Fields are neither local nor non local. Locality is about how information propagates. Classical Gravitation defines a force field that is nonlocal, as it propa

Fields are neither local nor non local. Locality is about how information propagates. Classical Gravitation defines a force field that is nonlocal, as it propagates instantaneously. Move a mass from point a to point b, and the entire universe immediately updates the force they experience. Classical Electromagnetism defines a field that only propagates changes at a finite speed. If you move a charged mass from point a to point b, the change in the electric and magnetic fields radiate outward at the speed of light. One way to think about this is to observe that time update equations for E+M only rely on values infinitesimally near a point. If you need to compute the next time step on a grid, you only need to look at the neighbors of a point to figure out how to update a given point.