The human soul can be defined in a very general way as whatever it is about us humans that enables us to have self-reflective consciousness and choice, to have intellect and free will in standard language. It is what the Catholic theologian Karl Rahner refers to simply as “spirit” or as the power of self-transcendence. The soul has also traditionally been defined more specifically as a spiritual reality in the sense of being non-material or non-physical, each soul in fact requiring a special act of creation by God. This definition goes a step beyond merely asserting that humans have intellect and will, to asserting that only a non-material reality could be the source of intellection and choice. That has provided a basis for saying that science cannot study the soul, because the object of science is material reality.

Nonetheless, current neurological studies, especially in concert with studies in paleontology, anthropology, evolutionary and developmental psychology, and information sciences, together contribute increasingly precise and thorough understanding of the origin and nature of human mental processes. The cumulative effect of the work of these sciences make it plausible to claim that the modern human power of thought and conscious choice emerged gradually over millions of year through the material process of evolution, and that even the most complex thought processes, including the power of reflective self-transcendence, are produced entirely by the human brain (and the cultural history which provides cognitive tools for that brain to use). As a result a number of Christians have proposed an emergentist and physicalist interpretation of the soul, notions to be explained below. These interpretations, on the face of it, seem decidedly contrary to standard Christian doctrine of a non-material soul created specially by God.

SOME MATERIAL ON THE EVOLUTION OF THE SOUL
IMPLICATIONS OF CONTEMPORARY SCIENCES

Paleontology, anthropology, evolutionary and developmental psychology, neurological studies, and information sciences (e.g., computer theory), together contribute increasingly precise and thorough understanding of the origin and nature of the human mind. The next few pages will touch on small pieces of those contributions, not to make a comprehensive case but only to suggest the many ways in which new scientific understanding addresses issues that were part of Aristotelian and Thomistic notions of the intellective soul. The purpose here is not to settle the issues but to keep them open, as relevant scientific inquiry continues.

We can start with our evolutionary cousins, the chimpanzees. They can recognize themselves in mirrors, engage in what appears to be deliberately political and also deceptive behavior (not necessarily two different kinds of behaviors, of course), and use a few simple tools as well as teach others how to use those tools. Probably the smartest chimp known to date is a bonobo or pygmy chimp named Kanzi. He grew up watching his mother being taught a kind of symbol-language, and turned out to be a truly excellent if accidental student. To date, Kanzi is the Aristotle of the bonobos. He can recognize and respond to a hundred different spoken words, and can manipulate numerous physical symbols in two-word sentences. This is far from “intellection,” of course. Yet self-awareness and an ability to learn a form of communication well beyond basic chimpanzee vocal signals, are signs of a fairly complex animal intelligence.

Analyses of the degree of divergence between chimps and humans of DNA in mitochondrial cells, tiny “organelles” which live within the larger cells of all multi-celled organisms (and all cells with nuclei), make it probable that there was a common ancestor of chimpanzees and humans around five million years ago. Over the last three or four million years diverging series of hominids walked the earth. They are called hominids because their small brain cases show similarities to current human skulls. This similarity increases as the time of their lives is nearer to our own. The placement of the space for the spinal cord to enter the skull is evidence for a gradually developing upright posture; the size and shape and placement of hip sockets and parts of the leg bones confirms the movement to a more upright position; and so on. The evidence also supports a gradual change in intellectual abilities. Occasionally a skull fragment has interior impressions suggesting that the areas of the brain involving speech in humans today were already partly developed towards ability for speech. The pathway for the nerves from brain to tongue increases in size over time, perhaps as speech increases. Some evidence identifies a shift in the larynx to a lower place in the throat than in apes, towards the position that aids in the formation of more precise consonant sounds. (Recent fossil evidence of the Neanderthal larynx suggests that they may have had a form of speech also.)

Particularly striking is the series of stone tools associated with hominid fossils. Physical anthropologists spend months practicing the art of chipping different kinds of rock to make the same tools that earlier hominids produced, and to learn from this how much care in the selection of the rock, how much skill and care in chipping, and how much awareness of diverse uses of diverse tools went into this or that tool. Early crude axes were in production for over two million years, among homo habilis -- “handy human.” Then about 500,000 years ago, better and more complex axes were created, apparently by homo erectus. About 250,000 years ago a hominid sometimes called “archaic homo sapiens” (Heidelberg homo) was using a variety of axes, scrapers, and cutters. More recently yet, as modern homo sapiens came on the scene, a multitude of stone tools — awls, needles, scoopers, and other carefully crafted tools for specific purposes appear. Through these long years, brain cases enlarged even as tool making got more sophisticated. The evidence points strongly to a gradual development of intelligence, from that possessed by a pre-chimpanzee down through a sequence of hominids. Humanness slowly developed, including the power of thought. Before there were fully modern humans there were complex tool production, the use of fire, and some early speech.

Studies about language provide further relevant information. Humans are born with innate tendencies that conduce to learning language. Even during the first year of life children will attend longer to vowel sounds that are part of the language they hear from their parents than they do to foreign vowels sounds. When a variety of vowel sounds are played in the presence of an American child, for example, the child ignores umlauted vowels but attends to each of the varieties of “u” or “o” sounds used by the child’s parents. During the second year of life the child works very hard to try out different sounds, adjusting them to approximate parental speech. During the third year the child is putting together words in patterned ways, creating sentences the child has never heard before, using a grammatical logic simpler than real languages tend to be (creating a past tense by adding “-ed” as in “Mama buyed me a toy”). During this and the next few years the child shows an astounding ability to learn new vocabulary. Out of this process comes the adult’s ability to use language to describe, persuade, analyze, and argue. The brain is apparently programmed to proceed through this learning sequence, if the overall environment provides the means for this.

