I mean I guess 0.5 is a human concept if you want to argue the universe only does integers, but 0.5 is defined relative to 1, as is every other number such as pi, phi, i and xi (dunno if the last one is actually a number).

Infinity might or might not be real. That can't be defined as a function of 1. 1*infinity is indeed infinity, but infinity/infinity isn't 1 unless they are identical infinities. This is mathematical philosophy.

There are other objects that square to -1, in other mathematical spaces aside from the complex numbers.
I'm gonna have to dig into this.