Thoughts of a Catholic convert

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Friday, August 20, 2010

David Hart and the zombie thought experiment

David Bentley Hart has a post at First Things ... Mysteries of Consciousness .... that touches on something I've posted about before - whether a person's consciousness/mind can be explained completely as a construct of the physical brain, whether consciousness/mind has a life of its own independent of the body, whether a soul has anything to do with all this. It's de rigueur for religious believers to eschew Physicalism (unless you're Nancey Murphy), so it should come as no surprise that Hart's post does so. Here's a definition of Physicalism from Wikipedia ....

Physicalism is a philosophical position holding that everything which exists is no more extensive than its physical properties; that is, that there are no kinds of things other than physical things ....

There are a number of arguments against Physicalism and Hart raises some, but one he doesn't mention is the Argument from philosophical zombies :). If I understand correctly (and I don't think I do), if consciousness is a construct of the physical brain, why then do zombies, who are just like us physically and do have brains, not have qualia or "minds"? The Stanford Encyclopedia of Philosophy has quite an entry for zombies. Here's just a bit of the part relating to Physicalism and consciousness ... ...


Zombies are exactly like us in all physical respects but have no conscious experiences: by definition there is ‘nothing it is like’ to be a zombie. Yet zombies behave like us, and some even spend a lot of time discussing consciousness. This disconcerting fantasy helps to make the problem of phenomenal consciousness vivid, especially as a problem for physicalism.

Few people think zombies actually exist. But many hold they are at least conceivable, and some that they are ‘logically’ or ‘metaphysically’ possible. It is argued that if zombies are so much as a bare possibility, then physicalism is false and some kind of dualism must be accepted. For many philosophers that is the chief importance of the zombie idea ......

A good way to make the apparent threat to physicalism clear is by adapting a thought of Saul Kripke’s (1972, 153f.). Imagine God creating the world and deciding to bring into existence the whole of the physical universe according to a full specification P in purely physical terms. P describes such things as the distribution and states of elementary particles throughout space and time, together with the laws governing their behavior. Now, having created a purely physical universe according to this specification, did God have to do something further in order to provide for human consciousness? Answering Yes to this question implies there is more to consciousness than the purely physical facts can supply. If nothing else, it implies that consciousness requires nonphysical properties in the strong sense that such properties would not exist in a purely physical world: it would be a zombie world. Physicalists, on the other hand, are committed to answering No to the question. They have to say that by fixing the purely physical facts in accordance with P, God thereby fixed all the mental facts about the organisms whose existence is provided for by P, including facts about people’s thoughts, feelings, emotions, and experiences.

It seems clear that physicalists are committed to the view that the physical world specified by P is all there is, in which case all other true statements are alternative ways of talking about that same world. In this sense physicalists must hold that the mental facts ‘supervene’ on the physical facts, and that zombie worlds are not ‘possible’. To show that zombies are possible would therefore, it seems, be to show that the mental facts do not supervene on the physical facts: that a zombie world is possible and physicalism is false. That is why opponents of physicalism do not have to point to actual cases of zombiehood: it is enough if such things are possible ...


OK, now my head hurts :)

David Hart comes at the subject in a more personal way - he mentions a past friend who he hadn't seen for years, but about whom he'd been thinking of in a very melancholy way, later finding out that she had just died. He also mentions dreams that had come true and other uncanny examples of what he sees as proof of the existence of consciousness independent of the body ......

[...] such experiences should chiefly remind us how many and how deep the mysteries of consciousness really are. And the profoundest mystery of consciousness is consciousness itself, because we really have little or no clear idea what it is, or how it could either arise from or ally itself to the material mechanisms of the brain.

There are, of course, intellectually serious books with titles like How the Mind Works (Steven Pinker) or Consciousness Explained (Daniel Dennett), but the preponderant consensus in the philosophical world is that they do not deliver more than a fraction of what they promise. The logical high ground is still occupied by consciousness “mysterians” like Colin McGinn or, at least, by skeptics like John Searle.

Most attempts to describe the mind entirely as an emergent quality of the brain, or as another name for the brain’s machinery, not only fail convincingly to bridge the qualitative distance between sensory impression and coherent thought, but invariably bracket out of consideration a great deal of what any scrupulous phenomenology of consciousness reveals. Certainly they do not seem to explain the “transcendental” conditions by which consciousness is organized: that primordial act within and prior to all our other acts of mind and will; that constant mediation between thought and world that we both perform and suffer in advance of all experience or volition.

Consciousness has not been explained until one can provide a comprehensive picture of how the mind not only “fits” the world, but also “intends” and “constitutes” it as an intelligible phenomenon. And that is not the straightforward mechanical problem it is often mistaken for .......

What I find interesting is this bit from the Stanford Encyclopedia quote ....

Imagine God creating the world and deciding to bring into existence the whole of the physical universe .... Now, having created a purely physical universe according to this specification, did God have to do something further in order to provide for human consciousness?

