WinAce

The human nervous system provides convincing evidence for mind-brain dependence and in the process refutes the existence of dualistic souls (and with them, any theistic belief system that claims they exist).

Conditions like Alzheimer's disease and amnesia can damage or even destroy parts of the mind in perfect unison with the appropriate brain sections. They can even produce, for all intents and purposes, two damaged minds for the price of one healthy one.

"Research shows that in such split-brain cases, the brain generates what seems to be two separate consciousnesses. Research on split-brain patients led brain scientist and Nobel laureate Roger Sperry to conclude, 'Everything we have seen indicates that the surgery has left these people with two separate minds, that is, two separate spheres of consciousness. What is experienced in the right hemisphere seems to lie entirely outside the realm of the left hemisphere.'"

A condition that damages the corpus callosum in the brain can result in one hand uncontrollably going for the patient's throat and strangling him. Damage to the frontal lobes can produce massive changes in both personality and mental abilities. Brain damage can even produce a person who's incapable of acquiring new memories - in effect, a mind trapped in the same time, one which will revert to his or her old memories every 15 minutes and nonchalantly ask his loved ones why they've aged so much after 20 years of asking them the same question.

A young priest once suffered a stroke that rendered him incapable of feeling sadness. Formerly compassionate and empathetic to his leukemia-stricken sister, he now made jokes about it and didn't understand why he should feel guilty about it. As his father commented, "... He looks like our son and has the same voice as our son, but he is not the same person we knew and loved... He's not the same person he was before he had this stroke. Our son was a warm, caring, and sensitive person. All that is gone. He now sounds like a robot."

"This wrenching story illustrates how a human property as fundamental as compassion arises from the brain and can be destroyed by altering the brain. A warm, caring, intelligent young man of God, as the result of brain damage, underwent a complete and drastic personality change. He became indifferent to his duties, unconcerned about the potentially fatal illness of a loved one, even light-heartedly joking about it with his grief-stricken parents, who said that he was "not the same person [they] knew and loved", not the same person he had been before his stroke. "

The author of the article I mentioned above, which explains a mass of other difficulties, closes with this apt statement:

"The materialist can explain the effects of frontotemporal dementia without difficulty. How does the dualist explain it? What is happening to these people's souls? Is the deterioration of the brain causing changes to the soul - or are personality traits a quality of the brain and not the soul? But that implies that these traits will be lost upon death. In that case, in what sense will the soul in the afterlife be the same person it was during life?"

In light of these and other facts, the existence of the soul is effectively falsified unless one postulates a literally enormous number of ad hoc hypotheses to salvage it from the data. But then again, one could defend the flat earth view if allowed to do that.

Readers are left to draw their own conclusions. For those willing to critically examine their beliefs, there's always the obvious, parsimonious answer.

Corso

I would assume a theist would reply with the following rebuttles:


1) Upon death, all damage to the mind/brain are reversed.

2) But the Bible says the soul exists and the Bible IS NEVER WRONG!

3) The explanation for the soul is to complex for our small mind to understand!



Anyway, I thought your post was very persuasive.
Maybe now I can stop worrying about going to hell!

Tercel

A minimalistic dualism -where the soul does little save be conscious and exercise free will (though interpreted through the physical brain)- is going to be fairly impervious to such attack.

You'll note the author, despite his extensive rantings on empirical data is reduced to a theological argument-from-ignorance to try to attack minimalistic dualism:
"or are personality traits a quality of the brain and not the soul? But that implies that these traits will be lost upon death. In that case, in what sense will the soul in the afterlife be the same person it was during life?"

The best he can come up with is a laughable theological question whos simple answer is "Whatever God sees fit to make it. Obviously if he felt so inclined he could restore the body into whatever state he felt was appropriate". The question almost assumes the non-existence (certainly at least the non-interference) of God.

In a minimalistic dualism, the system is a result of a close-knit interaction between the two elements of soul and physical brain, any damage to the brain will result in damage to the system as a whole and behavioural degredation indistinguishable from that of a materialistic-only system. Hence, no physical experiment will be able to decide between the hypotheses...

