Continuing from our previous article, let's look at another instance of this sort of error. Bridgman noted that the mathematician oftentimes may not recognize that immensely large or small physical quantities, the measurements we are using to describe concepts cause the concepts to become hazy by virtue of the extremity of their size (either because the measurements we are using are extremely small or extremely large, like the objects we are attempting to measure). Bridgman notes that we do not ordinarily distinguish between fundamentally different meanings of 'motion' when speaking about the motion of an electron around a nucleus vs. the motion of a star in outer space. We are almost psychologically compelled to speak of the two concepts of motion as comparable, although Bridgman was skeptical about the feasibility of speaking meaningfully of electrons engaging in 'motion.' To summarize:
Bridgman thus emphasized that our concepts did not automatically extend beyond the domains in which they were originally defined. He warned that concepts in far-out domains could easily become meaningless for lack of applicable measurement operations. The case of length in the very small scale makes that danger clear. Beyond the resolution of the eye, the ruler has to be given up in favor of various micrometers and microscopes. When we get to the realm of atoms and elementary particles, it is not clear what operations could be used to measure length, and not even clear what “length” means any more (Chang, 2009).
The insights of Bridgman's operationalism also influenced the field of psychology, particularly among the behaviorists; the doctrine, so far as it can be thought of as a unified doctrine, was known to psychologists as 'operationism.' The psychologist Edward Boring was particularly excited about Bridgman's operationism, as he believed it was a helpful alternative for postivism. Stanley Smith Stevens, a student of Boring's, would later become an enthusiastic advocate of the doctrine. Stevens wanted a procedure by which concepts could be defined and validated. We must test, he argued, the meaning of concepts, by noting the concrete operations according to which we determine the concepts.
Edward Chace Tolman would become yet another influential operationist psychologist. Tolman's experimental instantiation of the doctrine went as follows:
Starting with his research on problem-solving behavior in rats, Tolman gave an operational treatment of desire, for example operationalizing hunger in terms of “time since last feeding”. Tolman did not deny that desire was a subjective feeling, but insisted that doing scientific research on it required experimentally tractable operations that would allow scientists to get a hold on something related to that subjective experience (see Feest 2005, 136–138). In Gustav Bergmann's assessment, operationism helped behaviorism to move from its initial metaphysical Watsonian variety to its modern version (Bergmann in Frank 1956, 53) (Chang, 2009).
Bridgman himself, interestingly enough, opposed its usage in psychology. This was because Bridgman objected to the tendency of behaviorists to remove behavior from private, subjective experience. Indeed, Bridgman was quite hostile to behaviorism in general.
Chang, Hasok, "Operationalism", The Stanford Encyclopedia of Philosophy (Fall 2009 Edition), Edward N. Zalta (ed.), URL = <plato.stanford.edu/archives/fall2009/entries/operationalism/>.