The immaterial soul, at least as most theists conceive of it, does not exist. There is an abundance of evidence for this assertion, but I have focused recently (both here and at UD) on observations of split-brain patients in particular.
My argument, in a nutshell, is that split-brain patients have two minds in one skull. The left hemisphere can believe, know, desire, choose, and act on things separately from the right hemisphere, and vice-versa. Since theists typically attribute these characteristics to the soul, they can only conclude that there are two souls in each split-brain patient – or more sensibly, that the unified soul was a fiction all along.
UD contributor Vincent Torley has responded to my argument here and here. In essence, his argument is that most dualists do not believe in the kind of soul that is disproven by the split-brain observations. He attempts to show that these observations can be reconciled with three kinds of dualism: the well-known ‘substance dualism’, and two lesser-known kinds that he and Edward Feser espouse, respectively.
(By the way, Vincent, I think you need a better name for your version of dualism. ‘Thought control dualism’ sounds too sinister. 
)
I appreciate the care with which Vincent prepares his arguments, the tone in which he presents them, and his willingness to confront the key issues. Despite our differences, I think his intellectual style and his appreciation of open debate fit in far better at TSZ than they do at UD.
On to the issues. I think that most dualists are in bigger trouble than Vincent lets on. They believe not only that the soul has the capabilities I mentioned above, but that it can function independently of the body (after death, for example). That commits them to substance dualism, which is very hard to reconcile with the split-brain observations.
Vincent, for you the soul seems to be inseparable from the body. For example, you write
…mind and body (or rather, soul and body) are not two things; rather, the human person is an essential unity.
You also write:
It should be noted that memory is viewed as a bodily capacity on both versions of dualism being discussed here. Neither account envisages us as having an “invisible information bank” in an immaterial soul, where we keep our memories. Memories, on both accounts, are stored in the brain.
Those quotes seem to indicate that you, unlike most of your fellow theists, do not think that the soul can function independently of the body. Is that true? Don’t you think the soul lives on after death? If so, does it lose its memories?
I’ll have much more to say in the comments, but I think this is an appropriate stopping point until you have given us a better understanding of your exact position.
I do hope Vincent will comment over here.
This megaphone diplomacy business is very odd.
I think VJ has clarified his position in the second post. The soul/self goes with the left hemisphere and the right hemisphere is soulless as it were. So in addition to wanting to hear more about his position on the mind/body relationship I am very interested to understand the status of the right hemisphere.
I heartily agree that vj is head and shoulders above all the other ID proponents in manners, knowledge and logic. Only gpuccio comes close, but I give the prize to vj.
You all are just plainly missing the obvious. Split brain research merely confirms the validity of demonic possession.
To be honest, I don’t think the split brain thing is all that much of a problem (or not much more than any brain lesion is).
Most immaterial-soul-ers accept that brain lesions/abnormalities affect people’s ability to think and choose. One idea (I guess the one I used to hold) is that regardless of cognitive power, there is an immaterial chooser that does its best (or not) with what it’s got to try and make the brain choose Good. That might not leave much room for manoevre in many brains, but we can assume that God knows we chose well (or ill), even if the result came out all wrong.
With that model, the immaterial soul in the split brain just has to struggle to get its brain/body to choose well, with whichever bit of neural equipment it can get a grip on. Sometimes that’ll be the left, sometimes the right, sometimes even maybe the limbic system. Who knows, when one side says theist, and the other says atheist, what the soul chose – perhaps neither? And saying one of each was the only way it could relay that?
The results of removing left or right hemispheres isn’t radically different.
I’ll start by agreeing about Vincent Torley. I see him as the most thoughtful poster at UD, and often with arguments worth reading. His one failing is that he tends to be verbose, though his last few posts have been an improvement.
Now back to the topic.
I agree with that.
I disagree with that. As best I can see, the amount of evidence against dualism is precisely zero.
For perspective, note that I currently have open a pdf file for a preprint of a paper by William Lycan, titled “Giving Dualism its Due”. Sorry, I didn’t record the link where I found that. The paper is supposed to be published in Australasian Journal of Philosophy.
Lycan is not a dualist. But, quoting from the abstract, he also says “This paper argues that no convincing case has been against substance dualism, and that standard objections to it can be credibly answered.”
