Joined: Jan. 2006
Just posted this on the UD thread. Let's see if it gets out of moderation and whether Barry and Denyse respond:
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I enjoyed speaking with you and Denyse today on your radio show -- it's much more pleasant than debating by text.
I wish we'd had more time, because there were a few points I wanted to add:
1. I mentioned that the problem of qualia is a problem for dualists as well as materialists, just shifted slightly: materialists have to explain how the brain gives rise to subjective experiences (including qualia), and dualists have to explain how the soul can give rise to those same subjective experiences (not to mention that they violate the spirit of Occam's razor by proposing the existence of a soul simply to explain this subjectivity).
You replied that I was asking you to explain an infinite regress, but I don't understand what you meant by that. Could you elaborate? In any case, if asking you how the soul gives rise to qualia leads to an infinite regress, hadn't you already placed the same burden on me by asking how the brain gives rise to qualia?
2. You brought up the "brain as radio receiver" metaphor to explain why physical damage to the brain can affect a person's behavior even if the mind or soul is a separate, immaterial entity.
DaveScot used that metaphor on another thread, and I replied as follows:
There are some serious problems with that metaphor.
The most obvious is that in reality, information flows both ways between body and mind. The broadcast station/radio receiver metaphor represents the information as flowing only one way.
We can correct the flaw in the metaphor by stipulating that the receiver is really a two-way radio that can transmit as well as receive, and that the broadcast station is really a base station with two-way capability.
If we adopt the modified metaphor, another question arises: which functions are performed by the base station (soul), and which by the radio (brain and body)?
The naive view (held by a surprising number of people who are unfamiliar with the findings of modern neuroscience) is that all of the “interesting” stuff — thinking, feeling, remembering, deciding — is carried out by the soul, and that the body (including the brain) has only two main functions: passing information to the soul, and carrying out the commands issued by the soul.
Naive though it is, many people cling to this idea because it allows them to believe in a soul that survives death while retaining all of a person’s essential characteristics: memories, temperament, cognitive abilities, etc.
In reality, of course, the brain isn’t nearly as passive as the radio metaphor would suggest. Evidence shows that the brain is intimately involved with (and possibly fully responsible for) all of the characteristics mentioned above.
For example, the temperament, personality, cognitive abilities and memories of an Alzheimer’s patient may be damaged to the point that the person bears no resemblance to his former self. To a materialist, this makes sense. Alzheimer’s damages the brain, and when the brain is damaged, the person is damaged.
The naive dualist has a much harder time explaining how these faculties can be so seriously damaged if they are wholly (or even primarily) carried out by the soul and not the brain.
Even stronger evidence against the dualist position is provided by split-brain patients. There is a procedure, the corpus callosotomy, that disconnects the two hemispheres so that epileptic seizures cannot spread from one to the other. The hemispheres are only disconnected; neither is removed. This operation contains the seizures, dramatically improving the patient's quality of life, but it also severs the path through which the hemispheres normally communicate. The results are fascinating, and they're not very friendly to the dualist position:
a. In experiments with split-brain patients, it’s possible to pass information to one hemisphere but not the other. The left hemisphere literally doesn’t know what the right hemisphere knows, and vice-versa.
If there were a single, immaterial mind, it would know what both hemispheres know. Clearly, this doesn’t happen. As a dualist, how do you explain this? Surely the immaterial mind doesn't split in two at the moment the corpus callosum is cut, does it?
These fascinating videos of a split-brain patient demonstrate the phenomenon:
b. The left hemisphere controls the right half of the body, and vice-versa. When the connection between the two is cut, this results in bizarre behaviors indicating the presence of two “wills” in the same skull.
One patient was seen to pick up a cigarette with her right hand and place it in her mouth. Her left hand plucked it out and threw it away before the right hand could light it.
In another case, a man attacked his wife with one arm while defending her with the other.
If a single immaterial mind were running the show, this would not happen. How do you explain this within the dualist framework?
3. Denyse, you brought up a) the placebo effect and b) Jeffrey Schwartz's treatment of obsessive-complsive disorder via focused attention as examples of phenomena that support the existence of an immaterial mind or soul. I replied that materialism has no difficulty with these, because if mental events are physical events in the brain, it's no surprise that they can have effects on other parts of the brain or on the body.
Indeed (and I didn't mention this on the show) dualists have the harder problem of explaining how an ethereal mind or soul can manipulate the physical body. For materialists, this problem doesn't exist: of course matter in the brain can interact with other matter in the brain or in the body.
You were about to respond when we hit the final commercial break. What were you going to say?
4. You also stated that if free will is an illusion, there's no point in having democratic governments -- we might as well use the farm as our model for governance. Could you explain what you mean by this and why you believe it?
And the set of natural numbers is also the set that starts at 0 and goes to the largest number. -- Joe G
Please stop putting words into my mouth that don’t belong there and thoughts into my mind that don’t belong there. -- KF