It’s People with Guns that Kill People: On Multifactorial Causation and Ockham’s Quilt

 

It’s People with Guns that Kill People: On Multifactorial Causation and Ockham’s Quilt

By Don Curren

There’s nothing quite like the gun control debate to illustrate how simplistic and misconceived the ideas about causality embedded in public discourse can be.

Causality – the notion that every event has some kind of cause or causes – is all-pervasive in our thinking, and an essential tool in our efforts to understand the world.

But overly simplistic ideas about causation can be a serious obstacle to those efforts.

Some of the assertions about guns and gun-control made in the wake of unspeakable events in Uvalde, Texas – and of all its unspeakable predecessors – illustrate how problematic poorly conceived causal reasoning can be.

Take the assertion “Guns don’t kill people, people kill people,” one that frequently surfaces in public discussions about mass shootings and how to prevent them.

It’s actually people with guns that, in most instances, kill people.

According to data from the Centers for Disease Control, nearly eight-in-ten (79%) U.S. murders in 2020 – 19,384 out of 24,576 – involved a firearm, the highest percentage since at least 1968.

A little over half (53%) of all suicides in 2020 – 24,292 out of 45,979 – involved a gun, a percentage that’s generally remained stable in recent years, according to the CDC.

The idea that those with murderous intent would find some other kind of weapon to kill people with - and that severely restricting access to guns would not result in a reduction of murder - is also demonstrably false.

Guns are more lethal and enable murderers to kill more ruthlessly and effectively.

According to a 2018 article in the University of Pennsylvania’s Regulatory Review, research demonstrates that the type of weapon used is highly influential in determining whether the victim of an assault lives or dies.

 

”Fifty years ago, law professor Franklin Zimring demonstrated that serious knife assaults are similar to shootings in many respects, including apparent determination to kill or injure the victim, yet the gun assaults had a much higher ‘case fatality rate’,” the article says

 

Pretending murderous intention alone is the “cause” of mass shootings – and the access to guns is not also a contributing factor – is to make a fundamental mistake about the nature of causality.

A similar mistake is implicit in arguments that mental health is the “cause” of mass shootings rather than the availability of firearms.

They are both factors. Addressing both will potentially reduce the number of school massacres; but given the intractability of the issues surrounding mental illness, reducing access to automatic weaponry is an effective first step.

That this is the case is illustrated by the experience of other advanced-economy nations. Many have mental health problems broadly similar to the US. But by restricting access to automatic weaponry, they have sharply reduced the number of mass shootings they experience.

Thinking of mass shootings as caused by only one factor is to deprive oneself of many useful tools for addressing the issue – to deprive oneself, really, of any hope of addressing it effectively.

There is a myriad of causes for a complex and singular event like a school shooting. Like many important phenomena they are “multifactorial,” meaning they are caused by a complex array of different factors.

Indeed, mass shootings are identified as a paradigmatic example of multifactorial causation in a 2019 piece in a psychology text entitled “Multifactorial Causation of Behavior: A Fact of Psychology” by SUNY psychology professor Glenn Geher.

“The topic of mass shootings, which has emerged a major issue in the current environment of the United States, serves as a prototypical example of the kind of psychological phenomenon that is clearly caused by multiple factors,” Geher writes.

“Further, it seems that many people are hesitant to acknowledge the multifactorial nature of mass shootings,” he writes.

Citing the case of the 2016 Pulse nightclub mass shooting in Orlando, Florida, Geher cites several contributing factors, including homophobia, religious zealotry, loose gun regulation, among others.

“While people gravitate toward unifactorial explanations of complex behavior – once you think about it, it’s clear that the Orlando shooting, like any complex human behavioral event has multiple causes,” Geher writes.

“And any work by behavioral scientists looking to make sure that such events are less likely to take place in the future … will be wise to take a multifactorial approach,” he writes.

The results of not casting our causal net widely enough are suggested by Joanna Macy in her 1991 book The Dharma of Natural Systems: Mutual Causality in Buddhism and General Systems Theory.

“In assigning responsibility and in locating the points at which we will bring pressure to effect change, we tend to look for single, isolable causes. The tendency slants not only our personal lives, but our social and scientific endeavors,” Macy writes.

But discourse about guns and gun control is of course not the only realm of public discourse where a one-dimensional notion of causality can be a problem.

The pandemic is another. Take, for instance, some of the “reasoning” surrounding vaccination.

The fact that some fully vaccinated individuals succumbed to COVID-19 was sometimes cited as proof of the ineffectuality of the vaccines reflects an overly simplistic understanding of the casual relationship between vaccination and infection.

The causal links involved in immunization and infection aren’t simple. An individual may be fully vaccinated, but may have a diminished immune system, or may simply have the bad luck to have suffered lengthy exposure to an infected individual with a high viral load who wasn’t wearing a mask.

Outcomes in a pandemic are like other outcomes that occur in a social and psychological context, such as mass shootings. Causation is inevitably going to be complicated.

COVID-19’s erratic, unpredictable behaviour makes careful casual analysis especially urgent during the continuing pandemic.

But as humans we crave simplicity in our causal explanations. And in some areas, simply causal patterns do work: perhaps most strikingly, in the physics that govern everyday experience, the realm of moving bodies and objects.

That’s the realm that was captured so effectively and elegantly in the physics of Sir Isaac Newton, a science whose crystal-clear patterns of causation seem to serve as a misleading model for some when they’re thinking about other domains where more complicated forms of causation prevail.

The difference was captured nicely in an article by Siddhartha Mukherjee in the New Yorker in February 2021 on the subject of why the pandemic seemed to be hitting some countries so much harder than others.

Understanding the pandemic requires a different approach to causality, he suggests.

“Epidemiology isn’t physics,” Mukherjee wrote. “Human bodies are not Newtonian bodies. When it comes to a crisis that combines social and biological forces, we’ll do well to acknowledge the causal patchwork.’

“(To) come to grips with the larger global pattern we have to look at a great many contributing factors—some cutting deeper than others, but all deserving attention,” he wrote.

Mukherjee refers to “Ockham’s Razor,” the well-known principle that simpler explanations of phenomena are to be preferred over complex ones.

Ockham’s Razor has its uses. But causal explanations sometimes need to be complex, and to invoke a range of factors and phenomena if they are going to provide genuine insight into complex phenomena.

Maybe what’s needed is Ockham’s Swiss Army Knife, an instrument with the flexibility to adopt different approaches for different levels of complexity in causal explanations.

Mukherjee suggests that what’s needed isn’t Ockham’s Razor but “Ockham’s quilt, where the various causal factors involved in a phenomenon are carefully patched together to provide an accurate and comprehensive explanation.

Assembling a quilt of causal factors is more challenging than wielding an explanatory razor, but it’s something we’ll need to learn to do, if we’re going to deal effectively with the complex array of problems confronting us.

(Quilt in photo by Jean McQuattie)