Dr. Egnor's bad arguments for the soul

In #religion

Here's a video where Dr. Michael Egnor presents arguments and evidence for the existence and properties of the soul. For someone who studies the brain, Dr Egnor is remarkably sloppy with his facts about brain deficits and shows a profound lack of understanding of the methods of science -- and even basic logical arguments.

Introduction

He starts off by showing a number of brain scans that presumably show someone without a brain or large parts of a brain missing can actually function normally, and thus there has to be something other than the brain involved.

He shows Cindy, and he says that she's missing 2/3 of her brain and that's the way she was born. Then he shows Joshua, also missing 2/3 of his brain. And Maggie is missing most of her cerebellum and part of the central region of her brain. In each of these cases, he says things like, Maggie was in a gifted program and has a master's in English and literature, and basically, she's like a normal person.

Then he shows Nicholas, who Egnor says is missing both hemispheres of his brain, only has a brain stem, can't speak, can't walk, but is fully conscious. "He's kind of funny, he laughs, he cries, he's emotionally a normal person."

The Problem: Lack of Specificity

Basically, in all of these cases, Egnor doesn't actually show what these people actually have. There are a number of different brain issues that can perhaps look superficially similar but are actually quite different functionally, so being specific matters.

Digital Gnosis Explanation

There was an explanation of this on Digital Gnosis, where James Fodor goes through a number of different papers. And one of the things he shows is that there are at least three kinds of medical conditions that sound very similar. These are:

  • hydrocephalus -- functioning brain distorted by fluid
  • hydraencephaly -- missing most or all of a cortex
  • anencephaly -- only a brain stem

The first one, hydrocephalus—they have a functional brain, but it's just distorted by fluid. So when you look at it, it looks like they're missing parts, but what really is going on is that fluid is actually pressed against the brain and has distorted it. They still have all of their brain tissue, and most of its function—there are some deficits, but someone can be nearly completely normal with hydrocephalus.

There's hydranencephaly, where they're missing most or all of the cortex. These patients can generally function, but they're not going to have higher reasoning. They're not going to have a lot of things that we would often think of as normal functioning.

And then we have anencephaly, where the patients only have a brain stem. These patients will have the largest behavioral deficits.

Egnor's Sloppiness

The fact that he is not specific about these and simply lumps them all together, saying these people are "missing 2/3 of the brain", when in reality that's just not the case, is incredibly sloppy and actually professionally reprehensible. Cindy and Joshua above almost certainly have hydrocephalus, and thus have all of their brain tissue and thus a nearly fully functional brain. For Dr Egnor to say that they are missing 2/3 of their brain is just flat out wrong and he should know better. Even in these cases, we see exactly what the naturalist would predict -- the more distorted or damaged brain, the more severe the deficits. Note that the brain is also known to have multiple redundancies, so even severe damage may not result in severe functional deficits.

Wilder Penfield: Outdated Neuroscience

Then Egnor references Wilder Penfield. Wilder Penfield started working in 1915 and retired in 1960. Now, I would have thought Egnor would have wanted to bring in someone a bit more recent, given that we've probably learned something about the brain since 1960.

Egnor's Claims About Penfield

Egnor has written about Penfield on his blog, and he refers to some of this in his talk. He talks about how Penfield mapped people's brains, essentially by doing stimulation of the surface of the brain to see what would happen. People would experience a tingling or a flash of light, and sometimes they'd have a memory or an emotion. But Penfield never once stimulated the power of reason, for example.

Egnor points out that when people have seizures, they have these general experiences—you have twitching, you have tingling—but nobody ever gets a calculus seizure. No one has a seizure where they couldn't stop doing arithmetic or couldn't stop doing logic.

Further, Egnor points out that once in a while, stimulating a particular part of the brain made someone's arm move. And when asked, "Can you tell me when I'm making your arm move or when you're making your own move?" the patients could always tell the difference.

Egnor's point is that the sense of self and the process of reason must come from somewhere other than brain functioning.

However, all these observations can be explained by noting that reason, being a sequential, detailed process, can't be elicited by a seizure and doesn't show up easily in one place in the brain. Reason and other higher-order processes are distributed across many areas. If you're simply sending an electrical current, you're not going to stimulate something that requires that kind of sequential processing. This has been known since at least the 1980s (40-50 years ago) but Egnor seems to be stuck in the 1950s neuroscience which is one of Egnor's major problems.

Roger Sperry and Split-Brain Patients

Dr. Egnor then brings up Roger Sperry. Roger Sperry died in 1994—30 years ago. His work was mostly done in the '50s and '70s when he did some work on split-brain patients. I note that this work is still quite old in a fast-moving field.

The Experiments

Egnor describes some of the experiments that were done by Sperry and then describes some similar work by Alice Cronin. In Cronin's work on split-brain patients, she would present one picture in one hemisphere, and in the other hemisphere she would present three pictures. One of the three pictures would match the picture in the other hemisphere, and the other two would be unrelated. She did this hundreds of times, and people with split-brain surgery were virtually always able to easily identify the concept—pick out the images—even though "no part of their brain saw both images".

