Duplication doesn't entail computability
Duplication of behavior doesn't entail computability of internal states. Even if all human functions can be duplicated by an automaton, this doesn't entail that the internal processes that give rise to those functions can also be duplicated.
For example, there is good reason to believe that deliberation is noncomputable even though the behaviors that result from deliberation can be duplicated by an automaton.
Selmer Bringsjord, 1992.