It turns out this only pushes back the problem. You can write down second-order axioms for arithmetic which have a unique model, but in a model of a second-order theory predicates are interpreted as sets. So, you need…
It turns out this only pushes back the problem. You can write down second-order axioms for arithmetic which have a unique model, but in a model of a second-order theory predicates are interpreted as sets. So, you need…