The idea that we are animated by an immaterial soul that outlasts our body is an ancient one. Plato wrote that the soul is a nonphysical entity giving rise to our intangible abilities, such as thought, feelings, memories, and imagination. The concept that we are composed of both material components (the body) and nonmaterial components (the mind) is dualism, an idea that was most famously codified by the philosopher René Descartes in the 1600s with his dictum, “I think, therefore I am ” Dualism contends that the body is divisible and subject to decay whereas the soul, which represents our “essence,” is indivisible and ending.
Studies of Split-Brain Patients
If only Descartes would have lived to see what happens in split-brain patients, people who had their right and left hemispheres severed to control epileptic seizures. In the 1960s, Roger Sperry’s studies of split-brain patients proved that Descartes was wrong. In normal people, an object shown to one side of the brain is seen by both hemispheres. However, since the right and left sides of the brain are no longer connected in split-brain patients, objects shown to one hemisphere are not seen by the other.
Sperry’s work showed that the brain is divisible, like any other part of the body. Even more surprising, each hemisphere operates independently if they are divided, as if there are two conscious minds in a single body. If we possessed an indivisible soul, this should not happen. Exemplifying that two minds can exist in one brain are split-brain patients whose right and left hands want to do separate things. There are reports of split-brain patients trying to get dressed in which one hand picks out one outfit and the other hand selects a different one. Neuroscientist VS Ramachandran once described a split-brain patient whose right hemisphere believed in God but whose left hemisphere did not, which would create quite a conundrum for the admissions staff at Heaven’s gate.
More recently, studies of the brain have shown that our “invisible” abilities—thought processes, memories, and emotions—are actually visible in the brain. Sophisticated brain imaging techniques show distinct patterns of activation when study subjects complete a task, or merely think about completing said task. Neuroscientists can also evoke potent emotions, sensations, and memories simply by stimulating different areas of brain tissue with an electrical impulse. Importantly, brain stimulation can also produce the out-of-body experiences often pointed to as “evidence” for the soul. By eliciting these responses with an electrical current, we reveal that the brain takes care of all the things a soul is supposed to do. Our intangible thoughts and feelings are indeed made of earthly material after all—matter, not magic. In the words of the French physiologist Pierre Cabanis, “The brain secretes thought the way the liver secretes bile.”
While these observations constitute formal proof that dualism is wrong, evidence that the mind and body are one has been presented time and time again. Damage to the brain can damage one’s personality. The damage can come in the form of a concussion, neurodegeneration, stroke, cancer, or infection. Consider the behavioral changes seen in people with chronic traumatic encephalopathy (CTE), brain tumors, Alzheimer’s disease, or rabies. If our soul is immutable and immaterial, physical damage to our brain should not change who we are. If our soul contains our memories and experiences, then the amyloid plaques that form in the brain of Alzheimer’s patients should not rob us of them. If our soul was separate from our brain, lobotomies should not work. Anesthesia should not work. Novocain should not work. Perhaps the most damning evidence of all, people can lose or gain religious beliefs due to changes in their brain brought on by neurological disorders or disease.
Practical questions also emerge when you contemplate the idea of an eternal soul. We change as we age, sometimes dramatically. So which version of our soul lives on? Young you or old you? Who sings “Jailhouse Rock” in Heaven—young Elvis or old Elvis? What about people with severe mental disabilities? Would they still have the disability in the afterlife? If not, wouldn’t that fundamentally change who they are? Will your spouse be the one who used to laugh at all your jokes or the one that rolls their eyes and tells you to go clean the garage? If your spouse died and you remarried, who is the lucky one that spends eternity with you?
Our Essence in Flux
Your essence cannot be captured because it is constantly in flux. You are a Rolodex of personalities—a child, wife, mother, sister, best friend, boss, soccer mom, tennis player, someone’s worst nightmare, and a closet fan of `90s boy bands. Wearing all these different hats makes you wonder if there really is such a thing as a static, unchanging self. Given that we often act very differently around different people and in different circumstances, which one of these many versions of you lives on eternally?
If our essence is separate from our body, chemicals that affect the body should not affect our essence. Yet certain mushrooms, LSD, and my mother’s meatloaf all produce life-changing hallucinations. Acetaminophen has been shown to decrease empathy. Taking drugs for Parkinson’s disease can lead to compulsive gambling or hypersexuality. Statins can cause significant mood changes. Nutrient deficiency, dehydration, and fatigue can also have a dramatic impact on how we think and act. If the soul is immaterial, it should be immune to physical substances that alter the body. And yet these substances change our behavior and personality.
Science has definitively shown that all of the things that define us, including our thoughts, emotions, and memories, are generated by the brain. While we may not fully understand how these activities function yet, we know their function does not require a soul. Francis Crick, one of the co-discoverers of DNA in the 1950s, articulated this idea in his 1994 book, The Astonishing Hypothesis, In Crick’s words, “’You’, your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will, are in fact no more than the behavior of a vast assembly of nerve cells and their associated molecules. ” In other words, you develop from a complex and ongoing interaction between genes and environment, which creates a brain that mingles with our experiences to produce personality and behavior. As a product of our neurophysiology, there is no means for the continued existence once the brain ceases to function.
Bright Sides to Not Having Souls
Realizing that we don’t have souls may sound shocking and depressing at first. But living in the light of the truth is better than remaining in the dark. Moreover, good news rises from the ashes of the soul. Both deviant and admirable actions have long been misattributed to an evil or benevolent soul, which takes the focus of research aimed to understand the biological basis for behavior. Undesirable behaviors like violence, addiction, or depression do not stem from immaterial souls; they stem from a material problem with the brain. This is positive news, because the latter we have hope of fixing; the former, we do not.
There is another silver lining to accept that we are not spirits in the material world. As articulated by Julien Musolino in The Soul Fallacy, the notion of the soul has our ability to devise rational and humane laws governing criminal behavior, addiction, abortion, and the right to die. Concerning human nature, the soul was an incorrect hypothesis. It is one of those ideas that now needs to be retired, and with its disposal comes the promise of a much better understanding of our behavior and a more rational approach to policymaking. The dismissal of the soul does not rob us of life’s meaning; rather, it leads us to it. As noted by Steven Pinker, “Nothing gives life more purpose than the realization that every moment of consciousness is a precious and fragile gift.”
To view ourselves as flesh inhabited by a supernatural soul that is separate from the material world is woefully misguided and unhealthy. The soul is an idea rooted in selfishness and vanity, and it dilutes our sense of humility and empathy. Science has shown that we are intimately woven into the fabric of the universe, interconnected with everything and everybody. We are built from genes, and how those genes are expressed depends on our surroundings. Emerging studies also suggest that who we are is influenced by the intimate relationship we have with trillions of microbes that inhabit our body and cultural memes that inhabit our brain.
At conception, there are countless ways our genes and brains could have been shaped, but it was your unique environment and experiences that sculpted who you are from that clay. We did not get to choose our genes. We did not get to choose our microbes. We did not get to choose our brain. We did not get to choose our prenatal or childhood environment, including the belief systems we were taught. So much of what has made us who we are completely out of our hands. If that does not create humility for oneself and compassion for others, I don’t know what will.