Edinburgh School’s theory of natural rationality, enunciated to render symmetrical explanation plausible, thereby providing support for its relativism, is presented and evaluated. I have endeavoured to demonstrate that there are gross misinterpretations of Hesse’s theory of science, network model, and her conceptions of classification of objects and of universals; that Edinburgh School’s theory of natural rationality suffers from a considerable area of ignorance concerning its foundation. I have further shown that not only the theory is not descriptive of the actuality of people’s reasoning, but it in fact is normatively laden.