 They were also very easily overlooked in the thinking of philosophers who debated his ideas. What Bridgman says here is entirely contrary to the common image of his doctrines. When it came to constructs, “of which physics is full,” Bridgman not only admitted that one concept could correspond to many different operations, but even suggested that such multiplicity of operational meaning was “what we mean by the reality of things not given directly by experience.” In an illustration of these ideas, Bridgman argued that the concept of stress within a solid body had physical reality, but the concept of electric field did not, since the latter only ever manifested itself through force and electric charge, by which it was defined (Bridgman 1927, 57). This comes down to the stance that a theoretical concept without direct operational meaning is worthwhile only if it serves as a mediator connecting two or more operationally meaningful concepts, creating an empirically testable relation. This is in fact not so different from Hempel’s view quoted in Section 2.2, albeit with a different emphasis.