“0 is a bookkeeping symbol, which doesn’t represent anything all by itself.”
The view of it as a formal symbol on a piece of paper is only one viewpoint. Zero is also a concept grasped by the human mind. It’s the number of items left when you start with one item and take one away (number-as-a-construction). It’s the number of steps you have to take to stay in the same place (number-as a-motion metaphor). It’s where you’re standing right now (number-as-a-place metaphor)
“1 - 1 = 0” is a praxeological statement-form
I don’t see what it has to do with praxeology. It is simply a datum. Even birds understand 1 - 1 = 0. When one threat comes near its nest, and then one threat is seen to be leaving, the bird will relax.
most of mathematics is best demarcated as a sub-branch of praxeology
Are you saying that Earth, Venus, and Mercury weren’t 3 planets, and didn’t travel in ellipses, in the aeons when Earth was devoid of people?