Is the Non-Aggression Principle Axiomatic?

by | Oct 15, 2019

Is the Non-Aggression Principle Axiomatic?

by | Oct 15, 2019

The Non-Aggression Principle is one of the most well known and core ideas to libertarianism.  It succinctly lays the groundwork for how libertarians believe people should interact with each other.  But is it always the answer for interaction?  Does it hold literally hold 100% of the time?  Or is it more of a guideline where extenuating circumstances require us to appeal to some other principle or idea?  Let’s go deep into the weeds and explore whether the Non-Aggression Principle should be considered an axiom.


I hold that while the Non-Aggression Principle is both extremely relevant and important to both libertarianism and the general formation of peaceful societies, it is not axiomatic.  Before we go any further, it is important that we first define the two main terms that are up for debate: the Non-Aggression Principle and axiom.

Here are these terms defined:

  • The Non-Aggression Principle: the idea that it is wrong to use violence or the threat of violence against peaceful individuals
  • Axiom: a self-evident truth that requires no proof; a universally accepted principle or rule

This definition of the Non-Aggression Principle is generally accepted by libertarians and I don’t anticipate any confusion on it.  It would be useful, however, to add some clarification to the definition of axiom.  When I refer to an axiom, I mean that the proposition is always true in all cases, i.e. universal.  It can never be false.  This of course means that the requirements for categorizing something as an axiom are extremely stringent.  The proposition must still hold even for theoretical tests even if they are not likely to ever exist in practice.

The usefulness of the Non-Aggression Principle

As already mentioned, even if the Non-Aggression Principle is to not to be considered axiomatic, it does not render it useless.  The Non-Aggression Principle should be followed in most human interactions, but since I am claiming that it is sometimes justified to violate it, it is not suitable to be used as a foundational law of a philosophy that seeks truth and consistency.  Instead, it is a very useful guideline, just like the Golden Rule.

This ought to not be understated or forgotten later in the discussion.  There is nothing wrong with relying on the Non-Aggression Principle for most situations; it will generally direct you to the most ethical of outcomes.  The problem for libertarians comes when they claim that it is axiomatic, which usually functions as a challenge for someone to try to disprove it with any number of lifeboat scenarios.  If the libertarian holds strong to the claim that the Non-Aggression Principle is axiomatic, then he is forced to compromise other usually universal ideas in order to stay consistent with the claim.  Being incorrect here doesn’t make the libertarian incorrect in his assertion as to whether the action being discussed is ethical or not, but the perception is that it does (e.g. the claim that 2+2=4 is not proven wrong because it is subsequently incorrectly stated that 1+1=3).

To give an example of this idea that general principles are useful without being axiomatic, consider killing.  It is noncontroversial to state “it is wrong to kill another person” when in general discussion.  This statement would never be treated as axiomatic and no one would assume that the speaker is claiming that it’s never not true.  If someone raises the question of killing in self-defense, then obvious appeals can be made to self-ownership and theft to justify overriding the position that it is wrong to kill.  Casual, i.e. non-technical, conversation of the Non-Aggression Principle should be treated the same way.

The correct fundamental principle

To explain why the Non-Aggression Principle is not an axiom, I will put forth what I use as the foundational, or axiomatic, principle for my philosophy, which I have taken from Michael Huemer’s book The Problem of Political Authority.  It is essentially a restatement of the Non-Aggression Principle with one minor but important difference: individuals have the prima facie right to live free from harmful coercion.  Put another way, a person has the prima facie obligation to not impose harmful coercion on others.  The only difference between this and the Non-Aggression Principle is the inclusion of the “prima facie” qualification.

The qualification is an important one.  It is what allows the fundamental ideas of libertarianism to be applied consistently without contradiction to universally accepted moral norms.  As stated earlier, the Non-Aggression Principle is an excellent guideline that applies to nearly every interaction among people.  However, a person arguing against libertarianism and the Non-Aggression Principle can come up with a lifeboat scenario to disprove the Non-Aggression Principle.  The prima facie qualification provides the means to deal with them without some awkward explanations.

Lifeboat scenarios

It should be noted that the fact that critics need lifeboat scenarios to poke holes in the Non-Aggression Principle should prove its worth as a rule of thumb.

That said, lifeboat scenarios have merit on their plausibility that they could be real life scenarios.  Scenarios that are impossible to occur can be rejected as arguments against the Non-Aggression Principle.  Consider this example regarding the coffee cup sitting on the table next to me.  Do I have the right to drink from my coffee cup or even break it apart and destroy it because it might have human sentience?  We can reject that scenario because it is impossible for the coffee cup to suddenly change properties such that I would be obligated to treat it the way I would another human.  A coffee cup is distinctly different than a human, therefore the question doesn’t make sense.

Let’s use a literal lifeboat scenario as our example.  Imagine that Alice and Bob are floating in a lifeboat waiting to be rescued after their boat sank.  We will assume that both are equally blameless for the loss of their boat and no other persons can be blamed for the loss.  Both Alice and Bob are at equal moral standing: for reasons outside of each of their control, they sit on a lifeboat that they both need in order to survive.  Now imagine that the lifeboat springs a leak—again by no fault of any person—and in order for the boat to remain afloat, both Alice and Bob must bail water together or else they will drown.  Alice is doing her part to keep them both alive, but Bob decides that he wants to do something else to save them.  He decides to blow on the water in the boat, which clearly will not keep them stay alive.

Bob’s actions will lead to their deaths, and whether Bob wants to die or not is irrelevant because his death will be the result of his own actions.  But Alice wants to live and she will die as a result of Bob’s incorrect actions.  Despite how silly Bob’s blowing on the water might be, he is not violating the Non-Aggression Principle.  What is Alice to do?  Should she drown or should she violate the Non-Aggression Principle and coerce Bob into bailing water?

While coercing Bob would be a violation of the Non-Aggression Principle, no reasonable person would say Alice made the wrong decision.  That harm caused to Bob even if the coercion was physical harm would be less harmful than Alice’s (and Bob’s) loss of life.  So we could say that Alice’s coercion of Bob would be justified even if it were a violation of the Non-Aggression Principle.

Of course, this would not justify further violations of the Non-Aggression Principle.  Alice would not be justified in coercing Bob to tell her jokes as they bailed.  If another option became available, like if a scoop floated to the boat that allowed Alice to double her own bailing efforts, then the justification for violating the Non-Aggression Principle would disappear.


One of the rebuttals to lifeboat scenarios is the offer of restitution following the violation.  Someone may say, “Yes, I would steal from the unoccupied cabin in the woods to stay alive, but I would go back to the cabin at a later time and replace what I had taken.”  Or maybe Alice takes Bob out to lunch to try to make up for the coercion she placed on Bob in the boat.  While that is certainly a noble action to take, what you do following the action in question does not change the status of being a violation of the Non-Aggression Principle.

Everyday violations

Up until now, we’ve only discussed extremely rare situations that are not likely to happen, which is good for the Non-Aggression Principle if it is to be used as a rule of thumb.  There are, however, plenty of everyday cases where the Non-Aggression Principle is routinely violated.  An obvious example of this are aspects of the parent and child relationship.

Children, especially younger children, are usually not very well equipped at making decisions for themselves.  Parents set rules for their children with their best interests in mind.  Without getting into the details of the how a parent is best equipped at being the authority for his child, we should be able to accept that it is normal and justifiable for a parent to do certain things against the will of the child.

Every human owns himself and this remains true for children even if virtually all of society agrees that parents may make decisions on behalf of their kids.  This normally works out very well, but parents and children don’t always agree.  These are usually mundane disagreements like “Go to bed” or “Eat your vegetables.”  If a parent picks his child up and puts her into bed, he is using the child’s body in a way that she as the rightful owner of her body does not want, thus it is a violation of the Non-Aggression Principle.

This is obviously an extremely minor violation, but it is still a violation.  When not dealing with children, forcing someone to behave in a way that is truly good for him is not acceptable.  But one is seen as justified and the other is not.  The Non-Aggression Principle does not make exceptions for children.


An axiom must be true in all cases.  The conclusion must be that while the Non-Aggression Principle is useful and important, since there are some narrow cases where you are justified in violating it, it is not axiomatic.

Unfortunately, there is no clear and clean statement that easily categorizes all actions without exception as either justified or unjustified.  The good news is that while it may not be axiomatic in nature, the Non-Aggression Principle is more than suitable to steer all of humanity in a just, equitable, and productive direction.

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