Disclaimer: many sections of this essay were first-drafted or substantially rewritten by ChatGPT. The core arguments, analogies, and structure of the essay originate with the author.
This essay only covers USA criminal law. Comments are welcome about other countries’ insanity defenses and famous cases invoking them.
The insanity defense—which is raised to excuse a severely mentally ill defendant from responsibility for certain criminal acts—rests upon a fundamental philosophical and scientific error: the assumption that there exists within the human being a discrete inner entity, a “homunculus,” capable of reasoning, choosing, and directing behavior independently from the brain’s physical processes. This essay contends that the insanity doctrine, built upon this homunculus fallacy, lacks both metaphysical coherence and empirical foundation. It is a relic of pre-scientific dualism that has no legitimate place in a criminal jurisprudence committed to material reality, equal protection, and rational justice.
Table of Contents:
Introduction: Elements of a Crime, Generally
With few exceptions, every crime requires a voluntary act or omission (the actus reus) accompanied by a culpable mental state (the mens rea). The same voluntary act can result in different crimes depending on the perpetrator’s mental state. For example, a man shoots a gun into a dark alley, knowing his target victim is in the alley, with the purpose of killing the victim, and the shot does in fact kill the intended victim (or another person). The crime in this case is murder, which requires a mens rea of “knowingly” or “purposefully” killing a person. If, instead, the perpetrator shoots a gun into a dark alley for fun, believing the alley to be uninhabited, but consciously disregarding a substantial risk that a homeless person may be sleeping there hidden among debris, which is in fact the case and the bullet kills the homeless person, then the crime is manslaughter, which requires a mens rea of acting “recklessly,” and is generally a lesser offense than murder.
If the criminal defendant can show he lacked the mental state required for a given crime at the time of the act, he has given a complete defense to the charged crime, and the defendant must be acquitted or the charge must be dismissed.
Example mens rea defense: Deceived intentional killing
Consider the 2017 Wichita swatting incident. This case does not invoke the insanity defense, but will serve as a foundational comparison when we explore the insanity defense below. This incident was one of only a few instances where a deceptive swatting resulted in the death of a person (it is a surprisingly rare occurrence considering how often deceptive swatting occurs)1.
Tyler Barriss, for unimportant reasons involving the petty drama of an online Call of Duty match, swatted the house at 1033 West McCormick Street, Wichita, Kansas. On a VoIP phone call from a public library WiFi in Los Angeles, Barriss spoofed a Wichita phone number, contacted 911 dispatch in Wichita, and pretended to be rampaging. He claimed that he personally was inside the house at 1033 West McCormick, that he had just shot and killed a person, that he had other hostages, and that he was ready to set the house on fire to kill himself and everyone inside. Barriss’s conversation with dispatch was lengthy, detailed, and sounded sincere, so that dispatch did not suspect a hoax. Dispatch sent the WPD and paramedics to the address to resolve the apparent emergency.
There actually was a man at home at 1033 West McCormick at that moment: Andrew Finch, a stranger to Barriss and totally unrelated to the Call of Duty drama. When the Wichita police arrived with squad car lights flashing in front of his house, Finch stepped on to his front porch to see what was happening.
Finch heard officers yell commands from multiple directions, “Let me see your hands,” “Come out here,” “Walk towards me,” and the like. Finch was confused. He began raising his hands, but then lowered them to adjust his clothes near his waistband, a common habit for any grown man with a “dad bod”. Officer Justin Rapp, a 7-year WPD veteran, believed Finch was reaching for a weapon, and shot Finch dead with one bullet.
Barriss pleaded guilty to involuntary manslaughter for causing the death of Finch by his 911 call, and was sentenced to 20 years in federal prison.
The interesting legal question is whether Officer Rapp is also guilty of a homicide crime for killing Finch. The Kansas District Attorney investigated whether any charges were appropriate and declined to charge him, concluding that Rapp could lawfully use deadly force under the circumstances. Under Kansas Law, a person is authorized to use deadly force when they sincerely (subjective test) and reasonably (objective test) believe it necessary to prevent imminent risk of great bodily harm to another. Officer Rapp sincerely believed, based on the information relayed by dispatch, that Finch was a suspect on a fresh crime scene, that he had a gun, was violent, had threatened to escalate violence, and posed an immediate threat to himself and everyone at the scene. None of the officers on scene suspected that the call made to dispatch was a hoax or that the details relayed by dispatch were deceptive.
