Monday, October 02, 2006

Paranormal Phenomena and Substance Dualism

If you're going to be a dualist -- that is, if you differentiate the mental from the physical -- I think you ought to be a good old-fashioned substance dualist. You ought, in other words, to embrace the idea that there are distinct mental and material substances. The more fashionable form of dualism in analytic philosophy these days, "property dualism", which distinguishes mental from physical properties, as conceptually distinct, while denying that there is any distinctly mental substance, seems to me too far removed from the questions that we should care about in the dualism-materialism debate -- questions such as whether we have immaterial souls that could persist into an afterlife (property dualism, like materialism, says no), and whether our thoughts depend solely upon physical goings-on (property dualism, like materialism, says yes, for all practical purposes). I've not yet been convinced that I should care much about what would be the case in "logically possible worlds" where the laws of physics and psychology are suspended -- the sort of thing property dualists such as Chalmers want us to think about. (But if you are going to think about such things, Chalmers is a model of clarity and intelligence.)

The truth of substance dualism is empirically explorable, as the debate between materialism and property dualism (with its focus on the merely logically or "metaphysically" or "conceptually" possible) appears not to be. Of central relevance to the question, of course, is the dependency of our mental processes on how things stand in the material world -- on our brains in particular. The more it seems that mental life depends on and covaries with brain activity, the worse for substance dualism. With the advance of neuroscience, substance dualism isn't looking so good, I'd say.

However, there is one class of evidence that philosophers rarely explore and which, if it were to pan out, would spell serious trouble for materialism; that is "paranormal" or "psi" phenomena -- especially direct mind-to-mind communication (without a physical medium) and out-of-body experiences.

The evidence for paranormal phenemona is mixed. It is not as decisively negative as most contemporary academics tend to assume. The work of Daryl Bem (on direct mind-to-mind communication) and Pim Van Lommel (on out-of-body experiences in near-death situations) especially comes to mind.

Bem's classic "Ganzfeld" experiments (e.g. Bem & Honorton 1994 in Psych Bulletin) require a "sender" and a "receiver" to be sequestered in separate compartments; the "sender" is given a randomly selected image to concentrate on and to try to send; the "receiver" is to describe her thoughts and images aloud for 30 minutes. Finally the receiver is presented with four pictures (one the target) and asked to rate the similarity of each to her mentation during the 30 minute period. Results are generally above chance.

Bem, an eminent Cornell psychologist, knows how to design a study. Reading through his work, I generally think to myself, "If this were about anything else, I'd say this was a perfectly designed and utterly convincing study. He has controlled for everything." Carl Sagan was surely right in saying extraordinary claims require extraordinary evidence; but how extraordinary, exactly, is sufficient? Do we need to consider, for example, that Bem might simply be lying, or have been systematically deceived by unscrupulous collaborators and subjects?

Pim Van Lommel, similarly, has published work in the Lancet and elsewhere, work done in accord with typical scientific standards and suggestive of the reality and frequency of near-death experiences. Van Lommel has evidence that patients during cardiac arrest, with eyes closed and severely compromised brain function, were in some cases able to acquire otherwise unavailable information about happenings in the outside world (e.g., detailed descriptions of the what the doctor did with the patient's dentures) reported by the patient as having been seen from above. Van Lommel (personal communication) has even tried prospective studies of this latter sort of phenomenon, posting notes high in rooms where patients near cardiac death are being treated, notes facing the ceiling; but unfortunately, he reports, patients reporting near-death out-of-body experiences seem to be much more focused on their bodies and their religious experiences than on the contents of such notes!

I'm not saying we should accept Bem and Van Lommel; but I do think we should take them seriously. This is where I'd like to see the action in debates about dualism, rather than on questions such as the conceivability (or not) of various possibilities (e.g., "zombies"), if one suspends the laws of physics!

18 comments:

Eddy Nahmias said...

Eric, I agree that the substance dualism issue is more interesting--and seems to be more empirically accessible--than the property dualism issue. Personally, I think the most interesting question is whether mental states do causal work (this is one place where the property dualism issue may still have relevance).

