Chapter 4

 Chapter 4

The Soul and the Human Vessel

“What if consciousness does not begin at birth, but embodiment does?”

 

Words That Are Often Treated as One

Throughout history, people have used terms such as soul, spirit, mind, consciousness, self, identity, and awareness. These words are often treated as though they refer to the same thing. They don’t necessarily.[1]

In ordinary conversation, these words frequently overlap. But when philosophers, psychologists, neuroscientists, and theologians use them, they can mean very different things. That lack of precision has complicated conversations about consciousness for centuries. Two people may appear to disagree when, in reality, they are using the same word to describe different concepts—or different words to describe the same mystery.

Consider a simple example. When someone says, “I lost myself after the accident,” they are rarely suggesting that their consciousness disappeared. More often, they mean that their personality changed, their memories became fragmented, or their sense of identity no longer feels familiar.

Likewise, when someone speaks of a “soul,” they may mean an immortal essence, a person’s deepest identity, a spiritual self, or simply the emotional richness of being human. The meaning depends on the framework being used. So before we ask whether a soul exists, we need to establish what we mean by the word.

Otherwise, we risk arguing over a word before we have agreed on the reality it is supposed to describe.

  

Working Definitions

For the purposes of this book, I will use the following distinctions:

Body — the biological organism that exists in physical reality.

Brain — the physical organ that processes information and profoundly shapes embodied experience.

Mind — the ongoing stream of thoughts, perceptions, emotions, memories, imagination, and reasoning associated with mental experience.

Consciousness — the capacity for subjective awareness—the fact that experience is experienced by someone.

Soul — a philosophical term used in this book for the possibility of an enduring conscious identity distinct from the biological organism.

That last definition requires an important qualification. I am not defining the soul as something science has established. I am defining it as a possibility within the philosophical model being explored in this book. Its existence remains an open question.

These distinctions matter because the questions become almost impossible to discuss clearly if we treat the brain, mind, consciousness, identity, and soul as interchangeable. If the brain changes, does the mind change? If the mind changes, does the person change? If memory disappears, does identity disappear?

If personality changes, is the same person still present? And if everything we normally associate with a person can be altered, what—if anything—is left that deserves to be called the self? Those questions bring us directly into neuroscience.

 

The Human Vessel

Human beings enter the world through biology. A human body develops from a single fertilized cell into an extraordinarily complex organism. Organs form. Neural networks develop. Sensory systems mature. The brain becomes increasingly interconnected. The developing brain is not simply a miniature adult brain waiting to grow larger. It undergoes enormous structural and functional changes throughout development.

Neurons are generated and migrate. Connections form and are strengthened or eliminated. Different brain networks mature at different rates.[2] Sensory information begins shaping neural development long before a child can describe an experience.

The human brain is not fully developed at birth. It continues undergoing significant development for years.[3] This matters because the person we eventually recognize as “me” does not arrive fully assembled. Memory develops. Language develops. Emotional regulation develops. Self-awareness develops. Social understanding develops.

Even the sense of being a continuous individual develops through time. So, when did you begin? At conception? At birth? When your brain became sufficiently developed? When you formed your first memory? When you became self-aware? Or was there something present before any of those milestones that we simply cannot remember?

Science can investigate brain development. The philosophical question is whether brain development explains the beginning of consciousness—or merely the development of the particular human form through which consciousness becomes expressed. We do not currently have a definitive answer.[4]

 

Memory and Identity

One of the strangest things about being human is that our sense of identity depends so heavily on memory. You know that you are the same person who woke up yesterday largely because you remember being that person. You remember your childhood. Your family. Your mistakes. Your relationships.