It takes an unusual brain to use language as humans do, and not just because it took millions of years for these various now-innate abilities to evolve. We are normally unaware of the complex interacting brain processes that go into an ordinary conversation. In Broca’s area of the brain (like other so-called areas, not entirely a discrete section), we somehow select words out of long-term memory to express our ideas, and almost simultaneously, it seems, use the motor segments of the brain to coordinate precise motions of the lips, tongue, jaw, larynx, pharynx, and diaphragm. Even as we do this we employ an adjoining area (Warnicke’s) to monitor our speech, making almost instant adjustments in our word choice, pronunciation, volume, sometimes in response to the information our eyes are providing us about how our ideas are being received.

There are interesting speculative reconstructions of the sequence of brain developments, from proto-chimps to us, that led to this set of linguistic abilities. Whether any of these theories are adequate or not, they share in the general hypothesis that the biology that makes language possible developed over millions of years. Genetic changes are ‘selected’ (survive and spread) when they confer some advantage for survival and reproduction of the genes that carry those changes. There is always a cost to brain functionings, especially in us humans. Cat and dog brains use about five percent of the metabolic energy of these animals; monkeys and apes about ten percent. But twenty percent of human metabolism is devoted to brain maintenance and functioning. In all these animals brain mass is only about two percent of the mass of the whole organism. In terms of energy needed, human brains are expensive to maintain. Each evolutionary step along the way, as the brain placed more and more demands on the resources available to the whole body, it must also have been paying its way by conferring extra means for survival. It is reasonable to suppose that the development of language, from the original limited vocalizations of chimpanzees through to current human language ability, had to proceed step by step, with each step representing great linguistic “intelligence” than before.

A plausible hypothesis arising from all this is that the power of thought we humans now enjoy did not suddenly appear about 100,000 years ago or later, when fully modern humans first existed, but that such thought is the product of a long physiological evolutionary development. Nothing logically forbids a different hypothesis — that all these developmental steps were preparing a brain with excess capacity not yet used in intellection, that someday would work with a newly created spiritual soul in truly intellective activity, that God began to create human souls only when the brain was fully ready to allow at least some of the truly human beings to engage in such thought. Yet there are difficulties with this. How should we think of Neanderthals, or earlier tool makers and fire users. If they had ‘human’ souls were they lesser souls? If they did not have human souls, they were nonetheless able to think and plan better than any other animal on the planet, as their complex tools show. Homo erectus and later hominids were using their larger brains for cognitive skills beyond that of apes or chimpanzees. If this high intelligence could slowly emerge from material evolution, what is there to say that the next step, fully human mentition, did not? The usual answer has been that humans engage in abstract forms of intellection that requires an intellective power not limited by materiality.

The crucial question remains, however, whether current studies of brain development and operation make it plausible that the brain, if sufficiently developed and educated, could produce even the most abstract forms of thought, including self-reflective thought and choice, and the openness to the infinite this entails.

The notion of abstract reflection itself has been rethought in the last half century, as part of the attempts to make an intelligent computer. Engineers are very far from achieving that, but in the course of working on the problem have learned a great deal. On the one hand, the human mind works differently from computers. Computers have usually worked by sheer speed of computation along single paths. Human minds work by an awesomely greater complexity of interconnections along many paths simultaneously. Nonetheless, we are not entirely different from computers. Speculations about how to build an intelligent computer usually propose that intelligence requires multiple interacting processors such as the brain already possesses. The vivid visual images we have of the world, for example, are created in us by a set of distinct neural columns in our occipital lobe. One set of neurons responds to major differences in light or dark, another to specific linear boundaries, another to motion, another to certain colors. All of these columns of neurons are connected in turn to another set of neurons which integrate these various aspects of what we see into a single image. Here there is a hierarchy of functions, with one ‘higher’ integrating processor, as it were, making use of the distinct contributions of ‘lower’ processors dedicated to specialized tasks.

The earlier description of the interaction of sections of the brain in speech is a clue that the brain in general has a great number of different ‘processors.’ It is a disputed question among the psychologists and neurological researchers and philosophers interested in cognition whether there is (or needs to be) a “central processor” neurological structure in the brain, that can account for the more abstract and complex forms of reasoning or for the strong human sense of self-awareness and free choice. Philip Johnson-Laird, for example, argues in favor of a central processor function in the brain, while Merlin Donald supports the loose working group model, in which the neurological structures most relevant to a given task tend to take over for those tasks. The philosopher Leslie Dewart argues that it takes language to create explicit self-consciousness. Unless we learn to employ language in specifically self-referential ways, selfhood remains only liminally present.

An important basis for some claims about the nature of thought is introspection. How could we know what an experience is, subjectively speaking, except through having subjective experiences. But if we introspect to look at our subjective state of experiencing , we are objectifying those subjective states, as objects of our introspection. If we then think about those acts of introspection by which we objectify our experiencing, we then objectify our originally subjective act of objectifying our ( originally subjective) experiences. And so on. Analogously, the brain may have some processings, some states of awareness, which are aware of the result of other processings, followed by a processing concerning these previous processings. All such inner awareness may in fact be a kind of internal ‘conversation’ that aspects of the brain carry on with each other.

