Neuroscience and the Human Person PDF

Neuroscience and the Human Person Alan C. Weissenbacher Neuroscience is discovering the areas of the brain correlated with many aspects of the human personality once attributed to the human soul—such as rationality, emotions, ethical decision- making, social behavior, and memory—that lead to a view...

Neuroscience and the Human Person Alan C. Weissenbacher Neuroscience is discovering the areas of the brain correlated with many aspects of the human personality once attributed to the human soul—such as rationality, emotions, ethical decision- making, social behavior, and memory—that lead to a view of the human person as entirely physical. This view has challenged the conception of an immaterial soul often found within Christian theology, with some insisting that religion has been falsified by the failure to discover this immaterial entity. A strict dualism of soul and body in its current form, however, is more a legacy of the philosopher Descartes than a core Christian doctrine. Christianity posits a more holistic view of the human person. Neuroscience does not falsify religion (a conclusion that goes beyond the data provided); however, it does encourage an ongoing examination of various theological doctrines to determine how they may have been influenced by surrounding cultures in relation to Scripture. The main challenge of neuroscience, not just in regard to religion but also in other fields that explore the human person, is that of explaining consciousness and how subjective experiences can arise from a physical substrate. Philosophical, neuroscientific, and religious views abound ranging from reductionist, and materialist positions to monist, nonreductionist positions, and to dualistic positions. Regardless of the constitution of the human person, it is becoming apparent that an integrated view of the human person is gradually replacing the strict, traditional divisions between aspects of personality, such as emotion and reason or nature and nurture. Alan C. Weissenbacher is a doctoral candidate at the Graduate Theological Union in Berkeley, California. His research focuses on neuroscience and Christian spiritual formation. His recent publications include “Ten Principles for Interpreting Neuroscientific Pronouncements Regarding Human Nature,” Dialog 54, no. 1 (2015): 40 – 50, and “Wesleyan Theology and the Natural Law Theories of Jean Porter and Pamela Hall,” Wesleyan Theological Journal 49, no. 2 (Fall 2014): 187 – 204. He is the book review editor for the journal Theology and Science. ‘Neuroscience’ refers to the scientific study of the nervous system and the brain. While the term is often used interchangeably with ‘neurobiology,’ neurobiology refers specifically to the study of the cellular and molecular biology of the nervous system. Modern neuroscience began with the discovery of the microscope and cell-staining procedures, which enabled scientists to view the structure of the neuron. Using these techniques, scientists Heinrich Von Waldeyer-Hartz (1836–1923) and Santiago Ramón y Cajal (1852–1934) formulated the neuron doctrine, which defined nerve cells as developmental, functional, structural, and nutritionally independent units consisting of a cell body, dendrites to receive incoming messages, and an axon to serve as the output of the nerve cell. The neuron doctrine viewed nerve cells as building blocks, with synapses as the one-way communication link between them. It provided a reductionist approach to studying the brain and its connections, allowing scientists to study it in manageable parts. The discovery of the electron microscope, which enabled scientists actually to view the gap between neurons, helped firmly establish the neuron doctrine. Other important findings for the doctrine were the discoveries made by Kenneth Cole (1900 – 84) and Howard Curtis (c. 1906 – 72) regarding the electrical conductivity of the neuron; by Alan Hodgkin (1914–98), Andrew Huxley (1917 – 2012), and Bernard Katz (1911 – 2003), which revealed that the electrical conductivity of the neuron is due to an exchange of sodium and potassium ions in the cell; and by Katz and John Eccles (1903 – 97), which determined that signal transmission across synapses is due to neurochemicals. The neuron doctrine was not without opposition, however, and it faced scientific resistance for several decades. The debate occurred in the context of other scientific pronouncements that questioned human uniqueness, such as evolution’s claim that humans were related to other animals and cell theory’s assertion of a similar structure for all plants, animals, and humans. The neuro-scientist Ray Guillery (b. 1929) describes how the neuron doctrine provided an entry for reductively analyzing areas long thought to be the province of theologians and unknowable to science, which in turn created a controversy between a materialist and reductionist view of the brain on one hand and a holistic, often mystical, view on the other (Guillery 2005, 1283). This