Egnor's Quote from the Paper

And then he quotes from the paper:

"All subjects performed the non-verbal matching task well above chance, with scores comparable to those attained when the task was performed completely with one or the other hemisphere. Transfer was equally successful in the two directions."

Cronin-Golomb, A. (1986). Subcortical transfer of cognitive information in subjects with complete forebrain commissurotomy. Cortex: A Journal Devoted to the Study of the Nervous System and Behavior, 22(4), 499–519. https://doi.org/10.1016/S0010-9452(86)80012-0

And Egnor continues: "Is there a small secret back door by which messages could get through to the other hemisphere? The split may not be altogether complete," Dr. Egnor commented. "When you cut the corpus callosum, you virtually completely separate the two hemispheres physically, so there's no physical contact. There are roundabout ways the hemispheres can talk to one another, at least theoretically, but they're very small."

What Egnor Doesn't Quote

Egnor does not quote the end of the paper, which states,

"Along with behavioral and other physiological mechanisms, the subcortical bridge may in time be revealed to be a major factor in the ability to maintain a unity of conscious experience for split-brain subjects and perhaps for normal humans as well"

So what Cronin is saying is that while you might separate the cortex, there are subcortical circuits that cross the hemispheres. And while we haven't focused a whole lot on those particular areas, it seems as if they are important in the split-brain patients, because that's the remaining conduit for interhemisphere communication.

So essentially what we have is a brain rewiring itself so it can do normal, complex tasks by using a different subcircuit. Or this paper (Diffusion weighted imaging evidence of extra-callosal pathways for interhemispheric communication after complete commissurotomy) which points to other subcortical communication methods:

"These results point to specific cerebellar anatomical substrates that may account for the spared interhemispheric coordination and intact cognitive abilities that have been extensively documented in this unique patient."

Or another paper (Visual integration across fixation: automatic processes are split but conscious processes remain unified in the split-brain),

The results showed that we replicated the observation that split brain patients cannot match across fixation, but more interesting, that DDC was very confident in the across-fixation condition while performing at chance-level. On the basis of this result, we hypothesised a two-route explanation. In healthy subjects, the visual information from the two hemifields is integrated in an automatic, unconscious fashion via the intact splenium, and this route has been severed in DDC. However, we know from previous experiments that some transfer of information remains possible. We proposed that this second route (perhaps less visual; more symbolic) may become apparent when he is forced to use a deliberate, consciously controlled approach. In an experiment where he is informed, by a second stimulus presented in one hemifield, what to do with the first stimulus that was presented in the same or the opposite hemifield, we showed that there was indeed interhemispheric transfer of information. We suggest that this two-route model may help in clarifying some of the controversial issues in split-brain research. (emphasis mine)

Or from Unifying control over the body: consciousness and cross-cueing in split-brain patients,

"Looking at all the evidence, we believe that the most parsimonious and logical conclusion is that the right hemisphere of the commissurotomy patients includes a stream of consciousness that is separate from that of the left hemisphere, but the two hemispheres may interact closely via cross-cueing and subcortical connectivity. The evidence for a separate conscious stream in the right hemisphere includes the following observations: while pictures and objects in the left visual field cannot be named through overt speech, they can be matched with written or spoken words, matched to conceptually related items, stored in short term memory for matching with subsequent probes (Gazzaniga, 1995). [...]

Finally, cross-cueing should not be simply viewed as ‘(un- conscious) cheating’ (Pinto et al., 2017b), but as an incompletely understood mechanism that allows for information integration in the absence of direct neural connections and hence considerably contributes to the quality of life of split-brain patients. Hence, while we argue for a separate stream of visual consciousness in the right hemisphere, we agree with Pinto et al. that the seemingly normal, bilaterally integrated behaviour following commissurotomy requires further explanation. Despite illustrating the ingenious capacity of human adaptation, cross-cueing itself may hold valuable insights on how the intact brain integrates information from highly specialized neural systems."

So essentially the right and the left can tell the other what the answers are through other pathways other than the direct connection between the hemispheres. There's a number of these various mechanisms, and some of these papers are very recent. Egnor does not address any of them at all.

Egnor says things like, "No part of the brain saw both parts of the story, so there must be something in the mind that is not in the brain." That is patently ridiculous. It's fairly straightforward to explain this with subcortical connections and cross-cueing without resorting to magic. So Egnor's claim that there is no other way than magic for the hemisphere's to communicate in split-brain patients is unfounded.

The Laptop Analogy

Egnor then says that this is analogous to cutting a laptop in half and have it function. This is a terrible analogy and Egnor should know this -- it's nowhere near how the brain works. The brain is incredibly distributed. You can damage parts of it, and other parts of it will rewire themselves to try to get as much of the function back as possible. A laptop just simply does not work in that way.

Free Will Argument

Egnor moves on to Penfield, where Penfield stimulates the brain to get arm movement and asks the patient whether he or they did it, and they can tell the difference. Egnor concludes that Penfield couldn't find a place in the brain that stimulated free will, that free will isn't in the brain. This is ridiculous -- we shouldn't expect such a crude measurement technique to elicit free will responses just like we wouldn't expect them to elicit mathematical responses. Not seeing an effect doesn't mean the effect isn't there, it's just that the way you measure it isn't sensitive enough to detect it.