Rapp’s observation and interpretation of Finch’s bodily movements must be judged with respect to an objective standard of how a reasonable officer would react to the circumstances in light of the information relayed to him. In fact, other officers reportedly considered shooting Finch at the same moment Rapp did, because they too thought the clothing adjustment was Finch reaching for a weapon. Rapp’s belief in the necessity of shooting Finch was sincere and reasonable, and therefore Rapp committed no crime.
The killing of Finch is remarkable because it is a rare example of a “deceived intentional killer.” In this framework, an actor intentionally inflicts deadly force, but their intent and perception of necessity are entirely manufactured by a third party’s malicious deception2. Rapp’s sincere and reasonable belief in the necessity of deadly force negates the mens rea element required for any homicide crime.
From External Deception to Internal Delusion
At this point, we will depart from the historical facts of the Wichita shooting and enter a hypothetical. To clarify the boundary between fact and fiction, we will change the names as well. Officer Justin Rapp will become Officer Justin Repp, and Andrew Finch will become Andrew Flinch. Barriss, by contrast, will retain his real name when referring to the actual Wichita incident, because his existence—or absence—is precisely the variable the hypothetical is designed to examine. Nothing attributed below to Repp or Flinch should be understood as an assertion about the real Rapp or Finch.
Now alter the facts slightly. Suppose Barriss never made the 911 call. Instead, Officer Repp suffers from a persistent delusion. His own mind supplies him with the same false information that Barriss supplied in the actual case: Repp hears a voice telling him that Flinch has just murdered someone inside the house, is armed, has taken hostages, and intends to kill again. The voice seems perfectly real to Repp. He sincerely believes it comes from another police officer speaking through his radio. When Flinch reaches toward his waistband, Repp combines what he sees with what the voice has told him, sincerely concludes that Flinch is reaching for a gun, and intentionally shoots him dead.
The two cases initially appear almost identical from the shooter’s subjective perspective. In each, the officer intentionally shoots an innocent man because he has been deceived about the surrounding circumstances. In each, the deception causes him to perceive an innocent movement as an imminent deadly threat. And in each, if we confine our attention to the contents of the officer’s consciousness at the instant he pulls the trigger, his mistake may be indistinguishable: he believes he is defending himself and others from an armed murderer when no such murderer exists.
Yet the two cases differ in one fundamental respect. In the actual case, the false information originated with Barriss. Barriss and Rapp are two different human beings. Barriss manufactured a false representation of reality and transmitted it through dispatch to Rapp, whose conduct was consequently based upon facts invented by someone else. There is therefore an intelligible sense in which Rapp was deceived by another actor.
In the hypothetical case, there is no Barriss. The voice originates within Repp’s own brain. The information is generated by the same human organism that perceives it, believes it, reasons from it, and ultimately shoots Flinch. Repp may experience the voice as foreign to himself; indeed, the defining feature of the delusion may be his inability to recognize the voice as a product of his own mind. But his inability to recognize the source of the voice cannot change its actual source. The deception is endogenous. There is no second actor.
This distinction exposes a conceptual difficulty at the heart of the insanity defense.
The Insanity Defense
The insanity defense permits mental disease or defect, under specified circumstances, to excuse conduct that would otherwise constitute a crime. The precise formulation varies among American jurisdictions, but the recurring idea is that sufficiently severe mental illness can so impair a defendant’s understanding, appreciation, or control of his conduct that the law will not hold him criminally responsible in the ordinary manner. Thus, unlike the ordinary mens rea defense, insanity may become relevant even where the defendant performed the prohibited act with the requisite mental state. A delusional defendant may know that he is pointing a loaded gun at another human being, intend to pull the trigger, and intend that the bullet kill him. The insanity question concerns whether his mental disorder nevertheless renders him nonculpable for doing so.
