A funny thing happened on my brain’s way to the dentist. It began this morning when my brain was asleep, having a frightful dream about an evil wisdom tooth. In my dream I was running away, when in reality I was kicking my wife! Thanks a lot, special bundle of neurons in my brainstem that’s supposed to block motor signals during slumber. I woke up to Beverly’s screaming and, let me tell you, her limbic system was in high gear.
In a few minutes I was out the door, my brain aching for a stimulant. I know you’re not supposed to drink coffee before surgery, but my neocortex has never been great at self-control (probably a “deficiency in the way it interweaves with my subcortical structures” as my mother used tell me when I was a kid).
The Starbucks customers were the worst: new moms all gooey with vasopressin; an endocannabinoid-addicted hippy taking forever to order; and this big guy in a leather jacket who—I don’t mean to read a book by its cover or anything—had “high testosterone, low cortisol, low serotonin” written all over him. A real sociopath type, if you ask me.
My intuition must have been right, because next thing I knew he was robbing the store! Endogenous opioids flooded my brain, so I was alert and calm. “No individual undermines group solidarity on my watch!” my evolved cheater-detection module pulsed, prompting me to charge at him full speed. The next thing I remember is my brain waking up in an ambulance, all groggy from the adrenaline crash. “You’re going to be fine,” I heard someone say, “other than the knocked-out wisdom tooth.” My brain couldn’t believe it!
Like it or not, a new vocabulary is creeping into the language we use to describe ourselves and each other. Neurotransmitters and fMRI scans have approached the celebrity of tiaraed toddlers and charismatic chefs, and advances in neuroscience and psychology seem to indicate that even the most ephemeral aspects of human life can be traced back to the three pounds of flesh that we all carry in our skulls.
Could the new sciences of the brain be so powerful that we needn’t go looking elsewhere for insights into the human condition? Does the brain encompass an individual in totality, leaving no room for a transcendent soul? This is the thesis of Patricia Churchland, whose Touching a Nerve: The Self as Brain furnished the brain science in my opening ditty.
If the human brain needed a spokesperson, it could do no better than Churchland. A professor emerita at UC San Diego, Churchland pioneered the field of “neurophilosophy,” which, as the name implies, dwells at the interface between neuroscience and philosophy. Touching a Nerve offers a tour of this intersection, and Churchland meanders through the brain’s fleshy folds with a welcoming enthusiasm.
At each stop (including but not limited to: free will, sex, sleep, morality, LSD, anger, heaven, war, and self-control) Churchland draws from neuroanatomy and evolutionary psychology to explain the brain’s role in human culture and personal identity. I have criticized neuroscientific stories of this sort before—from the religiosity of Apple fandom to the caustic effect of analytic thinking on faith—but Churchland is more careful than most. She eschews the over-hyped and simplistic reductions of popular media—“neurojunk,” as she calls it—in favor of nuanced and self-consciously incomplete explanations. Aggression, for example, has no single gene or neuron, but is rather a complex cocktail of hormones, neurotransmitters, and evolved behaviors.
Churchland issues patience and nuance to differing degrees, delivering particularly sharp critiques of the transcendent soul and the possibility of heavenly visits during near death experiences. To debunk the latter, Churchland marshals a range of scientific evidence and medical findings: apparently there have been no medical records of actual brain death in which the patient has come to consciousness and reported seeing dead relatives or divine persons. Churchland posits that such experiences are likely those of “minimally conscious” patients whose low oxygen levels have triggered unusual feelings and perceptions.
As for the existence of the soul, on the other hand, Churchland’s skepticism is grounded in a lack of evidence. “Once you give slow thought to what sort of thing a non-physical soul might actually be,” she argues, “awkward facts begin to pummel the idea’s plausibility.” Naturalistic accounts of the brain can explain everything from our choices and actions to our emotions and memories. As the explanatory scope of neuroscience expands, she argues, there is less ontological room for the soul to occupy.
Anyone keen on popular neuroscience will luxuriate in these pages. Writing as a skilled teacher, Churchland balances empirical precision with accessible, biographical examples. When Churchland draws on her childhood on a farm, or her encounters with chauvinism as a young professional, one can’t help but admire an author whose life has both spanned and engendered a significant paradigm shift in the human sciences.
