👻 The Ghost in the Machine: Richard Swinburne and the Case for the Soul

Over the last few weeks, we have navigated the busy streets of physicalism. We saw Daniel Dennett argue that the mind is a clever trick of the brain—a “user-illusion.” We saw Galen Strawson argue for a “Real Physicalism,” suggesting that matter itself is inherently conscious. Despite their differences, they both shared a common boundary: they believed that, at the end of the day, there is only one kind of “stuff” in the universe.

Today, we cross that boundary into Substance Dualism—the idea that the mind is not just a property of the brain, but a separate substance entirely.

To the modern ear, “Substance Dualism” sounds like a relic of a pre-scientific age. If you ask a modern neuroscientist, they will likely tell you it is a “medieval” superstition—a desperate attempt to preserve a religious ego. But Richard Swinburne, Emeritus Professor at Oxford, has spent a lifetime proving that the case for the soul is built on cold, hard logic rather than mere sentiment. He doesn’t ask us to believe in ghosts; he asks us to look at the logical requirements of being a “self.”

Defining the Terms: What is a “Substance”?

Before we dive into his arguments, we must clarify what Swinburne means by a “substance.” In philosophy, a substance is not a liquid or a chemical; it is something that can exist on its own—a “thing” that carries properties. A “property” is a characteristic (like the color red), but a “substance” is the entity that is red (like an apple).

Physicalism claims that the only substance in the universe is matter, and the mind is just a property of that matter—like the “fastness” of a car or the “wetness” of water. Swinburne turns this on its head. He argues that the “I” is its own substance. You don’t have a soul; you are a soul, and you possess a body. This distinction is the foundation of everything that follows.

The Problem of Personal Identity: The Ship of Theseus

Swinburne’s strongest entry point is the question of what makes you “you” over time. Physically, you are a walking Ship of Theseus. In this ancient Greek paradox, a ship is repaired plank by plank until not a single original piece of wood remains. Is it still the same ship?

Biologically, you are in a state of constant flux. Your cells are dying and being replaced; the atoms in your brain today are almost entirely different from those you had ten years ago. If you are purely a physical object, your identity is just a “pattern”—like a wave moving through water. As long as the memories and personality traits remain stable, a physicalist says “you” exist.

But Swinburne argues that a “pattern” is a description, not a person. To illustrate this, he uses a provocative thought experiment: The Brain Bisection.

Imagine a scientist removes your brain and splits it into two equal halves, transplanting each half into a different identical body. Both people wake up with your memories and your habits. Physics can track every atom during this surgery, providing a 100% complete physical map. However, physics cannot answer the most important question: Which one is you? Are you the person in the left bed, the right bed, or have you ceased to exist? A physicalist must say that because all the physical facts are accounted for, there is no “real” answer—you are simply both or neither. But from the perspective of the subject, this is impossible. You cannot “be” two separate streams of consciousness simultaneously. Swinburne argues that because there is a factual, “yes or no” answer to the question of your survival—an answer that a complete physical map cannot see—there must be a non-physical truth about your identity. This “thisness” (or haecceity) is what he defines as the soul.

The Privacy of the Mental: The Patient and the Doctor

The second pillar of Swinburne’s defense is the Argument from Privileged Access. This is the idea that mental life is private in a way that physical facts are not.

Consider a man who goes to his doctor claiming he is experiencing vivid hallucinations of a mountain range. The doctor can use the most advanced technology available—fMRIs and EEGs—to monitor the man’s brain. The doctor might see a surge of activity in the visual cortex. These are “public” facts. Any trained professional with the right equipment can observe them, measure them, and verify them.

However, the doctor is ultimately “blind” to the most important part of the event. No amount of machinery can tell the doctor exactly what the man is seeing—the specific jaggedness of the peaks or the subjective quality of the light. The doctor must rely entirely on the man to report the content of his vision.

Swinburne argues that if the world were purely physical, everything would be publicly observable in principle. If I know the position and velocity of every molecule in a steam engine, I know everything there is to know about that engine. But I can know everything about the atoms in your brain and still not know what it feels like to be you. This suggests that the “mind” is a different kind of substance than the “brain.”

The Piano and the Pianist: The Logic of Interaction

The most common objection to dualism is the Dependency Argument: “If we have a soul, why do we lose our personality when the brain is damaged?” If the soul is separate, why does a glass of wine or a head injury change who we are?