There are compelling humanitarian arguments to treat such a defendant differently. A person suffering profound psychosis may require psychiatric treatment rather than ordinary punishment; his condition may diminish the deterrent value of punishment; and the circumstances surrounding his conduct may warrant mercy. None of those propositions, however, answers the antecedent question of who generated the cognition that produced the criminal act. Treatment, mitigation, and culpability are separate questions. The insanity doctrine becomes philosophically problematic when an internal defect is treated, for purposes of responsibility, as though it occupied the position Barriss occupied in the actual Wichita shooting—as though something other than the defendant had deceived the defendant and thereby authored the criminal choice.
The Homunculus Fallacy
Disney and Pixar’s movie Inside Out provides an unusually literal illustration of a common but misleading way of imagining the mind. Inside Riley’s head sit Joy, Sadness, Anger, Fear, and Disgust. They observe what Riley observes, react to events, argue among themselves, make decisions, and operate a control console that determines what Riley ultimately does. It is an ingenious storytelling device. Taken as an explanation of cognition, however, it presents an obvious problem: there are no little people inside Riley’s head.
This is the homunculus fallacy: explaining the workings of a person by positing a smaller person—the Latin homunculus, or “little man”—inside him who perceives, reasons, chooses, and operates the body. The explanation merely relocates agency without explaining it. Joy cannot ultimately explain Riley’s decisions because Joy herself perceives, reasons, chooses, and acts. What explains Joy’s decisions? Another control room inside Joy’s head populated by still smaller characters? The same question would recur indefinitely. Inside Out works because its audience understands the little people as personifications of mental processes, not actual agents inhabiting Riley’s brain.
Now imagine that Riley develops a severe psychosis and the filmmakers introduce another character into Headquarters: Psychosis. Psychosis whispers false information to Fear and Anger, generates voices that the others mistake for transmissions from outside, or shoves them aside and seizes the controls himself. This would be an intuitive way to depict mental illness: Psychosis has entered Riley’s mind, deceived or overpowered the familiar Riley, and caused her to behave in ways she otherwise would not. But Psychosis would be no more an actual person than Joy or Anger. All six characters would remain personifications of processes occurring within one brain. The metaphor becomes dangerous only when we forget that fact and begin treating one of those personifications as an independent actor capable of assuming responsibility for what Riley does.
The same problem arises when the insanity defense is conceptualized as a diseased mind deceiving or overpowering an otherwise rational person trapped somewhere behind it. To make that conceptual move requires dividing the defendant into actors that do not independently exist. There must be, on one side, the defendant’s diseased mental processes, which generate the hallucination, delusion, impulse, or false belief; and, on the other, some authentic or rational “self” that receives this defective information, is deceived or overpowered by it, and consequently directs the body to act. Mental disease is thereby placed on one side of a fictitious causal transaction and the morally responsible person on the other.
If the hallucinated voice is generated by the defendant’s brain, the belief in the voice is generated by the defendant’s brain, the reasoning performed upon that belief is generated by the defendant’s brain, and the resulting bodily movement is generated by the defendant’s brain, there is no remaining independent agent to locate. Calling one set of those processes “the disease” and another “the defendant” does not establish the existence of two actors. It merely personifies different processes occurring within one person.
Barriss therefore provides the crucial contrast precisely because he was real. He existed outside Rapp. He possessed a brain of his own, formed intentions of his own, communicated information across physical space, and altered another person’s perception of reality. A neurological delusion possesses none of these characteristics. However vividly it may be experienced as an alien intrusion, it remains an event occurring within the defendant.
The insanity doctrine must therefore confront a question more fundamental than whether a particular delusion was sufficiently severe to excuse a crime: why should an internally generated defect of cognition be conceptualized as something that happened to the defendant rather than something the defendant’s own mind did?
The Empirical Collapse of Dualism
The homunculus fallacy is closely related to an older conception of human nature known as mind-body dualism. In its classical form, associated most famously with René Descartes, dualism holds that the physical body and the conscious mind are fundamentally different kinds of things. The brain belongs to the material world; the thinking self does not. On this view, the brain can be imagined as an elaborate biological instrument that receives sensations and controls muscles, while an immaterial mind—the I who actually experiences, reasons, and chooses—somehow interfaces with that instrument. For centuries this distinction was intuitively plausible. Thoughts, memories, intentions, and subjective experience do not feel like flesh, electricity, or chemistry, and the workings of the brain remained largely inaccessible to observation.
