Opinion from a Libertarian ViewPoint

An Expanded Version of the NAP

Posted by M. C. on October 31, 2021

Regarded by many as the keystone of Libertarian philosophy.

This essay offers an expanded version of the Non-Aggression Principle (NAP). The traditional forms have been very useful as introductory statements into libertarian discussions. However, the Anarchist/Voluntaryist movement has matured to the point where the NAP requires formulations that are more sophisticated.

The simpler versions of the NAP

For the uninitiated, the typical NAP expressions have the advantage of simplicity, such as

“It is wrong to initiate force, threat of force, or fraud against others or their property, without consent”.

This speaks to a shared basic morality at the heart of human interactions. Moreover, it is highly comprehensive: a great deal is conveyed in a single sentence.

However, the expression fails in many cases. If I grab my watch back from a pickpocket, it may seem to a bystander that I am the thief. Relying strictly on simple forms of the NAP does not help, or at best creates confusion. It does not meet the needs at hand.

The need for an expanded formulation

Anyone who has engaged in conversations about the NAP has likely faced challenges, such as edge-cases or other difficult scenarios. Additionally, articles and blogs have been written presenting outright challenges to the NAP itself.

We can easily see the limitations of the simple form of the NAP, by examining what is not mentioned, or at best implied:

  • The terms “force” or “aggression” imply coercion by direct human action. They do not specifically mention the words we use, or physical objects under our control. This leaves many actions open to interpretation such as verbal abuse, pollution and other nuisances.
  • It does not account for degrees of force. Minor actions can be debatable, such as harmless threats.
  • It does not allow for degrees of harm. Trivial aggressions can appear as NAP violations.
  • Intent is only weakly implied. Pure accidents can appear just as egregious as willful coercion.
  • The concept of consent itself can be misinterpreted; a fraud victim may appear to give consent.
  • It does not address actions taken in defense of third parties. This leads to debates as to whether such defense is “initiated” force.

An enhanced version of the NAP

The author wishes to stress that this formulation of the NAP is by no means intended as definitive, complete or final.

The following is offered as an enhanced version of the NAP. It separates and emphasizes the fundamental concepts that underpin the principle, as it pertains to the actors and their actions. The concepts are: Initiation, Intent, Compromised Consent, Harm, and Causal Role.

To consider a human action as wrong, all components of the Non-Aggression Principle must be present:

  • Initiation. An action is initiated by a person or by means of property they control
  • Intent. The action is intentional, or its results are reasonably foreseeable
  • Compromised Consent. The subject either lacks reasonable capacity to give consent to the relevant actions, or has such capacity but is deprived of the choice to freely opt out of the harm
  • Harm. The subject experiences non-trivial harm to their person or property
  • Causal Role. The action has a sufficiently significant causal role in undermining the subject’s consent.

This formulation has the advantage of being useful across various normal and abnormal human interactions. It attempts to eliminate controversy by detailing the NAP’s components, then applying the situational specifics to these components.

The alert reader will likely notice the use of several subjective terms, such as “reasonably”, “freely”, “non-trivial”, “sufficiently” and “significant”. These are used by design. The purpose of this particular version of the NAP is to simplify discussions about detailed, specific cases. If it is to succeed in this, it must use terms that are both broad enough to generalize, yet meaningful enough to make sense when applying them.

The spectrum of right and wrong actions

Human interactions fall along a spectrum that extends from purely peaceful voluntary actions, to acts of pure violence. My Super Bowl ticket changed hands when my wife purchased it…a purely peaceful exchange. It changed hands when she gave it to me as a gift…again, peaceful. I got into a brawl and hurt a bystander; the ticket changed hands again when I gave it to him…as restitution for the harm I caused. Later it changes hands again…when he is murdered for the ticket.

The issue is not that these examples are difficult to resolve; our common sense tells us exactly which cases are right and which are wrong. The problem is that simple forms of the NAP are not always useful when we try to apply them to specifics. Our time is spent debating how to interpret the NAP and its terms. It is not a failure of our common sense, nor of the spirit of the NAP as a principle. It is rather because the formulation is too broad to adequately handle specifics.

Refer to this supplemental essay for examples demonstrating the value of an expanded formulation.


This essay’s use of the NAP terms is anarcho-capitalist, and based on contemporary scholarly understandings of property, consent, and Austrian economic theory.

Some terms used in the expanded NAP formulation…


This addresses the particular action that “started it” and makes defensive actions easier to evaluate. For example, the thief “started it” by stealing the watch. If a week later the owner takes it back, the owner did not take an “initial” action even though the two events were spaced apart in time. Rather, he responded to the thief’s initial action.

“Initiated…by means of property they control”

This insures that if physical objects are a factor in the action, the person controlling or responsible for the object is culpable. A dog’s owner allows it to run free and the dog then bites a child. The owner cannot claim to be innocent on the grounds that he personally did not commit the act of aggression.


Assumes the scarce-goods (rivalrous, conflictable) model, which includes a person’s body and justly acquired material objects. Ownership is essentially the right to exclude others from use.


In general usage the word “action” appears to subsume all forms of human activity. In this essay, “action” implies intent and purpose…the exercise of will. “Action” is therefore contrasted with (and does not include) other human movement such as moving while asleep, or accidental motions. To be sure, the phrase “The action is intentional” is self-describing. However, it is retained to make explicit the importance of intent when evaluating specifics.

“Intent is a necessary ingredient in human action; if there is no intent, then there is no action, only behavior: involuntary physical movements guided by deterministic causal relations.”

(Stephan Kinsella; Patrick Tinsley, Quarterly Journal of Austrian Economics, 07/30/2014)

For example: there is no intent to harm if, while walking, I faint, stumble and injure someone. But if I drive drunk and then injure someone, my driving in this condition was intentional (and, of course, its consequences reasonably foreseeable). This is why intent is a component in affirming or rejecting a NAP violation.

“Compromised consent”

This helps clarify the victim’s ability to agree to the interaction and its outcomes. Any one of the following can be considered a victim, whether they appear to give consent or not: a person sleeping or comatose, a child, a mentally challenged person, a person unaware of the conditions at hand.

“The subject…is deprived of the choice to freely opt out”

The core element of consent is the freedom to opt out of the interaction altogether. Choosing between a 10-year Life policy and a 20-year policy actually entails three options, the third being the choice to opt out. But say a parent pays a ransom for their child’s life. Using the simpler version of the NAP, one might argue they “consented”. However the opt-out aspect is absent and thus consent is “clouded”. Inclusion of the choice to freely opt out makes clear there is no consent.

“Non-trivial harm”

This eliminates unreasonable claims of NAP harm. The traditional libertarian challenge case is shining a flashlight at someone, who then claims a NAP violation, as they did not consent to being struck by light photons. This is trivial harm.

“Sufficiently significant causal role”

The action must have enough significance in causing the harm. Several examples presented in the supplemental essay show the importance of this part of the expanded NAP.


The Non-Aggression Principle is already highly implied as a basis of traditional common law and civil law. As we move toward a stateless society, the NAP will be refined in ever greater detail. Eventually a free society’s legal code is likely to have a highly robust formulation of the NAP as its foundation. This will represent the moral and philosophical aspect of the NAP; but its utilitarian aspect will emerge with each individual application, where the particulars will be examined within NAP legal frameworks.

Mark Maresca

March 2020

Be seeing you

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: