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Thusfar this course has elucidated theories and examples denoting what is and is not aggression. Now that we know what it means to be criminal, this lesson will answer the question of what actions are just in defending against and punishing aggressions.

Note that the question of justifying a punishment only arises insofar as the wrongdoer rejects the justice of the punishment. That is to say, if the criminal consents to a certain retaliation, this retaliation is per se just as there can be no conflicts where the wills of men are in harmony. Justifying a punishment is far more challenging when the criminal does not consent, i.e. when the criminal wishes to challenge the justice of a given punishment. We know from prior analysis that this challenge seeks to test the justification against the nature of argumentatively justifying as such. If the punishment cannot be justified without thereby falling into contradiction, it is unjust.

Therefore, the nature of argumentation is a suitable starting point to obtain a rational theory of punishment. Recall that contradictions are falsehoods, and thus not a feature of a correct argument, therefore a person can be prevented from making certain claims in a dialectic if those claims are inconsistent with his actions. To be abundantly clear, to avoid any confusion; the person is not being prevented from making these claims by a judge or a cop or whatever physically coercing him into not making the claims, he is prevented from making the claims by the very nature of dialectic as such—in other words, if he did make those knowingly incoherent claims he would not be engaged in argumentation, he would rather be babbling or telling a joke or something else. This forms the root of what Kinsella dubs “Dialogical Estoppel.”³ Lord Coke explains that the word “estoppel” is used “because a man’s own act or acceptance stoppeth or closeth up his mouth,”⁴ and “dialogical” refers to dialogue, aka argumentation. So we can say that a man is, by the nature of argumentation as such, estopped from making certain inconsistent or contradictory claims:⁵

Let’s apply this theory of estoppel to the case of $A$ punching $B$. Assume that this is the extent of the assault, as the question of defending an ongoing aggression shall be discussed in the next section, $B$ decides that he wants to punish $A$ in an eye-for-an-eye manner by punching him back, or perhaps by hiring a champion, $C$, to punch $A$ if $B$ cannot, or does not want to, do this himself. If $A$ were to challenge this punishment, he would claim that this punching of him is an impermissible action, i.e. that people should be prohibited from punching him. But, $A$ has previously demonstrated that he thinks that he should not be prohibited from punching $B$. In essence, $A$ has pre-supposed that punching people sans-consent is just, and is now explicitly making the claim that its unjust. This is a clearly incoherent position, thus $A$ is estopped from challenging his punishment, therefore we revert back to the simple case of an unchallenged punishment which is per se just.

Notice that this applies only to punching as the punishment; $A$ could coherently argue that it is unjust to murder him, or take a lock of his hair, or tear up his prized roses, as these retaliations would be of an entirely different sort. That is, by merely punching $B$, $A$ pre-supposes only that punching is proper conduct, but he does not per se pre-suppose that any other invasions of property borders are proper. This is where the concept of proportionality comes in—the retribution against an aggressor must come in the same form as the aggression, or else the punishment is further aggression and thus not just. In short, just retribution is an eye for an eye, not an eye for a tooth.

There are a number of potential objections to this theory that $A$ might forward. First, he might claim that his positions are not that punching is proper and that punching is improper; but rather that $A$ punching $B$ is proper and anyone punching $A$ is improper. Thus there is no contradiction and he is not estopped from challenging his punishment. The issue here is that any norm must in principle be universilisable if it is to be proposed in an argument, as Hoppe points out:⁶

This is because if one is to claim any proposition as being argumentatively valid, said proposition must be rational—what this means is that it must in principle be valid no matter who it is proposed to. To reject this would be to adopt a polylogism; i.e. that a proposition might be true when levied in one argument, but not when levied in another⁷—and it was shown in the first lesson, that polylogism implies contradiction, making it false. So universilisability is therefore a pre-supposition of the very normative discourse that $A$ would be partaking in by attempting to reject his punishment, but the norm that its fine for $A$ to punch $B$ but not for others to punch $A$ is not universalisable—we would be faced with a contradiction if we tried to swap out $A$ for $B$ and hold both norms simultaneously, meaning this norm cannot be applied to everyone:⁸

Kinsella points out further that even if we throw away the requirement of universilisability, and instead assume that norms can be particularised in this way, this would mean that $B$ could simply particularise his punishment norm and thus claim it to be just for him to retaliate—we would quickly regress into incoherent subjectivist ramblings of might making right.

