Authority has the character of intelligence directing to some end. God as the supreme authority directs all things to their ends. Man has a certain capacity in virtue of being in the image of God, that is in possessing rationality, to direct himself to certain ends. Man is then said in a certain respect to have a certain authority over himself.
This authority extends beyond himself in virtue of this capacity. He is also capable of directly other things to his ends. He can even direct things to ends that are opposed to a things nature, that is its intrinsic ends. Indeed, though this is strictly violence, it is actual to exalt the thing, because whereas an arrational thing of itself has only natural or sensitive ends, man is capable of directing it to rational ends.
Moreover, man can and does have authority over other men. This authority takes on a particular character, because man can direct his own ends. When a man has authority over another, he can direct the subject to ends which he does not choose and even detests. However, the authority cannot bind his subject to an absolutely evil end.
An authority can direct his subject to fight to the death for a just cause and the subject is bound to serve. Though this may destroy the man’s life, he is made better for his obedience and courage. An authority cannot direct his subject to commit some intrinsic evil. He cannot bind his subject to make himself worse or destroying his soul.
Authority then is ordered to bind and order its subjects to the better. The subject is bound to obey within the bounds of positive and natural law from which the authority finds his power to bind and order.
The authority that is property extends to men and things. The authority according to man’s competence allows him to direct things to his ends. A man who steals from another violates his authority over the thing to direct it to his ends. A man has authority to extend for a time his own authority over a thing, whereby he loans or rents a thing that another man uses. This authority binds the renter by the ends the proprietor has determined. The proprietor’s authority over his possessions in virtue of his rationality also binds other men.
This authority springs forth from the natural and positive law and therefore it is incoherent to suppose acts of authority contrary to these laws. A proprietor cannot licitly simply destroy his property as this is generally contrary to the natural law in the common end of all things. He may destroy it for some purpose, such as burning gas for heat or locomotion, but not for destruction simply.
Moreover, given the natural end, it is licit for a man to steal what he needs when in grave need. This is not contrary to the proprietor’s authority as thing becomes the man’s in virtue of his natural need and hence the natural law. The proprietor’s authority cannot be contrary to the natural law for such would be incoherent.