Which to choose?

The bounded potential energy field model is both powerful and simple enough to model either Newton or Einstein’s laws of motion and gravity through choosing between basic assumptions.

1. Newton:

   1. Changes to the field propagate instantly.

   2. Angles (velocities) add.

   3. Every particle’s perception of time and space are equivalent.

2. Einstein:

   1. Changes to the field propagate at a finite speed.

   2. Gradients add.

   3. The cosines of angles represent every particle’s perception of time and space.

That’s it. Those are the only changes you need to go from one model to the other.

Which should you choose? That depends on what sort of system you are modeling. For most every day purposes, the Newtonian model suffices. Either way, action arises naturally as a fundamental principle.