The human body shield problem is the following scenario. A criminal, holding your innocent neighbor in front of him, approaches you and begins shooting at you. You can stop him, but only by shooting through your neighbor and killing them both.
The apparent dilemma is that either a libertarian must admit that it is acceptable to aggress against an innocent individual or he must acknowledge a class of unstoppable super-villain against which no libertarian can stand. (1)
How do libertarians deal with the problem of human body shields? (2) The same way they deal with every other ethical choice: by adhering to the non-aggression principle (NAP).
The NAP can be used to determine whether a libertarian may take any particular action. The human body shield case is interesting because it decouples the rights in conflict from responsibility for the conflict. This prevents us from relying on well established, libertarian analysis of two party cases, where one party is responsible for the conflict.
In order to solve the human body shield problem, we must see how the NAP can be used to resolve conflicts between property rights. We must then examine how responsibility relates to the resolution of such conflicts. Thus equipped, we will tackle the human body shield problem and related examples.
I. Conflict Resolution
First, we must understand what the NAP is and implies. The NAP states that aggressive violence is prohibited. The NAP then implies that defensive violence is not prohibited. Therefore, the NAP implies a simple conflict resolution rule: when property rights conflict, antecedent rights prevail. (3)
In other words, conflicting property rights over invading property are surrendered. For example, normally your neighbor gets to decide how his finger is used, but if he pokes your body with it, then your right to determine how your body is used prevails over his right to determine how his finger is used. His finger was used to initiate the conflict and you would be justified in pushing it away.
Similarly, if your neighbor kicks his ball onto your land, then his right to determine how his ball is used might be in conflict with your right to determine how your land is used. You may not want the ball on your land and he may not want anyone to move his ball. (4)
The conflict resolution rule implies that because the ball was used to initiate the conflict, your conflicting rights in the land prevail over your neighbor's relevant rights in the ball. As a libertarian, you may remove the ball from your property, or leave it where it is, as you see fit. on the other hand, your neighbor would not be justified in going onto your land to retrieve his ball.
The situation is the same if the wind rolls your neighbor's ball onto your land. The ball is still the invading property, so the conflict of property rights resolves in the same way. Similarly, if a criminal kicks your neighbor's ball onto your land, then your rights over your land would prevail.
If, instead, you kick your neighbor's ball onto your land, then the situation is different. Though the same sets of rights may be in conflict, the way in which the conflict was initiated has changed. In this case, your land is used to initiate the conflict. (5) Thus, your neighbor would be justified in walking onto your land against your will to retrieve his ball. He could also leave his ball on your land, and you would not be justified in moving it.
only the rights of the invading property that are in conflict are suppressed. (6) So, in the first situation you would not be justified in destroying the ball. However, suppose the ball is trapped under a rock, and the only way to remove it is to destroy it. Then your neighbor's right to determine whether the ball is destroyed is also in conflict, and you would be justified in destroying the ball in order to remove it.
Since the rights surrendered are only those in conflict and no others, overriding rights that are not in conflict necessarily creates new conflict. …