The Logic of Modern Physics is a 1927 philosophy of science book by American physicist and Nobel laureate Percy Williams Bridgman. The book was widely read by scholars in the social sciences, in which it had a huge influence in the 1930s and 1940s, and its major influence on the field of psychology in particular surpassed even that on methodology in physics, for which it was originally intended. The book is notable for explicitly identifying, analyzing, and explaining operationalism for the first time, and coining the term operational definition.
Operationalism can be considered a variation on the positivist theme, and, arguably, a very powerful and influential one. Sir Arthur Eddington had discussed notions similar to operationalization before Bridgman, and pragmatic philosophers had also advanced solutions to the related ontological problems. Bridgman's formulation, however, became the most influential.
In the social sciences, the main influence has been in psychology. The influence on psychology has been even greater than that on methodology in physics, for which it was originally intended. Examples of the influence on psychology in the 1930s and 1940s include Stanley Smith Stevens (The Operational Basis of Psychology and The Operational Definition of Psychological Concepts), and Clark L. Hull (The Principles of Behavior: An Introduction to Behavior Theory). Since then, it has been the central influence of the official epistemology governing psychological method for the whole century." It was a major influence on behaviorism.