This essay discusses the character of the concepts used in modern physical theories and the symbolic structure they define. Are these symbols interchangeable free constructs and the theories artificial devices with in and out slots to accomodate observations? Are the symbols "read" up - that is, interpreted - from nature and are the physical theories directly referring to a final reality? Did our reason by itself fix immovable rules to build up these concepts? None of the "fundamentalist" stances hereto appears supported by the scientific process of developing physical knowledge. A more differentiate approach is suggested, which could offer for these questions a sustainable, less strong but may be more fruitful point of view.