Egnor brings up the work of Benjamin Libet about experiments where about the 500 ms before you claim to make a decision there's an EEG spike that predicts whether you're going to make the decision. As a further result, there seems to be no spike when you veto the decision. There's a whole history of all this and it's pretty interesting. Egnor then claims that "The free choice to do it or not had no new brain activity at all, was independent of the brain." This is so sloppy. At best, it had no measured activity -- we are measuring EEGs which average thousands of cells, so there are many signals that simply can't be measured by EEG. Just because a method for measuring didn't detect something doesn't mean that the something doesn't exist, or that the brain doesn't signal it, it is just that we couldn't detect it with (admittedly) crude methods

Persistent Vegetative State

Egnor quotes some work from Adrian Owen about patients in a persistent vegetative state still being conscious. Owen himself writes about this here. Egnor calls persistent vegetative state "the deepest level of coma, just a step above brain death", but Owen's observations clearly show that it is not that. Owen points out that persistent vegetative state is often misdiagnosed from a far more active state -- which is the point of Owen's work. So again, Egnor is being incredibly sloppy and not up to date with the content.

Near-Death Experiences

Egnor then starts talking about NDEs. There's a long discussion on Digital Gnosis about near-death experiences which walks through all the major cases, and shows where the data is severely lacking. Egnor talks about Pam Reynolds, but if you actually look at the case, you can show easily that the data is entirely consistent with a combination of anesthesia awareness and memory contamination -- no magic needed.

There's a claim that there are no reports of people ever seeing a living person at the end of the tunnel. I don't believe the claim without some demonstration. This doesn't impress me because we expect that this can occur with just expectation combined with biased reporting.

Intentionality Argument

Egnor says everything in your mind is "pointed at something"—it has a meaning to it. He contrasts it with a camera: "With a camera, does the camera care if you're taking a picture of a sunset or a snow scene?" This is pretty silly. The response of a retinal cell is analogous to a camera. It converts light into electrical signals, just like the photosensitive chip in the camera. It doesn't care about anything.

The only reason Egnor can say that the mind is pointing to something is because he's referring to an incredibly sophisticated organ—the brain—which he doesn't understand and which has a pretty complex input-output situation. Egnor lacks the imagination to see that the brain definitely could be a (admittedly complex) computational structure

Evolution Argument

He then goes on about "How did the mind evolve?" His only response is to ask a question, because his only argument for the mind being immaterial is that evolution couldn't work on it. This is begging the question.

What Is the Soul?

His final topic is "what is the soul". And he talks about the properties of the soul, including

  • loves and animates
  • immaterial
  • has no parts (cut the brain in half, you don't cut the soul in half)
  • has no location (cites the NDE)
  • not in time
  • abides (exists after death, even with brain injury)

Questions About the Soul

And so a few questions here:

  • What about those cases where half of the brain in a split-brain patient is an atheist and the other half is a Christian? Are there two souls there, or is there just one?
  • How do you know animal souls are actually different? Egnor claims that animals don't reason morally. What about all the various experiments showing ethical reasoning in chimps (https://link.springer.com/article/10.1007/s12110-015-9228-5) and other animals (https://blog.londolozi.com/2023/06/29/do-wild-animals-have-a-moral-compass/). I just did a quick search and it is easy to find.
  • What about the interaction problem? Specifically, how does that work in NDEs? If the soul sees things with eyes, it has to interact with photons, which would be detectable. Or how does the soul go back into the body and change the brain states so that the person remembers what actually happened?
  • If the soul can see, why do we need eyes?
  • What is the role of the brain in reasoning, given that brain damage can clearly affect reasoning? So what is the role of the soul in reasoning?
  • Egnor does come back to the question of the "soul seeing" and says it uses divine light. But then we have to ask the question: how is this different than saying "magic did it"? I mean, if souls could see with divine light, why do we need eyes at all? Does this explain hearing as well? Is there divine sound?
  • If souls have no position, why are all the reports from right near where the body is? Why don't we get, for example, corroborated reports of conversations from around the world or even from across town?

All his claims about spirit seem to be just made up. How could you test any of this?

Once you start seeing these unsupported claims for what they are, you can see that they are empty of actual content and are really just excuses for not having good evidence.

Conclusion

Overall, this video shows essentially a sloppiness at a level I'm surprised at for someone who does brain surgery. It shows outdated science on nearly every single topic. It is credulous about claims about near-death experiences and other paranormal claims. It makes faulty reasoning, claiming multiple times that if you don't observe something, then that thing must not exist. In several places, he misattributes things like persistent vegetative state and specific brain deficits. He makes terrible analogies with laptops and cameras. His description of the soul is, as far as I can tell, completely made up, and there's no way to test any of it. Further, his description of the soul is riddled with questions that just give rise to contradictions (e.g. how the soul interacts with the body, how it sees, etc...). When you actually start trying to be specific about these things, you start realizing that the evidence for the soul is incredibly thin and the entire concept falls apart.