How often have you been in a position of trying to get something done in the face of an illogical or bureaucratic impediment ?
It is enormously frustrating, Authority being exercised.
On the other hand when faced with complexity, ambiguity, or technology beyond our knowledge and understanding, sensible people seek advice from an authority, someone who knows more than us, and can clarify and explain.
This person often has no authority, but is an authority.
So often these two things get tangled up. Someone “in authority” exercises that authority as would “an authority”, and the outcome is usually rubbish.
As management of our institutions has become flatter, more collaborative and individually accountable, this distinction has become more important as those with the authority are less and less likely to also be an authority on any given topic.
Failure to recognise the distinction is a huge burden on productivity.