Immortality (26 page)

F
OR
a long time, students of the brain were limited to Gage-style cases. But in the past decades, a wholly new technology has revolutionized neuroscience: machines that can produce images of the living brain in action. Collectively, the techniques involved are known as “neuroimaging,” and they enable scientists to closely study the correlations between the airy world of thought and the measurable, physical matter of the brain. In laboratories around the world, you can now watch live as various parts of your cerebrum light up when you engage in such typically mental activities as remembering your mother’s face, imagining playing tennis or simply daydreaming.

The results show that for every mental process, there is an
accompanying brain process. Even more worrying for the Soul Narrative, they show that the physical brain process starts
before
the conscious mind is aware of it. So, for example, someone monitoring your brain activity could tell you which decision you have made (left or right, tea or coffee or whatever) before you even
consciously
know yourself. This makes no sense at all if the real you is a conscious soul. But it makes perfect sense if your mind is the product of the workings of a complex, physical brain.

In a way, of course, we are all aware of the intimate link between mind and brain: alcohol, for example, gets us drunk, substantially affecting our attitude to risk, respect for social norms and many other aspects of our personality. But alcohol is simply a physical substance; if our minds were dependent on a nonphysical soul, why would they be so radically altered by a particular molecule of carbon, hydrogen and oxygen? Similarly, we know that even a cup of tea or coffee can affect our mental states, not to mention drugs such as heroin and cocaine. Even the level of water in our bodies can affect our personalities. Neuroscience, along with a better understanding of our underlying biology, is beginning to explain these intimate bonds between mind, body and brain.

The world-renowned neuroscientist Antonio Damasio illustrates this with the example of hunger. He writes, “Several hours after a meal your blood sugar level drops, and neurons in the hypothalamus detect the change; activation of the pertinent innate pattern makes the brain alter the body state so that the probability for correction can be increased; you feel hungry, and initiate actions to end your hunger.” Some of the actions you take to end your hunger might be unconscious, such as reaching for another cookie without thinking about it, and others may be conscious, such as deciding what to choose from a menu or following a recipe in a cookbook. But all those mental processes are themselves just part of the larger loop of biochemical activity that began with the drop in blood sugar levels.

What happens if your blood sugar level drops too low illustrates
even more clearly the union of mental and physical: First, you will begin to feel anxious and become irritable, and your ability to concentrate—at least on anything not food related—will diminish. As diabetics know, if it suddenly drops lower still, you can become emotionally volatile, belligerent and confused. If, on the other hand, your hunger is prolonged, then you will eventually become apathetic and depressed. These are all profound changes to your personality—the part of you that is supposed to be the province of the soul—caused by chemical changes in the brain and body. Under the close scrutiny of modern science, the ancient distinction between mental and physical breaks down, and thought and feeling appear firmly grounded in biology.

T
HE
main argument for believing that a mind requires a soul is that it is difficult to see how the fine and ethereal world of thought could arise from crude matter alone. Those who make this argument—known as dualists—maintain that mental events like remembering and dreaming are fundamentally different in kind to the workings of physical things such as brains. Physical things can, for example, be measured, weighed and located, but not so your memory of your first kiss or your dream of a place in the sun. Physical things are observable to all, whereas mental processes seem to have an irreducibly subjective quality—only you know what it is like to be you. Summing up this view one hundred years ago, the
Catholic Encyclopedia
asserted that “the chasm that separates psychical facts from material phenomena is intellectually impassable. Writers, therefore, who make thought a mere ‘secretion of the brain’ … may be simply ignored.”

A century ago and earlier, such arguments were conducted largely in seminaries and colleges, on the basis of abstract principles. Even then, not all were convinced by the claim that only a soul could
explain the mysteries of the mind. Thomas Jefferson, for example, third president of the United States and all-around Enlightenment man, wrote that he should “prefer swallowing one incomprehensibility rather than two. It requires one effort only to admit the single incomprehensibility of matter endowed with thought, and two to believe, first that of an existence called spirit, of which we have neither evidence nor idea, and then secondly how that spirit, which has neither extension nor solidity, can put material organs into motion.”

