Every object that we perceive appears in innumerable aspects. The concept of the object is the invariant of all these aspects.
It has taught us new methods of thinking (complementarity), which are applicable far beyond physics.
I am now convinced that theoretical physics is actually philosophy.
I believe there is no philosophical high-road in science, with epistemological signposts. No, we are in a jungle and find our way by trial and error, building our road behind us as we proceed.