Mind-body dualism was a compelling explanation when the brain was a black box, but became progressively harder to maintain as neuroscience revealed the brain’s inner workings. Injury and disease revealed that physical damage to particular regions of the brain could destroy particular mental capacities or radically alter personality and behavior. Scientists observed correlations between neural activity and cognition, and learned to alter mental experience by electrically, magnetically, surgically, and chemically altering the nervous system. Perception, memory, emotion, judgment, impulse, deliberation, and voluntary movement increasingly appeared not as instructions delivered to the brain by an immaterial operator, but as functions performed by the brain itself. Alter the physical brain and one can alter what a person sees, what he remembers, what he desires, what he fears, what he believes, and what he does. Whatever philosophical mysteries consciousness may continue to present, neuroscience has discovered abundant evidence that mental life depends upon physical brain function and no corresponding empirical evidence of a second, immaterial decisionmaker sitting behind those processes and receiving their output.
Dualism has therefore lost much of the explanatory work it once performed. This does not mean that an experiment has disproved the existence of an immaterial mind; one can still formulate a metaphysical proposition so long as the hard problem of consciousness remains unsolved. The problem is instead explanatory. If damage to the brain can damage reasoning, chemicals can alter emotion, electrical activity can alter perception, and neurological disease can alter personality, there is progressively less left for an independent mental operator to explain. The physical place in which the homunculus could hide has steadily disappeared.
This point is easily obscured by ordinary language. We routinely say that “my brain is telling me” something, or that “my mind is playing tricks on me.” Such expressions are harmless figures of speech precisely because we ordinarily understand that the speaker and his brain are not two separate people. The grammar divides what biology does not. There is no me standing outside the brain receiving reports from it. The brain that generates the thought is also the brain that experiences the thought as its own—or, in pathological circumstances, fails to experience it as its own.
The counterthesis to dualism is materialism: the view that the mind is not an immaterial entity inhabiting or operating the physical body, but instead arises from the physical processes of the brain. On a materialist account, thoughts, beliefs, desires, impulses, hallucinations, and decisions may be radically different mental phenomena, but they are all processes of the same physical organism. This does not collapse all forms of human behavior into a single legal category. A seizure, reflex, delirium, compulsion, hallucination, and calculated decision can all arise from physical processes while remaining importantly different phenomena for purposes of criminal law. Nor does materialism itself tell us which of those phenomena deserves punishment. It requires only that the distinctions among them be justified without inventing an independent rational self who exists apart from the physical processes under examination. If insanity is to excuse conduct, its justification must therefore be found somewhere other than in a division between the diseased brain and the person whose brain it is.
The Moral Confusion of Excusing Insanity
The insanity defense does more than embody a mistaken conception of the mind. It creates a peculiar moral distinction between two defendants who possess the same criminal intent and commit the same criminal act, based upon the internal origin of the thoughts that motivated them. The sane murderer who thinks I want to kill is punished; the sufficiently delusional murderer who experiences substantially the same murderous thought as a voice is telling me to kill may be excused. Yet if the preceding account of the mind is correct, the grammatical change from first person to third person does not identify a change in authorship. Both thoughts originate in the defendant. The latter defendant’s inability to recognize his thought as his own may be powerful evidence of mental disease, but it cannot by itself transfer responsibility for the thought to somebody else.
The interrogation of Nikolas Cruz, who murdered seventeen people at Marjory Stoneman Douglas High School in 2018, provides an extraordinary real-world illustration. Shortly after his arrest, and before terminating his interrogation by requesting an attorney, Cruz began telling police about “demons” and a voice inside his head. He said the voice commanded him to “Burn. Kill. Destroy.” Most strikingly, Cruz divided himself almost exactly as the homuncular conception of insanity would: “The voice is in here,” he explained, distinguishing it from “regular me,” who was “just trying to be a good person.” Detective John Curcio was immediately skeptical and eventually accused Cruz of “using the demon as an excuse.” Cruz denied it and, shortly thereafter, invoked his right to counsel.
