Why Does Light REALLY Bend?

A lot of optical illusions can be explained by Fermat's principle of least time, but why does light obey it? On a fundamental level, it all comes down to quantum mechanics, specifically quantum optics, where we use the famous "Feynman path integral formulation" to explain light through photons.
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VIDEO ANNOTATIONS/CARDS

How Fast Is Light?
   • How Fast Is Light?  

Lagrangian Mechanics:
   • Lagrangian Mechanics: How powerful is it?  

You Don't Know How Mirrors Work:
   • You Don't Know How Mirrors Work  
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OTHER SOURCES

https://www.feynmanlectures.caltech.e...
https://www.feynmanlectures.caltech.e...
https://www.feynmanlectures.caltech.e...
http://www.vega.org.uk/video/subseries/8
https://www.physicsclassroom.com/Clas...
Optics by Hecht
https://www.engineeringtoolbox.com/re...
https://www.etymonline.com/word/refra...
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LINKS TO COMMENTS

   • Why aren't Mirrors White? Why isn't EVERYT...  
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