Do we have an immaterial soul or are we just electrified meat? Most arguments from consciousness advocate one form or another of dualism, which is basically the position that the mind is more than or separate from the biological activity of the brain. The vast majority of Christians are substance dualists, and the vast majority of neuroscientists and philosophers of mind are not. There are a variety of opinions among secular philosophers of mind, but substance dualism is really only popular with religious people at this moment in history.
But how does the soul violate science, exactly? I think Christians don’t often know what we mean when we say their beliefs violate scientific findings or trespass on the territory of science. Many religious people seem to think that as long as they don’t say the earth is 6,000 years old, then they’re not science deniers. So I think it’s important to lay out exactly what we mean if we want to say science conflicts with the conventional idea of the soul.
On substance dualism, the mind and the brain are entirely separable — the mind can exist completely independently from the brain. On this view, we could reasonably expect at least some mental activity to have no neural correlate. Meaning, there’s no reason to expect brain activity for every single mental event if our consciousness is not a product of the brain. But what we’ve found is that there is no aspect of consciousness that doesn’t have some physical correlate. There is no mental phenomenon that occurs where there is nothing going on in the brain. If the brain is not biologically active, there is no consciousness. If the brain is damaged, the mind is altered. As your physical brain changes through drugs, lack of sleep, or a chunk of it being removed – your mind changes. Even as you age, various mental abilities decline. No reliable observation or experiment has been able to separate the mind as a phenomenon from the brain.
Consciousness appears to be a product of the functioning of the brain. The mind is what the brain does, as neuroscientists like to put it. And all the evidence we have supports this idea.
Steven Novella, a neurologist at Yale and host of the Skeptic’s Guide to the Universe writes,
“Damage or alteration to the brain can change your sexual identity, your moral decision making, your personality, your ability to even think about the world. Patients with non-dominant hemisphere strokes, for example, often do not know that the left half of the world even exists. There is no model inside their brain for the left half of their body or the world, so they cannot even think about it. . . Synesthesia is the phenomenon of different sensory modalities mixing together, so syntesthetes will smell color or perhaps perceive numbers as having a physical texture. And there is evidence for more robust neural connections and activity between the relevant brain areas in syntesthetes. That is a pretty compelling neural correlate.”
Believers will often argue in response to data like these that correlation doesn’t equal causation. It doesn’t follow that the brain states we’re measuring are causing the mental states just because there is a correlation between mental activity and brain activity. Of course, they’re completely right; correlation is not sufficient by itself to establish a causal relationship. Correlation doesn’t always equal causation; but sometimes, it does. It’s not sufficient by itself, that’s why we need more than just correlation to think there could be a causal relationship. And indeed, we have more than just the extremely robust correlation that’s already been established.
For one, brain states do not just correlate with mental states — they precede them. Effects don’t come before causes, and there are not any documented cases of mental activity preceding brain activity. Changes to the brain always precede the corresponding changes to the mind, and this prediction of the materialist paradigm is perfectly replicable. It’s always brain activity or changes to the brain first, and then the change in mental state. We would not expect this temporal relationship if mind caused brain. It’s the exact opposite of what you’d predict if we had a soul that was pulling the levers of our brain and body, interacting with the physical matter you’re made of.
We don’t know everything about consciousness, not by a long shot. But people tend to mistakenly equate not knowing everything with knowing nothing. This isn’t just a Christian apologist thing, this is a broader problem. We don’t know everything, but we actually know quite a lot, probably more than most people realize. But one difference between scientists and Christian apologists is that scientists won’t pretend to know something they don’t know. They’re not going to go around shooting their mouths off publicly without being relatively certain that they’re correct, whereas apologists happily take a gap in our knowledge on a subject they know little to nothing about and are content to make claims that no scientist would be comfortable making.
As I mentioned, we know quite a lot, and I’ve linked in the description a few science-based sources on the neurological basis of consciousness. Crucially, they’re making steady progress on this naturalistic paradigm. If we were mistaken in our fundamental assumptions about neuroscience, you would expect researchers operating on a materialistic paradigm to be running up blind alleys, hitting brick walls, and generally frustrated with the lack of traction and progress in the neuroscience of consciousness. But rather, neuroscientists like Anil Seth who are actively working and figuring out how the brain creates our conscious experience report that progress is moving along steadily and has been for years.