I think this is Nancey Murphy's point, that dualism, the belief that there must be a physical body and then something spiritual added on to that in order to get consciousness and a soul, is not necessary. I mean, maybe the physical world somehow incorporates spirituality? I guess I'm not making sense, but here's a past post from Jonah Lehrer at The Frontal Cortex - it's not exactly about what I'm talking about (it's about free will and materialism instead of consciousness and materialism), but it sort of goes where I want to go .....


Morality and Materialism

Ramesh Ponnuru, of the National Review, says this:

What renders atheism incompatible with a coherent account of morality, when it is incompatible, is physicalism (or what is sometimes described as reductive materialism). If it is true that the universe consists entirely and without remainder of particles and energy, then all human action must be within the domain of caused events, free will does not exist, and moral reasoning is futile if not illusory (as are other kinds of reasoning).

Will Wilkinson offers up an astute reply:

This is a stupefyingly widespread view that flows from an elementary error in thinking. Suppose you know that there is free will or that moral reasoning is not futile. Next, suppose you find that the universe is made out of only whatever the universe is made out of. What do you infer? You infer that free will and moral reasoning, which occur inside the universe (or as aspects of the universe), whatever they may be, are made possible because of whatever it is the universe is made out of. And there you are.

Here is what you do not do. You do not start with a mystifying conditional like "If the universe is only physical (or whatever), then there is no free will," because how do you know that? You don't. But you may think you do and so you get caught in a retarded ponens/tollens showdown: the universe is physical, ergo no free will, or... free will, so the universe is not physical. But, again, through what method of divination do we validate this conditional? None. Because we already know it is false.

I think that's exactly right. Looking at the neural anatomy of morality didn't undermine morality, or disprove its existence. On the contrary, the "reductive materialistic" approach simply showed us where, approximately, moral questions are processed inside the brain. I think a similar thing will happen with the concept of free will. Although many commenters will claim otherwise, I'm very dubious that neuroscience or physics will ever "disprove" free will. Free will is such an elemental part of human experience that disproving free will would literally require some sort of Laplacean demon. Until we obtain that level of omniscience - and I'm not holding my breath - I'll continue to assume that free will is a natural side-effect of some element of the material universe. Quantum indeterminacy sounds about right.


Anyway, I still don't know exactly where I stand on the body/mind/soul issue - I'm having trouble really understanding what it's all about.


Blogger Cura Animarum said...

This comment has been removed by the author.

7:47 AM  
Blogger Cura Animarum said...

I really enjoyed this post crystal. It gets me thinking along lines I don't go nearly often enough. ;o)

From a faith perspective I find Physicalism a challenge merely because faith begins from the standpoint that God, the progenitor of all things physical, enjoys an existence outside of the physical. Not a great base from which to enter into a debate with a physicalist I know (merely has the ardent physicalist, who in my mind must also be atheistic for the same reason, shruging their shoulders and saying 'Yeah, so'?)

For me the 'so' lies in the same realm as David Hart, throughout my life's own expereinces, and throughout the histories of human culture pretty consistently in most every space and place and time around the globe, have shown that there is something more to this universe gig than meets the eye.

My experiences of the world and personal relationships as filtered through the lens of the Spiritual Exercises alone hinged wholly on there existing connections and relationships that remain concrete and real connecting the physical but being outside of the physical realm completely.

I even relate the story of an dream experience in the past that certainly defies physical explanation "The Weirdest Thing To Ever Happen To Me" on my blog.

If the physical is all there is, then all of these experiences are lies...yet I know them to be true. So that's a conundrum that's hard for me to get around (yet wouldn't fly in a full-out debate of course).

At the same time, even scripture is adamant that the physical and the spiritual are concretely linked.

Still if the physical is truly all there is then I find myself echoing Paul's words "If for this life only we have hoped in Christ, we are of all people most to be pitied." especially after reading this story earlier in the week - Universe's Fate: Cold, Dead Wasteland

If they're right in their calculations life in the universe is not a gift to be treasured, nurtured and cared for, no life is sacred, nothing physical matters. The Universe as a whole truly is a cosmic accident, much more than an awful joke, and there's not much point in working towards a future of any kind as the ultimate end for all things physical is pretty bleak.

But as I've mentioned, my personal experiences tell me there is something more. Thanks be to God! ;o)

7:48 AM  
Blogger crystal said...

Hi Cura,

Interesting about lucid dreaming. I've only been able to do that a couple of times that I remember. I dream a lot too and used to keep a dream diary so I could recall all my dreams. I did have one that came true once. In high school I dreamt that a friend's boyfriend would break up with her and like me instead. It was odd because I hardly knew him - he was an older college guy - and I was like the most unnattractive of all her friends :) but it did happen. Sometimes I dream about Kermit and other dead people and it's like they're visiting me.

It's not that I want to say that all that exists is the physical, or that there's no God. Maybe that's true for all I know but that's not what I want to be true. That person I mention, Nancey Murphy, is a Christian - she's a minister of the Church of the Brethren - and she thinks that the physical and the spiritual are somehow intermixed in a way I can't really understand - that we aren't bodies with spirits, but as she says "spirited bodies".

I 'm not sure that makes sense, though, and I don't understand all this stuff, but it's interesting :)

8:46 AM  

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