Then we find that inertia exists only as a consequence of the energy conservation law. Now we must consider the nature of limiting effects. The question is whether or not the internal energy can be driven beyond the zero energy condition. It appears that in the absence of the external medium, the laws of inertia would not apply. In the statement of the Mach principle, we may question what proximity is required in order to establish the effect of inertia.
Relativity theory takes the view that the only possible absolute is the velocity of light.
If this is the case, absolute rest and absolute motion cannot be defined. On the basis of the above analysis, we must question such a conclusion. Since the act of accelerating an object reduces its internal energy, we consider the object to be at rest when its internal energy is at a maximum. We must conclude that there is a fundamental difference between an object at rest and one in motion. This difference did not appear in the analysis given by the Greek philosophers.