Consider the classical scenario a stone falling in the Earth gravitational field. Classically we attach a Potential Energy to the stone and using the law of conservation of (mechanical) energy we are able to evaluate the dynamic of the falling stone. This model assume a stone in a "external" field (due to the Earth) with potential energy attached to the stone itself (here the physical system to take in account is actually "the stone"). On the other hand I was thinking we can attach a Potential energy to the field itself considering as physical system the union "stone + field": this way potential energy of the system is basically the energy attached to the field while the kinetic one is that of the stone. Does it make sense ?