To date there are 733 axioms
How do you get to 733 axioms? Maybe I’m being stupid, but doesn’t PA run on just 5?
Strictly speaking, PA uses infinitely many axioms—the induction axiom is actually an axiom schema, one axiom for each predicate you can plug into it. If you actually had it as one axiom quantifying over predicates, that would be second-order.
I think that Nelson denies that there is a completed infinity of predicates that you can plug into the schema.
Well, you’d certainly only need finitely many to prove inconsistency.
I think 733 is counting axioms, definitions, and theorems all.
That would explain it.
It said “733 axioms, definitions, and theorems”
I’m guessing 733 is the sum of the axioms, definitions and theorems, not just the axioms alone.
How do you get to 733 axioms? Maybe I’m being stupid, but doesn’t PA run on just 5?
Strictly speaking, PA uses infinitely many axioms—the induction axiom is actually an axiom schema, one axiom for each predicate you can plug into it. If you actually had it as one axiom quantifying over predicates, that would be second-order.
I think that Nelson denies that there is a completed infinity of predicates that you can plug into the schema.
Well, you’d certainly only need finitely many to prove inconsistency.
I think 733 is counting axioms, definitions, and theorems all.
That would explain it.
It said “733 axioms, definitions, and theorems”
I’m guessing 733 is the sum of the axioms, definitions and theorems, not just the axioms alone.