Hi Sara,
Thanks for the comments. I think you raise a very important issue: where *is* the line between tangible and representational reality? Is the line, if it exists, well-defined or fuzzy? And if we err on the side of caution, should we err on the tangible side or the representational side?
I'm torn on this issue, to be honest. I'm not a pure operationalist, but I'm not even sure operationalism, at least as it is practiced today, is even purely tangible. I do firmly believe that physics should be about the physical, but I also believe that well-founded theories are as broad as possible in their explanatory nature. So, to give you an example, if you've ever watched Susskind's videos on what you need to know about modern physics, he starts out talking about Newton's laws. Whenever I teach introductory material, I start with energy and momentum because Newton's laws are easily derived from conservation of momentum and energy. When I made this point to a friend of mine, he argued that introducing Newton's laws (and general laws of motion) first, made more sense from an operationalist view. So, in that sense, I am not an operationalist.
On the other hand, as I said, I do think we need to default to physical reality. Feynman said something about this once. In fact Carl Caves said something to me once many years ago to this effect: we're physicists and we're doing physics so we should default on the side of physics.
So, in short, I unfortunately don't have a neat and clean answer to your question. I think the line I painted in the essay is quite stark for that particular example. It may be that there is a stark line in *every* example, but that there is no single, unifying way of defining that line such that we can "know" it in a given case (if that makes any sense).
Cheers,
Ian