More importantly, most brain operations are not subjectively available at all. Introspection tells us only a small part of what is going on. Complex and interconnected brain activities show up clearly through magnetic resonance imaging technology. The brain tells us we feel a prick on our hand at the same time we see the needle applied to our hand, when in fact there is a lag in the time it takes the brain to register the feeling. Without our knowing it, the brain reconciles sensory input so it “makes sense.” A fairly well-localized part of the brain involved in making decisions shows activity a split second before a person is conscious of making the decision. It is as though the brain decides things prior to our consciousness; then we experience the decisions as though we just consciously decided them. We also know that the right side of the brain, normally lacking its own language centers, does not have conscious awareness of information it is in fact receiving and processing accurately from the senses. It is as though it is precisely language (usually in the left brain) that gives us the ability to have an “I” who consciously experiences or sees or touches something. It would be odd if the self-aware soul received information through only part of the brain. Plato put mathematics furthest of all above the line dividing the material and mutable from the immaterial and immutable. An ironic piece of information from brain studies is that mathematical ability is highly dependent on the functioning of a section of the rather material right brain.

Under the rubric “information theory,” a phrase I will use rather generally here, a modern scientific approach to the structures and processes of reality has further implications for how to think about mind or soul. Simple atoms of hydrogen and helium are torn apart in the nuclear reactions of large stars and some of the resulting materials are fused together into heavier elements like oxygen and carbon. Extremely large stars near the end of their lives rip apart even these heavier elements and out of them form iron, nickel, gold, even lead and uranium. One can try to “reduce” gold to the particles of which it is made, held together by nuclear and electromagnetic forces. In one sense that is easy to do. An atom of gold is composed of 79 protons, the same number of electrons arranged in six ‘shells,’ and enough neutrons to bring the atomic weight up to almost 197. The protons and neutrons are held together in the nucleus by the strong force; the electrons surround the nucleus in a certain way because of known characteristics of the electromagnetic force. But this accurate account is also grossly inadequate. What counts is the particular interrelated arrangement of protons, neutrons, and electrons of gold. This arrangement is not just a gathering of particles; it is a particular highly structured pattern bonded into a stable unity, which produces characteristics unique to gold -- the malleability and ductility, the shine and color, its particular conductivity. This arrangement is analogous to a code, an ordering of bits of the atom to produce a certain outcome. The arrangement is thus a kind of “information.”

The power of interrelational structure among particles to produce gold is exceeded enormously by the power of interrelational structure among elements — oxygen, carbon, nitrogen, hydrogen, and phosphorus especially, to form chains of compounds whose order produces life activities. Here a much more complex layer of information produces much more complex activity. Chains of compounds eventually developed differentiations and levels of interaction that constitute cells. Cells eventually achieved a set of stable interrelated activities that constitute multi-celled organisms. Each of these steps is a higher level of information. Each level of information produces more complex activities.

Showing that such complex activities can be produced by complexly functioning information codes is not the same thing as saying that the activities are nothing more than the codes. If the activities of the brain are, at least in part, what we mean by intellection, that does not mean that intellection is just brain. It is a set of activities carried out by the brain, under the influence of the human genetic code, as well as the influence of the individual learning that the code makes possible, as well as the influence of thousands of years of cultural developments handed on from generation to generation on how to do intellection in various ways. In humans the full set of informational codes of elements, compounds, cells, multi-cellular life, and neural cell interaction with trillions of potential interconnections are beyond computation except in the most superficial and general way. The activity and results of the DNA code in a single cell is already an achievement of nature exceedingly far beyond what ancient science even guessed at.

The activities of the human brain surpass that of a cell by many orders of magnitude. It is not surprising that the ancients thought they would have to invoke some sort of animating spirit to explain life, and a special immaterial soul to explain cognition. There is an alternative model now available, well-grounded in highly specific and complex information, of mind as code-and-learning empowered activities of the brain (and central nervous system in general).

None of these studies, of evolutionary history nor of the brain, disprove the existence of a immaterial intellective soul. Yet taken together these studies show the possibility that reflective intellection and self-awareness are processes that the brain might carry out without need of any further source of intellective power. These studies also need to be interpreted in the context of an enormous change in the background theories which once made the traditional notion of the soul plausible. Souls in general, vegetative and sensitive and intellectual, as well as the notion of substantial forms, no longer offer much as ways to account for what takes place in the world. Animism (belief in souls) is no longer is a viable explanation of how wounds heal or why an embryo develops (or why the planets move in regular orbits). Belief in a immaterial intellective human soul is a lonely holdout from a world full of souls

