A computer imitating a human successfully is difficult enough in some specialized application. The Turing test set no constraints, though, on what the two participants could talk about, so a true Turing test robot would have to be able to deal with any conversational gambit convincingly.

There's a world of difference between a computer passing this standard by persuading a human it was another human, and a human imitating a robot, though. It's not an equivalent proposition at all.

A