K7ITM wrote:
. . .
I've seen it written, by a well-respected expert on antennas, that
electromagnetic fields may be viewed in either of two different ways.
Are there more than two, other than minor variations on the theme?
I'm not sure. The two I know from that author are that (1) fields are
real physical entities, and (2) that fields are merely mathematical
abstractions to help explain our observations: in the case of
electromagnetic fields, that acceleration of a electron results in
sympathetic motion of free electrons throughout the universe. . .
. . .

Throughout my time at the USAF technical school, I was frustrated by the
hand-waving of the instructors when the topic was electromagnetic fields
(and many other topics, for that matter). It was obvious that they
really had a very poor grasp of the subject(s). So on the very first day
of my first college semester of fields, I asked the professor, "What is
an electromagnetic field?" His response: "Electromagnetic fields are
mathematical models we use to help us understand phenomena we observe."
The professor was Carl T.A. Johnk. I have his textbook _Engineering
Electromagnetic Fields and Waves_, which was in draft manuscript form at
the time I took the course. The first sentence in section 1-1 on page 1
is "A field is taken to mean a mathematical function of space and time."

Roy Lewallen, W7EL