Later forensic examinations gave substantial reason to share Curcio’s skepticism. Cruz undoubtedly had a long and complicated history of behavioral and mental-health problems; the point is not that he was psychologically normal. Rather, experts examining him found evidence that he fabricated or exaggerated symptoms. Forensic psychologist Heather Holmes, whom the defense had retained, reportedly concluded that Cruz’s subsequent stories about an internal voice were “nonsense” and that she was “100 percent certain he is not psychotic.” During the penalty proceedings, prosecution psychiatrist Charles Scott likewise diagnosed Cruz with malingering, testifying that there was “robust evidence” that Cruz reported extreme symptoms that were highly atypical and unsupported by his records. Another prosecution expert, neuropsychologist Robert Denney, similarly concluded that Cruz was exaggerating his impairments.
Cruz is important here not because he successfully invoked insanity—he did not. He pleaded guilty, and his later penalty trial concerned whether he would receive death or life imprisonment. His significance is that his behavior demonstrates how thoroughly the basic logic of the insanity defense has entered popular consciousness. Cruz did not need a psychiatrist to teach him the vocabulary of diminished agency. Before he had ended his first police interrogation and “lawyered up,” he was already presenting his homicidal thoughts as commands originating from another entity within him. If the experts who later evaluated him were correct that these symptoms were fabricated or exaggerated, then a nineteen-year-old layman apparently understood the legal and moral intuition well enough to imitate it: a murderer has something to gain by converting “I wanted to kill” into “a voice told me to kill.”
This does not suggest that genuine psychosis is fictitious or that defendants reporting hallucinations are always malingering. It demonstrates instead the moral distinction the insanity doctrine has taught even laypeople to recognize: thoughts experienced as one’s own belong to the actor, while sufficiently pathological thoughts may be characterized as something that happened to the actor. Cruz apparently understood that distinction well enough to attempt to place himself on its favorable side.
Mental illness may furnish compelling reasons for treatment, mitigation, or a different form of confinement. But those are questions about what society should do with an offender, not about whether an endogenous mental process belongs to the person whose brain produced it. The insanity defense converts the former question into the latter—and thereby makes the supposed origin of a thought within a “sane” or “diseased” part of the same mind determine whether its owner is criminally responsible for acting upon it.
Lindsay Clancy and the Exceptionalism of Insanity
Insanity doctrine distorts the moral purpose of criminal law by converting questions of social protection, punishment, and medical care into metaphysical inquiries about criminal responsibility. The practical questions are concrete: what danger does this individual pose, what punishment does he deserve, and what intervention will prevent recurrence? The insanity defense instead invites a more mysterious inquiry: was this act committed by the defendant’s “true self,” or by a “mad self” for whose conduct the true self should not answer? Such categories reanimate medieval demonology in the language of psychiatry.
The recent Massachusetts prosecution of Lindsay Clancy demonstrates how consequential this exceptional treatment can become. In January 2023, Clancy strangled her three young children—Cora, Dawson, and Callan—in their Duxbury home and then attempted suicide by jumping from a second-story window, leaving herself paralyzed. At trial, there was no serious dispute over who killed the children. The central dispute was instead whether the woman who unquestionably performed the killings was legally responsible for performing them. Her attorneys argued that Clancy was suffering from postpartum psychosis and lacked criminal responsibility; prosecutors argued that she remained capable of appreciating the wrongfulness of her conduct and conforming her behavior to the law.
Massachusetts makes that inquiry especially remarkable. Unlike most other states, Massachusetts assigns the burden of proving the defendant’s sanity to the prosecution. Once lack of criminal responsibility is properly put in issue, the defendant does not have to prove that mental disease rendered her legally insane. The Commonwealth must instead prove beyond a reasonable doubt that she was criminally responsible. Specifically, Massachusetts law requires the prosecution to establish that the defendant retained substantial capacity both to appreciate the wrongfulness of her conduct and to conform her conduct to the requirements of law. A reasonable doubt about criminal responsibility requires a verdict of not guilty by reason of lack of criminal responsibility. Massachusetts is in the minority among American jurisdictions in allocating the burden this way; in most states recognizing an insanity defense, the defendant bears the burden of proving it.
