Abstract

The "object theoretic operational view" suggests a new structure of physical knowledge. This view takes branches of physics as basic units. Its main concepts are primary (PIO) and secondary (SIO) ideal objects with the explicit definition of SIO through PIO and the implicit definition of PIOs within appropriate systems of statements, called a "nucleus of a branch of physics" (NBP). Within an NBP (which has a definite structure) the focus shifts from discovering "laws of nature" to definition of a physical object (system) and its states, and the distinct notion "measurable" replaces the vague notion "observable". On this basis the roles of physical models and measurements within physics, as well as two types (PIO- and SIO- type) of theories, activity, and experiment are discussed, and a different junction of "realism” and "constructivism" is presented.