Correction: An earlier version of this post misrepresented when violence can be used. This has now been corrected.

The Non-Aggression Principle (NAP) is often mentioned in Libertarian communities, but rarely defined in a way that makes sense to outsiders. Most of the important Libertarian websites, such as Mises Institutes, have no introductory articles with names like “What is NAP?” or “Introduction to NAP”. Instead, individual Libertarians either offer explanations that require a lot of previous knowledge, or recommend entire books*.

It’s a puzzling situation to have such a foundational topic so poorly covered when it’s such an essential part of the Libertarian ethical system — to the degree that rejecting it makes you no longer Libertarian.

For this reason, I decided to write this brief explanation, to the best of my current understanding.

What is NAP?

The Non-Aggression Principle (NAP) states that you cannot initiate the use of violence against others in an attempt to control or damage their property.

What is Aggression?

In the name, it’s called the non-aggression principle, not the non-violence principle. So what did I define it as being unable to initiate the use violence against others in an attempt to control or damage their property?

That’s because in the libertarian context, aggression is the initiation of the use of violence to try to control or damage someone else’s property. Aggression has many different forms, some more obvious and direct than others.

A classic example of obvious and direct aggression would be if you walk down a street and a complete stranger threatens you with a knife in order to gain control of the money in your wallet (which is part of your property). However, since the stranger initiated the violence, you have the right to respond in kind to defend yourself.

An example of indirect, non-obvious force would be taxation. Taxation is when the government decides it would like some of your money (which is part of your property), and paying them is not optional. If you fail to give the amount they want whenever they ask for it, they can use physical force (police with guns) to harass, arrest, and imprison you.

NAP forbids all aggression: direct and indirect, obvious and non-obvious.

Does this mean Libertarians are pacifists?

Following and advocating for NAP doesn’t make a person a pacifist because NAP doesn’t forbid violence itself, only aggression — the initiation of violence used to control or damage someone else’s property. If someone else has initiated violence, you can always use violence to defend yourself and your property.

What is Property?

If you can’t initiate violence in an attempt to control other people’s property, then it’s essential to know what counts as property.

• Property means total control. When you own property, any kind of property, you have complete control over how and when it is used. No one can tell you how or when to use it, except if that use is aggression.
• We own our bodies. Our first and most important possession is our bodies. No matter our circumstances, we always retain final and total control over our own bodies.
• When you mix labor with nature, it becomes your property. Suppose you go into nature, traveling on land owned by no one. You pick up some palm fronds and create a hat from them. That hat is now your property, and you have complete control over it.
• When property exists, it can only be voluntarily transferred. After you have created your palm frond hat, the only way another person can own it is if you give it to them, or you participate in voluntary exchange.

Conclusion

In conclusion, the Non-Aggression Principle (NAP) forbids aggression, which is the initiation of the use of violence to control or damage the property of another person. Your property includes your own body, things you create from nature with your own labor, or things which you purchase or are gifted. However, NAP doesn’t mean Libertarians are pacifists, since they can use violence to defend themselves and their property from acts of aggression.

Notes and Comments

• It is a huge failing of the libertarian community that they are so quick to recommend entire books to beginners. It is a huge barrier to entry, especially since the books recommended are in a style unfamiliar to the majority of interested people.
• This article initially omitted the concept of initiation of violence being forbidden, leading to a confusing discussion. The article has been updated to make things clearer.