When I refer to "order" I refer to the archival phrase "original order," that is, how the collector originally structured his collection. Did try to structure them chronologically? Thematically? By creator? All of these factors impose different perceptions on whoever would process the collection upon its arrival, and also would impact how users would engage with them. Often we see the ways archives organize collections and simply take it at face value, but the way we organize things influences the assumptions and inferences those who would use them make. Thanks for commenting!