In ordinary life, all fields describe properties of something material. But what are materials made from?
In the post-Einstein view of relativistic fields, widely adopted across modern physics during the last century, relativistic fields are what matter is made from; all material things are in fact manifestation of relativistic fields in action. But if that’s true, what are those fields made from?
If you think relativistic fields are associated with an ordinary medium, you’re wrong; that’s impossible. An ordinary medium can be stationary, or not; if you have two observers moving relative to one another, at most one of them can be stationary relative to an ordinary material. This is just a way of saying that if you have two drivers who are driving on a highway at different speeds, at most one of them can be driving at the same speed as the bus in the next lane. But if a relativistic field has a medium, then it’s a very strange one, because all observers are stationary with respect to the medium even though they are moving relative to each other!
It’s such a weird notion that most physicists take the point of view that there’s no medium at all. And certainly no experiment has ever forced physicists to accept that there is a medium there.
But there are people who don’t accept that there can be fields without a material medium. And the comment section to this webpage is where the discussion about who is right, or whether it is decidable who is right, can take place. Have fun! Just do your best to make sure you’re not making statements that violate experimental data. I will join in occasionally when I can.