So this objection by particularisation fails, leaving our aggressor estopped once-more; a second potential counter he might raise, however, is that he has changed his mind—i.e. that he used to think it proper to punch people, but he has had a change of heart and now realises that such conduct is evil, and therefore he is not currently in contradiction, and thus not estopped from objecting to his punishment.

There are a number of problems with $A$’s approach here, first, if changing one’s mind means that one is no longer liable for their prior actions, then all $B$ must do is punish $A$ then afterwards claim that he has changed his mind about that punishment, meaning he is also not responsible. You will notice that this would quickly devolve into a might-plus-regret-makes-right, which would be an irrational ethic.

Second, by $A$ changing his mind, he is per se denouncing his prior aggression, thus asserting that aggressions are indeed impermissible. This would mean that he could not coherently deny the right of the victim of aggression to punish said aggression—to say that an action is permissible is to say that one may not legally punish it.

Third, this mind-changing is still a form of particularisation—it’s the claim that the logical structure of what it means to pre-suppose an action as legitimate can change by the mere fact that the person pre-supposing said legitimacy also thinks that the action is illegitimate. Let’s unpack this—what $A$ is asserting here is that they believe in their heart that the punching is illegitimate, whether they only started holding this fact after doing the punching isn’t particularly relevant. All that matters is at the moment of the assault $A$ must pre-suppose that punching is a legitimate action—this could take place simultaneously with $A$ believing it to be illegitimate or not, men are capable of believing in contradictory things after all. What is important is that $A$ cannot drop the pre-supposition that punching is legitimate. He has already committed the act of aggression that pre-supposes this as a legitimate interaction. Because he cannot drop this pre-supposition, in order to resolve the contradiction he is left with only the option of dropping his challenge to the aggression. Therefore he is estopped by definition.

I will re-iterate this point for clarity; what makes a man estopped from challenging a given punishment is that the given challenge would imply a contradiction, meaning it cannot be uttered in an argument. When I perform some action $X$, I thereby pre-suppose by this performance that I think I should do $X$ as opposed to $\mathrm{\neg }X$. There is some confusion over this thesis, often I have encountered the counterargument of the man who is smoking and says that he should stop—does this man not believe that he should stop? Is he lying when he says he should stop? That is not necessarily the case. We can indeed imagine a man who is currently engaged in an act of smoking–a man who has chosen to smoke rather than not smoke–who nonetheless believes that he should not smoke. But, this does not establish that he is not also pre-supposing that he should smoke. It is possible for a person two hold two contradictory beliefs at the same time, we call this cognitive dissonance. Consider the anarchist who goes through the labour of demonstrating that taxation is theft and that theft is bad, therefore taxation is bad only to be confronted by his statist opponent who agrees that taxation is theft and that its bad but still asserts that taxation is a good thing that should continue. It is clear to anyone who has encountered stupid people that man is fully capable of holding contradictory theses at the same time. The upshot of this for our smoker is that by choosing to smoke rather than not smoke it must be the case that he believes that he should smoke rather than not smoke, but this does not preclude the possibility that our smoker also believes that he should not smoke—it’s just that his belief that he should smoke is in some sense over-powering his contradictory belief.

There is a further confusion to be addressed at this point which stems from a conflation between two different senses of the word “ought.” To highlight this, consider the statement “it is raining outside, therefore you ought bring an umbrella.” Now, there are two ways one could interpret this statement; either (1) ought is being used in its precise logical meaning, or (2) its being used as prudential advice. For (1) it simply does not follow that because it is raining you ought bring an umbrella, at least not without additional steps. For (2) “ought” is being used colloquially, if we were to precisely formulate (2) it would be something like “it is raining outside so if you do not wish to get wet when you go outside a potential means to achieve this goal would be to bring an umbrella.” When formulated precisely it becomes clear that when prudential advice is given like this, the statement is really an “is” statement rather than an “ought” statement. This insight will become crucial in the next lesson so I will not stress it too heavily here, but the key takeaway for now is that there is only ought; ought is ought. There doesn’t exist different “flavours” of ought in logic, it is a failure of imprecision to mix in colloquial usages of this word.

