Introduction
The insanity defense is a legal approach used by the defendant of a trial to absolve themselves of criminal responsibility. In an insanity defense, the defendant acknowledges wrongdoing but asserts a lack of culpability based on a mental illness or defect at the time of the offense. Unlike involuntary manslaughter, a successful insanity defense can still admit an affirmative association between the intent and consequences of a defendant’s actions. Instead, it must be shown that these intentional actions were somehow out of the control of the defendant. Of the forty-six states that permit a plea of insanity, legal standards for validity will depend on a state’s particular criminal code.
These discrepancies are not particularly relevant for my discussion of the insanity defense. Without getting too technical, they vary in how they define insanity, determine burdens of proof, and prescribe punishments (if any). On the contrary, what these criminal codes share is perhaps more insightful; Unlike Idaho, Kansas, Montana, and Utah, these states all have inscribed in their penal codes a belief that people may not always be accountable for their intentional actions in virtue of some mental defect. This notion echoes the more commonly held belief that children should receive lighter sentences than adults who have committed the same crime; juvenile offenders do not possess the same level of cognitive maturity that might have otherwise enabled them to act differently.
Determinism
Can any of us have “acted differently” than we decided to act? Do we ever actually “decide” on anything? Our legal conception of guilt rests on the assumption that we can and do. But first, a trip down the rabbit hole of determinism….
Roughly speaking, determinists believe that everything that will happen must happen as a result of causality. Our world is composed of matter and energy. All phenomena we observe are the result of some interaction between these two (interchangeable) physical entities. If we consider that the universe is governed by fundamental physical laws, such as those described by theories like Newtonian mechanics, quantum mechanics, and general relativity, we observe a consistent pattern of cause and effect. These laws govern the behavior of matter and energy, and their interactions can be described mathematically.
Thus we can be certain that a ball dropped in a vacuum near the earth’s surface will always accelerate downward at 9.8 meters per second squared. As a result, we can perfectly predict its velocity and position at any given time during its descent. Undoubtedly our predictive capacity of physical phenomena will weaken as causal sequences grow more complex; if a tornado runs into a billion quarters, what face will each coin land on? With enough computational power and perfect information regarding the initial conditions of this system (i.e, the positions, velocities, and orientations of each quarter, as well as the characteristics of the tornado’s motion), we could in theory predict this in advance. More importantly, we know that given these specific starting positions, there will only be one possible outcome whether we can predict it or not.
What about the tornado? While in this instance it is the cause of the coins’ repositioning, it itself is an effect of some past physical interaction (i.e, the collision and interaction of air masses, temperature gradients, and atmospheric conditions). Given the fundamental interconnectedness of matter and energy, the concept of determinism arises from the belief that every event, from the motion of celestial bodies to the interactions between particles, is ultimately a necessary consequence of preceding causes.
How does this relate to human action? Well, our decisions and subsequent actions are merely a consequence of a very complex, but still in theory determinate, neurological system. In other words, the interactions between cells that make up our brain activity are still governed by the same physical laws of the universe. How can we argue for free will when our actions are already determined by natural law?
Determinist arguments are difficult to dispute and there does not exist a bullet-proof defense of free will. In my personal view, determinists might have the edge in the age-old debate. However, like most world-shattering conclusions from philosophy (for another, read about skepticism), it is not unreasonable to ask the question “who really gives a shit?” Afterall, we possess at least an intuitive sense of free will; we all “feel” like our actions are our own, and we can decide on, or refrain from a wide range of future actions.
Furthermore, from a practical perspective it would be a nightmare to believe otherwise. To deny free will is to deny all responsibility for our actions (good or bad); all praise and blame would be undeserving.
The Contradiction
It should come as no surprise that legal systems reject determinist arguments and uphold a belief in free will and accordingly moral responsibility.
Consider the claim by Justice Jackson in the well-known case Morissette v. United States that:
The contention that an injury can amount to a crime only when inflicted by intention is no provincial or transient notion. It is as universal and persistent in mature systems of law as belief in freedom of the human will and a consequent ability and duty of the normal individual to choose between good and evil.
With all of this being said, I think that the insanity defense to some degree is an endorsement of determinism.
Consider the famous case of Michael Oft (pseudonym). Michael was a schoolteacher who in the year 2000 found himself engaging in increasingly uncontrollable pedophilic behavior. The 40 year-old man began secretly visiting child pornography websites and soliciting prostitutes at massage parlors. After making sexual advances toward his stepdaughter, Michael was reported and convicted of child molestation. However, right before his sentence was to begin, Michael was admitted to the University of Virginia Hospital for severe headaches and urinary incontinence. During the course of this visit it was revealed that Michael had a large orbitofrontal brain tumor. This revelation allowed Michael to skip jail time and seek treatment. Once it was removed, his behavior returned to normal; the tumor was located in the part of the brain thought to regulate social behavior and accordingly almost certainly caused Michael’s rapid development of pedophilia. When these urges returned a year later, it was revealed that Michael’s tumor had regrown. It was successfully removed again with the same result.
For the sake of this article, let us assume a John Doe was convicted of a crime less egregious than child molestation under the same circumstances. Perhaps his disability resulted in an irresistible urge for petty theft. I think most, if not all would argue that John should not be held criminally responsible in this context. Indeed, the real Michael Oft was spared by the judge under conditions of treatment and supervision. But why?
My theory is that this example and other successful insanity defenses are characterized by behavior that is very obviously causally determined. John Doe’s case comes with a nicely packaged cause and effect: John + Tumor → thief, John – Tumor = normal. The chain of causes are plain for all to see and are empirically measurable. However, this still contradicts the legal system’s notion of justice by conceding that physical entities casually determine our brain activity and subsequent actions. If physical entities are governed necessarily by natural law (i.e, physics), then does this not admit determinism?
How do we evaluate the moral responsibility of an individual with a tumor versus one with a mental illness that is difficult to conclusively diagnose? What about the individual with a traumatic upbringing that hardwired his brain with a criminal disposition? Isn’t our behavior merely some complex result of genes, environment, and environment-gene interaction? Aren’t all of these things causally determined by the interactions of matter and energy?
Conclusion
The intention of this article is not to argue for one viewpoint or another. I personally have no concrete beliefs on the validity of determinism and the role moral responsibility should play in criminal proceedings. Instead, my intent is to merely expose the philosophical complexity behind the insanity defense.