Comment on 'Relativity, potential energy, and mass'

The case has been made by Eugene Hecht (2016 Eur. J. Phys. 37 065804) that potential energy is a conceptual fiction, i.e. is not an objective physical quantity. This was based on a claimed absence of measurability of potential energy, changes in the mass of a body being measurable, and by a particular interpretation of the mass-energy equation from the special theory of relativity. However, if potential energy lacks measurability then kinetic energy is not measurable in the same sense. The absence of such measurability being used to conclude that potential energy does not have physical objectivity would then also require that kinetic energy has no physical objectivity either. Further, it is shown that appealing to special relativity does not help secure the conclusion of physical non-objectivity of potential energy.