Referring to his own rejection of dualism, Lycan goes on to say:
By comparison, I believe it is accurate that no evidence has ever been presented against phlogiston, nor against the lumeniferous aether. But there are strong cases against both. Namely, we now have far better accounts of combustion and of light propogation, and those accounts do not depend on phlogiston or aether.
The situation with dualism is worse. Not only is there no evidence against it, but there is also no better account of mind that is commonly accepted. Typical materialist theories of mind fail badly at explaining what most people see as of central importance.
I’d say that materialists typically fail badly at explaining what most people see as of central importance.
I don’t think the problem is with the theories.
I doubt if we can have a convincing theory of mind without being able to make one.
Split brains are just part of the problem for the existence of “souls.” There is a similar issue when cells split into identical twins early in gestation.
And what happens when the split is incomplete and the result is co-joined twins with two heads and one body? What kind of “soul(s)” does that produce?
Maybe “souls” split when brains split, however that splitting occurs? Somehow I don’t think that can work. There are still the underlying problems of “souls” interacting with a material universe and not violating conservation of energy.
I doubt that we will ever be able to make one.
I think we will, but it might be quite alien to us unless we give it a body of some sort early in its development.
If it’s on topic for this blog, I’d be interested in an OP from you discussing why you think strong AI is unlikely. Personally, I think it’s almost inevitable.
I think it will be as difficult as making life from scratch, and for the same reason. Intelligence — even insect intelligence — is an emergent phenomenon. It will have to evolve, even in silicon.
How are souls attached to bodies? Where are they attached? What is the binding energy of a soul? Is the bonding covalent? Ionic? Van der Waals?
How much energy does a soul have to expend in order to trigger action potentials in the nerves?
Hypothermia takes place when body core temperatures are about 60 degrees Fahrenheit (16 degrees Celsius); and hyperthermia starts somewhere around 108 degrees Fahrenheit (42 degrees Celsius).
This is an energy range from kT = 0.025 electron volts to about kT = 0.027 electron volts. In other words, the triggering of action potentials is disrupted outside this energy range.
So this gives us a range of energies in which souls are able to produce effects in the human body. It doesn’t tell us how tightly the soul is bound to whatever it is bound to; but it tells us the energy range in which the soul operates.
Further constraints on soul operations can be obtained from studies of injury, drugs, and alcohol on the body and brain. In fact, many drug effects are localized; as shown by fMRI and by which outward behaviors are primarily affected.
Do these localized effects mean that the soul is cut off from those parts of the nervous system that implements these behaviors? Can a soul be bound to a body yet not have any control over the body?
Does the soul “know” when it has no control over all or parts of a body?
To what part of the body does the soul have to be “attached” in order to receive input from the body’s senses and thoughts? How is that information transmitted to the soul? How much energy is required?
Does the soul know about phantom pain of an amputated limb?
Me too. But I think it will have to evolve in some way. But that’s OK, because brains, imo, function like evolutionary processes. I guess what I’m saying is that an AI brain will construct itself, rather as ours do, and will be part of a whole artificial, mobile organism that must find its own power sources in order to survive.
B
Mark,
Vincent is speaking for Eccles, a substance dualist, when he says that.
In Vincent’s own ‘thought control dualism’, it’s a bit more complicated:
I do hope that he (and the others at UD) will consider commenting here. Would you mind posting an invitation and a link to this thread at UD?
petrushka,
In children, it isn’t, because their brains are still quite plastic. In adults, left hemispherectomy tends to impair language skills, while right hemispherectomy impairs spatial skills.
I moderately disagree. I think it’s possible that AI will evolve to accomplish tasks like piloting aircraft and driving cars, but that isn’t necessarily the only route.
We already have much financial trading being done by programs, and there is an enormous incentive to “see” further into the future and take into account more and more variables.
I think of AI as a kind of instrument, like microscopes and telescopes, that extends our ability to see. Crude versions are already here. What’s currently missing is independent self-improvement, or the ability to evolve without human assistance.
I think that AI will evolve along the same lines as machines that augmented labor. AI devices will be fed because they are useful.