Places you have lived. Things you have learned. Experiences that changed you. Memory gives your life a narrative. It creates continuity between one moment and the next. But memory is not a perfect recording. It is reconstructive. Every time we remember something, the brain is not simply retrieving a video file stored somewhere inside the skull. Memories can change. Details can disappear. Emotional associations can strengthen or weaken. Memories can become distorted without the person realizing it.[5]

And yet we still experience ourselves as continuous. This creates a fascinating problem. If your memories changed dramatically, would you still be you? Imagine losing every autobiographical memory you possess. Your name is gone. Your childhood is gone. Your relationships are gone. The places you lived are gone. Your personal history disappears. Would the person who remains still be you? Most people would probably say yes. But why?

 If identity were nothing more than accumulated memory, then destroying the memories should destroy the identity. Yet our intuition tells us that something more complicated is happening.

Memory clearly contributes to identity.  But what if memory is not identical to identity?  That distinction becomes especially important when we examine neurological disorders and brain injury.

 

When the Brain Changes the Person

The relationship between brain and identity becomes impossible to ignore when the brain is injured. Damage to particular brain regions can alter language, memory, emotional regulation, impulse control, attention, perception, and personality.[6] A person can survive a neurological injury while becoming profoundly different from the person their family remembers. The face may be the same. The body may be the same. The name may be the same. But something about the person can feel different. This is one of the strongest arguments for the brain’s importance to identity. It is also one of the strongest challenges to any simplistic concept of the soul.

If an immortal soul contains our true identity, why can damage to the brain so dramatically change the way that identity is expressed?

There is no easy answer.

 

The materialist interpretation is straightforward: personality, memory, decision-making, and conscious experience arise from the brain, so altering the brain alters the person.[7] That explanation is supported by an enormous amount of neurological evidence. But another interpretation remains philosophically possible.

The brain may not contain the entirety of identity.  It is possible that  the brain determines how identity can be expressed through the physical organism. That possibility does not eliminate the neurological evidence. It has to explain it. And that distinction will matter throughout this chapter.

 

Split-Brain Research

Few areas of neuroscience challenge our intuitive concept of a single self more dramatically than split-brain research. In certain severe cases of epilepsy, surgeons historically treated patients by severing or significantly disrupting the corpus callosum—the massive bundle of neural fibers connecting the brain’s two hemispheres.[8]

The procedure could reduce the spread of seizures. But it also created an extraordinary opportunity for scientists to study what happens when communication between the hemispheres is disrupted. The two hemispheres do not perform identical functions.[9]

Language is typically more strongly lateralized toward the left hemisphere, while the right hemisphere contributes heavily to spatial processing, visual information, emotional interpretation, and many other functions.[10] When communication between the hemispheres is severely disrupted, researchers have sometimes observed striking differences in what each hemisphere can perceive, identify, or communicate. This raises an unsettling question. If the brain can be divided into systems capable of processing information with limited communication between them, what exactly is the “self”?

Are there two minds?

One mind with two processing systems? A single consciousness receiving information through two partially independent channels? Or is the ordinary sense of a unified self something the brain constructs from many separate processes? Split-brain research does not provide a simple answer. What it does demonstrate is that the intuitive idea of consciousness as a single indivisible thing sitting somewhere inside the head is probably too simple. The brain is extraordinarily distributed.

Different systems contribute different pieces of what we experience as ourselves. And yet, somehow, experience still arrives as one world. One moment. One perspective. One “I.” That brings us to one of neuroscience’s deepest mysteries.

 

The Binding Problem

Color is processed differently from motion. Sound follows different neural pathways than touch. Language depends upon networks distinct from those involved in emotion or spatial reasoning. The brain is processing enormous amounts of information simultaneously. Yet we do not experience these processes separately.

You don’t experience the color of a tree first, then its shape, then its movement in the wind, then the sound of the leaves. You experience a tree. One unified experience.

This is sometimes called the binding problem[11]. How does the brain combine countless distributed processes into one coherent conscious experience? Neuroscience has made enormous progress in understanding the individual components. But the subjective unity of experience remains deeply mysterious. There are billions of neurons. Millions of connections. Countless simultaneous signals. And yet there is one point of view.

Yours.

Whatever consciousness ultimately proves to be, it is experienced from somewhere. Not necessarily a physical location in the brain. But from a perspective. And that perspective is one of the central mysteries of consciousness.

