For the last two weeks now I have been debating with skeptics on a forum called infidels. Here's some of the exchanges I have had with some of them.
kaugust View Post
I would like to ask the robust dualists posting here some questions, if they can answer them:
If the mind is something independent of the brain, and is something that is so complex that the brain must "filter" it in some vague sense, then why does performance of complex mental tasks--like doing a math problem, or lying (since lying requires knowing the truth, inventing a lie, and then covering up any evidence of the truth to be consistent with the lie)--require more brain activity than when individuals are not engaged in such tasks? This can be measured with MRIs--in fact, they are being appealed to as lie detectors (currently being reviewed in a particular court case) for their very ability to measure the increased activity of lying.
If mental tasks are something that the immaterial mind can do best when "unconstrained" by the brain, wouldn't complex mental tasks be correlated with less or at least the same amount of brain activity as when such tasks are not being done? In other words, if it is my immaterial mind that does math and lies, why would increasing brain activity assist it? Wouldn't it do better without the brain's "interference" or filtering or "transmission"--i.e., less brain activity? Wouldn't more brain activity constrain it further?
It seems to me that the fact that the more complex the mental task, the more brain activity required, is pretty good evidence that the brain is what does the thinking, and not some immaterial mind. Why does the brain require more glucose or oxygen to burn it the more complex the mental task, unless that processing is being done by the brain itself, and not by the independent mind?
Perhaps a dualist might hold that when the mental task becomes more complicated, the "radio/television" of the brain has to extend its antenna a little more since it can't boost the mind's signal itself, and the increased activity is the tuner trying to get a better picture. Maybe the extra energy the mind puts into answering the math question means it has to lower its normally 50000-watt-signal and so sends a weaker signal to the brain--and the brain must adjust by fine-tuning its receiver, and that fine tuning requires extra brain activity.
But then why the localization--why does this area of the brain light up in mathematical problems, another area light up during creative writing, and so on? And why do more intelligent animals have much more complicated brains than simpler ones? The simpler the brain, the less resources that brain has to "limit" or "filter" or "constrain" the mind--so shouldn't simpler brains be more intelligent, and the most complex brains correlated with lower IQs, since brains merely "suppress" an otherwise unlimited mind?
Why doesn't damage to the visual cortex improve visual processing (assuming the eyes are left in tact), if the brain merely limits the soul's unlimited visual abilities? (As implied if we take out-of-body and near-death experiences at face value.) Why does damage to a specific area of the left hemisphere result in aphasia, a mental deficit, instead of improving an individual's understanding of language? Is it not true that on the transmissive hypothesis, the less brain activity, the better the mental processing? Mental processing, after all, is held to be something that an immaterial soul does, not something a brain does--else it wouldn't be mental processing on dualism. But in fact the opposite has been found to be true. Doesn't all of this make much more sense on the notion that the brain is doing the mental processing--i.e., that mind/consciousness/self/personality/what-have-you are simply simplifying words for specific brain processes?
So I leave it to you: Which is it? Does the brain cause our mental activity or does it merely "suppress" it, as implied by the "transmissive hypothesis"? Ask yourself which seems more likely given the neurophysiological data, putting your presuppositions either for or against dualism aside. If you answer honestly you'll see my point. Answering "But what about out-of-body experiences?" and so on does not answer the question--it simply aims to defuse the evidence by appealing to different evidence. Ignoring such other evidence for the moment, can you honestly say that dualism is just as good an explanation of what we know about mind-brain correlations than the position that mental processes are brain processes?
Incidentally, since it has come up in this thread and Irreducible Mind, I would like to know how robust dualism itself explains supposed instances of Alzheimer's patients regaining their cognitive faculties just before dying. After all, a dying patient still has that pesky brain "constraining" its unlimited abilities. If someone is dying and can still talk, obviously the brain is still "constraining" the mind at that point. It is the other body organs that are failing--the liver, say--at that point. It is only when brain activity ceases or is at least diminished to the point of causing unconsciousness that the "filter" of the brain is no longer holding back the mind--but then the patient cannot move or talk or do any physical activity normally allowed by the brain. (Since the brain is the instrument which allows the soul to control bodily movements, like moving one's lips to talk.) If a dying patient can raise his arm and hold a conversation, clearly the brain is still "filtering" things, is it not?
That's all for now--I just wanted to throw that out for you all to chew on.
I have posed this challenge as you call it over at Michael Prescott's blog you can read the comments
Originally Posted by kaugust View Post
Originally Posted by LeoM View Post
"And the vulnerability of consciousness to anesthetics, to caffeine, and to something as simple as a sharp blow to the head, shows its very close dependence on neural activity in the brain."
