# Fermat's principle of least time for reflection and refraction [duplicate]

In discussing geometrical optics, Fermat's principle of least time is often used to solve problems and is generally used as a replacement of laws of reflection and refraction. Fermat's principle is usually presented as an intuitive idea, but I wish to find a way where we can show that is is actually a result of least of reflection and refraction. We have explanation for laws of reflection and refraction and they must be the basic laws, with Fermat's principle being a consequence of it. Do we have any explanation suggesting that Fermat's principle is the direct consequence of laws of reflection and refraction?