when discussing topics libertarian, there inevitably arises the question of rights defense. this is one of the most contested and controversial of the philosophy. of course, that fact alludes to it being one of the most vital. there are various takes on the issue; here, i will interject my own thoughts.
we know what rights are and where they come from, but what actions are acceptable to defend them? i maintain that rights are, in practicality, little more than the tacit agreement between two parties to respect the property of one another. the violation of this agreement, through the violation of property, relieves the offended party of the obligation to respect the offender's property. when property is violated, there are two possible scenarios: the violator is caught in the act, or he is not. we are only concerned here with former. in the latter, the violator must be identified, charged and restitution arranged. the question revolves around the violator being caught in the act of harming property and the steps one may take to defend property. often property defense may require the use of some force, but does a person have the right to use any amount of force to defend his property against any violation?
let's take an example. bob owns an apple orchard. john walks onto bob's orchard and takes an apple. bob sees john violating his property and shoots and kills john in order to defend it. most people would agree that bob's use of lethal force to defend his property against a minimal violation is unreasonable. murray rothbard, arguably the leading philosophical voice of the libertarian movement, addressed this question with the concept of "proportional force". rothbard's idea was that one has the right to defend his property with whatever amount of force is necessary to repel a violator, but no more. in other words, he may use "proportional force"; force in defense proportional to the force used by the aggressor.
where the problem arises, is when this is translated into enforcement. in reality, how will this be acted upon? in the rush to defend one's property, there is little time to sit down and negotiate with the criminal on how much force he is planning to use to violate property in order to formulate an appropriate amount of resistance. in addition, the definition of what is proportional will be different for each individual and some will claim any arbitrary amount of force to be too much and some will disagree. some may say that bob's use of lethal force was not unreasonable, most would probably say that is was. but rights are not up to majority rule. rights, such as the right to property, are absolute. the most appropriate point is how society, the final arbiter, reacts to such uses of force.
though bob may, technically, have the right to use lethal force against john for violating his property, the exercising of said right doesn't happen in a vacuum. if john's brother, tom, found out that his brother had been killed by bob for stealing an apple (later, it was found out that the destitute john was merely trying to feed his children) and retaliated against bob with force of his own out of anger, tom's reaction would, like john's, be a violation of bob's property. but, which arbitrator would, under pressure of a certainly sympathetic market, punish tom severely? remember that all arbitrators in the stateless society are under the constant pressure of the markets they serve. if an arbitrator were to mete out a harsh punishment to tom for his actions, how would the market served react? would they be more or less likely to find favor with such an arbiter? the disproportionality of the use of defensive force will affect how justice is applied and as such force becomes more disproportional, so does the disadvantage in seeking justice for retribution. this doesn't even take into account the inevitable hit bob's reputation will take in the society he attempts to function in. screw you, bob. i don't want to buy your apples and i won't sell you my peaches!
this is a place where philosophy and consequence inevitably meet. in the example, both john and his brother, tom, were violator's of bob's property. but bob brought upon himself a disadvantage to justice when he used disproportional force to protect his property from john's initial violation. proportional force can't be used as a philosophical absolute because its definition is subjective. the idea of proportional force is not one that can be adequately accounted for philosophically, but is a consequence of the functioning of the market society. it is not a philosophical axiom, but a guide in the practical application of justice.