Steven Novella has written,
“Another reason to accept the materialist paradigm of neuroscience is that it has been and continues to be extremely successful. In science, theories are judged not only by how well they fit the data, but by how useful they are as predictive models – and the materialist position that brain function is the mind has been fantastically successful. There does not appear to be any intrinsic limit to our ability to map and alter anything considered to be part of our subjective experience.”
“This brings up another aspect of the strategy [of neuroscience deniers] — focusing on the snapshot of a science rather than its progress over time. Creationists often point to gaps in evolutionary knowledge – whether it’s the fossil record or, more recently, genetics or biochemistry. However, there will always be gaps in our scientific knowledge. The presence of gaps don’t really tell us anything about the power and success of a scientific explanatory paradigm. A better assessment is to look at the history of a scientific idea and then see how successful it has been in making predictions. Pseudosciences like homeopathy and ESP have not progressed – they are chasing their tails going around in circles without making any forward progress. . . the materialist paradigm of mind and consciousness – the notion that the brain is the cause of mind – has been and continues to be a very successful model. One manifestation of this is that neuroscience, as a discipline, has grown and progressed. As new tools come online our ability to explore the brain, and to explain the phenomenon of mind, has increased. The dualist paradigm, by contrast, has not produced anything tangible or reliable. It is still chasing its tail and pointing at the current gaps in neuroscience, without looking at the big picture.”
We don’t have to know how something happens to know that it happens. We don’t know how the earth generates gravity, but we do know that it generates gravity. Before we knew of genes, we still knew that heredity was a real thing. We could see that parents passed physical traits on to their children long before we had any clue how it happened specifically. Any incompleteness you may find in neuroscience models will be of this type. We aren’t sure of all the details of how things happen, but that the arrow goes from brain to mind is as certain as anything else in science. To deny this as mere correlation at this point would be like denying that genes cause heredity because genes only correlate with hereditary traits, or massive objects only correlate with gravitation. We don’t fully understand how the brain works and creates the phenomenon of mind. That’s just the moment of history we live in. But that doesn’t give us license to confuse the question “Does A cause B?” with “How does A cause B?”
We also have Occam’s Razor on our side. We have a well-defined physical model that is consistent with all the data we see. We just don’t have any reason to add unnecessary metaphysical baggage on top of that. As an analogy, imagine I suggested that an angel was causing the motion of the Earth. We already have a clear and complete physical model that accounts for the data we see there. The equivalent to what dualists are doing with the brain would be to assert that there is also an immaterial angel that is causing motion in the same exact way Newton’s Laws predict. They’re essentially saying, “Oh sure, the brain accounts for everything about you; but in addition to the brain, there’s this other metaphysical thing on top of all that, and it’s unnecessary to explain anything, but I still think it’s there.”
Occam’s razor gets rid of the angel pushing the planets for the same reason it gets rid of an immaterial soul in addition to the brain. Of course, it’s possible for there to be a superfluous soul in addition to the brain, just like it’s possible that there is an invisible angel moving the Earth in addition to our well understood naturalistic model. But Occam’s Razor advises us that if we’re choosing between two equally plausible hypotheses, we should tend to opt for the one that needs fewer unjustified assumptions to get off the ground. Of course, we’re not looking at two equally plausible explanations; there are problems with substance dualism that materialism doesn’t have and the evidence is overwhelmingly supportive of materialism. But if you’re going to go the ‘you can’t prove we don’t have a soul’ route, Occam’s Razor, Bayesian reasoning, and the fact that you also can’t prove there aren’t any angels driving the planets around should disabuse you of that notion. Or at least force you to recognize that you have passed the threshold of motivated reasoning.
The Brain as an Interface
One objection dualists raise is that the brain could just be an interface for the soul and the body. The brain could just be a sort of antennae for the soul. The soul “plays” the brain and body like a pianist plays the piano; if a string is broken or there’s a problem with the instrument, the pianist’s music is impaired. This is supposed to account for the robust neural correlation we’ve observed.