Damaging the circuitry of a TV set will impair its ability to display an image, but the TV signal is unaffected.
Talk about missing the point, Leo. Consciousness is what is vulnerable to anesthetics and so on. Consciousness is the signal in your analogy. According to your analogy, the TV set could be destroyed and the signal would go on. But consciousness is affected by brain manipulation--it is not unaffected, as a signal is by what one does to a TV set. So why does injecting a person with anesthetics cause consciousness to "go out"? Why isn't it hovering there above the body waiting for the anesthetics to wear off to it can regain control of its "vehicle"?
Ah, yes, that old canard. Yes, correlation isn't always evidence of causation. But it often is. It depends upon the kind of correlation. Just Google "Mill's methods." After all, there is a correlation between smoking and lung cancer sufficiently robust for us to know that smoking causes lung cancer. Or is that "mere correlation"?
You're missing the point again: On your analogy the picture and sound of the TV is human behavior, and the signal is the mental processing. Nothing you do to the TV can affect the signal it receives. Thus on your analogy nothing you do to the brain should affect mental processing, since that is done somewhere other than the brain--in a soul.
So you are forced into a dilemma: either admit that (1) mental processing is done completely by the brain, or (2) partially by the brain and partially by the immaterial mind. The problem with the latter is that once the brain's processing is removed from the equation, the immaterial processing by itself is not enough to make a human mind. Either way, persons cannot think without brains. This conclusion is inescapable given the evidence.
Originally Posted by LeoM View Post
So if the brain becomes a receiving devise, it could in fact be configured differently in every case to give the temporary illusion of one person being intelligent, another talented musically and the other slow and docile
This would allow people to exist on earth as individuals, these character traits could then be incorporated in to the soul for future reference.
Thank you, Leo, for giving me a wonderful analogy on which to base the argument. Consider the difference between a computer which processes a problem locally, and one connected to the internet, the internet being the "signal" and the processing being done on some other computer.
You can degrade that internet connection in any number of ways, affecting the data received. But you cannot affect processing that is done locally on the computer in front of you without affecting the local computer.
On pure production, mental processing is done locally. On transmission/dualism, it is done remotely. On some hybrid like C. D. Broad's compound theory, there is some production on the immaterial side, and some on the material side. The question is whether you can get the full effect of all that combined material and immaterial processing once the physical processing has stopped. And the answer is clearly "no."
The transmissive and production hypotheses can yield different testable predictions, and the analogy of computer A which locally processes information (a brain) connected via a modem connection (a signal) to a computer B which remotely processes information (a soul) can show that there are things that you can do computer A locally which will not affect computer B's remote processing. Such an analogy can intuitively show why tampering with the brain should not affect the mind itself if the mind is remote and the brain is local. And if you hold that the mind is some thing neither the local nor remote processing, like the connection between a local and remote computer, clearly that mind no longer exists once the connection is severed--since the connection by definition requires both computers.
If you mess with the signal between the two computers--between the soul and the brain--you can affect the data that is processed, but not how the machine receiving it processes. If the soul is what thinks, perceives, loves, and what have you, then messing with the brain should not affect thinking, perceiving, loving, or what have you. But it does. Repeated used of crystal meth can turn a compassionate person into an uncaring one. Why is this so, if the soul is what cares, and the brain merely does the soul's bidding like a puppet?
But determining if it's productive, permissive, transmissive is the question at hand.
Originally Posted by kaugust View Post
Originally Posted by LeoM View Post
I like this sentence by Titus Rivas where he refuts your position that the mind is dependent on the brain.
Leo MacDonald being convinced by Titus Rivas, when their positions are nearly identical to begin with? Wow, who would've imagined!
Of course there is more to the argument than merely the mind being influenced by the brain. Of course one object can be influenced by another, so that alone is not going to be a problem with dualism. The problem is how the mind seems to be dramatically altered by brain damage--that shouldn't happen if the mind is independent of the brain. And if the argument were as easily disposed of as you like to pretend, would a prominent philosopher like C. D. Broad, who also happened to be very sympathetic to parapsychology, have conceded that it is a strong argument?
I'll quote Broad below--bolding is mine:
If you want to put your head in the sand and pretend that all is well on dualism, that's your prerogative. But honest researchers have at least admitted that prima facie this sort of evidence strongly undermines the scientific possibility that one's mind could persist absent a brain. Are they all wrong in making this concession? Why would dualists and parapsychologists make such a concession unless honestly looking at the neuroscientific evidence compelled them to do so, considering that it doesn't help their position to concede this point? John Beloff, Douglas Stokes, and Garner Murphy--all parapsychologists sympathetic to dualism and survival--also conceded this. But why?
