Matter Over Mind

Neuroscience, Psychology, and Religion: Illusions, Delusions, and Realities About Human Nature
By Malcolm Jeeves and Warren S. Brown
Templeton, 168 Pages, $17.95

There was a time when people worried whether God existed. Now, strangely enough, they are beginning to worry whether they exist”whether beneath the flux of their experience there can be found any enduring “self” or “soul” or autonomous person. Not according to some of the prophets of science, and especially of neuroscience, for whom such ideas are mere romantic fictions.

Fifteen years ago, the famous biologist Francis Crick announced in his book The Astonishing Hypothesis that

‘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. As Lewis Carroll’s Alice might have phrased it: ‘You’re nothing but a pack of neurons.’

Even then, that hypothesis wasn’t new. It is exactly what the French physician Pierre Cabanis famously asserted two hundred years ago: “ Les nerfs”voilá tout l’homme !” (“The nerves: that’s all there is to man”). In Cabanis’ time this idea could be dismissed as the loosest sort of speculation because hardly anything was known about nerves or the brain. But no more. In our own day, meetings of the Society of Neuroscience draw 30,000 participants, and brain research has at its disposal an array of sophisticated techniques, from functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) to transcranial magnetic stimulation. Could it be that the ideas of Cabanis and Crick, crazy as they sound, will soon be proven right? After all, hasn’t science vindicated many other ideas that once seemed absurd?

Among those who look to science for ultimate answers, this is a time of great anticipation. There is a sense that mankind is on the verge of some final, unifying intellectual triumph. Many believe that it will be the privilege of neuroscientists to drive in the golden spike that will link human nature to the rest of the natural world in one all-encompassing, reductive explanatory scheme. In this “physicalist” framework, all the supposedly spiritual dimensions of human life”moral, aesthetic, and religious”will be accounted for as electrochemical processes in the brain.

Malcolm Jeeves and Warren S. Brown are accomplished neuropsychologists and believing Christians. In Neuroscience, Psychology, and Religion , they attempt to sort out the human, and in particular the religious, implications of recent discoveries. They provide a readable overview of the history of their field and of what has been learned so far about the structure and functioning of the human brain. They repeatedly emphasize the “rapid growth” and “remarkable advances” of neuroscience. These advances have largely been driven by the development of noninvasive techniques (such as fMRI and PET) for measuring the activity of different parts of the brain while subjects are engaged in particular cognitive tasks or experiencing various mental states.

Here is a small sampling of the things that have been learned so far: Different parts of the language center of the brain are used to understand speech and to formulate speech. Our brains analyze facial expressions differently from all other visual data in a specialized part of the temporal lobe called the “fusiform face area.” Different kinds of moral dilemmas (for example, ones that involve accidental versus deliberate harm to others) activate different neural circuitry in our frontal lobes. The parts of the limbic cortex that register the bodily responses associated with social emotions such as empathy and shame are connected by exceptionally long neurons to the regions of the brain where higher mental faculties are based. These special “von Economo neurons” are almost unique to human beings, and it has been suggested that this linkage is what allows us to reflect on and understand our own emotions and those of others and so to be more “deeply social” than other animals.

Much has also been learned from the effects of brain injuries. Most famous is the case of Phineas Gage, a railroad-construction foreman who in 1848 had a metal rod driven through his head by an explosion, damaging his frontal lobes. “From being a reliable, industrious pillar of society,” Jeeves and Brown say, “he became dissolute, capricious, and irresponsible.” Another curious case occurred in 2000, when a schoolteacher who had begun to collect child pornography and make advances on his stepdaughter had a tumor removed that had been pressing on his right frontal lobe. His lewd behavior ceased. The impulses returned when the tumor began to grow again and ceased again when the regrown tumor was removed.

Such findings show how intimately every aspect of our mental life is tied to neural processes, which often can be precisely located. The principal lesson that Jeeves and Brown draw from this (quite correctly, I think) is that our mental life is “embodied” and that concepts of the mind or soul as “free-floating” and “separate” from the brain and body must be rejected. Frequently throughout their book, Jeeves and Brown disparage the idea of a “separate immaterial part” of the person, a “separate inner agent,” a “‘self’ or ‘mind’ separate from the body,” or a “real ‘I’ [as] an immaterial ‘something’ separate from my body.”

