Before revision: Benacerraf considers two such set-theoretic methods: Set-theoretic method I (using Zermelo ordinals) 0 = ∅ 1 = 2 = 3 = ... Set-theoretic method II (using von Neumann ordinals) 0 = ∅ 1 = 2 = 3 = ... As Benacerraf demonstrates, both method I and II reduce natural numbers to sets.
After revision: ======Benacerraf considers two such set-theoretic methods: Set-theoretic method I (using Zermelo ordinals) 0 = ∅ 1 = 2 = 3 = ... Set-theoretic method II (using von Neumann ordinals) 0 = ∅ 1 = 2 = 3 = ... As Benacerraf demonstrates, both method I and II reduce natural numbers to sets.