Watch this video on theoretical systems
Commonly called a paradigm, a theoretical System is the structure of concepts used by a scientific community
forming the bases for developing testable theories and interpreting data. A theoretical system is accepted as true by the scientific community that uses it and it is generally fixed and not subject to change with new data. This is true only of the core concepts to which theoretical patches are often added to make a theoretical system fit reality when reality is not what was originally expected.