challenge was not limited merely to the presence or absence of a human soul. It also called into question the existence of free will and even consciousness itself. The Search for the Soul With the advent of modern neuroscience, human capacities once attributed to the soul—such as memory, emotion, social behavior, rationality, personality, language, and moral deliberation—began to be studied as brain processes with a physiological basis. Brain- scanning techniques such as functional magnetic resonance imaging (fMRI) were able to see what areas of the brain were activated during cognitive and behavioral tasks. Joseph LeDoux (b. 1949) and Antonio Damasio (b. 1944) demonstrated the neurological processes behind various emotions. Peter Hagoort (b. 1954) discovered the neural correlates of language. Even social behavior had a neural substrate as Leslie Brothers demonstrated. Studies on Alzheimer's patients revealed that changes in brain structure have debilitating consequences for memory. Patricia Churchland (b. 1943) and William Casebeer found the neural structures responsible for making moral decisions, with Casebeer suggesting that neuroscience confirms virtue ethics as the ethical theory by which people naturally live. These physiological discoveries led to the advancement of a materialist and reductionist view of the human person, with some, such as Michael Persinger (b. 1945), even suggesting that the discoveries falsified religion with what they felt was a negation of the idea of the immaterial soul. There is no uniform consensus, however, in theology regarding the metaphysical constitution of the human person. The Christian church fathers held differing opinions. Tertullian (c. 160–c. 220), following the Greek Stoics, believed that the soul was corporeal and generated within the body. Origen (185–254) followed Plato in teaching that the soul was incorporeal and eternal. The primary belief by the time of Jerome (347 – 420) was that the soul was created at the time of conception. Augustine (354 – 430) modified Plato and conceived of the person as a consisting of an immortal soul that used a body as a tool, raising the question of how the soul influenced the body. Thomas Aquinas (1225–74) developed an Aristotelian alternative to the accounts based on Platonism, in which the soul was the form of the body, with the form being the principle that makes an entity to be what it is. A trichotomous view is also present within theology. This view holds that the words ‘soul’ and ‘spirit’ represent different immaterial aspects of human nature. In this view, the soul is considered the essence of a person while the spirit is what connects a person to God. While dualist and trichotomous views are distinct, they are both challenged in a similar manner by a strictly materialistic account of the human person. The modern controversy regarding the human person is often attributed to René Descartes (1596 – 1650), who described the world as consisting of two kinds of substances: the physical, characterized by spatial extension, and an immaterial mind or consciousness. A person is a composite of immaterial mind and physical body, which causally influence one another and are capable of independent existence. The evidence for this is based on human experience since through introspection people have felt that their conscious experiences are not the same as physical objects, so they have tended to locate personal identity in the mind, with the body as contingent. While this view kept the peace between theology and science by giving the mind to theology and the body to science, it encountered the problem of how to account for the causal relationship between the immaterial and the material. The nature of the interaction is a challenging question. An immaterial mind either transfers energy for the body to move, and hence this energy can be measured—an energy neuro-science has not yet found—or else the mind is unable to move the body. For Descartes, since brain anatomy occurs in duplicate while mental events are unitary, the place in the brain for soul-body contact should be unitary. Thus, Descartes advanced the pituitary gland as the locus of mind-body interaction, although he left unexplained how such interaction occurred. Many modern Christian theologians, following Descartes, have assumed a dualistic (or trichotomous) account of human nature. Some, however, have advocated that the Bible promotes a monist and physical position that coincides with the majority view in modern neuroscience. Old Testament scholar H. Wheeler Robinson (1872–1945) argued that the Hebrew conception of the human person was an animated body, contrary to the Greek idea of a disembodied soul, and that this unitary conception was also found in the New Testament. Karl Barth (1886–1968) favored a unitary Hebrew view over a Hellenistic, dualist conception of the person, and theologian Rudolf Bultmann (1884 – 1976) argued that Paul used the term ‘body’ to refer to the whole person, asserting Paul to be a monist