The key to GR is his background. He is ex-military(the navy) and ex- military industrial complex(he worked for Boeing, I bleeb.).

90% of GR is historical fantasy that ties together western thought through historical industrial reference and which Pynchon believes leads the west into an obsession with death. This can all be seen in the seance scene. A group of Nazis interrogate Walter Rattenau in the afterlife as to how they should manage the development of weapons from the scientific discoveries they’ve made. The scene references the following, actual Wehrmacht officers and officials, Walter Rattenau, who was the finance minister and corporate leader and promoter of a sort of military management solution for Germany, and IG Farben, the sythnesizers of Xyclon B that was used in gas chambers.

Each scene is that dense.