Robin,
We laugh, but Steve made that very suggestion on the other thread:
Sal also made it at UD:
I will work on that, though it might be a few weeks. And perhaps I’ll prefer to post on my own blog (where it is more on topic), with a summary here that we can use to lead discussion.
Yes, I agree with that.
So don’t cross the streams.
Lizzie,
The problem isn’t merely that brain abnormalities have an effect. The kind of effect they have is extremely important. In split-brain patients, the effect of the lesion is that they have two separate minds, one in each hemisphere, which is very difficult to reconcile with the existence of a unified soul that does the mind stuff.
You seem to be contradicting yourself in that statement. Is the soul the chooser, or is it the brain?
Most theists think that the soul makes the choices, and this is important, because the soul is what gets punished or rewarded after death. It would be quite unjust for God to punish or reward a soul for choices it didn’t make.
If the soul wanted to say ‘neither’, it could have declined to point, or it could have pointed to both answers with both hands. And if the soul controls speech, it could have stated ‘neither’. For one hemisphere to consistently point to one answer, while the other points to the opposite answer, suggests that there is no unified soul. Each hemisphere had its own opinion, and they differed.
And remember, this isn’t just about beliefs. It’s also about knowledge. In my ‘dog’ example, the left hemisphere knows something that the right hemisphere doesn’t. Thus, the left hand can point to the correct answer while the right hand cannot.
None of this makes sense if there is a single soul that knows the correct answer. I’ll reproduce my example below for convenience.
From an earlier comment explaining how the immaterial soul, as envisaged by most theists, runs afoul of the split-brain evidence:
Note that assumptions #5 and #6 aren’t really necessary, and obviously won’t be held by most people who have never heard of split-brain patients or considered the split-brain evidence.
As far as I can tell, “soul” is the phlogiston of consciousness – an imaginary something that emerges as a side effect of what a conscious process subjectively seems like to that process. I imagine there were learned scientific treatises on what the nature of the phlogiston must be, considering its implied properties derived from observations resting on, and not capable of being decoupled from, the assumption of its existence.
Of course if soul is just another perspective on mind, and mind is what the brain does for a living, surviving our own death is a lot more complicated (and NOT surviving it is stone ordinary). So we’re painted into a corner. We DO survive our own deaths (we do! we do! we do!), which means we must have an undying part, which means that part must be entirely independent of any physical substrate – the very substrate it can’t exist without.
Wishful thinking leads to strange convolutions.
It’s obvious–so obvious that its importance is frequently neglected–that, epistemologically, dualists and theists need to support their theses in the first place, rather than we who need to knock down.
Not that there isn’t good evidence against the soul, in particular, but we should keep the fact clear that they haven’t given us any good reason to suppose that there’s a soul in the first place.
Since I’m not opposed to evidence against the soul–even though I think that’s counter to the true burden of “proof”–I’ve tended to think that one of the worst sets of evidence for soul-believers is that a lot of criminals have had brain damage, which apparently has affected their choices for good and evil. There are specific cases of lesions that led to rather more “immoral choices” that could be brought up, yet which do not involve a loss of “free choice” as, say, courts would consider it to exist. So if the soul is independent, how can it be shifted to choose evil by brain lesions?
A rhetorical question, since I’m not waiting for a convincing answer.
Glen Davidson
Neil,
I obviously disagree. Perhaps I’ll do a follow-up OP on that, though for now I’d like to keep our focus on the split-brain evidence.
You probably found it here. I did an OP on it after Vincent mentioned it at UD.
You quote Lycan:
I responded in the other thread:
Neil:
I suppose it depends on how you define ‘evidence against’. But there are strong cases against phlogiston and ether, and there is likewise a strong case against the immaterial soul.
It’s a good topic for a future OP, but for now let’s talk about the split-brain evidence.
I agree that since life after death is an undeniable given, it has some entailments. Any theory of mind that doesn’t account for eternal life is necessarily wrong and incomplete.
It’s an inescapable result of right reason.
I want to emphasize a paragraph from the comment above:
Too many dualists approach the problem by asking, “Is there some way I can interpret (or less charitably, twist) the evidence so that I can hang on to my belief in the immaterial soul?”
