"Unperformed experiments have no results."
Asher Peres (1934-2005)

"I have also a paper afloat, containing an electromagnetic theory of light, which, till I am convinced of the contrary, I hold to be great guns."
James Clerk Maxwell, 1865, in a letter to his cousin.

"Of course not. But they say it works even if you don't believe in it."
Niels Bohr, when asked if he thought the horse shoe in his office brought good luck.

Casimir effects can be formulated and Casimir forces can be computed without reference to zero point energies. ... The Casimir force (per unit area) between parallel plates vanishes as α, the fine structure constant, goes to zero, and the standard result, which appears to be independent of α, corresponds to the α → ∞ limit.
R. L. Jaffe, "The Casimir Effect and the Quantum Vacuum"

"The subject of this book is the structure of space-time on length-scales from 10-13cm, the radius of an elementary particle, up to 1028cm, the radius of the universe."
Hawking and Ellis
The large scale structure of space-time

"Quantum phenomena do not occur in a Hilbert space, they occur in a laboratory."
Asher Peres
Quantum Theory: Concepts and Methods

My complete answer to the late 19th century question "what is electrodynamics trying to tell us?" would simply be this: Fields in empty space have physical reality; the medium that supports them does not.

Having thus removed the mystery from electrodynamics, let me immediately do the same for quantum mechanics: Correlations have physical reality; that which they correlate, does not.
N. David Mermin, "What is Quantum Mechanics Trying to Tell Us?"

"Time is defined to make motion look simple."
John A. Wheeler

"In general, a quantum system is defined by an equivalence class of preparations."
Asher Peres
Quantum Theory: Concepts and Methods