Bringing this back to our criminal, $A$, who wishes to challenge his punishment for punching $B$, he has already demonstrated by his conduct that he thinks punching is a legitimate interaction. If he then states that it is not a legitimate interaction, which is required for him to challenge his punishment, he is in a contradiction. To resolve a contradiction between two statements, one of the statements has to be dropped, because $A$ simply cannot drop the statement that punching is proper, he is left only with being able to drop the statement that punching is improper, but the statement that punching is improper is the one that is required for him to challenge the punishment. Therefore, $A$ cannot challenge his punishment—he is dialogically estopped from doing so.

An important note must be made with respect to the application of this theory of dialogical estoppel—a keen eye will notice that men are only estopped insofar as they chose to commit the aggression, that is, a man is only estopped when he purposefully engaged in the trespass in question. If a man did not purposefully aggress, but rather accidentally aggressed we say that he lacks “mens rea.” Mens rea is a legal term meaning “guilty mind,” it is characteristic of the man who decides that he wants to aggressively stab his neighbor to death, but not of the man who is hiking and accidentally wanders onto a farmers field. Mens rea is contrasted with actus reus, meaning “guilty act.” Actus reus is present in every man who trespasses, whether they did so knowingly or not. Restitution can be justified on the grounds of actus reus, retribution requires mens rea. Here, restitution refers to the act of making the victim whole again, say I steal 5 ounces of silver from my neighbor, restitution would involve me giving my neighbor 5 ounces of silver, retribution would involve a further 5 ounces of silver. In total, assuming I knowingly stole, my neighbor would be due 10 ounces of silver, 5 in restitution and 5 in retribution.

As a point of clarification, mens rea does not require that the person in question actually understands that their action was criminal, all that is required is that they knowingly performed the invasion. For instance, the nazi prison guard who shoots an escaping Jew has knowingly invaded that Jews body with his bullet, however that guard may well believe that his action was justifiable because he believed in German law, rather than natural law. But, his belief that the action was just does not absolve him, as he knowingly performed what is objectively an invasion.

With an objective theory of the just means of punishment elucidated, we shall move onto an analysis of what means of defense are just. Recall that a property right in $X$ held by a person $A$ implies the right of $A$ to exclude other people from the use of $X$. It is from this recognition that defense is justified—namely, $A$ is permitted to use whatever means are required to go about excluding people from $X$. This simple principle is, however, not so simple to actually apply to complex scenarios. First consider the case of a man trespassing onto your front lawn to take a look at your roses. It is clear that insofar as you do not wish for him to do this there is trespass occurring—that is, he cannot use your lawn to stand on at the same time that you wish for him to not stand on your lawn. Therefore, you may exclude the man from doing so, but could you do so through arbitrary means? For instance, would you be permitted to fire a rocket at his feet thereby blowing him up, or would you have to take “gentler” means first? Let’s consider the relevant rights; the man owns his body and therefore has a right to exclude you from his body, but you own your lawn, and thus can exclude him from using your lawn—therefore you are permitted to possess him to the extent that is required to remove him from your lawn and no more.

For instance, perhaps the man did not realise it was your property, but rather a natural feature that is not owned by anyone. Here, the man would lack mens rea, and perhaps simply informing him that he is trespassing will suffice to remove him from your lawn. Here, no possession of his body would be required, and thus no possession could be justified. However, the man might be stubborn and wish to look at your roses still, this more stubborn man may require that you grab him by the arm and walk him off of your property. Here, because the grabbing of the arm was required to remove him, it can be justified. You could not grab his arm and begin stabbing at him with a needle, because the stabbing with a needle does not serve the purpose of excluding the man from your property and is not required for this exclusion. Therefore this stabbing would be an additional aggressive invasion of the man, rather than of your lawn. Here it becomes clear that you would not be permitted to launch a rocket at the man unless said launching of the rocket was required to successfully exclude him.