Leaving us to decide the question on purely philosophical grounds... hence the author's silly theological "difficult question". Personally, I am of the opinion that there is a fundamental distinction between perception and non-perception. Hence, I think, if we are to say that the material universe is non-perceptive we need to posit a non-material "soul", or we can adopt the opinion that the material universe is inherently perceptive and avoid dualism by going for some form of Berkeley-type monistic idealism. Neither solution is particularly conducive to atheism... the first leads to Monotheism and the second to Pantheism or Monotheism. Personally, I go for a mixture of the two solutions.

That's a good point. A bit (ie a lot) of thought is sufficient to show Monotheistic dual-aspect monistic idealism (now there's a clunky phrase) significantly more parsiminous than the atheistic alternatives.

Lobstrosity

Explaining complicated things as the result "undetectable magic" doesn't count as parsimony. Saying the brain does it all, but only because it's coupled to undetectable magic, certainly doesn't count as more parsimonious than simply hypothesizing that the brain does it.

Your solution to understanding consciousness is extraordinarily closed-minded in that you're content to place it all in a black box that you deem unphysical, undetectable, and impossible to ever understand. I understand psychologically why a person might need to take this stance--it's quite intimidating to think that you're not divinely special and that your behaviors really are just deterministic processes run by a glorified biological computer--because it's quite similar to the need some people have to believe in an afterlife. It's not based on reason so much as it is emotion. Sadly, emotiontionally-based reasoning is hardly logical.

Think, for a minute, what would happen if scientists in general (rather than just those studying cognition) decided used your rationale in their exploration of the world. Any time some complex new process was found that didn't conform with current theory, standard practice would be to define it as "something God does that we can never understand" and leave it be. The Casimir effect cannot be explained by current physics, which means clearly it must be due to the unknowable hand of God. Case closed! Yay, that was easy.

Why does it rain? Who knows, that's just God's doing...there's no point in investigating it because it's all due to God's unfathomable will. Why do we have emotions? Who know's, that's the soul's doing...there's no point investigating because it's undetectable. But wait, we have findings from neurochemistry that show how physical portions of the brain coupled with specific neurotransmitters affect our emotions. That's ok, the soul is still responsible for them in the end. How? Who knows, but I'm sure it's there doing its thing--but don't worry, even though it's fully-responsible for all core aspects of humanity and consciousness, it's completely undectable, so I can always say this and be right, no matter what you find. I will never be reduced to a mere bundle of neurons!

In short, if the soul has a function, it's quite feasible to detect its influence--your claim that no experiment can detect it only betrays your true motivations: keep the hypothesis unfalsifiable at all costs. If you have to define it from the outset as something that can never be detected, you don't make a very persuasive argument for anything. It makes it look like you're desparately grasping at straws in an effort to maintain belief in something irrational. Have you ever seen a valid scientific theory put forth that not only makes no testable predictions but goes so far as to tell people that it is inherently untestable. If one did put such a theory forth, how likely do you think people would be to adopt it? For example, let me put forth one: water boils because of blarghs. What are blarghs? They're what's most fundamentally responsible for water's boiling, though they're also inherently undetectable. No experiment will ever reveal their presence, but they're really the only thing that can explain how water can boil, if you think about it. It's really the simplest solution, too, because you can't seriously believe that simple little water molecules in liquid state can vaporize on their own without help from blarghs, can you? Ok, so, are you all ready to believe in my blargh theory yet?

lpetrich

Actually, gods and souls are independent hypotheses -- one can exist without the other.

The Old Testament has very little conception of afterlife. The Book of Ecclesiastes (chapter 3?) suggests that our death is the absolute end, though in one of the Samuel books, the witch of Endor calls up the ghost of the prophet Samuel when King Saul wants his help.

And some forms of Buddhism are essentially atheist, though most Buddhists believe in reincarnation. Buddhists also say that there is no real "soul" or "self", which makes one wonder what gets reincarnated.

WinAce

But even those most basic cognitive functions are deeply rooted in the physical brain. As mentioned above, a stroke in the appropriate section can irreperably alter personality, empathy or even leave a person indefinitely suspended in the same time (from his perspective), whereas Alzheimer's disease can leave a working brain with no consciousness.

