In a sense, this is still an exercise in determining essences, but the focus of our attention turns out to be an abstraction. Hence what follows is, in philosophical terms, the ontology of phenomena, or more prosaically, what reality is made of. Since both matter and energy have a long and established history of definition and discussion, their essence is not usually considered either controversial or mysterious anymore. Mass is the source of inertial resistance, and matter is its substance . This derives directly from Newton's mechanics.
Energy is the capacity to produce work, or provide heat .
This derives from the laws of thermodynamics. What information science needs is a definition of its focus that resembles the previous two definitions in being a high-order, generalised abstraction. What is consistent between all forms of information however, is the representative or referential function. There are other definitions in the literature, but none with the accuracy, simplicity, elegance, and inclusiveness of this one. It would be possible to go on to elaborate and defend this definition at length, but that would be beside the point.