Even those dubious of today’s neuro-babble should find something to agree with in Churchland’s central thesis, that “I am who I am because my brain is what it is.” The brain is, indeed, a central cause of who we are as individuals and as a collective species. Anyone seeking self-knowledge ought to at least consult these pages, even if it’s with a critical eye (or should I say visual cortex?).
Given Churchland’s appreciation for complexity, the most surprising element of Touching a Nerve is its triumphalist appraisal of neuroscience as the end-all discourse for understanding humanity. She is not alone in this—if neuroscience’s champions share anything it is an exclusivist confidence in their methods—but it is alarming that an author as nuanced as Churchland would take such an unashamedly teleological view of her preferred discipline, placing neuroscience at the end of a long line of revolutionary struggles against religious naiveté and ignorance: Galileo forced to recant his hypothesis that the Earth revolves around the sun; the refusal to believe in William Harvey’s claim that the heart is a muscular pump and not a locus of animal spirits; and the horror Ignaz Semmelweis was met with when he suggested that doctors wash their hands between dissecting cadavers and delivering children.
So to, she argues, have neuroscientists faced resistance at the hands their tradition-bound intellectual despisers. As our author tells it, we can remain optimistic as new discoveries may butt up against old ways of thinking, but they inevitably outlast the detritus of falsehood.
This narrative informs Churchland’s response to her critics, who in Touching a Nerve are personified as a colleague who screams, “I hate the brain!” at a conference and later accuses Churchland of reductionism. Here is Churchland’s response:
Reductionism is often equated with go-away-ism—with claiming that some high-level phenomenon does not really exist. But wait. When we learn that fire really is rapid oxidation—that is the real underlying nature of fire—we do not conclude that fire does not exist. Rather, we understand a macrolevel thing in terms of microlevel parts and their organization.
In other words, for Churchland it’s a mistake to confuse an explanation of a phenomenon with a denial of its existence. This is an apt point, but it makes an easy straw man out of a potentially incisive critique. Let’s start with fire, which has a vast and complicated existence. At a chemical level fire is, of course, rapid oxidation. But fire is also a revolutionary technology for early humans; an ecological agent and economic force on the American West coast; a symbol of passion; an arbiter of s’mores; a weapon; a preferred stove-top technology in bourgeois kitchens; and a widely-imagined symbol of eternal damnation. Atop molded wax, fires can denote age and engender vigils. Fire was a powerful agent in the expansion of the American nation-state, the dawn of the Neolithic Revolution, and the saturation of your couch with weird chemicals.
There’s no doubt that rapid oxidation is a very important aspect of fire’s reality, since it is an empirical description of its most basic existence. However, if we follow Churchland in claiming that rapid oxidation is “the real underlying nature of fire,” and privilege chemistry above all other approaches, we run the risk of forfeiting other dimensions of this phenomenon. If a rich and textured account of fire is desirable, then reductionism should serve as one of many methods for describing and understanding it.
A more nuanced critique of reductionism, like the warning that it often begets tunnel vision, would have served Churchland well in Touching a Nerve. In today’s frenzy of neuro-facts, it’s easy to forget that there are forces and phenomena that fundamentally inform human identity, but which exist beyond the human brain.
As we’ve learned from neuroscience itself, our brains are deeply enmeshed in our bodies and our environments. Your brain’s neural structures have been patterned by human history, the city you live in, the guardians who raised you, and the food you eat. Your identity is expressed in a culturally-specific language, and you navigate the world within economic patterns and socio-political grooves. All of this is imprinted on your brain, yes, but these forces exceed it as well. Just as with fire, a robust account of human identity must draw on a variety of perspectives if it’s to capture, say, the unique influence of ethnicity and community, or the subtle play of politico-economic power.
If we ignore the richness of our world and the plurality of means to describe it, we run the risk of cutting everything to fit into our preferred boxes. Although Churchland avoids this trap throughout most of her book, there is a degree of myopia in her view of religion. Touching a Nerve approaches religion through reductive cognitive lenses, portraying it as a relatively static set of platitudes that will inevitably be overturned by scientific truth. This is some disappointing deck stacking, and anyone who believes in a soul, or in the flexibility of religious thought, will find this rigid, simplistic account easy to reject.
Still, despite the lack of nuance when it comes to religion, Touching a Nerve is an approachable and engaging tour through the neuroscience of the self. My brain, for one, enjoyed her brain’s book about the brain.