I've been looking for that question for months but no luck. According to the classical electrodynamics the attraction between two magnets is due to the inhomogeneous magnetic field acting on the atomic loop currents (through Lorenz forces). The homogenous field does not produce any attraction but the not homogenous field produces forces that have some component not laying in the current loop plane, resulting in attraction or repulsion. Let's imagine that one of the two interacting magnets may produce very inhomogeneous field. And the other - very homogenous. That could be due to the shape of the magnets. Why the attraction that the two magnets feel is the same (3-rd principle of Newton) since the degree of homogeneity may be very different at the places where the 2 magnets reside? Thanks in advance to anyone that may want to discuss that matter!