theo‧ret‧i‧cally [sentence adverb]
used to say what is supposed to be true in a particular situation, especially when the opposite is true:
Theoretically, Damian's the boss, but I coordinate the team on a day-to-day basis.
according to a scientific idea that has not been proven to be true in a practical way:
It is theoretically possible for computers to be programmed to think like humans.