Wednesday, November 21, 2007

Materialism Is Not (or Shouldn't Be) a Metaphysical Thesis

Materialism is the view that the world is entirely material (or physical). There are no immaterial souls or properties. There is no ghost in the machine.

David Chalmers argues against materialism as follows:

(1.) I can conceive of a world in which everything material is as it is in the actual world, yet in which there is no consciousness. (This would be a zombie world, which has a counterpart Eric Schwitzgebel who says and writes and does exactly the same things as I do, but who has no light of consciousness inside and is in the relevant sense an empty machine.)

(2.) Although such a world may not be naturally possible -- that is, although such a world may violate the laws of nature that hold at our world -- the fact that it is conceivable shows that it is metaphysically possible. (Compare: It is conceivable, and metaphysically possible, that my coffee cup rise of its own accord into the air and circle around my head in violation of the laws of gravity and inertia. A three-sided square, in contrast, is neither naturally nor metaphysically possible.)

(3.) Since in that world my counterpart does not have the property of being conscious though he shares all material properties with me, the property of being conscious must not be a material property.

(4.) So the world is not entirely material.

(Obviously, this argument is condensed. See Chalmers's 1996 book for the full details!)

What has always struck me as strange about this argument is how it derives a conclusion about the fundamental structure of reality from facts about what we can conceive. How could that possibly work? How could doing thought experiments in my armchair reveal whether the world is purely material or not?

Most materialist responses to Chalmers either deny that we can really conceive of such a world or deny that conceivability is an adequate test of metaphysical possibility. However, I find Chalmers convincing in his responses to both lines of attack. My thinking, instead, is that we should conceive metaphysical possibility as conceptual possibility but deny that materialism is (or should be) a thesis about what is conceptually possible.

To make this work, I need to play around with the concept of a "property". For a simple, concrete example, let's say that that in all naturally possible worlds I'm in brain state #1117A if and only if I'm having the conscious experience of pain. My zombie counterpart without consciousness (in a conceptually possible but naturally impossible world) has #1117A but not conscious pain. We might define thinly-sliced properties as properties individuated such that if they diverge even only in conceptually possible worlds, they are different properties. Thickly-sliced properties, in contrast, might be individuated such that if two diverge only in conceptually possible worlds but never in naturally possible worlds, they really are only one property. Conscious pain and #1117A would thus be different thinly-sliced properties but the same thickly-sliced property.

Now the question is, should we think of materialism as a claim about properties thinly sliced or thickly sliced? Let me suggest that the proper spirit of materialism, as a scientific hypothesis, confines it to being a claim about what is naturally possible, not a claim about what is conceptually possible. So zombie worlds and thinly-sliced properties are irrelevant to its truth. Materialists can give Chalmers "property dualism" if "property" means thinly-sliced property. In some sense, I do have non-material properties, but that's just a function of the fact that such thinly-sliced "properties" are individuated in accord with the concepts of the person attributing them and the human concept of consciousness pulls apart from the human concept of the material.


Anonymous said...

Hey Eric,

You say "what has always struck me as strange about this argument is how it derives a conclusion about the fundamental structure of reality from facts about what we can conceive".

I think that you are overestimating Chalmer's argument when you say that it is a conclusion about "the fundamental structure of reality". What I see as a result of it is a purely negative claim, which simply points to an incommensurability of two notions - that of "matter" and that of "consciousness", both of which we are supposed to be able to "hold clearly before our inner eye". I think it is supposed to be analogous to how a mathematician clearly holds in his thoughts two mathematical notions, and figure out if they are commensurable or not, without having for a moment to test anything.

In my personal view, the meaning of both terms is far from clear. In light of Rylean type of criticism suddenly notions like "mind" , "consciousness" , "phenomenal experience", etc... loose that apparent clarity of things of which we are directly aware. It seems to me, we are not in better position about the concept of "matter".