Note that Jefferson is not denying that it is mysterious how “matter” such as a brain can produce thought. Rather, he is saying that the alternative soul-based view is even more mysterious: First, it requires us to accept the existence of some nonmaterial, spiritual stuff that can produce the conscious mind. No evidence is given by the soul theorists for this stuff’s existence, nor an explanation for how it produces thought. It is taken to be obvious that spiritual stuff can secrete consciousness in a way that material stuff cannot. But this is not obvious—certainly no more obvious than how the brain could produce consciousness.

Second, Jefferson is pointing out that if we accept a soul-based explanation of the mind, we must additionally explain how this spiritual stuff can seamlessly interact with and control the physical body. When you make a decision to get up, your body usually responds by getting up—a manifestly physical event. But how does an entirely nonmaterial thing move around the atoms, molecules and cells of the brain and body in order to cause this physical event? If the mind is itself part of the physical brain, this is much less mysterious.

Such theoretical considerations have, as we have seen, now been supplemented by the evidence of neuroscience. Unlike Jefferson and the authors of the
Catholic Encyclopedia
, we can begin to appreciate the true magnificence of the human brain. Each one of us has in our skulls somewhere in the region of one hundred billion neurons, each of which in turn has on average seven thousand synaptic connections to other neurons. It is no surprise that we cannot envision how the
brain produces the conscious mind, because such complexity is indeed quite literally far beyond anything we can imagine. It is not an exaggeration to say that the human brain is the most complex thing in the known universe. If this hugely intricate system involving trillions of connections forming millions of interconnected networks is
not
producing our minds, then we might wonder just what it is doing.

F
OR
the idea that your personality might survive your bodily death the situation therefore looks hopeless. This is not to say that all the mysteries of mind and brain have been solved; they have not. Neuroscience is still in its infancy, and there is a great deal about the intricate workings of the brain and the production of the conscious mind that is not yet understood. Perhaps indeed we will never properly understand how the mind arises. But
all
of the now-voluminous evidence so far accumulated points to the complete dependence of the mind on the body. The psychologist Jesse Bering sums it up so: “The mind is what the brain does; the brain stops working at death; therefore, the subjective feeling that the mind survives death is a psychological illusion operating in the brains of the living.”

That illusion is of course generated by the Mortality Paradox. It is a testament to the success of the Soul Narrative in resolving this paradox and assuaging our fear of death that it remains so popular in the Western world despite the evidence of science. Nonetheless, in particular in Europe, this belief is thought to be on the decline (though accurate figures for earlier periods are hard to come by). Not so in India, for example, where religiosity remains high. But as we saw earlier, the Hindu and Buddhist ideas of the soul are abstracter and leaner than those of the Abrahamic religions common in the West. In particular the Buddhists strictly reject the idea that the entire personality, complete with memories, beliefs, dreams and dispositions, survives bodily death; this they have long believed to be dependent on the body.

When the Dalai Lama met with leading neuroscientists in 1989
for a symposium to discuss the implications of brain science, he explained, “Generally speaking, awareness, in the sense of our familiar, day-to-day mental processes, does not exist apart from or independent of the brain, according to the Buddhist view.” The soul in the Western sense of an independent entity that supports the full personality, he accepts, is “thoroughly refuted.” But Buddhists do believe in some essential part of you that survives the body in order to be reincarnated in accordance with the laws of karma. This is pure consciousness, stripped of all memories and convictions and the rest of the accumulated baggage of a lifetime. The Dalai Lama describes it as a “continuum of awareness that … does not depend upon the brain.” Can this pared-down soul, this “continuum of awareness,” survive the onslaught of neuroscience?

