What if he steals a Rolex? Is there some arbitrary limit that justifies shooting someone? It’s the thief who lacks common sense. If I make the choice between a bag of candy and the chance of getting shot, and choose the candy - I have to live with the consequences. How do I know the guy isn’t armed? Do i wait until he pulls a gun on me? Do I ask him if the bag of candy is all that he’s going to steal, or does he have plans to help himself from the cash register? What I’m saying is that if you come on my property with the intent to steal, I have the right to stop you from doing so.
How do I know my life isn’t about to be threatened? How do I know the guy isn’t armed? Do I wait until he pulls a gun on me? I would have no reason to shoot him if I knew for certain he wasn’t posing a threat to me.
How does one ever “know for certain” that one’s life isn’t about to be threatened? There are an infinite number of variables that prevent such a universal assumption; therefore, a reasonable person would only feel threatened if there was strong enough evidence to justify it. I don’t think that an attempt to steal a bag of candy is really evidence of any kind of life-threatening behavior, nor would most others, including police, courts, PDAs, etc.
So the non aggression axiom does not hold if you are on someone elses property? To kill someone is the most invasive action into someones property possible. To have a right to do so requires that you yourself, at least belive that you are threatened by a third party to be killed. I can not see that stealing anything, without threatening the owner with serious injury or death can be justified with the non aggression principle. It is simply murder. The age old discussion about the candy store owner shooting a 10 year old in the back because he stole a candy is a neat way to blame libertarians and anarcho-capitalists for being cruel monsters.
Different libertarians offer different standards for punishing criminals. For example Walter Block advocates the eye for two eyes approach. When a criminal is proven guilty of a crime they owe the victim double the damages plus the money they spent in order to catch them. The problem with this standard is it cannot be applied to all crimes i.e. a murder is not capable of paying the victim his life twice.
I tend to agree with the eye for an eye approach which basically states that a criminal owes the victim for all the damages his crime caused. In the instance that a thief stole candy from a store the thief would owe the storekeeper money for the candy plus for the time that was spent pursuing them. I’d also advocate banning the individual from the store and making other store owners aware of his actions.