THE “SOUL” AND MATERIALISM

Many complex issues related to the topic of the soul remain. What of purgatory, for example? Or is abortion more justifiable at a stage when the brain is minimally developed? Or can a mind produced by a physical brain be free of physical determinism? In fact, theologians have already addressed these and other issues. Ladislaus Boros, for example, proposes the possibility of a final option at death, noting that a purely spiritual soul presumably would not experience any temporal lag between death and final resurrection, because such a soul is not temporal of its nature except inasmuch as it is both ordered to the body and actually united with the body. Rahner more cautiously proposes simply that at death there can be an ‘intermediate state’ [partial quotes in the original] constituted by the difference between the finality of an individual life and the consummation of the world. On abortion, Joseph Culliton argues that Catholic opposition to abortion at any stage in the development of the embryo or fetus does not rest on a claim that a spiritual soul is present throughout but on the finality of the developing life towards consciousness, freedom, and God. The issue of human freedom is difficult in any framework. Nancey Murphy borrows the idea of “supervenience” to sum up her analysis of mind exercising a ‘downward’ causation on the brain, just as the brain does on the body, and so forth. I cite these various theological efforts here not to adequately address the problems but to suggest that theologians have already been at work on rethinking the notion of the soul, and that many apparent problems with an emergent view of spirit may be at least as easy to resolve as such long-standing conundrums as traducianism (that parents pass on soul when they conceive) vs. special creation, or how the soul (the agent intellect) actively takes up information from the body.

On a more positive side, the integration of the soul with the whole of creation provides a basis for a more unitary theology of creation; and it is also a further step away from the gnostic belief in transmigrating souls so popular in New Age thought today. On the first point, William Wallace, O.P., distinguishes between the natural and human sciences by adverting to the different kinds of souls involved. He notes that where we now attribute life activity to “energy” we nonetheless also still use the word “soul.” His goal is to show that a hierarchical integration of the levels of nature, from the basic four forces and the nuclear, physical, and chemical activities based on them, to organic processes of cellular life and reproduction, to the sensations and responses of animal life, to the cognition and volition of humans. He gathers all the natural sciences under the one label to distinguish them collectively from the human sciences, in line with the sharp traditional distinction between humans and the rest of nature. Yet the goal of his article is precisely to counterbalance this division by showing the natural unity of all levels of reality in the person. He would have achieved this even more fully were he able to speak of human intellection and freedom as arising from and upon general animal intelligence, just as animal intelligence arises from and upon more general life processes, and so on.

Part I: BACKGROUND ON THE STATUS OF THE SOUL

Work by theologians on the topic of the soul in the light of modern brain science is in process. Warren S. Brown, Nancey Murphy, and H. Newton Maloney, along with six other contributors to their book Whatever Happened to the Soul, many of them professors at the somewhat conservative Fuller Theological Seminary, have perused the relevant scientific literature. They are persuaded that what we call the soul has emerged from the material process of evolution. As a result they now proclaim their support for what they call a “non-reductive physicalism.” The word “physicalism” signifies that mind/soul arises from activities of the physical brain. The word non-reductive indicates that mind/soul is nonetheless distinct from the brain, though not separate from it. These authors claim the emergent mind is then in a position of supervenience — of “top down” causality — in relation to the brain. This is intended to preserve the notion of human free choice; the mind is not fully determined by the activities of the brain.

Work by theologians on the topic of the soul in the light of modern brain science is in process. Warren S. Brown, Nancey Murphy, and H. Newton Maloney, along with six other contributors to their book Whatever Happened to the Soul, many of them professors at the somewhat conservative Fuller Theological Seminary, have perused the relevant scientific literature. They are persuaded that what we call the soul has emerged from the material process of evolution. As a result they now proclaim their support for what they call a “non-reductive physicalism.” The word “physicalism” signifies that mind/soul arises from activities of the physical brain. The word non-reductive indicates that mind/soul is nonetheless distinct from the brain, though not separate from it. These authors claim the emergent mind is then in a position of supervenience — of “top down” causality — in relation to the brain. This is intended to preserve the notion of human free choice; the mind is not fully determined by the activities of the brain.

There are in fact a variety of physicalist or emergentist positions on the soul. Keith Ward agrees that the soul emerges from the evolution of matter. He supports a “soft materialism,” as he calls it, which takes seriously that what emerges from matter might be yet more than material. Richard Swinburne also concludes that the soul is a product of the material evolution of the universe, but he claims that soul has become so distinct from matter that only a new sort of body-mind dualism adequately describes the nature of this evolved soul. William Hasker proposes that the human mind is a “soul-field” generated by the brain, analogous to a magnetic field generated by a magnet, both fields real and distinct from what generates them. He too is concerned to assert that this “soul-field” can exert “downward causation” in order to escape determinism.

Fortunately, we do not have to decide yet among these and other speculations. Scientific explorations of the evolution, development, and functioning of human consciousness are impressive but a great deal of work still lies ahead. This is evident, for example, in heated debates among philosophers of consciousness who are knowledgeable about the state of neurophysiological studies and yet cannot agree on the nature of subjectivity or self-awareness. Duke University philosopher Owen J. Flanagan coined the name “mysterians” to label those who argue that human consciousness is far too complex and strangely different to be analyzed out into neurophysiological categories alone. Two of the best known mysterians are David Chalmers of the University of Washington and Colin McGinn of Rutgers. A common answer is the sort offered by Thomas Metzinger, who says think we are selves because we have formed a “self-model.” This model is transparent — i.e., we do not see it; rather we use it to see ourselves. Metzinger is in general agreement with the influential philosopher Daniel Dennett. The number of books on the topic keeps expanding.

The rest of this first section of the chapter, instead, will focus more narrowly on the question of what is essential in the traditional doctrine of the soul and what is legitimately open to change. There are several parts to this analysis. The first is to articulate in a general way which notions associated with belief in a spiritual soul are probably essential to a Christian understanding of the person. The second is to survey briefly some early history of notions of the soul, to see to what extent these notions were indeed part of ancient science.