Would evidence of psi, etc. really be evidence for substance dualism? Wouldn't it have to be supplemented by evidence that the effects were not caused by transfer of energy or something else still governed by and explained by laws of physics (perhaps laws yet to be understood)?

Undergraduates often think that substance dualism is consistent with thinking the mind is some form of energy rather than dull matter, but it'd have to be a sort of "energy" that's not really matter (a la Einstein) and not really part of the physical world. At that point, it becomes harder to understand just how the evidence from paranormal phenomena would have to be to show that the mind is a nonphysical substance. Perhaps evidence that the information between minds was transferred faster than the speed of light? It does seem that if NDEs could really show the mind perceives the world completely detached from the physical body and brain, that would suggest a radical problem for materialist views to explain away!

Eric Schwitzgebel said...

Thanks for the comment, Eddy! I agree that if psi phenomena and near-death experiences of the sort discussed by Van Lommel turn out to be real, that will open up tricky questions about how to define the "physical"; even faster-than-light information tranfer might be interpretable as physical in some sense.

I think it would depend on exactly how such phenomena presented themselves, and by what means they were detectable, and what they interacted with, whether we decided to call them physical phenomena or non-physical. But, for sure, they'd blow apart conventional materialism with its current sense of the physical, requiring either the abandonment of materialism or a radical revision of materialists' thoughts about what is physical and how the mind is physically implemented!

Pete Mandik said...

I think Eddy's questions re whether this stuff indicates anything nonphysical are right on.

I would like to question additionally whether this stuff indicates anything about substances. I take it that substance dualism is supposed to be the view that mental properties aren't properties of any physical objects, but instead are properties of non-physical objects. But why would, eg., my ability to see what's in your house without being there be evidence that ESP is a property of a nonphysical object (aka my immortal soul) and not just a far-out nonphysical property of a particular organism (aka Pete Mandik)?

Eric Schwitzgebel said...

That's a good point, Pete -- thanks! My intent is not to get into the metaphysics of substances vs. properties -- though I confess I may have invited it.

The main thought is this: "Substance dualists" and "property dualists" in philosophy -- whatever the accuracy of those labels -- tend to endorse different positions regarding the relationship (in the real world) between mental processes and physical processes. "Substance" dualists generally see a disconnection of some sort in the actual world; "property" dualists generally see that disconnection as occurring only in "nomologically impossible worlds" -- imaginary conditions in which the actual laws of nature are not assumed to apply. The idea of an "immaterial soul", in particular, that can persist after bodily death is natural on the "substance" view and difficult to sustain (as a reality in the actual world) on the "property" view.

If mental-physical disconnection is nomologically impossible (but conceptually possible, per the "property dualist"), then no experimentation could discover it; if it is actual (per the "substance dualist"), then it should reveal itself to clever enough experimentation.

Now maybe clairvoyance and transcendent near-death experiences and the like, if real, can be accommodated on materialism; but I think it's a mistake to be too sanguine about that unless by material you just mean "real" -- in which case materialism is vacuous.

Richard said...

The discussion has already brought this out to some extent, but I think the property vs. substance dualism question is orthogonal to what you're really after here, which is the nomological vs. metaphysical supervenience of the mental on the physical.

That the two distinctions tend to be correlated in practice is an interesting sociological fact. I wonder what's behind it?

Eric Schwitzgebel said...

Very nicely put, Richard! Of course, the way you pose the question assumes that property dualism doesn't more naturally fit with nomological supervience (and metaphysical non-supervenience) than does substance dualism; and maybe that assumption isn't warranted. But that gets into matters metaphysical about which I'm a pragmatist rather than a realist....

Purely sociologically, could it be that the merely metaphysical denial of supervenience and property dualism are married as fallback positions from the historical marriage between substance dualism and denial of nomological supervenience?

kboughan said...

Here's a dumb question from the historian: There's no room for a view of the "spiritual" and the "physical" as endpoints of a continuum? Does current physics force a Cartesian sort of dualism, if we want to be "substance dualists"? (Deeper: Is the terminology inherited from Descartes still useful? [Yeah, I tried to read Searle once.])

