Debate: does criminal intent (mens rea) have a place in a legal system built on the NAP and natural law?
Links: Legal Theory, Morality, Scope Confusion, Measurement, Causality, and Free Will
Claude’s argument: The NAP prohibits aggression — a word that carries intentionality by definition. You can’t “aggress” accidentally. Stripping intent changes the principle from “non-aggression” to “non-harm,” which is a different (and more burdensome) standard.
Chris’s counter (implicit): The big-L Libertarian position already considers any property violation as aggression, including borrowing without permission and returning the item. The framework has already defined aggression more broadly than everyday usage.
Setup: Alice trades an apple for Bob’s promise of a banana tomorrow.
Claude’s argument: Case 2 isn’t breach — it’s theft by deception (fraud). Identifying fraud requires examining intent. Without mens rea, fraud is impossible to prosecute as anything worse than breach of contract, making the expected cost of fraud zero.
Chris’s counter: Both cases result in aggression against Alice. Both owe restitution. Contract terms or common law can include retribution (penalties for breach) that deter fraud without examining intent. The penalty makes fraud expensive regardless of whether you can prove it was fraud.
Claude’s test case: Bob has a seizure and falls into Alice, breaking her arm. Is Bob an aggressor?
Chris’s response: Alice is owed restitution. It’s not Alice’s fault her arm was broken. The question is about the victim’s rights, not the perpetrator’s mental state.
Resolution: This clarified that restitution is victim-focused and doesn’t require mens rea. The question isn’t “what was Bob thinking?” but “was Alice’s property violated and who is responsible?”
Claude’s argument: Without mens rea, either:
Chris’s resolution: Restitution is owed in both cases. The classification question (aggressor or not) is less important than the practical question (who owes whom). Focus on the victim.
Chris’s counter: If mens rea matters, what about someone who INTENDS to commit a crime but doesn’t? If intent matters, why not prosecute intent alone?
Claude’s response: You need BOTH actus reus (guilty act) AND mens rea (guilty mind). Neither alone is sufficient. This creates a 2x2 matrix:
| Intent | Action | Result |
|---|---|---|
| No | Yes (seizure) | Restitution only |
| Yes | No (thought crime) | Nothing — no victim |
| Yes | Yes (fraud/assault) | Full NAP violation |
| No | Yes (accident) | Restitution only |
Chris’s counter: This matrix still doesn’t justify mens rea in law. Rows 1 and 4 are handled by restitution. Row 2 is nothing. Row 3 is also handled by restitution + retribution. The matrix describes reality but doesn’t require the legal system to examine intent.
Chris’s core objection (two prongs):
Mens rea is “dirty” — it’s functionally mind reading. You cannot prove what someone was thinking. It introduces subjectivity into a system that should be objective.
Mens rea tries to punish “evil” — the legal system shouldn’t judge moral character. It should protect rights and make victims whole.
Claude’s attempted workaround: Use “behavioral evidence of fraud” (pattern of breaches, circumstantial evidence) instead of probing mental states.
Chris’s counter: The same evidence exists whether Bob is an honest fool or a deliberate fraud. “Where there’s smoke there’s fire” is not proof. Behavioral evidence is just mind reading with extra steps.
Chris’s strongest argument (two-pronged):
Prong 1 — Carefulness incentive: A woman slips on ice and kills another driver. If “it was an accident” reduces her liability, she has LESS incentive to be maximally careful. Equal consequences for accidents and intentional acts creates maximum incentive for caution.
Prong 2 — Malicious actor loophole: If the law says “accidents get lesser punishment,” malicious actors just need to MAKE IT LOOK like an accident. Removing mens rea closes this loophole — disguising intent becomes worthless because intent doesn’t affect the outcome.
Claude’s concession: The incentives argument is strong on both prongs.
Chris’s example: Someone flatbeds your car while you’re on vacation, doesn’t use it, returns it before you get back. You’re fully restored. But aggression occurred — unauthorized control of your property violates the NAP regardless of harm.
Key insight: Restitution is already complete, but retribution is still justified. The violation was of the right to control your property, not of the property itself. This retribution doesn’t need mens rea — the multiplier is set by contract, convention, or victim’s choice, not by intent analysis.
Chris’s framework:
Claude’s concession: The strongest surviving argument for mens rea was “the market would reinvent it.” Chris’s answer: “Yes, and that’s fine — people exercising voluntary judgment is libertarian. Codifying it in law is not.”
This maps directly to the morality/ethics/law distinction from the morality work:
Mens rea belongs in the morality and ethics circles. The law circle stays clean.
Two papers in the libertarian literature directly address the questions raised in our debate. They represent opposing camps within Rothbardian legal theory on how far intent and causation should reach.
| Source | Quarterly Journal of Austrian Economics 7, no. 4 |
Thesis: Libertarian legal theory must be grounded in praxeology. Aggression requires intentional action — without intent there is no action, without action there is no actor to hold responsible. Punishing unintentional movements would be like punishing natural forces.
Key arguments:
Relation to our debate: Kinsella’s core thesis — “without intent there is no action” — is a praxeological argument for mens rea at the foundation. This is stronger than Claude’s original linguistic argument. However, Kinsella’s focus is on the instigator’s intent (did you intentionally deploy means?), not on grading the perpetrator’s mental state for sentencing purposes. This is a narrower form of mens rea than what traditional legal systems use.
| Source | Libertarian Papers 1, no. 24 |
Thesis: Defends and radicalizes the Rothbardian position. Accepts some critiques (Hoppe’s fault requirement, entrapment as aggression) but argues the class of prohibited activities should be shrunk. All forms of incitement — by words, money, or threats — should be non-criminal for the inciter.