There are several problems with this analogy. If our soul can play the piano, why can’t it play any other instruments? What’s being posited here is that you have this immaterial soul that can affect the atoms in your brain and move them around according to your will. So if you can move your arms and legs for example, which are nothing but large collections of atoms, why can’t you move other collections of atoms? It might sound like a joke but it’s a serious question. You believe that you have an immaterial soul that is “playing the piano” of your brain. This must mean that your soul is moving around the physical stuff that is your brain and body. Why wouldn’t your soul be able to telekinetically bend a spoon, just as it can apparently telekinetically move your fingers to bend a spoon? What’s the difference, exactly? If William Lane Craig is right, and I can use my will to bend the collection of atoms that is my thumb, why can’t I use my will to go an inch or two outside my thumbs and bend the spoon directly?
Another objection to the piano analogy and the general claim that the brain acts as an interface between the soul and body is the interaction problem. Everybody agrees that my body is made of physical material, even substance dualists. We all agree that our bodies are made of atoms. But when my mind wants to raise my right arm, my physical arm goes up. How is it, if I have an immaterial soul, that my non-physical mind moves the chunk of atoms we’re calling my arm? If you want to say there is something else in addition to the brain, you have to explain how that something else interacts with the protons, neutrons, and electrons that make up your brain and arms and legs.
You also have to explain how the laws of physics governing the atoms in your body are incomplete or just wrong. Believers are trying to say that there’s this stuff that routinely influences matter; but somehow, every controlled experiment we’ve ever performed has failed to detect such an influential particle. If this stuff does somehow interact with physical matter, why haven’t we actually found it in experiments? It apparently interacts with physical matter all the time, so you’d think the laws of physics would violated regularly, since they currently don’t include any reference to this substance or it’s interacting with matter. You’d think that all kinds of things would be screwed up all the time, in the same way we’d expect all kinds of experiments and technology to stop working if we suddenly stopped taking electrons into account. If we just chose a particle at random to ignore completely in all our experiments, nothing would come out right. And yet, this isn’t happening even though we’re ignoring this very influential soul stuff that routinely affects protons, neutrons, and electrons. Somehow, we’ve missed it while managing to build incredible technology and create life-saving medicine, and while building other fields of science that are contingent on our understanding of physics, like chemistry and biology, without ever discovering a single thing that contradicts these laws.
If we just removed any mention of protons from our standard model of the stuff that exists in our everyday world, everything we saw would stop making sense because protons are influential. You can’t just make the extraordinary claim that there’s some poorly defined metaphysical substance that routinely interacts with the physical world without providing any evidence that our current understanding of the everyday world is incomplete, since it currently does not include any mention of this very influential substance.
This comes back to explaining exactly what we mean when we say dualism violates scientific knowledge. That’s obviously been the theme of this episode, but let’s look a couple specifics.
In order for an immaterial soul to influence physical matter, it would either violate conservation of energy or conservation of momentum. You need energy to do work, so you’d have to inject new energy in the system for anything physical to be influenced by the non-physical system, and this would violate the conservation of energy. The first law of thermodynamics states that energy can never be created or destroyed. Violating conservation of energy is kind of a big deal; it’s not a petty objection. No part of your body would move if new energy weren’t being put into the physical system. If we don’t have to inject new energy into the physical system to do work, it would have to rearrange the energy already in the system, which would violate conservation of momentum.
Additionally, if your soul interacts with matter, it must either exert one of the four fundamental forces (gravity, electromagnetism, the strong and weak nuclear forces); or it must use some additional and so-far undetected kind of interaction. There’s no evidence for another kind of interaction, and if there were another one, you’d think that anything we did based on our standard model would be failing all the time, just like we’d be failing all the time if we removed the weak nuclear force from the standard model and tried to do things while ignoring it completely.
I’m also not satisfied that dualists have adequately defined what they’re defending in the first place. A soul is supposed to be an “immaterial substance”? What does that even mean? It almost sounds like a contraction in terms, like you’re saying it’s an immaterial material. You’re saying that it’s like matter but it’s not matter, which has the convenient side effect of preventing me from being able to investigate it.
