Because the essay is in German, an English summary is in order (see also this previous post):
The antiquities we see on display in museums constitute only a tiny part of the objects found in excavation, and those in turn form only a tiny part of the material that actually existed back then. The selection process between being buried in the ground and being exhibited in a museum is rigorous. It includes the decision of where to excavate, what to do with the excavated material, and what material is chosen for exhibition—based on money, available space, and the personal interest of museum staff and visitors. Sometimes the decisions are carefully made, while sometimes coincidence or luck takes over (it does happen that excavations miss an important find by just a few centimeters, leaving it undiscovered). Realizing that there is a complex process behind the scenes is one step towards understanding museums as a laboratory, not a finished presentation of a topic we know everything about. The "Pergamonmuseum. Das Panorama" exhibition is great for driving this home because the explanatory texts often mention uncertainty or differing scholarly opinions. For visitors this can be exciting, or unnerving—but either way it promotes the critical thinking skills we need to deal with our modern world.