Refraction of light is not caused by a force but rather by the change in the speed of light as it passes through materials with different refractive indices. In a quantum mechanics context, photons do not experience a force during refraction; instead, their path is altered due to variations in light velocity. This phenomenon can be likened to a photon moving on a sloped surface, where it receives an impulse perpendicular to the refractive boundary. Classical wave behavior also demonstrates that direction changes occur without the involvement of a force when waves enter a new medium at angles other than 0 or 90 degrees. Understanding refraction requires recognizing these principles rather than attributing it to a force acting on light.