A Brief History of the Soul: Some Options from the Past.

The history of Christian belief about the soul is complex. It is probably safe to say that the earliest Christian belief in salvation was not based on belief in a Platonist sort of purely immaterial and therefore naturally immortal soul. It was based on belief in God’s power and promise to raise the dead to a new life. John Cooper argues persuasively that it was common for Jews of Jesus time to believe that a ghostlike self (psyche)did survive death, but its fate was a dreary hades-like existence. Jewish and Christian apocalyptic thought instead offered a glorious risen life of the whole person into wonderful kingdom of God.
In antiquity there were a number of theories of human nature in contention. The Stoics used a deistic sort of argument to show that there was a divine Logos at work in the universe and that every person’s rational and animating principle was a spark of that Logos. Here cosmology and anthropology merged. The Stoics, however, believed that at death the person’s inner rational self was dissolved back into the Logos, so Christians could not adopt Stoic anthropology. Various forms of Platonism argued that the universe emanated from an ultimate One. Following one or more of Plato’s leads, Platonists claimed that the inner powers of abstract thought indicated that each person had a immaterial soul whose natural mode of existence was other than the concrete conditions of materiality. The Platonist desire to escape materiality entirely conflicted with Christian belief in a physical resurrection, so Christianity could not accept an unqualified Platonism.

It was apparently not long until most Christians had arrived at their own modified Platonic anthropology of the sort one finds in the works of Augustine. In his work The Literal Meaning of Genesis, for example, he wrestles with various notions of the soul and how it relates to the body. Augustine’s main problem concerning the soul in this work is where souls come from. Are they pre-existent and sent to their bodies at the appropriate time, as Origin might have thought? Or do they exist in the “causal reasons” which God planted in the universe at the beginning, out of which the many later kinds of things in the world eventually emerge? Or did God specially create the very first soul in Adam, out of which subsequent souls are passed on through reproduction (or in Eve’s case by a kind of spiritual cloning)? Or does God create every new soul individually, as needed? To some of these questions Augustine could not provide firm answers, though he favored special creation of each soul by God..

Though this is theological analysis, much of this speculation has its roots in ancient science. It was Aristotelian science, for example, to explain plant life by vegetative souls, animal life by sensitive souls, and human life and thought by intellective souls. Modern biology addresses the same questions about life activities, but uses a different explanation to account for them. In the cosmology of the Neoplatonists, the hierarchy of being from the One, then the Nous and World Soul, through gods (some of them planetary souls), humans, animate beings, down to dirt, explained the order of the universe. Modern science has reversed this order. Today the order is explained by the story of cosmic evolution, from the Big Bang energy, to the emergence of the four basic forces of the universe, to the formation of particles, then atoms, then stellar furnaces churning out heavier elements, then complex compounds, and then on this planet at least the appearance and evolution of life including eventually human life. In Neoplatonic physics and biology (though the latter name had not been coined yet) soul-power emanating from the One, given certain categorical order by the Nous and passed on by the World Soul, provided the motive power and the goal-orientation to the patterns of the cosmos and to the living beings within it. In modern science the DNA information code, developed over billions of years of variation and natural selection, now accounts for the life processes and their apparent goal-directed behavior. Christian understanding of the human person wrestled with ancient philosophies functioning as science, adapting them to fit basic belief in the freedom of the person to choose good or evil and the possibility of eternal life with God after death offered through Christ.

It is similarly easy to identify what we could call ‘scientific’ aspects of ideas about the soul in medieval theology. A major problem in astronomy, for example, was whether the regular motion of the planets meant they also had souls. Aquinas finds it natural to discuss why the nature of sensation requires that the human soul is united to a complex body made up of all four of the basic elements rather than to a simple and more refined single element such as fire. This is not our science, but it is clearly an attempt at a philosophy which seeks what current science still seeks — to know how the natural world works, by what forces and what elements. Soul-energy and soul-guidance were once part of that explanatory framework. The question now is how far we might legitimately go to extricate key notions about the human spirit from these ancient frameworks

The Emergence of Spirit in the Evolution of Matter

Robert North is correct, I believe, to point to Karl Rahner’s reflections in Hominisation as a valuable guide for rethinking the Christian doctrine of the soul. This has been spelled out well by North and elsewhere, so it is possible to be brief here.

Rahner beings with the outline of cosmic history sketched by Teilhard: the universe has developed from raw energy to complex forms to planetary systems to cellular life to multi-celled life to sensate and conscious life and to human life. Even before there were humans around to raise the question of their inner spirit, matter was constantly becoming more than it had been. Matter had already become more than mere matter when even the simplest life appeared. For a Christian all of this is part of the ongoing creative concursus of God. If the inner consciousness and freedom of the earliest humans (wherever we might locate this) emerged from the evolutionary process of the universe, this is God’s creativity at work. The same is true of each new child conceived. That this universe can bring forth both rational thought and consciously chosen love could be a religiously comforting thought to those who claim that the evolving universe is truly God’s Creation.