Should we avoid metaphysics then, and leave the issue aside? Should we just work with the concepts which show themselves as pragmatically useful in science? We might, but it seems to me the resulting stance is not "materialism" any more than it is "dualism".

Eric Schwitzgebel said...

Thanks for the comment, Tanasije!

I do think Chalmers sees his arguments as revealing something about the fundamental structure of reality -- but that's not incompatible with your analogy to mathematical reasoning. While I (and maybe you?) think that mathematical reasoning is just about concepts, not about the mind-independent world, I don't think Chalmers sees it that way.

I don't think we should leave metaphysics aside -- but I do think that "metaphysical" facts are just facts about what our concepts are, or should be, rather than facts about a mind-independent reality that we tap into (somehow!) by armchair intuitions!

Anonymous said...

I tend to think this...

Either something from the reality falls under the concept, or it doesn't. And as much as something falls under a concept, the conclusions about the concepts are conclusions about that part of reality which falls under the concept.

Even if one accepts this, and says that arm-chair intuitions of mathematicians do tell us about any part of reality which falls under concepts of math, it is still open question if something similar can be done with notions of "matter" and "consciousness".

Do those concepts ("matter"/"consciousness")
a) succeed to be clear notions which metaphysician can handle as mathematicians handle mathematical concepts, or are they just vague ideas. and
b) how much from reality falls clearly under those concepts.

I'm under impression (which of course doesn't mean a lot given my ignorance) that there is generally no clear ideas (on par with mathematical notions) behind the terms "matter" and "consciousness", and that because of this, how Zombie argument or similar ones are accepted by people, is dependent a lot on personal vague intuitions about those terms.

Eric Schwitzgebel said...

Thanks, Tanasije! I agree with you about the metaphilosophy. However, I think the concepts of "consciousness" and "matter" *can* be made clear -- or clear enough! -- even if they're a bit muddled in everyday language.

Chalmers doesn't do too much with "matter" (which I think is interesting to explore further), but I think he does pretty well with "consciousness". I don't think any helpful functional or analytic definition of consciousness is possible, but I do think one can make it clear through example and ostension, which is what he does.

Anibal Monasterio Astobiza said...

It seems that Chalmers reproduce the standard "ontological argument" but in this case to disprove materialism or to arguing in favour of non-concious beings instead to prove the existence of God.
The transition from thought to reality is always problematic, i think.

? said...
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? said...

Hi Eric,

Is your fundamental point that Chalmers's conceivability argument can't rule out that dualistic construals of phenomenal properties are Cambridge properties of some sort?

Eric Schwitzgebel said...

Thanks for the continuing comments, folks!

Anibal: I'm not seeing the parallel to the ontological argument. Could you explain further?

Elvis: That's in the ballpark of what I'm saying. I have no problem with "Cambridge properties" per se -- they're perfectly fine properties, I just don't think they're likely to be very useful. So likewise, maybe one way of putting my thought is that a distinction between two properties that diverge only in naturally impossible worlds may capture a difference in properties, but it isn't going to be a scientifically useful distinction -- except for the science devoted to undestanding our concepts....

Anibal Monasterio Astobiza said...

The standard version of the ontological argument made by St. Anselm of Canterbury says: that "nihil maius cogitare potest" in reference to God, and because you cannot think anything bigger (in the sense that God posses all and the best positive atributes) the only possible thing that God lacks is to "exist".
But if God lacks existence then he is not the thing by which you can think possess the best and all atributes.

In this sense St. Anselm made a fallacious move or transition from thought to reality. I can imagine a superbeing with all and the best atributes, but not for that reason it deserves to exist (I imagine a fly spaghetti monster but this is not guarrante of the existence of the fly spaghetti monster)

In similar fashion, Chalmers parallels the ontological argument because " metaphysical conceibility" does not mean "metaphysical REAL existence" so he does so too, a fallacious transition from thought to reality.

Eric Schwitzgebel said...

Thanks Anibal! I see the parallel now. In the leap from premises about conception to conclusions about reality, Anselm and Chalmers have something in common!