If I work hard enough, I can come up with convoluted and implausible defenses of phlogiston and the luminiferous ether. I can force-fit them to the evidence by making additional ad hoc assumptions, but physicists wouldn’t find my explanations persuasive, and they shouldn’t.
Likewise, if dualists work hard enough, they can come up with convoluted and implausible defenses of the immaterial soul. They can force-fit it to the evidence by making additional ad hoc assumptions, but most neuroscientists and philosophers don’t find their explanations persuasive, and they shouldn’t.
The question is, and should always be, “Which hypothesis fits the evidence better?”
Yeah, what good is reason if it doesn’t give us the answers we’re longing for?
Mike,
All very good questions. I will definitely do a future post on the interaction problem and other evidence against immaterial souls.
It’s interesting how Lycan tries to brush off the interaction problem:
Which evidence? And how do you measure “goodness of fit?”
The real problem here is that mainstream academic philosophy itself is fundamentally dualist, even though most philosophers are not dualists. Philosophy attempts to explain or describe things from the vantage point of a immaterial being, perhaps a “God’s eye view” or the view from an immaterial soul. This is sometimes referred to as the view from nowhere. Because of this, dualist accounts fit better than materialist accounts.
If you want a materialist account, then start with:
1: an entirely materialist account of truth;
2: an entirely materialist account of “belief” or of propositions;
3: an entirely materialist account of justification.
And I have only asked about epistemology. Metaphysics (or ontology) would present another set of challenges.
An entirely materialist account allows emergent phenomena and levels of description.
Materialism does not imply complete reductionism.
Hi everyone,
Just thought I’d pop over for a very brief visit. (I really am busy, as I’m working on several posts, but I thought I’d try and be more neighbourly.)
In answer to your question, KeithS, I agree that a separated soul, left to itself, would be quite unable to function, as it would be unable to retrieve information. So what do I think happens after death? One obvious solution is that the soul “plugs into” God’s awareness, which could account for the transcendental qualities of NDEs. (I might mention as an aside that I once watched an ABC TV program in Oz on NDEs, and in the audience was a person who said they’d tried a variety of drugs in the past, but none of those experiences came anywhere close to the near-death experience they had.) That would however fail to account for people who die in a state of willful defiance of God: presumably plugging into God is the last thing they’d want to do.
Perhaps a better way of putting it is that God infuses the separated soul with information on a need-to-know basis. Aquinas said pretty much the same thing in his Summa Theologica I, q. 89, art. 4: http://www.newadvent.org/summa/1089.htm#article4
I freely acknowledge that this solution might strike some as artificial. But to my mind that’s not a knockdown argument. Like Paine, I regard the mechanics of immortality as God’s problem, not mine.
In any case, I would argue that the immateriality of thought is pretty obvious, given our ability to entertain purely abstract concepts (such as true, false, real, prime etc.) which cannot be cashed out in material terms.
By the way, KeithS, if you’re interested in dualism, you might want to check out Ed Feser’s latest paper, “Kripke, Ross and the Immaterial Aspects of Thought” in “American Catholic Philosophical Quarterly”, Volume 87, Issue 1, Winter 2013, (abstract at http://www.pdcnet.org/acpq/content/acpq_2013_0087_0001_0001_0032 ). Hope that helps. Bye for now.
keiths:
Neil:
All of the available evidence. Why should we neglect any of it?
In the standard scientific ways. A model fits well if it makes distinctive predictions that are confirmed by observation, and if it doesn’t require lots of ad hoc assumptions in order to force-fit it to the evidence.
The “immaterial sou”l hypothesis fares very poorly under those criteria, while the “two (material) minds in one skull” hypothesis works beautifully.
First, the “view from nowhere” doesn’t require us to actually posit the existence of an immaterial being. It just asks us to consider what such a being would “see” if it existed.
Second, even if philosophy were dualist in that sense, it wouldn’t need to posit dualism in any other sense. It could be monist with respect to the entire universe, including humans.
A quick welcome to vjtorley, who has joined our forum.
My apologies for not noticing that his post was stuck in moderation for a while.
Can you provide a link to a non-dualist model that is complete enough to make useful predictions?
Neil,
I don’t need to provide a link — we’ve been discussing such a model right here!
