Instrumental Theory is a theory about the criteria that make an action rational or irrational. It is not a theory about the reasons for acting (although it is usually accompanied by a theory about the reasons for acting - but that is another story). However, as it is customary to speak of it as "theory of practical reason" and not as "theory of rationality in action", I will follow that custom. But don't be fooled: the instrumental theory of practical reason is not a theory about the reasons for acting.
The instrumental theory of practical reason is a minimalist theory of practical reason (I will explain later why I call it "minimalist"). According to her, a given action X will be irrational if and only if the agent thinks (correctly or incorrectly) that there is another action, let us call it Y, which is also available to him, and that carrying out Y would fulfill his desires more efficiently. than doing X and prefers, however, to do X.
Developed since 1950. Concerned with integrating all the theories of the different schools above and numbered.
The Structuralist School started with the theory of bureaucracy with Max Weber.
Structuralist Theory focuses on the “organizational man”, the person who plays different roles in various organizations.
In the society of organizations, modern and industrialized, the figure of the organizational man who participates in several organizations looms large.