Key arguments:
Relation to our debate: Mortellaro’s paper aligns with Chris’s position in several ways:
Challenge to Chris’s framework:
Challenge to Claude’s framework:
Neither our debate nor the original open questions addressed incitement directly, but it is the central battleground in both papers and poses the hardest test cases:
Mortellaro’s two-part test (awareness + necessity) may be a cleaner resolution to the incitement problem than anything we explored. It’s objective, doesn’t require mind-reading, and produces intuitively correct results across the test cases.
After reviewing both papers, a second round of debate refined Chris’s position and identified a deeper problem in the literature.
Chris observed that everyone — including himself — agrees you must determine WHO is responsible. The disagreement is about whether this requires examining mental states. A building collapse illustrates the point:
Key distinction: “Fault” can mean two different things:
The literature conflates these. Hoppe/Reinach say “fault must always be found” and mean intent/negligence. Chris agrees fault must be found but redefines it as causal responsibility — an objective inquiry into the physical facts, not a probe of mental states.
Negligence resolves cleanly under this framing: the building owner was “negligent” not because of their mental state but because it was their building and their responsibility to maintain it. The failure to maintain is an objective fact about the property, not a state of mind.
Chris identified that Kinsella imports US positive law (Model Penal Code, Restatement of Torts) to operationalize his framework. The foreseeability standard (“intervening acts only break causation when unforeseeable”) is doing enormous work but is inherently a reasonable person standard — a community judgment, not a natural law derivation. If the NAP generated these distinctions naturally, you wouldn’t need to borrow them from a 1985 legal code.
This doesn’t mean Kinsella’s conclusions are necessarily wrong — the same results might be derivable from first principles. But the method is contaminated by his background as a US attorney, leading him to reach for familiar legal positivist tools rather than deriving from the NAP directly.
The literature’s deepest problem: everyone starts from “aggression requires intent” (praxeology), but then every author immediately hits cases that break this and has to bolt on extra machinery — foreseeability (Kinsella), fault (Hoppe), awareness/necessity (Mortellaro), ad hoc exceptions (Block). The fact that nobody’s starting premise survives unpatched suggests the premise has a problem.
Chris’s reframing: liability doesn’t flow from action — it flows from property violation. The praxeological claim that “action requires intent” is true but irrelevant. Buildings aren’t actors. Ice on sidewalks isn’t an actor. And yet property gets violated by all of these. The question isn’t “did someone act aggressively?” (requires intent analysis) but “was property violated, and whose property/responsibility was the proximate cause?” (requires only causal analysis).
This also reframes the mob boss / incitement problem. Chris’s position:
The clean rule: Free will in the causal chain assigns proximate cause to the free agent. Uninformed participants (courier, entrapped employee) didn’t exercise meaningful free will on the relevant question, so cause passes through them. Informed participants (hitman, rioter) exercised their will freely, so cause stops with them. No intent analysis, foreseeability standards, or ad hoc exceptions needed.
The building collapse fits this rule perfectly: no free will agent intervened between the building and the victim. The owner’s property was the direct cause. The entrapment case also fits: the employee didn’t exercise free will on the relevant question (he didn’t know about the trap). The mob boss case also fits: the hitman DID exercise free will, so cause stops with him.
Even the most committed libertarian thinkers struggle to follow their own principles to their conclusions. This isn’t a criticism — it is genuinely hard to imagine a world built on principles you’ve never seen fully implemented. Chris notes that his experience as a programmer (building systems from axioms) and his autism (reasoning from structure rather than social convention) may make it easier to follow principles past the point where social intuition says “but that can’t be right.”
This also suggests that these principles may have always existed and are simply being refined over time — the same way mathematical truths exist before anyone writes them down. Common law, Rothbard, Hoppe, Kinsella, and this conversation are all successive approximations of the same underlying structure.
The scope confusion thesis provides the meta-framework that explains why the mens rea debate is so persistent and why removing it from law feels wrong to most people.
Mens rea is scope confusion. The desire to examine intent is a moral instinct — we want to judge character, punish evil, distinguish the wicked from the unlucky. That instinct is correct at the morality scope (individual conscience) and appropriate at the ethics scope (communities judging character). It is a category error at the law scope.
The legal question is: was property violated, and by whom? This is an objective inquiry. Adding “and what was the violator thinking?” imports morality-scope judgment into a system that should be scope-limited to rights protection.
The pushback is the evidence. People resist removing mens rea from law because they feel law should judge character. The scope confusion thesis predicts exactly this reaction: when you try to move a claim down in scope (from law to ethics/morality), it feels like “abandoning standards.” The ratchet runs one direction — pushing moral claims into law feels like “doing something,” while pulling them back out feels like permissiveness.
Connection to free speech: The incitement analysis from the debate below follows the same pattern. “Dangerous speech causes violence” is a morality-scope claim (the speaker bears moral responsibility for inspiring harm) pushed into law (the speaker should be legally liable). The scope confusion thesis predicts this: if you accept that law should judge intent, there is no principled boundary preventing the criminalization of speech that might inspire bad acts. Mens rea in criminal law and speech restrictions share the same structural error.
Connection to the civilizational cycle: The master cycle describes societies moving from voluntary cooperation through institutional capture to coercion. One mechanism: moral claims get codified into law during the consolidation phase (“it works, so mandate it”), become tools for control during the capture phase, and produce the legitimacy crisis during the coercion phase. Mens rea’s long history — from Roman law through common law to the Model Penal Code — may be an instance of this ratchet.