instead of the dualist that many conceive him to be. New Testament scholar Joel Green (b. 1956) argues that the New Testament presents a monist account of human nature, yet not one that is fully reducible to the material, as the person should be understood as also constituted by relationships with others as well as God, a view that dovetails with assertions made in social neuroscience. Other theologians such as John Cooper (b. 1947), however, assert a counterargument that Scripture does in fact espouse a dualist anthropology. Lest one thinks that opposition to a monist and materialist account of human nature is found only in the province of theology, a minority of neuroscientists also support body-soul dualism. Of note is neuroscientist Wilder Penfield (1891 – 1976), who pioneered the technique of electrically stimulating the brain to map various functional locations prior to surgery. He noted that patients distinguished between when they intended for an action to occur and when it was the doctor who was stimulating the brain. Penfield believed that this suggested scientifically that a soul operated the brain, as people knew when an action was performed by mere neurological activity as opposed to when actions were self-initiated. Nobel Prize-winning neuroscientist Sir John Eccles (1903 – 97) also supported dualism in his attempt to explain how the soul inter-acted with the body without violating the principle of conservation of energy through information transfer at the quantum level. A strictly physical understanding of human nature has prompted critical reflection regarding the influence of Greek philosophy on various theological doctrines. What is the place of humans in the rest of nature? What does it mean for humanity to be created in the image of God if humanity has no immaterial aspect? If the soul is considered the location of God’s interaction with the individual, how does one understand religious experience if the person is entirely physical? Given that the Christian hope in the afterlife has traditionally rested on the immortality of the soul, what does a physical understanding of the person mean for the doctrine of heaven? Theologian Ted Peters (b. 1941) argues that the ancient Hebrews conceived of an entirely physical person undergoing a complete death to be then bodily resurrected by God, in contrast to a Greek understanding of an independently surviving, disembodied soul becoming reunited with a body at a final resurrection. Continued existence after bodily death is dependent on God and not due to a soul. As a further challenge, if humans are continuous with the rest of creation, does this prompt a broader understanding of redemption, which is often thought of in individualistic terms? Theologian Wolfhart Pannenberg (1928–2014) argued that the resurrection of the physical body of Jesus points to the idea that the entire physical cosmos will be transformed, as opposed to the salvation of individual souls alone. Psychologist Warren Brown (b. 1944) and philosopher Nancey Murphy explore many of these questions in their seminal work Whatever Happened to the Soul? Scientific and Theological Portraits of Human Nature (1988) and have been intentional in bridging neuroscience and the theological study of the soul in the hope of avoiding conflict between the two areas. While various debates continue on the subject, both internally within each field and between religion and science, overall neuroscience has not falsified religion with its challenge to dualism. Rather, it has encouraged theologians critically to reflect on the philosophical concepts that Christianity may have incorporated from the surrounding culture in relation to various doctrines and Scripture. Multitude of Perspectives The challenge from science pointing to the human person as an entirely physical entity comes to a head in what philosopher David Chalmers (b. 1966) calls the “hard problem” of consciousness. The easy problems are those readily explained by brain mechanisms, such as neural correlates of experience, emotion, attention, or behavior. The hard problem is subjective experience and how subjective experience arises from purely physical mechanisms. The term often used is ‘qualia’: what it is like to have a certain experience. How does one explain the relationship between mentality and physical nature and how the mental can depend on, yet remain distinct from, physicality? Philosopher Thomas Nagel (b. 1937) highlights this challenge in his article “What Is It Like to Be a Bat?” A human could understand the entire biological workings of the bat brain and still not know the subjective experience of actually being a bat. On one side of the debate explaining consciousness is a body-soul dualism. On the other side is materialism which reduces all mental life to nothing but neurological function. This leads some—such as Francis Crick (1916–2004), the co- discoverer of DNA—to hold that mental states are nothing but neural processes. A person is entirely reducible to his or her neurons, which are themselves reducible to microscopic particles. What one thinks of as mental states can be mapped onto specific neural events, and thus mental states, desires, beliefs, and free will are an illusion. They do not actually exist. A slightly modified version of this view is epiphenomenalism, which grants that mental states exist, but they do not influence the physical. Mental states are causally inert, like froth on a wave or the light blinking on a computer when it is in use. They are a shadow cast by neural processes. The only causation is physical-to-mental or ‘bottom-up’ as opposed to ‘top-down.’ This also means that free will is an illusion, a conclusion that was bolstered in a famous experiment by Benjamin Libet (1916–2007), in which he claimed to have discovered that the brain activated one-third of a second before a subject made a decision. The conclusion that the brain made the decision before people consciously thought that they themselves had decided, however, has been called into question. The timings measured in the experiment varied widely and relied on subjective reporting. Perhaps what the experiment measured was not the decision-making process but activity resulting from watching a clock or some other spontaneous brain activity. There was no way to be sure, and hence the jury is still out. Within the philosophy of mind, reductionism is typically advanced in a position termed ‘computationalism.’ This position considers the brain to be a computer and mental life to be the program that runs on the hardware. As a guiding research metaphor, this enables scientists to ignore the difficult question of subjective consciousness and to focus on information- processing by using commercial machines to model brain function. This position becomes reductionist, however, when the metaphor is said to be the reality. It is important to distinguish between reduction as a method of study, which can be important and fruitful, and reduction as a statement of something’s nature. The computer metaphor is only the latest in a series of metaphors throughout history that have described the brain in terms of the major technology of the time. The Greeks described the brain by using hydraulics, in which the balance of various humors produced moods. The humoral model eventually became the ‘animal-spirit’ theory of Greek physician Galen (129–218), in which fluid flowed in the nerves, enabling the brain to send and receive messages. By the time of the modern machine, the machine metaphor began to dominate and change as machine technology changed. Thomas Hobbes (1588–1679) felt that small clockwork motions in the head created ideas. Sigmund Freud (1856 – 1939) used the metaphor of the steam engine in describing how urges, when left under pressure, can find destructive outlets. Donald Hebb’s (1904 – 85) theory of memory employed the idea of reverberating circuits. Hermann von Helmholtz (1821–94) used the idea of a telegraph in his studies of nerves. Alan Hodgkin and Andrew Huxley used the equation for electrical transmission across the transatlantic undersea cable to win the Nobel Prize for their study of the propagation of nerve-action potentials. The computer metaphor itself has evolved with the increasing complexity of computers. The image of the solitary computer is already obsolete, as computers are now connected to global- spanning networks that produce different functionalities. To have the genuine mentality, however, a system must be embedded in its natural environment, interacting and coping with it and other systems like it in the ever-changing stimulus conditions encountered, something that would be difficult for a computer to fully represent. Reductionism is seen in neuroscientific studies that locate the neural correlates of religious experience such as those by Persinger that attempt to link religious belief with temporal lobe epilepsy (TLE). These studies are sometimes used for an agenda of promoting the view that religion is nothing but brain malfunction. While they have been criticized for methodological problems and for neglecting the differences between typical religiosity and that of the patients under study, they are essentially irrelevant, for the question of the truth of the experience is left open. Finding neural correlates of religious experience should not be surprising. In an experiment attempting to find neural correlates of religious experience, brain scans of Tibetan monks during meditation and Catholic nuns during prayer showed similar changes in brain activity. This led some to declare that there was a particular area of the brain responsible for spiritual experiences called the ‘God Spot,’ and, therefore, that belief in God is nothing more than a physical process. However, any activity, whether petting a cat or playing with a child, involves areas of the brain dis-coverable by a scan, and neither the cat nor the child is a mere illusion. One could conclude that an active area on a brain scan is where God interacts with an