For some reason you keep skipping the qualifiers in what I write. It does not say "some metaphysical notion" but "some metaphysical notion of truth". In other words, what matters isn't whether an axiom is "true" or not in some way that is external to mathematics, but what use could be made of that axiom. You did the same above; I didn't write "from a philosophical perspective" but "from a philosophical perspective where ..."