If you have ever discussed the merits of libertarianism with anyone and appealed to the Non-Aggression Principle (NAP), you have undoubtedly come across this challenge:
“What if someone doesn’t agree with the NAP?”
Does a society based on the NAP fall apart if not everyone agrees with it? Think of it this way: as libertarians, we are against taxation, but taxation exists nearly everywhere. No country has ever fallen apart because a few people decide that they do not want to pay taxes. So it follows that it takes more than just “someone” to decide to not follow some given rule to threaten the fabric of a society.
Furthermore, it is not true that everyone needs to agree with the NAP or to even be aware of it. The fear of retaliation, i.e. self-defense, is often enough to keep someone from committing aggression against another person. If you do not believe that you would be able to get away with something, then you will probably not do it.
You may want to smack someone in the face during an argument, but knowing that would probably be enough to start a fight makes that option a lot less appealing. So given that, why would someone decide to commit violence just for kicks? Or why would someone with a preference for violence always choose it over other options? Why is there an assumption that there would be no consequences for violent behavior? Shouldn’t we looking for ways to empower people to be able to adequately deal with aggression?
Like many objections to libertarianism, the idea that a lack of total agreement on the NAP would lead to grave societal problems fails with the injection of just a little bit of common sense.