 

Predictive Processing

Another fascinating development in neuroscience is the idea that the brain does not simply passively receive information from the outside world. It constantly makes predictions. Your brain receives sensory signals, compares them with expectations, updates its internal model, and uses previous experience to anticipate what is likely to happen next.[12]

 In other words, perception may be less like a camera recording reality and more like an ongoing negotiation between incoming information and the brain’s predictions about what that information should mean. Think about walking into a dark room. Your eyes receive incomplete information. Your brain already knows what a room is supposed to look like.

It uses that knowledge to interpret ambiguous sensory information. As more light enters, the predictions are adjusted. The same principle operates throughout ordinary experience. The brain is constantly trying to answer:

What am I seeing?

What am I hearing?

What is happening to me?

What should happen next?

This helps explain why two people can experience the same event differently. Their brains do not enter the moment as blank slates. They bring expectations, memories, emotional associations, prior knowledge, and learned patterns. Reality reaches us through an interpretive system.

 This is important for the philosophy of consciousness. Because if the brain is actively constructing our experience of reality, then our conscious experience is not simply a transparent window onto the world.

It is an interpretation of the world. But this raises another question. If the brain constructs the experience, does that mean the brain creates consciousness itself? Not necessarily. It could mean that the brain constructs the contents of consciousness. Those are not necessarily the same question. The distinction may be subtle. It may also be fundamental.

 

The Brain as Interpreter

Imagine looking at a sunset. Photons enter your eyes. The retina converts light into neural signals. Those signals travel through networks involved in visual processing. Your brain identifies color, brightness, depth, movement, and shape. Memories and emotional associations become involved.

Perhaps you remember another sunset. Perhaps you associate the color with a person you love. Perhaps you feel peaceful. Perhaps you feel grief. The physical event is one thing.  Your experience of the event is another. The brain is clearly involved in transforming physical signals into the richly interpreted world you consciously experience.[13]

But then we reach the same question we encountered in Chapter 2. Why does any of this feel like something? Why isn’t there simply information processing? Why is there an experience of red? Why is there an experience of beauty? Why is there someone watching the sunset? Neuroscience can increasingly explain the machinery involved. The subjective observer remains difficult to explain.

 

Altering the Vessel

If the brain is essential to ordinary conscious experience, then altering it should alter that experience. And it does. Sleep changes consciousness. Anesthesia changes consciousness. Medication can change consciousness. Brain injury can change consciousness. Neurological disease can change consciousness. Trauma can change consciousness. Psychedelic substances can change consciousness. Meditation can change consciousness.[14] This gives us an important observation:

The state of the brain strongly influences the state of consciousness.

That conclusion should not be weakened. It is one of the strongest findings available to us. But there are two possible interpretations. The first is that the brain produces consciousness, and changing the brain changes the resulting consciousness. The second is that consciousness exists independently in some form, but the brain determines how that consciousness can be experienced and expressed through a human organism. The evidence we currently possess strongly establishes the relationship. It does not necessarily settle the ultimate metaphysical interpretation of that relationship.

 

The Vessel Is Not the Traveler

Imagine a diver exploring the ocean. The diving suit is essential. Without it, the diver cannot survive beneath the surface. Every movement, every sensation, and every interaction with the underwater environment depends upon that suit functioning properly. If the visor becomes scratched, the diver’s vision is distorted.

If the oxygen supply is interrupted, the experience changes immediately. Damage the suit severely enough, and the dive must end. Yet the diver and the suit are not identical. The condition of the suit profoundly influences what the diver can experience. It does not necessarily follow that the suit created the diver. Within my current philosophical model, the human body functions in a similar way. The body allows consciousness to participate in physical reality. The brain shapes perception, memory, emotion, language, personality, and decision-making. Everything we know from neuroscience demonstrates that changing the brain changes the lived experience of the individual.

