I suppose that means that when Descartes' law was shown to be incorrect,
refraction as a physical phenomenon was also shown to be false.
Yeah, right, and I have seafront property for sale in Colorado.
Let's not confuse the physical phenomenon itself with our abstract
mathematical description of it, even though we tend to call both a "physical
law". When Burgy and I talk about falsifying a physical law with new
evidence, we mean demonstrating that the physical phenomenon itself, not
just our abstract mathematical description of it, is false. Refraction is
still recognized as a legitimate physical phenomenon; what's more, it is
also recognized that it is caused by the decrease in the speed of light as
that light passes through dense material, such that as a general rule of
thumb the greater the density, the greater the angle of refraction.
Descartes' attempt to describe this phenomenon may have been shown to be
incorrect, but the phenomenon itself is still very much real.
Kevin L. O'Brien