Eric Schwitzgebel said...

That's a good and interesting (not dumb!) question, kboughan! Descartes thought that mental and physical substances had disjoint attributes -- physical substances being spatially located, mental substances not -- and thus had no room in his system for a spectrum. Later philosophers interested in questions of dualism have generally followed Descartes in thinking that if there is a crucial ontological distinction between mental and physical, it must be a clean bifurcation; but I'm not sure we have to accept this.

In fact, as a number of people have pointed out recently -- as as came up in earlier comments -- it's not clear exactly what properties make something physical. (Barbara Montero, playing off the "mind-body problem" has called this the "body problem".) I don't have sophisticated views on this, but I don't see why the properties most useful for demarcating the physical (I recognize my metaphysical pragmatism is implicit in this sentence) mightn't turn out to come in degrees.

Eddy Nahmias said...

This article on "materialistic" causes of out-of-body experiences is kinda relevant to this discussion: http://www.nytimes.com/2006/10/03/health/psychology/03shad.html?ref=science

Eric Schwitzgebel said...

Cool! Thanks for the link, Eddy!

Clark Goble said...

I know Moreland has pushed supposed NDEs as evidence of substance dualism. But I just don't see it. Not just because NDEs are typically problematic when tested empirically. Rather it seems like the phenomenal character of NDEs suggest a location and place which seems to argue against substance dualism. After all if a mind is immaterial how on earth can phenomena with place be an argument for it?

Eric Schwitzgebel said...

Thanks for the comment, Clark! I assume you're thinking about the conventional substance dualist view that minds are not located in space? I suppose the dualist could respond by your concern by either attributing spatial locations to immaterial minds or by allowing that light entering some particular region of space but not other regions may be experienced by an immaterial soul -- which is close to the normal case anyway, isn't it?

I think that you're right that if you push on these issues in the right kinds of ways, there might be trouble for the dualist or at least unforeseen entanglements -- but on the other hand if NDEs are real (esp. with very limited brain function), that seems even worse for the materialist than the dualist, no?

Sam said...

Hi Eric, I'm happy to see such a post on such a wonderful topic. I know you probably won't remember me, but I was (and remain) a loudmouthed substance dualist (although I like the word "energy" more than the word “substance” when talking about mind) who took your philosophy of mind class at UCR in the late 90s (1996 or 97 maybe). It was probably the best philosophy class I've ever taken.

Needless to say, I’m happy surprised you’re even considering this these kinds of evidence/reports. I continue to read philosophical stuff; I am currently researching to write an accessible book that deals directly with these kinds of issues. You even gave me some names to use in my research. Thanks, Sam

P.S. If you are having any trouble remembering me, I was in the same class as Dawn Fang.

Eric Schwitzgebel said...

Hi, Sam! Yes, I remember you (though I confess I had to go look at my grade sheet from 1998 to trigger the memory). Very cool that you're working on a book on this! I hope you'll send me a copy once it has all come together.

I redesigned the syllabus for my Philosophy of Mind class the year after you left, and I now spend a full week on the possibility of consciousness after bodily death, including one entire class session on psi phenomena and near-death experiences. (For that, I use a chapter of RWK Paterson's Philosophy and the Belief in a Life After Death. I would highly recommend that book, though its 1995 publication date puts it before Van Lommel's interesting work.)

Mark Steen said...

You probably know about this already, but, if you don't, you might want to check out some of CD Broad's work (e.g. Mind and its Place in Nature). Broad was one of the few analytic philosophers to deal with paranormal research and psi phenomenon and its relation to substance dualism. He was, either rightly or wrongly, somewhat vilified by doing this kind of work.

Eric Schwitzgebel said...

Yes, Broad was one of the last eminent academic philosophers to take the paranormal seriously (apart from Flew, who took it seriously and seriously opposed it). Of course, a slightly earlier generation (James, Sidgwick, etc.) also took "psychical research" quite seriously!

Mark Steen said...

Huh, cool. I had no idea about Sidgwick...

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