Nothing in this analogy denies those observations. The question is whether they answer the deeper philosophical question: Does demonstrating that the brain shapes consciousness necessarily demonstrate that it produces consciousness?

I don’t know. And that uncertainty is important.

Brain injury demonstrates that memory, personality, and our narrative sense of self are deeply dependent upon the functioning of the brain. Yet science has not thereby demonstrated that these changing characteristics exhaust the entirety of what a person is[15].

 

What Happens to the Self?

Suppose a person loses the ability to remember their childhood. Are they still the same person? Suppose their personality changes after a brain injury. Are they still the same person? Suppose language disappears.

Are they still themselves? Suppose their emotional responses change dramatically. Suppose they no longer recognize the people they once loved.

At what point would we say the original person has disappeared? [16]

There is no universally accepted answer. And perhaps that is because we have been using the word self to describe several different things at once. There is the biological organism. There is autobiographical memory.

There is personality. There is agency. There is the narrative identity we construct from our experiences.[17] [18] There is subjective awareness. And perhaps—if the philosophical model explored in this book is correct—there may also be something deeper. Something that experiences all of these changing states without being identical to any single one of them. That possibility is what I mean by the soul. Not a ghost hidden somewhere inside the body. Not a supernatural explanation inserted wherever neuroscience becomes difficult. But the possibility of an enduring conscious identity whose relationship to the brain remains unresolved.

 

Meditation and Contemplative Practice

Not every altered state depends upon drugs or neurological injury. Across cultures, people have deliberately trained attention through meditation, contemplative prayer, prolonged silence, fasting, chanting, and other practices. People report experiences of unusual clarity. Some describe a diminished sense of ego. Others report profound feelings of unity, compassion, timelessness, or peace. Modern neuroscience has found measurable changes in brain activity associated with some forms of long-term meditation.[19]

This gives us another fascinating example of the brain-consciousness relationship. A person can intentionally change the contents and qualities of conscious experience through mental practice. The brain changes. The experience changes.

But what exactly is being changed? The brain? The contents of consciousness? The sense of self? Or the relationship between all three? We do not yet know. And once again, the scientific observation is stronger than the philosophical interpretation. We can observe changes in brain activity. We can observe changes in reported experience. What remains open is what those changes ultimately tell us about the nature of consciousness itself.

 

The Question Beneath the Question

Taken together, neuroscience presents us with an extraordinary picture. The brain is not a simple container. It is dynamic. Predictive. Adaptive. Distributed. Plastic. It constructs models of the world. It stores and reconstructs memories. It regulates emotion. It shapes personality. It influences decisions. It determines what information reaches awareness. And when it changes, the person changes. These observations make any simplistic separation between brain and consciousness impossible. But they also lead us toward a deeper question. If the brain shapes so much of our experience, what exactly would remain if we removed everything the brain contributes? Remove memory. Remove personality. Remove language. Remove sensory perception. Remove the body’s ability to move. Remove the narrative of your life. What remains? Nothing? Consciousness itself?

It could be something we do not yet have the language to describe. That is where neuroscience ends and philosophy begins. Not because science has failed. But because the question has changed. We are no longer asking: What does the brain do? 

We are asking: What is the relationship between what the brain does and the fact that someone experiences it?

 

My Current Model

After examining the neuroscience, I arrive at a tentative framework. I emphasize tentative because I do not regard this model as a finished theory. It is a working philosophy—a way of organizing questions rather than claiming to have solved them. At present, I distinguish between five closely related but different concepts. The body is biological. It is the physical organism that develops, grows, ages, and eventually dies according to the laws of nature.

The brain is neurological. It is the extraordinarily complex organ that receives sensory information, predicts and interprets the world, forms memories, regulates emotion, coordinates behavior, and makes embodied experience possible.

The mind is the ongoing process through which thoughts, emotions, imagination, language, perception, memory, dreams, and reasoning become part of lived experience.

Consciousness is the subjective awareness underlying that experience—the fact that there is something it is like to be the person having it.

