The assignment of "cause" and "effect" is a philosophical, and not a
physics, concept. It is neither operationally definable nor conclusively
testable. The mathematical models of physics never address such concepts.
However, by their nature, the conceptual models by which we interpret our
mathematical models will make use of such philosophical concepts. This is
OK and a help to human understanding and pedagogy, but it should be
understood that we are now in a philosophical discussion, about which
physics is mute.