The authors consider this notion of the soul as a separate entity to be the dominant view throughout most of Christian history and blame this on the influence of Greek metaphysics and Cartesian rationalism. This dualist conception, they say, overlay and distorted the original “biblical” and “Hebrew-Christian” ideas, which were more in accord with modern science and which must now be “recaptured.”

This misreading of Christian tradition may have its roots in a common confusion between the idea of “distinction” and the idea of “separation.” One can distinguish , but not separate , the three dimensions of space, for instance, or the brightness of light from its color. So, too, the traditionally drawn distinction between spirit and matter in the constitution of a human person need not imply their separation, any more than the infinite and absolute distinction between Creator and creature implies for the orthodox Christian a separation of the two natures of Christ. (“For, as the rational soul and flesh is one man,” says the Athanasian Creed, “so God and man is one Christ.”)

Apparently unaware of how deeply and pervasively incarnational traditional Christian theology is, Jeeves and Brown imagine that the “embodiment of the mind” supported by neuroscience is something that must be restored to theology and that this requires the abandonment of the concept of a “spiritual soul” distinct from matter. They flee from the dreaded “dualism” they think typified by Descartes into the arms of a materialist monism. For them, the mind is to be identified, without remainder, with the functioning of the neurons of the brain.

Jeeves and Brown are following a well-worn path. It has become the custom to discredit the idea of a soul by trotting out poor old dualist Descartes. The question Descartes notoriously failed to answer was how an immaterial soul could affect a material body. His admittedly unhelpful suggestion that it happened somehow or other in the pineal gland is regarded as the reductio ad absurdum of the whole idea. But few who pose this question have stopped to ask themselves how it is that a material body can be affected by anything whatsoever, even by another material body. That is, ultimately, no less mysterious a question.

Material bodies are made up of electrically charged particles that interact with each other through the mediation of electromagnetic fields: The charged particles affect the fields and the fields affect the particles. By what “means” or “mechanism” this happens, physics does not say. It simply says that when electromagnetic fields are present, the charges are, in fact, affected as described by a certain equation; and when charges are present, the fields are, in fact, affected as described by another equation. In other words, physics posits two types of entities and mathematically describes, but does not otherwise explain, their influence on each other.

Fundamentally, we are in the same position today as Newton was: He discovered precise equations describing how mass and gravity affect each other but he famously said, in his Principia, “I have not been able to discover the cause of those properties of gravity . . . , and I frame no hypotheses, . . . to us it is enough that gravitational forces really exist, and act according to [these] laws.”

It is no less reasonable to accept the existence of both mental and physical aspects of reality and to say that they do in fact affect each other in predictable ways that can be described, without having in hand or even supposing that there exists a “mechanism” for that interaction. Indeed, this is really all that neuroscience itself can do. For instance, it can tell us that a lower than normal concentration in the brain of a molecule called dopamine (a certain arrangement of eight carbons, eleven hydrogens, one nitrogen, and two oxygens) leads to the subjective experience of boredom or apathy. It can find that the electrical stimulation of a certain tiny region of the brain produces mental states ranging from mild amusement to hilarity. It can report, as Jeeves and Brown do, that “damage to a certain small area of the cortex serving vision (called ‘V4’) can strip color” from one’s visual experiences.

But in none of these cases can it explain the connection between motions of material particles and mental experiences any better than Descartes was able to do. For neuroscience, in effect, the entire brain is just Descartes’ pineal gland writ large.

But there is one key difference. Neuroscientists, unlike Descartes, tend to see the action as one-way: Matter can affect mind but not the other way around. Some justify this by saying that any effect of mind on matter would violate the laws of physics. Nothing that is known about physics, however, compels that conclusion.

In a famous essay on the mind“body question written in 1961, the physicist Eugene Wigner noted that there was a time when “the brilliant successes of . . . physics and chemistry overshadowed the obvious fact that thoughts, desires, and emotions are not made of matter.” The successes of contemporary neuroscience are also brilliant; but what was an obvious fact in 1961 remains so today. Science can measure the behavior of “nerve cells and their associated molecules,” to recall the words of Francis Crick, but it cannot measure “‘you,’ your joys and your sorrows, your memories and your ambitions.” That we are creatures of flesh and blood and bone”and, yes, nerves”no believing Christian or Jew has ever denied. But that these are “all there is to man” is quite beyond the power of any measurement or computation to demonstrate.

Stephen M. Barr is professor of physics at the University of Delaware and author of Modern Physics and Ancient Faith and A Student’s Guide to Natural Science.