In nearly every physics textbook I've encountered, it is always claimed in the optics section of the textbook that light travels slower through glass, water, diamond, etc. The speed of light in vacuum is divided by the material's index of refraction in order to calculate the "new speed" through the material. Now, this idea of light slowing down perplexes me because it seems contrary to SR's postulate that the speed of light is constant and is the same for all observers. This contradiction is never explained in textbooks, yet there must be some logical reason for why light seems to slow down. Would it be correct/accurate to say that as light travels through a transparent medium, it only seems to be slowing down because of absorption and re-emission of photons from atom to atom inside the medium? Each absorption/re-emission results in a time delay which creates the illusion of slower light?