarchy from an empirical observation of nature. Bunge derived his specifically from the dictionary definition. There may very well be systems that would, from Simon's point of view , qualify as hierarchies and would not from Bunge's, With this in mind, we can examine Bunge's discussion of level structures.
Emergence is a concept that has been ill-defined in systems literature.
A level is newer than another level of the same level structure if and only if the former has emerged from the latter. Emergence, then, as seen by Bunge, is a temporal property. He presented five theses of integrated pluralism. The newer levels depend on the older ones both for their emergence and for their continued existence. Assuming these hypotheses to be true, and reality is organized in levels and is know able, then that structure, the author maintained, must be mapped in our scientific knowledge.