Dear Branko,
Yes, I think you are right, it is the Philosophy of Nature. But, here's the rub: physics is firmly based in maths, and physicists certainly do a lot of maths, and if maths is a 'logical system' or 'a language', that is consistent with being scientific. However, thinking a bit more deeply about maths, calculations always need to be done with physical things, like counters, or an abacus, or electrons in a calculator. It doesn't matter which you use, so the maths is clearly using something that they all share. If the only thing that they all share is quantity, change, and a position in space, then maths, and so physics, becomes about manipulating position, change, and position in space, and, as you say, that seems more like an area for Natural Philosophy.
I actually prefer not to draw a distinction between philosophy, maths and physics. It seems to me that all three disciplines are to do with interesting ideas about the world we live in, and the great pleasure in finding new things out, and if you claim to belong to just one particular discipline, then you are missing out.
You mention in your essay that, in your work, you use mass, radius and time. Using E=hf and E=mc², then mass=hf/c², and as both h and c are constants, mass can then be described in terms of frequency, which in turn is an amount of cyclical change in a certain time. Also, radius is a quantity in space, while time is change, for, without time, you can't have change. So, in that sense you, just like me, are using quantity, change, and space, which I think is what you are saying in your post. I like using quantity, change and space because they are simple things which can all be directly experienced, and they also seem to be the things that the maths of QED is actually using.
All very interesting!
All the best,
David
