My previous post on neurophysiology was a response to an e-mail sent to me by Jim Lippard. I thought I should ask his permission before sharing his comments, so I responded to them rather than reproducing them. Lippard originally wrote:
I've been out of academia for 11 years now, and a lot has happened in
cognitive science (and neuroscience in particular) since I've been
actively keeping track, as I learned last weekend while attending the
Skeptics Society's conference on Brain, Mind, and Consciousness at
Caltech.
There were fascinating presentations by Christof Koch on neural
correlates of consciousness, by Paul Zak on neural correlates of
economic transactions (the hormone oxytocin is correlated with trust),
and many others (see http://www.skeptic.com/conf/speakers.html).
I was struck repeatedly by how much the evidence is growing in favor
of a completely physical explanation of mind--and how little room is
left for a dualist one. (Frankly, I think dualism for anything more
then epiphenomenal qualia has been dead for decades already, and is
certainly scientifically moribund.)
One speaker who was unable to attend due to a family emergency in
India was V.S. Ramachandran, but I purchased his short book, _A Brief
Tour of Human Consciousness_, and read it on the plane home from
Pasadena. In that book, I learned of "mirror neurons"--there are
specific neurons which activate when we perform certain actions, and
which also activate when we see others perform the same actions.
Ramachandran has some very interesting speculations about how these
structures may have enabled the origin of language. I've just found
he has an article on the same subject (accompanied by commentaries
from other luminaries--a feature of the journal Behavioral and Brain
Sciences that I always loved) here:
http://www.edge.org/3rd_culture/ramachandran/ramachandran_p1.html
Commentaries:
http://www.edge.org/discourse/mirror_neurons.html (I particularly
recommend Raul Nunez's for a critical view)
I believe it's quite likely that many of the philosophical problems
about the mind will evaporate with scientific advances.
Meanwhile, Plantinga's proposal for a new paradigm of theistic
science--along with the "intelligent design" hypothesis--is still
barren of any empirical fruit, so far as I know (and I'd like to
hear of any evidence to the contrary).
As I have indicated, my previous blog entry on neurophysiology was in response to Lippard's e-mail. He answered:
I don't see what evidence there is for causal interaction from a
nonphysical substance, or what functions are present in nonphysical
machinery.
Surely you're not suggesting a "radio receiver" or "remote control"
model of the brain.
The evidence is overwhelmingly in favor of not just visual awareness
being localized in the brain, but pain processing, emotional
processing, face recognition, the storage of memory, and everything
else that makes us who we are. Who we are is clearly deeply causally
connected to our brains, and when the brain is damaged or
deteriorates, we have mental deficits, lose capacities, lose
awareness, and cease to be. I don't see how the phenomena that are
actually observed can be made sense of with a model in which the brain
is just a body control center for a disembodied mind. Perhaps that's
not what you have in mind (pun intended)--but if you are offering
something other than, say, Chalmers' nonreductive property dualism, I
don't know what it is. If memories are stored in the brain, then of
what value is an immortal soul that survives when everything I know,
my ability to recognize people, my language capacities, my stored
emotional connections to memories, all goes away? (I take it the
only possible answer there is a physical, bodily resurrection, including
all of the neural connections.)
Where is the spirit model that explains Capgras' syndrome, where a
person becomes convinced that those he knows best have been replaced
with exact duplicates who are impostors? A physical explanation is a
severing of the neural connections between the visual
processing/facial recognition on the one hand, and the emotional
processing on the other. (Ramachandran's book gives an example of a
patient with Capgras who still has the appropriate emotional reaction
to a parent's voice on the telephone, and doesn't consider them an
impostor, but seeing them in person yields the imposter result.)
Where is the spirit model that explains both blindsight (no conscious
awareness of seeing, but when asked to "guess" where objects are, a
patient points accurately), neglect (patient claims to be consciously
aware of seeing, with no gaps, but is clearly not seeing part of their
visual field, usually an entire hemifield), and denial (e.g., where a
patient's left side is paralyzed, but the patient insists that nothing
is wrong and that he can, for instance, move his arm)? These are
explainable on a physical model, and the mirror neurons mentioned
earlier can explain an even more bizarre phenomenon, where a patient
with denial will deny that *another* patient is paralyzed.
Where is the spirit model that explains the mapping of amputated
limbs to other body parts that are physically proximate in brain
maps (but not on the body)--e.g., an amputated left arm maps
the fingers of the missing hand to the left cheek? The neural
model involves the physical connections between the neurons
processing the face stimuli and the immediately proximate neurons
that used to process the hand stimuli.
Where is the spirit model that explains motion-induced blindness,
where objects disappear from the visual field as a result of other
moving objects in the visual field (yet still produce afterimage
effects)?
Have any dualist neuroscientists written commentaries on the works of
Oliver Sacks, A.N. Luria, V.S. Ramachandran, or others?
Your response, Victor, seems to be an attempt to completely isolate
the mental from the physical--that seems to me essential
in order to avoid empirical refutation, but not very productive or
useful in gaining knowledge or understanding.
And I replied:
I thought my point was that sophisticated dualists like Bill Hasker have never denied the extensive reliance of the mind upon the brain. 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. It's substance dualism not because the soul that thus emerges does not occupy space (I never try to argue for that) but rather the activities of the emerging item are teleological at the ground level and can exercise libertarian free will. That would be to commit "skyhookery" according to people like Dennett, though, as I have argued, we could even call this a nonstandard form of materialism. If "material" means "occupies space" then I think I am a materialist about the mind. It's what the thing does that matters (no pun originally intended, but now that it's there...), not whether we call it matter or not. Even Charles Taliaferro, a more traditional Cartesian dualist, believes in "integrative" dualism; there is an extensive dependence of the soul upon the brain. 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.
One move I like to make at this point is to grant, for the sake of argument, that materialism is true, that whatever it is that we are talking about should be referred to as matter, but then to argue that that "matter," which is found in the "brain" has some rather weird, teleological, "soulish" properties. 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.
Now if standard materialism accounts for all the stuff that I appeal to, then I suppose you have an Ockham's razor argument not only for accepting standard materialism not only over dualism but over nonstandard materialism. But I think the interthoeretic reductions that would permit you to do that invariably go awry. But that's the other big debate.
The radio receiver analogy looks, on its face, like a good one. When I started this e-mail, my computer crashed, and I had to start over. Clearly, deficits and enhancements in my computer result in defecits and enhancements of the message I received. So can we argue that the computer I am using is sufficient to itself, and that there is no Lippard who sent me the message? You should hope not.
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