Just like one and one don't make two
One and one make one
It has been said that the libertarian perspective is grounded in two primary principles: property rights and non-aggression. But aren't these two principles really one in the same?
Property rights endow all individuals with inalienable authority to dispose of their property (broadly construed) as they see fit--as long as they do not invade the pursuits of other individuals. Invasion of someone else's pursuits constitutes aggression. Thus, property rights cannot exist without non-aggression.
The non-aggression principle states that aggressive, or offensive, force is unjust because it interferes with the pursuits of others--i.e., it limits the liberty of others to dispose of their property as they see fit. The only just use of force is for purposes of self-defense--i.e., force used to fend off against aggression by others. Thus, the non-aggression principle makes little sense without the notion of property rights.
Property rights and non-aggression go hand-in-hand.