Swinburne’s response involves a crucial distinction between existence and functioning. He views the soul as the musician and the brain as the piano.

A world-class pianist has the skill and the intent to play a masterpiece. However, if the piano has broken keys, out-of-tune strings, or a cracked soundboard, the music produced will be distorted or silent. In this model, the soul is the “player.” While we are embodied, the soul depends on the physical brain to “write” and “read” data from the physical world. Memories, in this life, are stored physically in the synapses—they are the “sheet music” the pianist uses to navigate reality.

When the brain is damaged, the soul isn’t being “deleted”; rather, the instrument is failing. This explains why we are so heavily influenced by our biology without requiring us to be identical to our biology. The musician is not the music; the player is not the piano.

The Simplicity of the “I”: The Binding Problem

Neuroscience shows us that the brain is a collection of trillions of moving parts firing in parallel. There is no “center” of the brain where everything comes together in a single point. This creates The Binding Problem: How do trillions of separate physical events result in a single, unified “I”?

When you see a red ball bouncing, one part of your brain processes “red,” another processes “circularity,” and another processes “motion.” Physically, these are disparate events occurring in different “zip codes” of the cortex. Yet, your experience is not a fragmented list of data; it is a single, unified perception.

Swinburne argues it is “simpler” (invoking Occam’s Razor) to posit that the subject of experience is a Simple Substance. In science, we accept fundamental units like quarks that cannot be broken down further. Swinburne suggests the “Subject” is one of these fundamental units. You feel like a unified thing because you are a unified thing—a non-composite substance that “owns” the experiences of the complex brain.

The Modal Argument: The Logic of the Possible

Finally, Swinburne leans on what is known as the Modal Argument, which deals with the logic of possibility and necessity. He asks us to consider what is “logically possible.”

It is logically impossible to imagine a “square circle” because the definition of a square contradicts the definition of a circle. However, it is perfectly “thinkable” to imagine yourself existing without a body. You can imagine waking up as a floating consciousness with no limbs, no brain, and no physical presence—much like a dream.

Swinburne’s logical move is this: If it is even possible for you to exist without your body, then you cannot be identical to your body. If A is identical to B, then A cannot exist without B. For example, you cannot have water without H2O; they are the exact same thing. But if I can logically conceive of “Me” existing without “My Brain” (even as a thought experiment), it follows that “Me” and “My Brain” are two different things. Even if they are currently joined together like a driver in a car, they remain separate entities.

Conclusion: The Driver and the Car

Substance Dualism explains why you feel like a single “I” in a world of moving parts. It suggests that even if we can map every atom in the brain, the most important part of reality remains the “Pianist” who is making the music.

This isn’t just an academic exercise. If we are just “brain-states,” then we are determined by the laws of physics—meaning free will is a myth. But if the soul is a separate substance, then the “I” has the room to act upon the brain, making us the authors of our own stories rather than just spectators of our own biology. We are the drivers, not just the cars.

But if we are willing to accept that the soul is a separate substance, we must eventually ask an even more radical question: What if the physical world isn’t the primary reality at all?

Next week, we step into the world of Idealism. We will explore the thinkers who argue that mind isn’t just part of the universe—it is the very fabric the universe is made of.

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Deepen Your Journey: Suggested Reading

If this logical defense of the soul has sparked your curiosity, these resources are the best places to explore the analytical side of the debate.

Transparency Note: The links below are affiliate links. If you choose to purchase through them, I earn a small commission from Amazon at no extra cost to you. This helps support the research and writing of this series!

• The Evolution of the Soul by Richard Swinburne: The definitive modern text for dualism. A rigorous defense of why the “Subject” cannot be reduced to the brain.
• Mind, Brain, and Free Will by Richard Swinburne: Addresses how the soul might interact with physical laws and quantum physics.
• The Blackwell Companion to Substance Dualism edited by Loose, Menuge, and Moreland: A massive collection of essays covering modern dualist thought.
• The Self and Its Brain by Karl Popper and John Eccles: A landmark collaboration between a philosopher of science and a Nobel Prize-winning neuroscientist. While Popper’s “Three Worlds” theory differs slightly from Swinburne’s theological dualism, this remains the most famous scientific defense of the idea that the mind and brain are distinct entities.