[dleviwing]

In this analogy it is just as correct to say M=mc^2 as it is to say E=mc^2. These only define the state of the substance.
Of course this is also assuming that "matter" and "energy" are referring to the fundamental essence of a fundamental physical entity. Thus a rose by any other name.
The current problem is that science today is interpreted as though energy and matter are referring to two autonomous entities just as they view the forces of nature as being individual autonomous forces of nature, each with their own attributes and properties.