Complex sentence: Duerr argues that modern Western society lacks important facets found in "archaic" societies who adhere to shamanic beliefs, and he asserts that the majority of Western anthropologists who have performed ethnographic fieldwork in these cultures have failed to truly understand them.
Split into simpler sentences: Duerr argues that modern western society lacks many important facets that can be found in those "archaic" societies who adhere to shamanic beliefs. Furthering this argument, he asserts that the majority of western anthropologists who have performed ethnographic fieldwork in these cultures have failed to truly understand them.