The Non-Aggression Principle
(Excerpts from a Post to Quora.com by Dan Shielding)
An ethical principle that states, “One should not commit aggression.”
Aggression is the initiation or escalation of force against others.
Coercion is force or threats of force.
If Jack swings a stick at peaceful Jill, Jack is “initiating or escalating” coercion against Jill and thus committing aggression.
Jill, who uses the minimal amount of force necessary to block Jack’s attack to prevent injury to herself is not aggressive because she is not “initiating or escalating” coercion.
But if Jill kills Jack and his friends in retaliation, then she is committing aggression by “escalating” coercion against Jack and “initiating” coercion against his friends.
Consent
If Jack gives you consent to hit him, and you hit him, you’re not the one who initiated force. Jack initiated force against himself by giving you consent to hit him. Since he’s initiating force against himself and not against others, he is not committing aggression, and neither are you.
If two mixed martial arts fighters both voluntarily sign a waiver so they can fight in the ring for a title belt, it’s not aggression. It’s a mutually voluntary fight. Each fighter is initiating force against himself. As soon as one fighter taps out or goes limp, he’s withdrawing consent to continue the fight according to the contract. Any violence after that is aggression, because the attacker no longer has the other’s consent.
Ayn Rand maintained that “no man may initiate the use of physical force against others.… Men have the right to use physical force only in retaliation and only against those who initiate its use.” This quote is similar to Murray Rothbard’s thesis that “no man or group of men may aggress against the person or property of anyone else.”
Economist Murray Rothbard maintained:
The fundamental axiom of libertarian theory is that no one may threaten or commit violence (“aggress”) against another man’s person or property. Violence may be employed only against the man who commits such violence; that is, only defensively against the aggressive violence of another.
In short, no violence may be employed against a nonaggressor. Here is the fundamental rule from which can be deduced the entire corpus of libertarian theory.