T
HERE
is one big problem with the idea that your consciousness or “awareness” can in some form survive the death of your body. It is something with which we are all in fact very familiar, not least from countless Hollywood films: simply that if you get hit on the head with sufficient force, you will be knocked unconscious. Your awareness of the world ceases; your lights go out. The hitting is itself a physical act, with measurable, physical effects on the brain, and its result is that your consciousness is temporarily extinguished. Similarly, if you are injected with general anesthetic—a syringe full of chemicals—your awareness will be extinguished. For anyone who thinks consciousness can survive bodily death, this is an embarrassing state of affairs.

The reason is this: the soul, which even in its pared-down form is supposed to maintain some minimum degree of consciousness, is supposed to be an entirely nonmaterial thing independent of the body—only thus can it survive the body’s death. Now it is natural to suppose that a hard blow to the head would stop your
body
from
working—we might expect you to collapse to the ground and even to seem, from the outside, unconscious. But if consciousness were being maintained by an entirely
non
material thing, we would expect your consciousness to continue regardless. If you have a nonmaterial soul, you should, after the ordeal, be able to tell us how frustrating it was that your body had stopped working and what you thought while you were waiting for your body to recover. But this is not what happens.

To return to our analogies: If a ship is damaged and is stuck for a time out at sea, once it is repaired and returns to port we expect the captain to be able to tell us what it was like throughout the ordeal. If captain and ship are quite separate things, then the ship not working should not affect the captain. And so if consciousness is in your body like the captain of a ship, immaterial and able to survive the body’s destruction, then a failure of the body should not stop consciousness from working. But it does.

Believers in a soul can and do find ways of explaining away this uncomfortable fact. They can, for example, argue that we really
are
conscious when, for example, under general anesthetic—but because the brain is not working, we cannot create new memories, so it retrospectively
seems
like we were unconscious. This is a terrifying thought, suggesting we really do experience what must be the agony of, for example, invasive surgery. The eerie feeling of falling off into darkness only to emerge after what seems like a few seconds but can be hours would be just a trick of the memory.

Islam takes a different approach. According to the Qur’an, “God takes the souls of the dead and the souls of the living while they sleep—He keeps hold of those whose death he has ordained and sends the others back until their appointed time” (39:42); this argument could be extended to unconsciousness: when under general anesthetic, as when asleep, your soul returns to God. This is a wonderfully poetic retort but does not explain why we have no memory of going to, being with or returning from Allah.

Many more such explanations are possible, and they all have three things in common: they are ad hoc, untestable and pose as many questions as they answer. And this, as any philosopher or scientist knows, means we ought to be very skeptical. The basic fact remains: what happens when you are knocked hard on the head or injected with general anesthetic is exactly what we would expect if your consciousness is entirely dependent on your brain and not at all what we would expect if consciousness is dependent on an immaterial soul.

Therefore even the very pared-down soul of Buddhism is not a plausible doctrine. Reincarnation, like going to heaven, requires that some essential part of you can separate off from the corpse and carry on in some other form. But what the overwhelming evidence of science teaches, and what many have long suspected, is that there is no essential part of us that is not wholly dependent on the body. If you have a soul, yet it does not take your mind, personality or consciousness with it, then its survival after the death of your body should be of as much interest to you as the survival of your toenails.

T
HE
problem with the Soul Narrative is therefore not that, having looked closely, science has not
yet
found the soul, nor that it has just not
yet
looked in the right place. Many scientists have indeed been believers who desperately hoped to find proof of an immortal core to their being. An American doctor by the name of Duncan MacDougall, for example, constructed an elaborate hospital bed–cum–scales that weighed patients immediately before and after death. Assuming that any difference between the two measurements would be caused by the departing spirit, he concluded in 1907 that the soul weighed twenty-one grams. He later expressed the hope that he could use an X-ray machine to photograph the soul as it left the body. Needless to say, neither his results nor his hopes have been borne out by subsequent research.