Moreover, your soul is now becoming superfluous to consciousness entirely. Where does it connect with the physical brain to "interact" with it? How does a non-physical entity affect material change at all? And the most burning question of all: if consciousness is the net effect of an interaction between the "soul" and brain, what prevents consciousness from being the net effect of interactions in the brain itself?

Good one.

lpetrich

However, Tercel's "monotheistic dual-aspect monistic idealism" can be separated into two independent theories, the monotheistic part and the "dual-aspect monistic idealism" part.

Thiat is become both "polytheistic dual-aspect monistic idealism" and "atheistic dual-aspect monistic idealism" are also possible.

Separable souls can exist without gods.
Gods can exist without separable souls.

Tercel

Yup... and why should I care?

The way you are using the word consciousness here probably quite different to what I meant by it. I am using the philosophical/metaphysical understanding of "consciousness as perceptual experience". I was intrigued recently while reading a paper by Baddeley which said "Bisiach points out that the concept of consciousness is used in three very different ways. The first is the almost metaphysical use of the term... The second meaning... is concerned with consciousness as the stuff of experience... The thrid meaning... is concerned with consciousness as an emergent property of a system, whereby it constitutes one way in which information from one part of the system can influence the system as a whole. Viewed in this way, consciousness becomes a problem of cognitive science and cognitive psychology, to be tackled using techniques that are essentially no different than those applied to other aspects of cognition."
I was quite amused by this hijacking of the word. By stealing the word conscious to mean something that even I agree can be done by matter, they can then explain it. And the poor theist like me who wants to use the word for the first and/or second meanings (looking closely at his definitions, I think it's the second meaning that I'm using) can no longer make their argument.

You say "Alzheimer's disease can leave a working brain with no consciousness". Under my understanding of "consciousness as perception" that doesn't really make sense. Are you saying Alzheimer's has killed the person? Or that the person is still functional but you magically know (and I cannot conceive of how you would know this) that they are not conscious?
So I'll guess that you've got some modified meaning in mind, but I'm not really sure what.

Is that question related to the previous sentence? I hope you're not trying to suggest that previously there was thought to be point in the brain labelled "plug in the soul here" which we haven't been able to find.
Most dualists would say that the soul connects to the physical brain on the quantum level, which from all accounts appears to provide a very suitable interface for this.

Because at a quantum level the collapse of the wave functions is "conveniently" observer-related.

Er, consciousness as I would understand it, is soul. What prevents it from being the net effect of interactions in the brain itself? Nothing - if you're an idealist and believe that physical reality is conscious. However, if you believe that physical reality is purely mechanical then you have a big problem explaining how a purely mechanical reality can give rise to beings such as us which have awareness/perception. (And by this I mean the quality of being able to say "I think therefore I am" or being able have a subjective existence we can call "I" that experiences things, not "perception" as in "the ability to respond to sensory input".)

Tercel

Neither one makes any sense to me.
"Pantheistic dual-aspect monistic idealism" is probably possible. (It doesn't seem to me to be logically incoherent) Jobar has yet to convince me it's true though.

Lobstrosity

This statement is as ridiculous as the following analagous assessment:

What prevents life from being the net effect of interactions between subatomic particles? Nothing -- if you're an idealist and believe that physical reality and all subatomic particles are really alive. However, if you believe that subatomic particles are unliving, purely mechanical entities, then you have a big problem explaining how an unliving reality can give rise to living creatures.

Do you not see the fallacy of your reasoning? You say that the constituent parts (e.g. neurons) do not possess a certain trait (e.g. consciousness) and thus jump to the conclusion that the whole (e.g. the brain) cannot possess that trait either. This is known as the fallacy of composition. In short, the behavior of the whole is not simply the sum of its parts. The parts couple to each other to produce novel results. There is absolutely no problem with the idea that consciousness can arise from purely mechanical constituents, just like there's no problem with the idea that living creatures are built from lifeless elements (or just like there's no problem understanding how logic can arise from purely mechanical computer circuitry).