Abstract

A standard illustration' of this situation in this: let M~ be a theory of mechanics employing mass points as basic objects and let Mz be similar yet with only extended objects as its primitive elements. Let M> postulate that mass points come only in dense collections. Granted reasonable assumptions about the further details of Mq and M2, we can define the extended objects of Mz in M~ as dense sets of mass points whereas the latter can be defined in Mz as nested sets of the former. Both theories offer equivalent descriptions of the world in the sense that any claim of Mq can be systematically translated into a theorem of Mz and conversely