The Clancy trial consequently became an extraordinary inquiry into the condition of one person’s mind at a particular moment more than three years earlier. Experts disagreed over whether Clancy was psychotic and over what her symptoms and behavior demonstrated. The defense characterized her mind as essentially gone and placed considerable emphasis on the psychiatric treatment she received before the killings, including the succession of medications prescribed as clinicians attempted to manage her symptoms until Clancy ultimately began hearing a voice commanding her to kill her children and herself. In closing argument, defense counsel went so far as to attribute Clancy’s choice to kill to “the damn medicine and the lousy medical care that she got.”
The prosecution disputed that account, arguing that Clancy fabricated the voice, understood what she was doing, and deliberately created an opportunity to kill the children by sending her husband to pick up food far away. The competing narratives therefore offered the jury radically different explanations for the same physical acts: either Clancy made a horrific choice, or pathological processes—perhaps themselves precipitated by medications administered to her—had so altered her mind that the law should no longer regard the choice as criminally hers. After weeks of testimony and seven days of deliberations, the jury could not unanimously resolve that question. The result was a mistrial. According to jurors who spoke afterward, eleven were prepared to find Clancy not guilty by reason of lack of criminal responsibility, while a single juror prevented a unanimous verdict.
There is something strange about what the law demanded of those jurors. The Commonwealth was not merely required to prove beyond a reasonable doubt that Clancy intentionally performed the physical acts that killed three children. Once criminal responsibility was placed in issue, it also had to dispel reasonable doubt about whether an invisible pathology within the person who performed those acts had sufficiently impaired her capacity to appreciate their wrongfulness or conform herself to law. The distinction between murderer and legally blameless killer thus depended upon jurors reconstructing and classifying mental processes that no observer could directly perceive.
The humanitarian impulse behind this exceptionalism is understandable, but compassion does not require metaphysical exculpation. Severe mental disease can properly matter enormously to sentencing, confinement, treatment, dangerousness, and eventual release. Those questions concern what society should do with a profoundly disordered offender. They do not require the antecedent fiction that the disorder somehow makes the offender cease to be responsible for acts generated by her own mind and performed by her own body.
Indeed, an insanity acquittal does not necessarily mean freedom. Massachusetts law provides mechanisms for involuntarily committing a defendant acquitted for lack of criminal responsibility when hospitalization is required, followed by judicial proceedings concerning continued confinement. Clancy herself remains confined to a psychiatric hospital while her criminal case remains unresolved. The real policy dispute is therefore often not whether society may restrain a dangerous mentally ill killer, but why that restraint must depend upon first declaring the killer not criminally responsible. Treatment and humane confinement can be justified directly. They need not be purchased at the price of pretending that mental disease supplies another author for the crime.
Toward a Materialist Jurisprudence
A coherent criminal jurisprudence must abandon the myth of the homunculus. It must recognize that all conduct—sane or insane—is ultimately produced through the physical processes of the person who acts. The law’s task is not to determine whether a crime originated in a defendant’s “true self” or his diseased mind, but to determine what he did, what he intended, and what consequences should follow. Abolishing the insanity defense would not require abolishing mens rea, ignoring mental illness, or treating every mentally ill offender identically. It would require only the elimination of mental disease as an independent basis for declaring an otherwise culpable criminal actor not responsible for his acts.
There is nothing constitutionally prohibitive about such a reform. Utah, Idaho, Montana, and Kansas have already traveled much of the road toward abolition. Kansas, for example, abolished its traditional affirmative insanity defense in 1995 and generally permits mental disease to defeat guilt only when it prevents the prosecution from proving the mental state required by the offense. Mental illness may then return at sentencing, where it can mitigate punishment and, in appropriate circumstances, support commitment to a mental-health facility instead of ordinary imprisonment. In Kahler v. Kansas (U.S. 2020), the United States Supreme Court rejected the argument that federal due process requires Kansas to acquit a defendant merely because mental illness rendered him incapable of recognizing his intentional crime as morally wrong. The Court emphasized that the relationship between mental illness and criminal responsibility remains substantially open to state choice. Abolition can therefore occur through the ordinary legislative process without waiting for a revolution in constitutional doctrine.