Rahner also elaborates a metaphysical basis for the Teilhardian approach. He begins by invoking the traditional idea of divine “concursus.” The major point that distinguished the doctrine of God from Hellenistic concepts in ancient times was the insistence that God created the universe out of nothing. The universe is not an overflow of divine reality, emanating from the One. Nor is the universe some everlasting stuff which either the Unmoved Mover keeps active or to which the divine Logos gives form. For its continuing existence the universe is radically dependent on a continuing sustenance in being by God. God is “creating” the universe at every moment, by actively keeping it in being rather than allow it to collapse into nothingness. Were this a static universe, the concursus would simply sustain everything more or less as it is. But this has been an evolving universe, in which raw space-time/matter-energy has continued to achieve ever greater levels of complexly interrelated order and functioning, even ever greater levels of responsiveness and consciousness and, in us humans, reflective self-awareness. Rahner argues that the divine concursus has always apparently been empowering what would otherwise have been mere matter to become more than mere matter and to arrive at even human consciousness. So God has been creating all things all the time — including that most significant of creations, human souls. As North points out, this perspective allows Rahner to say both that God creates every soul just as God is constantly creating everything, and also that the parents of a child are the parents of the whole person, including what we mean to identify when we speak of both body and soul. Here distinctively human thought and freedom may be a product of God’s creativity exercised through the secondary causality of evolution.

The speculations of Swinburne and others mentioned earlier here, however, press beyond the brain towards a new dualism, towards belief that the soul which has emerged from evolution is now non-physical. So the question is still whether the soul — i.e., the power of self-transcendence and its capacity for the Infinite, for freedom, and for the eternal — can be entirely the workings of a material brain. Unfortunately, the language we use militates against this by distinguishing rather sharply between matter and spirit.

Those who take a “physicalist” position on the mind are taking the path of materialism, it would seem, and denying any real spiritual quality to the human person. Karl Rahner offers a way around this sharp dualism of matter and spirit. Because materiality, like all aspects of creation, comes from nothing except God’s power, from the Infinite Spirit, then even matter is a kind of “frozen” spirit. He argues that “materiality itself must be understood as the lowest stage of spirit.” Matter and spirit both share the status of created reality, aspects of the evolution of the cosmos created by the Uncreated Mystery. Conversely, for our purpose here, we are exploring the notion that “spirit” is what matter does in the form of certain complex brain activities.

Part II. THREE FURTHER ISSUES

As the introduction noted, this section will address the questions of 1) the degree to which doctrine on the soul uses outmoded science, 2) whether a physicalist interpretation of the soul is a form of reductionism, and 3) whether a physicalist interpretation is deterministic and thereby eliminates free will. A common element in the comments offered here will be the role of history — of doctrine, of the overall evolutionary process including hominization, and of the individual and the culture which forms the individual.

1. Ancient Science in the Notion of the Soul
It has happened before in Catholic tradition that old science was mistaken for true doctrine: the condemnation of Galileo’s Copernicanism by the Roman Inquisition. The Inquisitors said that the Copernican hypotheses “are contrary to the true sense and authority of Holy Scripture.” This was not an aside. They repeated that heliocentrism “ is absurd and false philosophically, and formally heretical because it is expressly contrary to the Holy Scripture.” Ironically, the astronomy that the Inquisitors were defending was as much Ptolemaic as it was scriptural. Galileo had already made the point that the astronomy of the bible was different from the Ptolemaic view which the Inquisitors defended. In his now famous letter to the Grand Duchess Christina, he cited Augustine’s attempt to reconcile the account of creation in the Hebrew scriptures with the Hellenistic science of his time. “What is it to me,” Augustine asks, “whether heaven, like a sphere, surrounds the earth on all sides as a mass balanced in the center of the universe [as the Greek astronomers said], or whether like a dish it merely covers and overcasts the earth? [as Genesis 1 seems to say] (De Genesi ad Literam, ii.9)” Galileo continues to quote Augustine as Augustine discusses whether the heaven is indeed a “firmament,” as Genesis says, and if so how it is possible for heaven to rotate, carrying the fixed stars imbedded in it around and around the earth. Even though the flat earth of Genesis, covered with a solid dome which held back the surrounding waters, was not the geocentric multi-heavened world of Hellenistic natural philosophy, Christianity nonetheless came to adopt the Ptolemaic view and used it to interpret what the scriptures must mean.

The case of Copernicanism, however, differs in one very important way from Platonist or Aristotelian notions of the soul. Both the Ptolemaic view and the Copernican were proposals that could in principle be shown by empirical evidence to be false. There is no way, however, to provide empirical evidence against the existence of a non-material soul. No matter how much mental activity can be tied directly to brain states or processes, it could nonetheless still be possible that there is an additional, invisibly operating, non-material soul lurking behind these material processes.

A more relevant comparison here is to 19th and early 20th century vitalism and the effect that the theory of evolution, the discovery of genes, and of DNA had upon vitalism. Vitalism supporters argued that life activities could not be accounted for by materiality alone or by “mechanistic” processes. The amazing and orderly development of every embryo, the ability of animal bodies to heal wounds, the power of regeneration of limbs in some organisms, could not possibly be the result of material processes alone. Some guiding and vital force, some goal-directed non-material agent had to be involved, the vitalists argued. As in the case of the soul (or of miraculous interventions such as special creation of each soul) there is no way to disprove vitalism. Some such soul-like power might be at work in a hidden manner.

