The Speed of Light: Can it Travel in Opposite Directions?

[swampwiz]

Is it really possible for light to travel at different speed in opposite directions? This video seems to say that this is assumed as a fact (with of course Einstein being the one to make the assumption), and that since it is impossible to measure the speed of light in one direction, we really can't determine it.

 

[PeterDonis]

We already have a thread open on this video:

https://www.physicsforums.com/threads/measuring-the-one-way-speed-of-light.995539/

Please make any comments there.