And the soul, if such a thing exists, is the possibility of an enduring conscious identity that participates in embodied life through the brain and body. Whether that identity exists before birth, survives death, or is simply a philosophical construct remains unknown. These distinctions are not scientific conclusions. They are definitions adopted for the purpose of exploration. Science may eventually demonstrate that consciousness is entirely produced by biological processes. Future discoveries may require this entire framework to be revised—or abandoned. I accept that possibility. At the same time, I believe these distinctions give us a more precise language for asking some of humanity’s oldest questions. Because perhaps the question is not:

“Is the brain important?” It obviously is. The question is:

“Is the brain the whole story?” That is the question I cannot yet answer. And perhaps that is exactly where this investigation should remain. Not at certainty. At the edge of what we know.

 

The Skeptic’s Challenge

“You have introduced a soul without evidence that one exists. Everything we know about personality, memory, decision-making, and conscious experience changes when the brain changes. Injure the brain, and the person changes. Alter brain chemistry, and perception changes. Interrupt neural activity with anesthesia, and conscious awareness disappears. Why introduce an additional entity when the brain appears sufficient to explain the evidence?”

 

My Response

This objection is powerful. The brain clearly explains an enormous amount about human experience. Any theory of consciousness that ignores that fact should be rejected. The question is not whether the brain matters. It does. The question is whether explaining the mechanisms through which the brain shapes experience is identical to explaining why subjective experience exists at all.

At present, I do not believe we can honestly claim that neuroscience has completely answered that question. But neither can I honestly claim that the existence of a soul has been demonstrated. That leaves us with an uncomfortable middle ground. We know much more about the brain than we once did. We know that changing it changes us. We know that memory can change. Personality can change. Perception can change. The sense of self can change. And yet the fundamental mystery remains:

Why is there an experience of any of it? 

Perhaps the answer will eventually be entirely biological. Perhaps consciousness will turn out to be an emergent property of sufficiently complex neural systems. Perhaps our current categories will prove inadequate. Or perhaps consciousness is more fundamental than our present scientific framework assumes. I do not know.

But I believe the honest position is to keep the question open without pretending that openness is proof. The soul, in this book, is therefore not a conclusion. It is a hypothesis. And hypotheses exist to be tested.

 

 

Questions That Remain

If memory can change, what makes a person the same person?

If personality can change, where does identity reside? 

If the two hemispheres of the brain can operate with partial independence, what does that tell us about the unity of consciousness?

If the brain constantly predicts and constructs our perception, how much of experienced reality is interpretation?

If the contents of consciousness can change dramatically, what remains constant?

Can consciousness exist without memory?

Can identity exist without personality?

Is subjective awareness generated by neural activity, or merely expressed through it?

If the brain is an interface, what exactly is it interfacing with?

And perhaps the most important question of all: If there is something we call the soul, what would we expect to observe that could distinguish it from the brain’s extraordinary ability to create the experience of a self? That question will follow us forward. Because if the soul exists, we should not merely ask what we hope it is. We should ask what evidence could tell us that it is there. And if it does not exist, we should be willing to discover that too.

 

[1] ] “Self-Consciousness,” Stanford Encyclopedia of Philosophy, revised June 14, 2024.

 

[2] Jenelle L. Wallace and Alex A. Pollen, “Human neuronal maturation comes of age: cellular mechanisms and species differences,” Nature Reviews Neuroscience 25 (2024): 7–29. 

[3] Mark H. Johnson, “Functional brain development in humans,” Nature Reviews Neuroscience 2 (2001): 475–483.

[4] Christof Koch, Marcello Massimini, Melanie Boly, and Giulio Tononi, “Neural correlates of consciousness: progress and problems,” Nature Reviews Neuroscience 17 (2016): 307–321. 

[5] Daniel L. Schacter, Kenneth A. Norman, and Wilma Koutstaal, “The Cognitive Neuroscience of Constructive Memory,” Annual Review of Psychology 49 (1998): 289–318. 

