Keener's first argument: Paul never elsewhere appeals to 'the apostles' as a group

Keener argues Paul nowhere else refers to 'the apostles' as a group whose opinion he appeals to, so the exclusive reading is unlikely. Mike finds this argument weak: (1) there is no reason Paul can't do something here that he doesn't do elsewhere; (2) Galatians 2:9 is a counterexample where Paul appeals to James, Cephas, and John (apostles) as a group to confirm his calling for the Galatians' benefit.