In the absence of charges, Maxwell's equations reduce to `\nabla^2 F = d^2/dt^2 F`, (where F is the electromagnetic field tensor) which has solutions given by superpositions of traveling waves.
What I suspect you want, however, is some sort of substance or essential nature that makes the thing go. If that's the case, then the answer is that there are no such things. Not for light, not for ordinary classical mechanics, not for anything. Physical systems are what they do.
You could say that the thing that makes light go is the distribution and motion of charges in the electric field. As they move, they generate waves in the amplitude of the EM field, and these waves are what we perceive as light.
Right that’s the point of my original post. I see lots of people trying to understand how QM “works” when it’s just a thing that’s works the way it does. I have never seen anyone trying to understand how light moves in a vacuum, which (at least to me) seems just as mysterious if you were to try and understand it in some sort of intuitive macro physical sense.
> I have never seen anyone trying to understand how light moves in a vacuum
People have been doing this since pre-helenics, "what is the medium where everything operates" or along the questions of "what is the medium that contains vacuum".
It's not that anyone isn't trying to understand that, it's just that thinking about unprovable things is boring and uninteresting from science point of view. At that level we may as well accept we all live in the Rabbit's Hole with Magic.
> But Maxwell’s most celebrated insight was when he combined the work of Ørsted and Faraday to explain the essence of light.
> He realised that a changing electric field could create a changing magnetic field, which would then create another electric field and so on. The result would be a self-sustaining electromagnetic field, endlessly repeating, travelling incredibly fast.
It’s generally studied in undergraduate E&M courses.
Now if you’re curious about how E or M fields propagate you’ll start getting into quantum again. Generally this leads up to quantum electrodynamics, where as I understand it everything is treated as fields and interactions as particles.
How those fields propagate is the same as asking how wave functions “travel”. We simply don’t have to tools to even ask the right questions, IMHO.