If all of the things I mentioned above — belief, knowledge, will, choice, and the initiation of voluntary action, plus some others I didn’t mention, like communication and perception — are functions of the brain and nervous system alone, with no immaterial “assistance”, then certain things follow:
1. Those functions should cease when the brain ceases to operate.
2. Those functions should be disruptible by damage to or perturbation of the appropriate parts of the brain.
3. If pieces of the brain are disconnected from each other, then those pieces may stop functioning altogether; if they do continue to function, they should function independently, as we see with the hemispheres of split-brain patients.
All of these predictions are borne out.
Under the ‘unified immaterial soul’ model, we expect altogether different results — unless you start piling on the ad hoc assumptions, which I warned against in an earlier comment.
Welcome, Vincent. Glad you found time to visit.
Hi Vincent,
Welcome to TSZ! I hope you’ll keep dropping by.
Not just artificial, but God of the Gappish. You’re essentially saying “Where my theory works, it works, and where it doesn’t work, God fixes things up so that it does work after all.”
If I were trying to make that kind of argument (but relying on an unknown but powerful material mechanisms, say, instead of God) you wouldn’t let me get away with it.
Also, your idea raises an obvious question: If God is willing to prop up the soul after death, why doesn’t he do so during life? Why do we need brains at all? They burn around 20% of our energy. Many people have died — quite literally — because of the amount of energy consumed by their brains. Why does God saddle us with such a burden if brains aren’t really necessary at all?
The same argument applies to eyes and ears. Why do we have them at all if we can see and hear perfectly well without them during NDEs and OBEs, as many dualists claim?
You and I were discussing that at UD when Barry rudely brought the conversation to a halt. I hope we can pick it up here. As you know, I think that physical systems are capable of representing and operating on abstract concepts.
Thanks. I’ll check it out.
See you later.
Well, depending on the situation sometimes absense of evidence IS evidence of absense. If we thoroughly search for and try to find evidence that confirms dualism but fail to find any that unambigously support it, this is evidence that dualism probably isn’t true. As in dualism is then less likely and consequently, less believable.
It isn’t proof, but it’s evidence nonetheless.
I think Richard Carrier explains the general principle here pretty well:
In the few cases of split personality there is no need to see anything other then a single soul with their memory acting out two or more different personalities.
JUst like an actor.
These are cases where there is a failure. They are not normal.
Not being normal means there should only be one personality.
It is the dysfunction of having more that is the only problem.
It simply is the memory being divided. They remember differently what they want or like or who they are.
We only remember everything about ourselves as a memory thing in the first place.
Its not who we are as souls.
In fact split personalities might be excellent evidence we are just souls and from babyhood we develop a personality but its not organic. Its a creation.
This creation can be forgotten in all its desires and conclusions.
Being immaterial souls would predict split personalityism very well.
Our personality was a creation and stays with us because its in our memory about its journey.
VJ contributed this:
“Perhaps a better way of putting it is that God infuses the separated soul with information on a need-to-know basis. Aquinas said pretty much the same thing in his Summa Theologica I, q. 89, art. 4: http://www.newadvent.org/summa/1089.htm#article4”
Is this argument meant to make a belief in immortality attractive? That when we die and enter communion with the deity, we lose any independent access to information? Could you explain the theology behind this idea?
And while you are at it, this argument suggests that the immaterial soul loses free will following death (if it receives only information that the deity decides it needs to know, what could it decide upon “freely”?). There is at least one case in your theology that suggests immaterial beings do not lose free will (Lucifer).
So your model seems to be “the brain did it” which tells us about as much as a creationists “god did it.”
But this is assertion, not evidence. You don’t have a good theory of how the brain does that, or even if the brain does that. As best I can tell, the “belief” story of knowledge is mostly BS.
At the time that Descartes came up with his dualism, he was surely well aware that damage to the brain can damage cognitive abilities. I looked at the SEP entry on the pineal gland (which Descartes mentioned), and it is clear from that SEP entry, that there was knowledge of the brain’s relevance to cognition well before the time of Descartes. What they knew was very thin compared to what we know today. But they knew enough for me to suspect that the version of dualism you are attacking is a strawman.
The proper way to debunk dualism is to come up with a decent non-dualistic theory that explains the major features of human cognition, and that has been well tested. As best I can tell, such a well tested theory does not currently exist.
