The transverse force reduction on a charge moving relative to a source, Fₚerp = Fₛ / gamma, is a well-established empirical fact. Special Relativity explains it through Lorentz transformations of the electromagnetic field tensor—a kinematic account that leaves the physical mechanism unexamined. This paper presents a constructive alternative grounded in the experience principle: electromagnetic forces are what charges physically undergo based on their interaction with propagating fields, not what observers compute from transformed field components. We first establish rigorously that force is invariant—all inertial observers measure the same force because proper acceleration is a Lorentz scalar—and locate the real puzzle: why does the interaction itself change with relative motion? We then introduce a physical picture of the electric field as a real entity co-moving instantaneously with its source charge yet composed of propagating structure at intrinsic speed c. Five postulates formalise this picture into the propagation model: quantization of charge, field decomposition Eₛ = psi c cₕat, field invariance under relative motion, effective coupling qₑff = kappa cq, and interaction geometry relating cq to the velocity triangle. A self-consistency lemma establishes that the triangle decomposition is a necessary consequence of the postulates, not an independent assumption. Using the law of sines we derive geometrically the effective propagation speed cq = c sqrt (1 - beta² sin² theta) and the force law F = Fₛ (cq / c) = Fₛ sqrt (1 - beta² sin² theta), which reproduces the empirical transverse force and yields the Lorentz factor from geometry alone. We prove that the derived magnetic field B = (vₚerp / c²) x Eₛ satisfies div B = 0 identically. The electromotive field Eₘ = psi vₚerp is shown to satisfy Eₘ = c cₕat x B, demystifying magnetism as the transverse component of the electric interaction. Throughout, we distinguish the Experience Principle from Special Relativity at the conceptual level.
Akintunde Abiodun Olawale (Wed,) studied this question.