Donald Palmer
Yes, the mass and distance categories, and the numbers we use to represent them, are just words and symbols that we use to represent/ model something that exists “out there” in the real world.
But, in a world of “fake news” and “alternative facts”, fake realities that only exist in people’s minds, can science/physics be different? Can physics at least say what are the genuine characteristics of what exists “out there”?
I think that one characteristic is that the world “out there” is indeed inherently categorised, because logically, a coherent physical world can seemingly only exist if interconnections exist: categories that are connected via relationship to other such categories. But just saying that a category that we would label as “mass” exists, that seems to be genuinely related to other such categories, doesn’t tell you anything much: one needs actual numbers to make things more specific, numbers that we would represent with number symbols. Another consideration is that people and other living things, with their conscious imaginations, are a part of, not separate from, what exists “out there”.
You say: “I fail to see how such abstract scientific concepts can be considered existing 'out there in the real world'”. But would you say that there are any genuine characteristics of what exists “out there” in the real world?