Other states could follow the same basic architecture more completely. Legislatures could abolish the affirmative insanity defense while preserving the prosecution’s ordinary obligation to prove every element of the offense beyond a reasonable doubt. A defendant whose neurological condition actually prevented him from forming a required intent could still argue that the prosecution failed to prove mens rea. A defendant who intentionally killed another human being while suffering a profound delusion, however, would not receive an additional acquittal merely because the delusion supplied his reason for forming that intent. Mental disease would instead become relevant principally to disposition: sentencing, psychiatric treatment, conditions of confinement, dangerousness determinations, and eligibility for release.
Judicial abolition presents a narrower path. Courts ordinarily cannot simply erase a legislatively created defense because they find its philosophical foundations unpersuasive. But courts determine the constitutional boundaries within which legislatures operate, and Kahler is important precisely because the Supreme Court declined to constitutionalize the traditional moral-incapacity rule. Future courts could continue resisting efforts to transform particular formulations of insanity into immutable constitutional requirements, leaving legislatures free to experiment with mens rea -centered systems aligned with our scientific understanding of the mind.
There is also a less orderly mechanism by which popular rejection of insanity can manifest: jury nullification. A juror convinced that the law commands an insanity acquittal may nevertheless refuse to return one because he believes that a person who intentionally killed should be held criminally responsible regardless of psychiatric explanation. Such a verdict would be contrary to the juror’s legal duty, and nullification should not be confused with a lawful reform of the insanity defense. But its occurrence would be sociologically significant. It would indicate that the legal distinction between an intentional killer and an insane intentional killer had lost its moral authority for at least some of the citizens charged with applying it.
Something resembling that possibility may have appeared in the Lindsay Clancy trial. After the mistrial, several jurors reported that the jury had stood eleven to one in favor of finding Clancy not guilty by reason of lack of criminal responsibility. According to those jurors, the lone holdout acknowledged reasonable doubt yet still refused to join the insanity verdict. Because the holdout has not publicly supplied a complete account of his reasoning, it would be improper to declare that he deliberately nullified Massachusetts law. But if their account is accurate, the episode illustrates the possibility vividly: a juror may understand what the insanity instruction demands and nevertheless find himself morally unable to declare an admitted intentional killer “not guilty.” Jury nullification is no substitute for legislation, but resistance of that kind can reveal a widening separation between formal doctrine and popular intuitions about responsibility.
Formal abolition of the insanity defense would substantially simplify criminal trials. Cases like Clancy would no longer require jurors to choose among competing psychiatric reconstructions of whether a defendant possessed sufficient capacity to appreciate wrongfulness or conform her behavior to law at a particular instant years earlier. Psychiatric evidence would not disappear. Where relevant, experts could still address whether the defendant actually formed the mens rea required by the charged offense, and mental illness could be explored extensively at sentencing. But the trial on guilt would return to the familiar questions asked of every defendant: What did this person do, and with what mental state did this person do it?
The consequences for punishment need not be draconian. Abolition of insanity is not abolition of mercy. A materialist jurisprudence can recognize that a severely psychotic murderer may be less deterrable, differently blameworthy, differently dangerous, and more urgently in need of treatment than a calculating murderer. Legislatures could require psychiatric treatment within correctional systems, authorize secure psychiatric confinement where appropriate, allow judicial consideration of mental disease at sentencing, and devise release standards responsive to continuing dangerousness. The difference is conceptual but important: these accommodations would be made because of the offender’s condition, not because the condition is imagined to be a separate author of the offense.
Indeed, abolition could make punishment more candid. The present system sometimes performs a strange two-step: it declares a person “not guilty” because of insanity and then confines that person, potentially for years, because the same mental condition makes him dangerous. A materialist system could say directly what the state is doing. The defendant committed the crime; the defendant was profoundly mentally ill when he committed it; the illness affects what punishment is just and what treatment is necessary; and society may confine him for legitimate purposes without pretending that someone—or something—else committed his acts.