I would say that their brains are reorganizing synaptic connections wouldn't you? Let me guess--the implication is that their "souls" are doing it, given that their souls are some sort of mini-god capable of making physical changes in some mysterious way. Do you invoke souls to explain why the body heals a cut?
It's odd that none of the people who argue that the brain is so unnecessary for high-functioning thought volunteer for lobotomies to prove their point, isn't it?
I've read Bill Lycan's paper. In fact, I would say he and Frank Dilley are the only people who have even come close to addressing the full force of the neuroscientific evidence against dualism. Odd that in the case of Lycan it takes a materialist to make the dualist's argument for them. Considering that the evidence for mind-brain dependence is the major obstacle to most thinking people taking survival seriously (at least according to John Beloff), one would think that dualists would have addressed it more fully than they have in the past.
My response to this is that any dualism which would allow for the survival of Leo MacDonald after death would have to maintain that most of Leo MacDonald's mentality resides in a soul rather than in a brain. But if that's the case, then most of Leo MacDonald's mentality resides "somewhere else" than his brain, since death destroys his brain (and yet most of Leo MacDonald's mentality supposedly survives this). In that case, most of Leo MacDonald's mentality must be somewhere else, interacting with his brain. The implication is that the brain is merely an instrument for the soul; but just as destroying a drumset has no effect on the drummer playing it, so destroying the brain should have no effect on most of Leo MacDonald's mentality, if any sort of survival-friendly dualism were true. And this is basically what is required of such a dualism: your personality could shed the body like a winter coat, and take on a new body, since mind and body are so independent of each other. But if that were true, we shouldn't see the sort of mind-brain correlations that we do.
In other words, that "that the mind is dependent on the brain for nothing more than sensory experiences as input and volitional executions as output" is not explicitly stated by dualists, but implied given the degree of independence that they typically grant the mind from the body. Supposedly when Leo MacDonald dies he will take his personality and memories and so on with him--except for the fact that long-term memories are formed by strengthening synaptic connections in the brain, and lost as those connections are lost.
Originally Posted by LeoM View Post
And the transducer explanation applies here as well. We may even add that cognition may interdepend in a close way with brain activity: There is no reason to suppose that the mind can do complicated reasoning without the aid of a physical calculator; in the real world, most people cannot do complicated reasoning without the aid of a physical calculator.
Aye, there's the rub: If so much of the mental processing we do is known to be done "brain-side," and so little of it is left to be potentially done "soul side," then whatever survives death will lack all of that "brain-side" mental processing. But all of the things we know to be done "brain side" are what are distinctive of us: "memories, feelings, behavioral dispositions, and other personality traits" as parapsychologist Douglas Stokes concedes. Subtract that and what is left of Leo MacDonald? Hardly anything at all--certainly not enough to allow most of Leo MacDonald's mentality to survive death.
In other words, if the mind cannot remember, feel emotions, or be disposed to behave in certain ways, or have a personality "without the aid of a physical calculator"--then all of those things must disappear once the brain dies. And what would be left behind, if anything would be, would be some remant of a person, not the person. This supports dualism only in a sense incompatible with survival: It is like lighting a firecracker, inserting it into a watermelon, watching the watermelon explode, and then, upon looking at some red fiber where an entire watermelon used to be, exclaiming "Look! The watermelon survived the firecracker!"
But don't get mad at me; I didn't make the world the way it is--I'm just the messenger.
Incidentally: Why do you think that men and women think differently, and have very different kinds of interests, by and large? (For example, why do girls tend to play with dolls while boys tend to play with toy guns?) Souls are gender-neutral, so men and women should have about equal interests on average, wouldn't you say? But since brains are not gender neutral, being affected by different hormones in different genders, some physical thing is determining their interests for them. But I thought only minds had interests? And minds aren't brains, supposedly.
Hmm and what about people like David D Hoffman that see physicalism is wrong.
Brain specialists, Prof. J.C.Eccles, Sir Cyril Burt, Dr.Wilder Penfield and Prof.W.H.Thorpe stated that in their opinion the brain appears to be more a complicated organism to register and channel consciousness rather than produce it. "The brain is messenger to consciousness", Eccles said. In his famous debate with philosopher Popper "The self and its brain" this matter was examined further.
” The exact type of functional dependence between the brain and consciousness – production or transmission/permission – is the issue at stake.
No dualist denys that the soul will be effected when the brain is damaged. The i thinker will fluctuate from time to time.
Who ever said souls are gender neutral?
There is also the full fledge assault on materialistic views in neuroscience in the book the Irreducible Mind.
I for one think Sir William James was on too something.
Inadequacies of Contempory Mind/Brain Theories
Long Term memories stored in the brain you say? All we have now is neural correlates
1 week ago