3 ms·

By Fermat's principle, a ray of light has to know where it will ultimately end up before it can choose the direction to begin moving in. So either something is

By Fermat's principle, a ray of light has to know where it will ultimately end up before it can choose the direction to begin moving in. So either something is computing it or some exploration is happening at quantum level and we just see the final result.

embedding-shape 4mo ago
> a ray of light has to know where it will ultimately end up before it can choose the direction to begin moving in I'm no physicists, so I guess I'll ask it: Why? Also related, why do some ray of light then "see" a black hole yet decide to head into them anyways, if they saw it before they went in that direction? Seems like a dumb move :)
- lloeki 4mo ago
  Its future isn't over there because it moves in that direction, instead it moves in that direction because its future lies over there. Relatedly: > [General Relativity] basically says that the reason you are sticking to the floor right now is that the shortest distance between today and tomorrow is through the center of the Earth. https://physics.stackexchange.com/questions/250800/gr-and-my-journey-to-the-centre-of-the-earth https://physics.stackexchange.com/questions/250800/gr-and-my...
MeteorMarc 4mo ago
Fermat's principle is an outcome of constructive interference of waves. It works both for classical and quantummechanical descriptions. E.g. check https://phys.libretexts.org/Bookshelves/University_Physics/University_Physics_(OpenStax)/University_Physics_III_-_Optics_and_Modern_Physics_(OpenStax)/01%3A_The_Nature_of_Light/1.07%3A_Huygenss_Principle https://phys.libretexts.org/Bookshelves/University_Physics/U...
- sumitkumar 4mo ago
  True, so the interference is the "computation"(heavy emphasis on quotes) which gives rise to the principle.
- pava0 4mo ago
  > a ray of light has to know where it will ultimately end up before it can choose the direction to begin moving in A ray of light doesn't know or choose because it has no agency, just like an apple doesn't know or decide to fall because of gravity. It's an anthropomorphization.

embedding-shape 4mo ago

> a ray of light has to know where it will ultimately end up before it can choose the direction to begin moving in I'm no physicists, so I guess I'll ask it: Why? Also related, why do some ray of light then "see" a black hole yet decide to head into them anyways, if they saw it before they went in that direction? Seems like a dumb move :)

lloeki 4mo ago
Its future isn't over there because it moves in that direction, instead it moves in that direction because its future lies over there. Relatedly: > [General Relativity] basically says that the reason you are sticking to the floor right now is that the shortest distance between today and tomorrow is through the center of the Earth. https://physics.stackexchange.com/questions/250800/gr-and-my-journey-to-the-centre-of-the-earth https://physics.stackexchange.com/questions/250800/gr-and-my...

MeteorMarc 4mo ago

Fermat's principle is an outcome of constructive interference of waves. It works both for classical and quantummechanical descriptions. E.g. check https://phys.libretexts.org/Bookshelves/University_Physics/University_Physics_(OpenStax)/University_Physics_III_-_Optics_and_Modern_Physics_(OpenStax)/01%3A_The_Nature_of_Light/1.07%3A_Huygenss_Principle https://phys.libretexts.org/Bookshelves/University_Physics/U...

sumitkumar 4mo ago
True, so the interference is the "computation"(heavy emphasis on quotes) which gives rise to the principle.
pava0 4mo ago
> a ray of light has to know where it will ultimately end up before it can choose the direction to begin moving in A ray of light doesn't know or choose because it has no agency, just like an apple doesn't know or decide to fall because of gravity. It's an anthropomorphization.