Keith Augustine responded to some of the comments that I have blogged. Instead of answering his comments I want to underscore them. This is why physicalists are physicalists.
VR: I thought my point was that sophisticated dualists like Bill Hasker have never denied the extensive relaince of the mind upon the brain.
KA: Acknowledging mind-brain dependence is not the same as making sense of it. If I may quote Paul Churchland in _Matter and Consciousness_:"If there really is a distinct entity in which reasoning, emotion, andconsciousness take place ... then one would expect reason, emotion, andconsciousness to be relatively invulnerable to direct control or pathology by manipulation or damage to the brain. But in fact the exact opposite is true. Alcohol, narcotics, or senile degeneration of nerve tissue will impair, cripple, or even destroy one's capacity for rational thought.... 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. All of this makes perfect sense if reason, emotion, and consciousness are activities of the brain itself. But it makes very little sense if they are activities of something else entirely."Note that this empirical argument would establish the improbability not only of Cartesian dualism, but of any sort of dualism which maintains that the mind is something separable from the brain, whether it is a pure disembodied mind or some quasi-physical astral body made of exotic matter. The mind-brain dependence argument does not establish that the mind depends upon some physical system, but upon a specific organic physical system which decays at death and thus, in all probability, destroys the mind as well.
VR: So we would not be appealing to soul theory to explain the Capgras > problem, for example, or blindsight. In fact, Hasker specifically appeals to these things to argue that a more traditional, Cartesian form of dualism is inadequate, in favor of an emergent kind of dualism in which the soul emerges from the activity of the brain.
KA: I think Jim's point was that such mental disorders, caused by neurological deficits, makes a soul thery--*any* soul theory--scientifically implausible. The issue is not whether emergent substance dualism can explain these syndromes; it is that the details of these syndromes are what we would expect to obtain if physicalism or property dualism were true, but not if substance dualism were true.I don't understand how an emergent *substance* could be highly dependent upon a brain. Emergent properties clearly could be. But a substance by definition is something that can exist independently of other substances. So if at some point in the development of a human being a "soul" emerges from neural activity, that means the brain has just ex nihilo created a soul. It does not explain why, once A has generated B, the states of B continue to depend upon the states of A. If A and B have separate existences now, there should be no dependence between them beyond that of a driver and his car. That is, if one's car engine catches on fire and is destroyed, the driver's heart should not automatically catch on fire too. And yet those who take psychedlic drugs effect the mind *directly*, not merely the mind's ability to control the body--the mind itself. Psychotropic drugs do not merely produce paralysis or cut off one's sensory information--they affect the mind's functioning. That seems to indicate that mental functioning cannot occur without brain functioning.
VR: I don't see how the sort of dualism Hasker has in mind is refuted by these sorts of phenomenon. If I am right a lot of anti-dualist arguments attack a straw man.
KA: Perhaps an analogy is appropriate here.Let's say we have two separate, interacting things: A Predator drone and the remote pilot controlling it from a distance. The drone is captured and its captors start fiddling with its transmitter/receiver. What's the worst the captors can do to the remote pilot, miles away? They can destroy the drone's camera, making it blind. The person controlling the drone will no longer be able to see the environment around the drone. They can destroy the microphone, making it deaf, and again, the radio controller will no longer be able to hear what is going on. Ditto if the wires connecting the camera and microphone to the transmitter are severed. Information from the senses has been cut off. Next, suppose that the wires connecting the receiver to the drone's engines are severed. Now the pilot cannot even blindly control the drone.It seems inescapable to me that any form of substance dualism is committed to predicting that the mind (the controller) is largely independent from the brain (the drone's transmitter/receiver). The worst you can do to the controller by manipulating the drone's transmitter/receiver is make the controller deaf or blind regarding the drone's environment, or unable to move the drone. You cannot affect the the controller's ability to do math, to understand language, or recognize undistorted faces. You cannot get the controller to go into a psychotic rage by manipulating the drone's radio. But you can make someone psychotic by spiking his drink with PCP, or prevent him from being able to do simple addition by lesioning certain areas of his brain. In short, basic neuroscientific facts are simply inexplicable on any variety of substance dualism.
VR: That has the effect of taking away the illusion that the "soul" is something radically separate from the brain. It's matter all right, it just doesn't obey the normal laws of matter.
KA: It doesn't matter (no pun intended) if the soul is a nonphysical substance or a physical substance separate from the brain. The argument from the dependence of consciousness on the brain cuts across both versions of dualism.
VR: The radio receiver analogy looks, on its face, like a good one.I strongly disagree for the reasons above. When I started this e-mail, my computer crashed, and I had to start over.
KA: Yes, but when your computer crashed, you did not have to check into a mental institution. But if your brain "crashed," you would have to--or worse. It's amazing how a ministroke in a specific area of the brain can cause one to behave in a way that seriously jeopardizes one's salvation... as if one freely chose to have a ministroke. And not just a ministroke that causes reflex-like reactions, but a ministroke that affect one's behavior because it affects one's mind. A frontal lobotomy can change one's personality (to say the least!). How, then, can one's personality persist after the full-brain lobotomy called death?
VR: Clearly, deficits and enhancements in my computer result in defecits and enhancements of the message I received.
KA: Certainly. But a distorted message does not affect your IQ, your beliefs, or your desires, in the way that LSD, schizophrenia, or Alzheimer's disease could, does it?Regards, KA