But developments in science have made vitalism unnecessary and implausible. Darwin’s theory explained how complex life forms might arise, not through goal-directed forces like souls, but through a blind process of variation and natural selection. Darwin’s theory gained a further foothold in the early 20th century when it became clear that each organism had a complex body of genetic units which could be passed on in various combinations. A staunch vitalist could still argue, however, that perhaps each “gene” had its own goal-directed soul. In the mid 20th century, of course, Watson and Crick described the basic structure of DNA, a highly coded structure which “directed” the production of various proteins and thereby accounted for reproduction, healing, and other life processes. Our devoted vitalist could argue that there still might be hidden soul-like forces at work. But this hypothesis has become unnecessary; there is no longer any evidence to make it at all plausible.

The same has become increasingly true of the notion of a non-physical soul. As the relevant sciences continue their work on the brain, as they continue to be able to account for more and more aspects of human thought, a non-physical soul is increasingly becoming an unnecessary hypothesis. If neurological sciences do in fact turn out to be able to account well for human intellection, that will make it much more plausible that whatever the human soul is, it is part of the evolving natural world of space-time / matter-energy.

This would be consistent not only with the overall scientific picture we have of the universe but also with a certain theological vision. As Rahner has pointed out, there is only one truly supernatural reality which is the infinite God. All else, including the soul, is part of the created order, the order of finite, determinate, and contingent being. It should not be surprising that modern empirical sciences have something to say about even the soul, just as ancient sciences once provided a different framework.

2. The Threat of Reductionism or  reductive "naturalism"

To say that science can study the soul still may sound like a simplistic reductionism, whereby the enormous complexities and subtleties of the workings of the mind are reduced to the relative simplicity of neurological activity. It is important to say “relative” simplicity, because the countless billions of neural connections in the brain are staggeringly complex. When neurophysiologists declare they are reductionists, this is often misleading. In practice most of them simply mean that they think mind activities are entirely due to brain processes, not to an additional spiritual agent. A comparison to a different problem in science may be helpful.

In the part of physics that is concerned with working out mathematically such things as the effect of gravity on physical bodies, there has long been what is called the “three body problem.” It is not horribly difficult to work out the mathematics of the gravitational interplay between earth and the sun. Nor is it difficult to do this with Jupiter and the sun. But the interplay of the gravitational pull of both the sun and Jupiter on the earth is too complex to handle. In the 18th century physicists armed with Newton’s laws tried to figure out whether the pull of Jupiter upon the earth would eventually drag the earth from its orbit and set it adrift in the cosmos. Right through the 19th and 20th century they kept trying to get the math right, but the many factors involved made the problem intractable. A first major step towards a solution was to simplify, to pretend that certain parameters could be ignored. Modern supercomputers have brought physics closer to a solution, but still through an artificially simplified model.

The actual workings of the human brain are on a level of complexity that makes the three body problem as simple as 2 x 2 = 4 by comparison. Neurophysiology will undoubtedly be able to tell us a lot about how the brain operates, about which parts are active when making choices or analyzing a problem. But no matter how complex the neurophysiological description becomes, it will remain only a severely simplified model of what is actually going on. Consider five words you are familiar with: “Tomorrow, and tomorrow, and tomorrow . . . .” Your minds may have already jumped ahead “to the last syllable of recorded time,” perhaps even to the “sound and the fury, signifying nothing.”

Brain scans can identify which neural pathways are involved, which long and short term memory functions, which emotional centers, and so forth. Yet there are countless allusions, connections, implications, connotations already rumbling just beneath the surface in your mind. Perhaps you see Great Burnam wood walking up high Dunsinane Hill. Perhaps you hear echoes of general human ambition, betrayal, and loss. Perhaps you are slipping into reveries about high school and the teacher who introduced you to Macbeth. On and on the mind reaches, crowded with personal stories built upon hundreds and thousands of years of human cultural development. Perhaps these words even remind you of the ever-receding horizon of mystery, within which all this memory and experience and thinking take place. The neurophysiologists may be correct that all this is what the brain does. But they mislead themselves when they think their science can get much beyond the relatively simpler “3-body” stage of mind. The realm of human thought and choice covered in the humanities in academia is something like a multibillion-body problem. Freeman Dyson has called this the “complexity frontier” of science. What we could describe also as an ever-receding complexity horizon. The neurophysiologists often forget this when they write about how much our understanding of the brain has increased. Theologians and philosophers and humanists in general can stand ready to remind scientists of the transcendental reach of human thought. The humanists will not have much of an audience among scientists, however, if they insist on retaining ancient science to explain that transcendentality.

3. Determinism and Free Will

If the brain is fully material, then it would seem to be restricted by the cause-and-effect determinism that rules nature. This determinism itself seems limited in nature in two instances. One is the “chaos” element. The famous image of a butterfly’s wing setting in motion what will become a major storm on the other side of the world illustrates this element. But it would be more accurate to see this as another instance of the complexity frontier or horizon. Chaos theorists do not deny cause-and-effect determinism here; they only note that the variable effects of events are far too complex to predict.

The instance where strict determinism in fact does fail is on the quantum level, where only statistical probability and not deterministic cause-and-effect rules. Quantum indeterminacy gets rid of full determinism in favor of a degree of randomness. But if free will exists only as a function of a somewhat random quantum indeterminacy, then free will it is not the reflectively conscious choosing which the idea of free will seeks to save.

Oddly, there is good reason in Catholic tradition not to try to save the concept of free will. Thomistic scholasticism did quite well without it for centuries. Aquinas proposed that we do indeed make free choices. But the will is determined by its nature to seek whatever the intellect presents to it as the good. Choice lies with the intellect, as it reflects on things and determines where the good lies and where it does not. The fallen intellect is not very good at this; hence the frequency of sin. But it is the responsibility of every person to seek to understand clearly what is good and what is not — to develop an informed conscience in the traditional language.