individual. Science can explain the biology of a spiritual experience, but it does not explain the experience away. The results of these experiences can be interpreted for or against religious belief depending on one’s worldview. Multiple views exist between dualism and materialism that advocate reductionism. Some views attempt to describe what the mind and brain are, while others describe how the mind and brain function and avoid questions of the mind and brain’s true nature. Two common functional positions are behaviorism and functionalism. Behaviorism attempts to describe behavior without any mention of mental states. This position was popularized by B. F. Skinner (1904–90) and is seen in many conditioning experiments involving reward and punishment. Functionalism simply defines subjective mental states by what they do. As a means of illustration, a mousetrap is defined by catching mice, not the material out of which it is made. This position is typically adopted by neuroscientists, as they can then go about their research while completely avoiding the hard question of consciousness. Other approaches attempt to describe the true nature of the mind and brain in contrast to reductionism or substance dualism. There are various dual-aspect theories (property dualism, dual-aspect monism, neutral monism, non-reductive physicalism) that posit a single substance with two types of properties. These hold that mental states rely on physical states for their existence but cannot be reduced to them, and many also grant that these mental properties have a causal influence on the physical properties that brought them into existence. These positions use the ideas of supervenience and emergence. Supervenient properties are understood as dependent on subsequent properties without being reducible to them. Emergence, a concept much indebted to the work of Ilya Prigogine (1917 – 2003) and Stuart Kauffman (b. 1939), states that complex systems exhibit global properties not predictable by their components. Novel and coherent properties emerge during the process of self-organization in complex systems that are neither predictable from nor reducible to their components. Mental phenomena result from the brain, yet they represent a new explanatory level that is not reducible to its parts. In this case, the whole is greater than its various components. And in a move that borrows ideas from Aquinas and Aristotle, some researchers have even suggested that the idea of soul as form can provide an explanation for the emergence and downward causation. A Systemic Approach Ideas such as emergence require a method of studying the brain other than reductionism. Much research proceeds according to the building-block approach, in which large problems are broken down into smaller units. This approach is favored because it provides an easier research project than the unified, systemic approach, which studies systems-wide neuronal firings. Yet concepts such as emergence require a more systemic approach. In the 1970s various researchers realized that they were each studying the brain, mind, and cognition from unique perspectives and recognized the benefits of collaboration. This prompted the Sloan Foundation to organize the fields into a new discipline termed ‘cognitive science,’ a term that now covers collaborative inquiry that includes neuroscience, philosophy, linguistics, the social sciences, psychology, and computer science. This collaboration recognizes that higher mental faculties are best understood as highly interdependent and thus require the involvement of multiple fields of study. They are not likely to be completely understood through biology alone but rather require an embodied sociocul-tural context. Prior to the late twentieth century, the dominant discourse when speaking of the brain has been to regard it as a machine along with what is termed ‘localizationism.’ This view holds that the brain is a complex mechanism, con-sisting of many parts, each performing a specialized mental function, lying in a hardwired or genetically predetermined location. Various scientific discoveries, beginning in the 1960s and 1970s, began to show that the brain can change its morphology with the activities it performs, rewiring and perfecting its circuitry. The discourse contrary to the fixed machine model is termed ‘neuro-plasticity,’ where ‘neuro-’ refers to neurons and ‘plasticity’ describes the ability to be alterable or malleable. No longer is brain structure considered to be fixed post-childhood, only changing when undergoing the decline involved in aging, but rather it is an open system that dynamically interacts with and changes itself through life experience. To use a machine term, the brain can rewire itself. This open system, however, is not completely open, a blank slate for environmental input. Nature is still seen as providing constraints as well as being open to possibilities. This means that the brain is open to nurture, challenging the theories that attempt to see nature and nurture