Zweckrational?

In our wonderful German language, we may spontaneously form compounds of all kinds. We may walk around traumverloren or, for philosophers, even better: gedankenverloren. For the English translation you must choose between “absentmindedly” (but absent where? In dreams or in thoughts?) or “lost in dreams”, “lost in thoughts”.

Our actions may be zweckrational, as Weber believed: "rational regarding a purpose", you will have to translate. The noun, then, would be Zweckrationalität: rationality of purpose. Some suggest “instrumental rationality” – but this would presuppose critical thoughts expressed by Lukàcs and the Franfurt School after Weber's death: it's a bad translation.

In Weber's eyes, or words, this rationality of purpose was the dominating kind of rationality in today's Western world. He thought even the omnipresent bureaucracy could be described as zweckrational. Today we don't believe this to be true. To be zweckrational you need to be able to choose freely between the means you can employ in order to achieve your purpose. Once you have a bureaucratic organization with its directorates and departments and offices, you cannot do this; rather, you have to choose between the options provided by your organization. Well, it took us 40 years before Niklas Luhmann pointed out Weber's faulty re-use of a word applying to the behavior of individuals for organizations.

Maybe in English this would not have happened? Is Zweckrationalität “rationality of purpose” - or "of purposes”? One or many? Would this expression - ambiguous and cumbersome - have become the central metaphor of certain sociological and philosophical schools for describing modern society? In any case, we could be considered sprachverloren.