[6] Barry R. Bryant et al., “Behavioral and Emotional Dyscontrol Following Traumatic Brain Injury: A Systematic Review of Neuroimaging and Electrophysiological Correlates,” Journal of the Academy of Consultation-Liaison Psychiatry 63, no. 6 (2022): 548–562. 

[7] Thomas W. McAllister, “Neurobiological Consequences of Traumatic Brain Injury,” Dialogues in Clinical Neuroscience 13, no. 3 (2011): 287–300. https://doi.org/10.31887/DCNS.2011.13.2/tmcallister

[8] Michael S. Gazzaniga, “Cerebral specialization and interhemispheric communication: Does the corpus callosum enable the human condition?” Brain 123, no. 7 (2000): 1293–1326. 

[9] Edward H. F. de Haan, Paul M. Corballis, Steven A. Hillyard, Carlo A. Marzi, Anil Seth, Victor A. F. Lamme, Lukas Volz, Mara Fabri, Elizabeth Schechter, Tim Bayne, Michael Corballis, and Yair Pinto, “Split-Brain: What We Know Now and Why This is Important for Understanding Consciousness,” Neuropsychology Review 30, no. 2 (2020): 224–233. https://doi.org/10.1007/s11065-020-09439-3.

[10] Nathalie Tzourio-Mazoyer, Marcela Perrone-Bertolotti, Gael Jobard, Bernard Mazoyer, and Monica Baciu, “Multi-factorial Modulation of Hemispheric Specialization and Plasticity for Language in Healthy and Pathological Conditions: A Review,” Cortex 86 (2017): 314–339. https://doi.org/10.1016/j.cortex.2016.05.013. 

[11] Jerome Feldman, “The Neural Binding Problem(s),” Cognitive Neurodynamics 7, no. 1 (2013): 1–11. 

[12] Shohei Furutachi and Sonja B. Hofer, “Rethinking Predictive Processing,” Annual Review of Neuroscience 49 (2026): 471–494. https://doi.org/10.1146/annurev-neuro-102124-031410. 

[13] Christof Koch, Marcello Massimini, Melanie Boly, and Giulio Tononi, “Neural Correlates of Consciousness: Progress and Problems,” Nature Reviews Neuroscience 17 (2016): 307–321.

[14] Koch et al., “Neural Correlates of Consciousness,” 307–321. 

[15] Elizabeth Jane Beadle, Tamara Ownsworth, Jennifer Fleming, and David Shum, “The Impact of Traumatic Brain Injury on Self-Identity: A Systematic Review of the Evidence for Self-Concept Changes,” Journal of Head Trauma Rehabilitation 31, no. 2 (2016): E12–E25. https://doi.org/10.1097/HTR.0000000000000158.

[16] Brian Levine, “Autobiographical Memory and the Self in Time: Brain Lesion Effects, Functional Neuroanatomy, and Lifespan Development,” Brain and Cognition 55, no. 1 (2004): 54–68. https://doi.org/10.1016/S0278-2626(03)00280-X.

[17] Mohamad El Haj, Pascal Antoine, Jean Louis Nandrino, and Dimitrios Kapogiannis, “Autobiographical Memory Decline in Alzheimer’s Disease, a Theoretical and Clinical Overview,” Ageing Research Reviews 23, Part B (2015): 183–192. https://doi.org/10.1016/j.arr.2015.07.001.

[18] Anne E. Wilson and Michael Ross, “The Identity Function of Autobiographical Memory: Time Is on Our Side,” Memory 11, no. 2 (2003): 137–149. https://doi.org/10.1080/741938210.

[19] Kilian Abellaneda-Pérez, Ruby M. Potash, Alvaro Pascual-Leone, and Matthew D. Sacchet, “Neuromodulation and Meditation: A Review and Synthesis toward Promoting Well-Being and Understanding Consciousness and Brain,” Neuroscience & Biobehavioral Reviews 166 (2024): 105862. https://doi.org/10.1016/j.neubiorev.2024.105862.