I’m not sure such a theory will ever exist. I respect cognitive science, and I think given time, we may create strong AI, but I’m not sure the even that will give us a complete theory.
Do we have a complete theory of emergent chemistry?
I suspect we will eventually have good descriptions of cognitive activity, but I doubt if it will satisfy philosophical curiosity.
I asked above:
And a related question: Why, in the case of Alzheimer’s, stroke, etc., is God unwilling to prop up the soul during life? Why does he allow those conditions to persist for years or even decades, if he is going to step in and rectify the situation at the moment of death?
It’s a bit too convenient and ad hoc to say that “Well, God doesn’t do these things while we’re alive, so we have absolutely no evidence that he does them at all, but nevertheless we can be sure that as soon as we die, he starts doing them.”
The question is, and should always be, “What hypothesis fits the evidence best?”
An ad hoc hypothesis in which
…just doesn’t cut it.
Vincent, I know you’re smart enough to see what an implausible mess that hypothesis is. I know you can see how much cleaner and better-supported the materialist hypothesis is.
I think you are letting your desire to believe get the best of you. Give your intellect a voice at the table, and may the best hypothesis win.
Neil,
Are you kidding? Creationists can’t demonstrate that God exists, they can’t explain how creation happened (or happens), and they have no evidence to back up their claims.
We know the brain exists. We can observe it and manipulate it. We already know quite a bit about how it works, and we’re learning more every day. Neuroscience is an exploding field. We have tons of evidence suggesting that the functions of the mind are utterly dependent on the brain, and no evidence that they can continue without it.
Creationism vs. neuroscience is night vs. day.
If you believe that there is no evidence, then I highly recommend learning more about neuroscience. There is abundant evidence that the functions of the mind depend on the brain, and that they cannot happen without it. What role does an immaterial soul have in such a system?
The version of dualism I am criticizing is held by many, if not most, theists. If you have an alternative, I’d be happy to consider it.
No, the proper way to debunk any theory is to show that its predictions are not borne out, or that it requires too many ad hoc assumptions in order to be salvaged. Dualism, as most theists conceive of it, fails these tests. It is falsified by the split-brain evidence (and an abundance of other neuroscientific evidence).
A successful dualism needs 1) to be compatible with the evidence, and
2) to make distinctive testable predictions that are confirmed by experiment and/or observation.
There are some ad hoc versions of dualism that satisfy #1 (such as the idea that the soul is just a free-floating consciousness that is causally irrelevant to the body), but I am unaware of any that satisfy #2.
Do you know of any?
I have not criticized neuroscience, nor have I equated it to creationism. I will thank you to not suggest otherwise.
Do dualists deny that? And if they do, aren’t they talking only about alleged functions of the mind that have no behavioral effects?
I don’t go around asking theists for their version of dualism, and I don’t have my own version. I’m not a dualist. I consider dualism to be nonsense.
I am not defending dualism. I have been criticizing the argument that you gave against dualism.
Neil,
Yet you wrote:
You realize that neuroscience provides strong evidence that “the brain does it”, don’t you?
keiths:
Neil:
Yes, many of them do deny it, and no, they are not restricting their claim to noncausal functions of the mind or soul. Their reasons are largely theological, having to do with moral responsibility:
1. They want humans to have libertarian free will. If the mind is completely dependent on matter, they feel that libertarian free will is threatened. (LFW is threatened either way, but they typically don’t realize that.)
2. They feel that the soul is rewarded or punished after death, after it has separated from the body. For this to make moral sense, the soul itself needs to be fully responsible for the person’s morally significant actions and beliefs. Otherwise it is being rewarded or punished for beliefs and actions that were out of its control.
3. They want for the soul to be a complete, or nearly complete, repository of the person’s identity (personality, knowledge, beliefs, memories, etc.). They see the soul as the true self, with the body as mere vehicle.
Good! Then we’ve made progress. Yesterday you were still defending it:
Neil,
Commenter ‘tragic mishap’ at UD exemplifies the widely held kind of dualism I’ve been talking about:
Actually, no, it doesn’t. It has strong evidence that the brain is involved, but I don’t think dualists deny that.