I'm a carnal, organic anagram.
Yes and no. Plane can't go anywhere without the FO. The guy in the right seat is vouching for the captain by not walking off the plane.So long as there's only one guy who has to sign his name on the release, the "other guy" up in that room in the front of the airplane will remain an assistant.
Edit: maybe it's best to say that the captain has to sign for the flight, and the FO has to sign for the captain. It's a two man system for a reason.