The word “authority” has two quite different meanings.  If you are an authority on a subject that means you know quite a lot about that subject.  And if you are in authority over a group of people, that means you have positional power to manage and direct them. 

Sometimes people in authority conclude that their positional power automatically makes them an authority on anything and everything that happens in their domain.  The unspoken rule here is:

Positional authority confers subject matter authority.

This may have been a pretty fair assumption in organizations a century ago when it was managers’ knowledge and understanding of all the work going on beneath them was the very thing that propelled them into management.  Today this is a much more dubious proposition.  Modern teams often depend on bringing together many different disciplines, and even the best manager can’t be master of all of them.  Managers of such cross-functional teams have to be ready to push some decision-making downward, that is, they decide who makes the decisions rather than make the decisions themselves. 

Following the unspoken rule assures that decisions get made too high in the organizational structure and risk being therefore less connected to the real criteria that ought to drive the decision.

Power corrupts when it makes a powerful person feel almost omniscient.  Consider some of the autocratic (or wannabee autocratic) national leaders now in power in various countries. It doesn’t matter which one you pick, he is bound to be someone who ignores expert counsel from advisors and subordinates, and makes each decision based on his own inclination – clearly not a recipe for the best decisions.  When dissenting voices are silenced (fired, demoted, jailed, or accused of disloyalty) then the very fact that they aren’t heard anymore may be judged sufficient confirmation that the boss really does know best.