That would imply that 4.2 is an object of Peano arithmetic; but there is a simpler way of getting this.
The first-order statement: “there exists an x, such that x times 10 is 42” can be phrased in artithmetic. Therefore if arithmetic is inconsistent, it is true. And I define 4.2 to be a shorthand for this x.
From an inconsistent system (such as ZFC would be if arithmetic were), yes. An inconsistent system has no models.
That would imply that 4.2 is an object of Peano arithmetic; but there is a simpler way of getting this.
The first-order statement: “there exists an x, such that x times 10 is 42” can be phrased in artithmetic. Therefore if arithmetic is inconsistent, it is true. And I define 4.2 to be a shorthand for this x.