as opposing categories. One can often find studies that attempt to determine how much of a behavior is nature and how much is nurture. The very statement ‘nature or nurture’ is disingenuous in that it seems to deny a physical substrate to nurture or to maintain that once one discovers a natural element, there is no room for nurture. Neurological terms can often imply a rigid internal process that leads inevitably to only one behavior. ‘Biological’ does not necessarily mean hardwired. Biological systems develop in close connection with the environment, and neither system functions without the other. Neuroscience is revealing that it is not genes alone that cause behavior, nor is it the brain, or culture. Behavior emerges from the em-bodied person actively engaged in the world. The systems approach presents a holistic view of the human person. It is not nature or nurture, but rather both. The same is revealed in studies of emotion and rationality. It is common in both neurological and theological writing to regard emotion and rationality as two contrasting forces involved in decision-making. One is logical and deliberative and the other irrational and spontaneous. When examining the neural circuitry of emotion and decision making, however, one finds them to be integrated to a large degree, with emotion as a much-nuanced concept composed of overlapping, indiscreet processes that are not represented by a single neural system. While certain brain regions are associated with emotions, almost all these regions have roles in cognitive and sensory processes as well. A primary role that emotions serve is to highlight what is important for ‘rational’ deliberation, as well as for what memory should encode and retrieve. Emotions are a part of rationality. Joseph LeDoux’s (b. 1949) studies on the survival value of various emotions calls into question the idea of emotions as antirational. There is no sharp demarcation between emotion and reason. Affective neuroscientists have abandoned the idea that there is a single emotion system in the brain. Older brain studies advanced the concept of a limbic system responsible for emotional processing, yet there have never been definitive criteria for inclusion therein. According to Ledoux, the term has become more descriptively useful than scientifically informative, and some have advocated for abandoning it as a concept altogether. Choices are not clearly led by the head or the heart but rather by both in an integrated fashion. The Ongoing Debate The relationship between religion and neuroscience is not one of open dis-agreement or one in which neuroscience can be said to have falsified religion. There are elements of conflict, in which some wish to believe that religion can be dismissed. However, this view represents conclusions beyond what the data present, and it reflects ideology and not science. More often than not, neuro-scientific data can be interpreted as either supporting religion or challenging it, depending on one’s preexisting worldview. The relationship between neuroscience and religion is best represented as an ongoing debate that includes multiple fields and multiple positions. A material, reductionist position is hostile to religion, but it could also be seen as being hostile to itself. To deny mental properties implies that one has understood them, which appears to concede the point. Scientific experimentation itself requires intervention in the course of physical events. Setting up experimental conditions for observation requires mental-to-physical causation, and forming conclusions requires mental- to-mental, inferring beliefs from other beliefs. One can make all sorts of mistakes about the contents of conscious states but not about their existence. One must be conscious to doubt the existence of consciousness. The true nature of the human mind remains an open question. Researchers and philosophers have advanced many other theories that are not hostile to religious belief, as well as adopting more functional approaches to what the brain does without worrying overmuch about the true nature of mind. The details of some religious beliefs have been challenged, encouraging theologians to reexamine current beliefs in light of how they were originally conceived in Scripture. The picture that emerges seems to be a much more integrated one than the strictly dualist, individualist, and cognitive view of the human person inherited from philosophy and incorporated into a variety of theological systems. And other dualisms, such as those between reason and emotion or nature and nurture, should also be considered in a more holistic manner. Despite some claims to the contrary, neuroscience has not demonstrated that spiritual experiences are nothing but brain function and are there-fore dismissible but rather that they are part of an embodied existence involving the brain, nervous system, and body in relationship and action with the outside sociocultural world, a view very much in line with current theological scholarship.