See here and here for reflections on whether or not there is still room for a ghost in the machine. Money quote from neuroscientist Martha Farah:
Brain imaging indicates that all of these traits have physical correlates in brain function. Furthermore, pharmacologic influences on these traits, as well as the effects of localized stimulation or damage, demonstrate that the brain processes in question are not mere correlates but are the physical bases of these central aspects of our personhood. If these aspects of the person are all features of the machine, why have a ghost at all?
My questions:
- Why not simply think of the “soul” as an epiphenomenon of neuronal activity—as an ant colony is the epiphenomenon of the movement of individual (and unconscious) ants?
- Does religion require that the soul be a transcendent ghost separate from the properties of matter? Perhaps for eternal life, but maybe not for this one?
What is astounding about souls is that there are any of them at all—whether transcendent or as the product of material processes. If souls transcend matter (a position that I would reject) that would be quite mind boggling, but equally mind boggling is this: THE UNIVERSE—THE MACHINE THAT WE ARE EMBEDDED IN—MAKES SOULS—OR “GHOSTS”—AS AN EPIPHENOMENON OF MATTER, AND IT DOES SO IN PROFUSION.
Right now there are, for example, six billion of us human ghosts, embedded in bodies, moving around just on this planet alone. And there may be other intelligent “souls” inhabiting other planets in other parts of the universe.
This fact is part of the ontological mystery—the mystery of being.
Prometheus Unbound 
Zuits may have been falling in the woods forever. If no one were there to hear them, was it occurring. Now that you are there to hear them, do you recognize the sound as zuits falling? Do you know what a zuit really contributes to the ecosystem? Do you know why the specific zuits are where they are and why they must fall? If you cannot answer these questions when the zuits are lowly trees, what are the merits of trying to define the soul with primitive tools?
There are so many ideas about the soul and what it might represent. I personally think of it as a very physical thing – something similar to the spark that motivates an engine to run.
Chris
This is only in response to your second question.
Definitely not. Christians, at least, are not doctrinally committed to substance dualism. In fact, my impression is that most Christian academics do not embrace that view.
When I was in England, I went to a talk given by Francis Collins (American scientist who mapped the human genome–also a committed Christian). I asked him afterward what his view was of the mind/body correlation and he told me that he was a materialist.
Peter van Inwagen, a very prominent Christian philosopher working in one of the top philosophy department in the U.S., is probably the most popular mind/body Christian materialist. He has written on this subject.
I know of no theologian who maintains that the Bible demands a substance dualist reading–in fact, most associate that idea almost exclusively with Descartes in the 17th century.
Jared,
I’ll read up on van Inwagen. Thanks for the tip.
As to Christianity and materialism, I think you have a very strong support from scripture: the notion of resurrection. Early Christianity seems to link the soul’s ongoing life very definitely to the body’s life—that is, its ongoing physical existence via literal resurrection to “eternal life.”
This, of course, makes for its own difficulties. It means that the resurrection of Jesus must be taken literally—and brings us to Dostoevsky’s issue of the all or nothing gambit—the patent absurdity—of Christian faith. One must throw in with a belief that represents a disjuncture from all we know about existence—that when bodies die they stay dead. Dostoevsky thought that this was the leap of faith that every Christian must make—that God raised the battered body of Jesus from the dead (however contrary to the laws of nature that this was)—and that this must represent the hope of humanity. Dostoevsky plays with this theme in his novel, The Brothers Karamazov, where, at the end of the novel, Father Zosima dies, and people lose faith because such a holy person’s body suffered such rapid decay before them, and stunk up the place where he was put on display before burial (the peasants thought God would preserve his body miraculously, but He didn’t).
—Santi