Finally, abolition would change more than courtroom procedure. Law teaches. For generations, the insanity defense has reinforced in popular consciousness the intuition encountered throughout this essay: that sufficiently abnormal thoughts cease somehow to belong to the thinker. The sane person says, “I wanted to do it”; the insane person says, “my mind made me do it.” As the Cruz interrogation demonstrated, even a lay defendant can understand the advantage of describing culpable thoughts as the commands of an alien internal agent. A jurisprudence that ceased recognizing that distinction as an independent route to acquittal would gradually teach a different conception of human agency.
That conception need not deny mental illness, compassion, or the profound differences among healthy deliberation, delusion, compulsion, and neurological dysfunction. It would insist upon only one proposition: there is no other person inside the defendant to whom responsibility can be transferred. Mental illness can explain conduct. It can mitigate conduct. It can determine how society should respond to conduct. But it cannot become the author of conduct. A criminal jurisprudence reconciled with a material understanding of the human mind should finally stop pretending otherwise.
Conclusion
The insanity doctrine survives as a relic of Cartesian dualism—a fallacy that mistakes metaphor for mind and moral intuition for ontology. To speak of a “diseased mind” is to invoke a ghost in the human machine, a homunculus whose existence science denies and whose invocation justice cannot sustain.
If American criminal law is to remain rational, coherent, and humane, it must purge this fallacy entirely. The doctrine of insanity, born of a time when brain and mind were thought to dwell in separate realms, has no place in a legal system that acknowledges the unity of the human organism. To expunge it is not to deny mercy—it is to ground mercy in truth.
In another deceptive swatting incident in 2020, Mark Herring, a 60-year-old Tennessee man, died of a heart attack because he was frightened of the multitude of police vehicles and officers rolling up to his home.
In another incident in 1983, Gordon E. Murdock, a legally blind Virginia man, was shot to death by 3 officers on his front porch after shooting his .357 magnum pistol at police cruisers driving up to his house in response to a 911 call. Murdock believed the officers were his rival Joseph Bailey coming to kill him. Bailey lied to Murdock over CB radio that he was coming to get him, and also lied to 911 that Murdock was waving his gun around on his front porch, threatening neighbors. Here, the police were not “deceived intentional killers”. The use of deadly force was, in fact, necessary once Murdock started shooting at them—the officers’ perception of necessity was not itself the product of Bailey’s deception. Bailey had actually deceived Murdock into committing suicide by cop. Incredibly, Bailey only received a 6-month jail sentence for involuntary manslaughter for conniving this deadly confrontation. The light sentence was probably given because Bailey was well-liked by the judge and jury when he took the stand in his own defense to explain he was drunk and didn’t remember doing any of this, and that he would bring Murdock back if he could.
I think that the argument made by Lindsay's defense isn't completely comparable to Nikolas Cruz's claim about "demons". Lindsay's desire for homicide-suicide may have been affected by medications that she had been taking, whereas Cruz's actions were not. Cruz had displayed anti-social behavior throughout his entire life, so anti-social and homicidal behavior is clearly intrinsic to his nature.
Lindsay might've acted differently if she had different medical treatment, but that still doesn't excuse her from murder:
- She might've still killed the children even if she never took the medications.
- She had weeks to speak up and get sent a psychiatric ward away from the victims.
- She needs to be punished for game-theoretical reasons, i.e. to discourage similar crimes.
The prosecution should state Anglo's argument during the next trial.
"Treatment and humane confinement can be justified directly."
Not in reality they can't. Most people want the most violent criminals to be executed that's why almost no place on earth removed the death penalty through referendum (Ireland is the only exception I know of and even there they only did it to make it illegal for England to execute IRA members).
The current prison system is a function of profits, the public would greatly prefer that many of the current inmates would be in coffins, yet the state prefers to undercut the wages of workers with the "sweat equity" of prisoners.
The arguments against what the people want have never "won a debate" instead they were imposed on the populace.
Unless you're going to argue treatment and confinement can be profitable for the ruling class you won't get their support (the only support that really matters) and the masses are a tough sell since they already see the current system as 'soft' and want to go the opposite direction entirely