A further example to elaborate upon this principle is your neighbor kicking his ball onto your lawn. Let’s imagine first that your neighbor doesn’t want anyone else to touch his ball and you do not wish for the ball to be on your lawn. Here, the ball is invading your property so you could justly remove the ball at will—i.e. you are allowed to exclude the ball from your property and touching the ball is required to remove it. Imagine an alternative scenario where the ball is on your property and to teach him a lesson you tell your neighbor that you will not let him retrieve the ball himself and you will not remove the ball from your property on your own. This would be a case of excluding the neighbor from his ball which you are not trying to exclude from your property. Because you aren’t trying to exclude the ball from your property it could not be said that the ball has invaded your property, the neighbor still owns the ball and therefore you are engaged in an act of forestalling—you are excluding your neighbor from the ball that you do not own.

However, if you did attempt to exclude the ball from your property, perhaps by erecting a fence, and your neighbor was nonetheless able to overcome your exclusion the ball is invading your property. Perhaps this fence completely encloses your property such that for the neighbor to retrieve his ball the fence would have to be removed. Certainly you would be permitted here to continue to exclude your neighbor from stepping on to retrieve his ball, as his stepping onto your property would involve a further invasion because you are already excluding people from your property prior to the ball being kicked on. Here the principle is that antecedent rights must prevail. You were excluding people and balls from your lawn which is why you own your wall, you cannot be compelled to allow further invasions to recover the costs of prior invasions. Your neighbor must suck it up and hope that you decide to return his ball to him. This is because your rights in the lawn are antecedent to your neighbors rights in the ball, as the ball was used to initiate the conflict. You are rightly allowed to take possession of his invading ball—Dominiaks contradiction from donut homesteads⁹ is resolved here by your possession of that ball being just, you gain ownership of that ball by virtue of it being invasive. This is not “full-monte” ownership, however, like in the case of owning a stick where you can trade it or use it however you wish. This ownership of the ball would be specifically for the purpose of excluding invaders from retrieving the ball, if you removed the ball from your property it would revert back into the ownership of your neighbor. This analysis applies also to the cases where a bird drops the ball onto your property or where a third party kicks the ball, but not where you kick your neighbors ball onto your property, as you initiated the conflict there.

The insight that even where your neighbor was not the one responsible for the invasion of the ball you may still take possession of it is key for understanding the libertarian answer to the human-body shield. Consider the case where a criminal steals your neighbors sword and attempts to stab you with it, and the only way to prevent this from happening is by damaging the sword, because damaging the sword is required in excluding the invasion it is just, even if your neighbor does not want the sword to be damaged. Similarly, if the criminal instead picks your neighbor up and tries to use him as a sword you would be justified in damaging your neighbors body insofar as this is required to exclude the criminals invasions.

In such a scenario you would be justified in taking whatever actions are required to exclude the criminals attempted invasion as always. It is required that you shoot back in order to thwart him, thus this is just, even though it would imply damaging your neighbors quilt. Moreover, your neighbor would not be justified in attacking you to defend his quilt—you are doing no wrong by shooting through the quilt, therefore your neighbor cannot justify attacking you as he is not responding to an aggression on your part. We can then trivially move from a criminal using a quilt-shield, to one using your neighbor as a shield—again, you are justified in shooting back at the criminal, even if this implies shooting through your neighbor.

This is distinct from the situation where your neighbor is a bystander to the aggression, in such a situation attacking him is not required to exclude the aggressive invasions from the criminal, so randomly turning around and shooting at him during the gunfight would be additional aggression insofar as this is not required to thwart the bad guy. The same is true if you were given an ultimatum by the criminal where he will shoot you if you don’t kill your neighbor. You are allowed only to engage in exclusionary actions against the aggressor, not against bystanders. These exclusionary actions may well damage the property of third parties, but this does not provide carte blanche for any invasions you may wish to engage in to exclude. To clarify, exclusion is only justified against aggressors, however exclusion against an aggressor may or may not involve damage to the property of third parties, this damage can only be justified if it is required to exclude the aggressor.