 One of the most fundamental interpretative obstacles concerning QFT is the question which formalism to consider and to then identify which parts of the respective formalism carry the physical content, and which parts are surplus structure, from an ontological point of view. Roughly, one may distingush “Hilbert space conservatists” and “algebraic imperialists” (Arageorgis 1995 and Ruetsche 2002 coined these terms). While Hilbert space conservativism seems to be the default position, often adopted without further justification, algebraic imperialism usually comes with an explicit justification.