As I mentioned, I think it’s important to explain exactly why the idea of the soul trespasses on the territory of science. Steven Novella has gone as far as calling dualists “neuroscience deniers,” and I think he’s completely right to do so. You have to outright reject scientific evidence and it’s implications to believe there is a ghost in the machine. Most Christians who aren’t young earth creationists look down on those who are, treating them like they’re these unsophisticated science-deniers. I mean — they are. But most of those same “sophisticated” believers would get very upset if you suggest they don’t have a soul. Just because your particular form of science-denial is more socially acceptable than creationism doesn’t make you any less of a science denier.
What about things that make sense on dualism, like mind to mind communication, but don’t make sense within a materialistic framework? None of the non-materialist phenomena stand to scrutiny, and this is a huge strike against dualism. This is related to the piano analogy I mentioned earlier.
If dualism were true, there’s no reason to expect certain things to be unrealistic. Mind reading, mind to mind communication, telekinesis, and body-switching are all things that are conceivable on dualism and would be completely unexplainable on materialism. If what we really are is a soul, and not a mind that emerges from physical processes, why wouldn’t I be able to directly communicate with another mind? Why couldn’t our souls switch bodies, hypothetically? What keeps my soul anchored to my particular body in the first place? Our current materialistic understanding of neuroscience and physics could not accommodate these phenomena. Observable, repeatable evidence for these parapsychological phenomena would be extraordinary evidence in favor of dualism. But as I’m sure you know, the evidence for any parapsychological phenomena is nonexistent. There has not been a single example of mind reading, mind to mind communication, telekinesis, or body switching that has been demonstrated, let alone that can be repeatedly produced in controlled experimental conditions. There are plenty of unverifiable, second-hand motivated anecdotes; but that’s obviously not good evidence, unless you’ve already decided you’re going to believe in these things regardless of evidence.
Out-of-body experiences and NDEs are the most popular parapsychological phenomena to reference in a discussion like this. I’m going to devote an entire episode to NDEs, or near death experiences, since they come up so often. But the most frequently reported aspect to these experiences is the out-of-body character. Many people have reported the experience of rising out of their body and looking around. At face value, this appears to fit perfectly within the dualistic account, but is awkward to explain on materialism.
I’ll go into more detail in the NDE episode, whenever that one is released. But neuroscientists can actually cause you to have an out-of-body experience just by altering your brain activity. They can do this reliably, under controlled conditions. Your brain actually creates the sense that you’re inside your body, and neuroscientists long ago identified the specific brain region that creates this sense. When researchers use trans-cranial magnetic stimulation to inhibit the functioning of the temporal parietal junction, subjects have an out-of-body experience. When this brain region is inhibited by reducing the flow of electricity to that region, you float out of your body. We can reliably create the subjective experience of an out-of-body episode by altering brain activity.
If you’re a Christian, and you want to deny neuroscience to maintain the Bible’s teaching that we have an immaterial soul, then be my guest; you’re driving smart people away from Christianity by doing so. And if you’re a Christian who accepts science and is not a substance dualist, thank you for conceding yet another thing we used to attribute to god and driving more people away from Christianity. I’m only trying to point out that if you’re going to deny science, you’re inevitably going to create problems for yourself. But if you bite the bullet, you don’t just erase the last two millennia of Christian history. If you accept neuroscience or evolution or that stars can’t fall on the surface of the earth, you’re admitting that Christianity got the wrong answer for the majority of its history.
Neuroscience is progressing, and the gap where apologists are trying to jam their god is slowly closing. If you insist on placing god in the current gaps of our knowledge and claiming that’s evidence, you’re making the same mistake your predecessors made over and over again throughout history. As this gap continues to be filled in, the Christians who stubbornly bet against naturalism and insisted on using this argument will have to deny more and more evidence. The Christians who see the writing on the walls will try to reinterpret the Bible’s teachings and claim that only simple-minded, unsophisticated literalists would ever dream of taking the Bible for what it says. Meanwhile, the number of people who see that they’re both wrong slowly grows. If you want to chain your god to a sinking ship like you did with creationism and intelligent design, be my guest.
Steven Novella’s Excellent Blog [NeurologicaBlog]
Consciousness – Anil Seth and Sam Harris [YouTube]
Causation and Emergence – Sean Carroll [PreposterousUniverse]
Sean Carroll – Zombies and the Hard Problem [Nautilus]
Substance Dualism – QualiaSoup [YouTube]
Richard Feynman – Science [YouTube]
The Interaction Problem – TMM [YouTube]