There is another problem that appears in attempts to save the concept of free will. Two alternatives dominate the discussions. One is the possibility favored by many theologians and philosophers that there is some non-determined causality exerted by the will in making a genuinely free choice. This possibility, however, posits a cause other than God that in some small way is like God — uncaused. This is a rather awkward position for Christian theology. The other alternative is that our choices are made by our brains, which are fully physical and therefore fully determined by the ordinary laws of cause and effect of all material reality. This might seem to eliminate freedom altogether.

There is a third way of thinking about freedom. This focuses on the historical reality of a person’s life and choices. Some have sought to save free will by the idea of a top-down influence, a “vertical” image of mental causality. It would be truer to the historical nature of existence to use a “horizontal” image, to represent the ongoing influence of sequences of past states of self-reflective consciousness on subsequent states of the brain. Every state of human self-consciousness is part of a stream of consciousness, a changing stream in which thoughts upstream determine something of the path of thoughts downstream.

The causal flow from past to present and future states of consciousness is highly complex. Most of what the mind does is not part of waking consciousness. The brain keeps the autonomic nervous system running, for example. This keeps our innards operating as they should, without our awareness (except when things go wrong). Similarly, when we are prompted to identify ourselves by typing in our mother’s “maiden” name, our brain somehow pulls that name up out of storage into consciousness without us knowing or even experiencing what the brain is doing to accomplish this. This is only one of a thousand acts of memory our brain performs for us, without us experiencing the actual neural activity as such. We also carry on oral arguments without being able to sense the operations of Broca’s area, Warnicke’s area, the relevant motor control areas of tongue, lips, and larynx, yet they are all highly involved in the process.

Interestingly, much of even what we think happens first in self-conscious choice and then is carried out by our brains seems to work the other way around. The neurophysiologists tell us that a non-conscious activity first takes place in the part of the brain whose activity signals decisions being made. This non-conscious activity occurs as much as a half second before there is activity in the part of the brain where people consciously make decisions. Should we therefore conclude that non-conscious brain activity and not conscious choice determines what we do or think? We should conclude that only if we forget that the non-conscious activity was itself preceded by prior conscious activity. Philosophical analyses of how a given decision takes place, whether from the top-down or the bottom up, often commit a form of Whitehead’s “fallacy of misplaced concreteness.” It is not the single moment of reflection or choice that should be the object of attention; it should be the stream of states of reflective consciousness and unconscious that constitute the actual and concrete mental life of any person.

It is all even much more complex than this “stream” image implies. From before the time we are born our minds are developing. Sometime after the age of 3 we develop a “theory of mind.” A child becomes aware that other people’s minds can be different from the child’s. This also leads to an awareness in the child that all the talking and thinking and imagining the child has been doing also has behind it what we call a “mind.” The notion of being a “self” takes a step forward in the child’s own self-awareness at this time. Through years of development we all have millions of conscious experiences in the midst of the ongoing flow of the larger non-conscious activities of the brain. Cumulative those conscious experiences have a strong impact on the non-conscious part. As note, one of the results of this cumulative life of learning and reflecting consciously has been called an “informed conscience.” It is a determinant of our choices. This is free choice in the Thomistic sense.

Cultural development is part of this story also. If we can now choose to forego revenge against someone who has harmed close kin, it is because culture has educated and even habituated us to act contrary to our normal human tendencies. If we can extend kindness and compassion to those who are unlike us and who will not contribute to our well-being, it is because culture — perhaps the religious tradition — has educated and even habituated us to this. Ideas that become part of our conscious life partly determine non-conscious habits (virtues?), which in their turn will determine what our next state of consciousness is like.

The linguist Derek Bickerton divides consciousness into two types, online and offline. Online consciousness belongs to animals in general including humans. This is the cat fascinated by the chirping of a fledgling, or the dog who marks its territory. It is immediate awareness. Offline consciousness seems to belong almost exclusively to us humans (chimpanzees may be a partial and very limited exception). This is the ability to create scenarios in our minds of past conditions or events, as well as of alternative possible present and future states. We get this ability partly just from being human. But society and culture can teach us how to do it well and usefully and morally. This ability is determined, by our genetics, our personal development, and our social context and its history. But it is not therefore a loss of conscious choice. For in the ongoing flow of consciousness, we can set before ourselves with deliberate consciousness the alternative paths of action we can take, the possible outcomes of those actions, and the moral standards our life and education have given us to be able to evaluate those outcomes. This is the power of moral choice, with none of it requiring some uncaused cause activity by a non-physical soul.

Conclusion

All this is possible with a mind that is simply brain processes. The words “soul” or “spirit” still serve the important purpose of reminding us of our humanness, of our ability to come into even exquisite degrees of deliberative self-consciousness, influencing both non-conscious activities and online consciousness. The words remind us of the awesome complexity horizon within which we operate. They remind us of our dignity and our orientation toward the Infinite Mystery.

These few thoughts certainly do not encompass all the issues related to soul. The most important, perhaps, is the traditional idea of eternal life. But specific issues such as ensoulment and abortion or the soul and purgatory, need to be and have been addressed more thoroughly. I hope only to have offered some further support for those who are seeking a way to see the soul as an emergent part of the evolving creation.