| ▲ | czgov 4 hours ago | |
It’s clearly true in The Natural Numbers. It’s not provable because in some model it’s false. Being clearly true in one model does not make it provable. | ||
| ▲ | 4 hours ago | parent | next [-] | |
| [deleted] | ||
| ▲ | jojomodding 4 hours ago | parent | prev [-] | |
Yes it is true in the unique model of second order PA, aka the computable model, aka the "standard" model. | ||