Why does light take an extremum path according to Fermat's Principle?

[Nitin Gupta]

According to Fermat's Principle (modified version) a light ray takes an extremum path. Can anyone explain the physical reason behind this? I mean, sure the light can take the least path but how can it take the longest path? And if it can indeed take the longest path, why not the paths shorter than longest? (Please, I don't want mathematical explanation. I am new here, if this is posted at wrong place or any other problem please PM me)

 

[ShayanJ]

People can tell many different things but they all boil down to this: That's the way it is!