Thursday, September 12, 2019

Naturalism and property dualism

It is generally taken that a view on which there are mental properties that do not supervene on the properties of physics is a non-naturalistic view: it is a form of property dualism.

But now imagine that we find out that:

  1. There are chemical properties that do not supervene on the properties physics speaks of.

That would be a really exciting discovery, but it wouldn’t be a discovery incompatible with naturalism. The new chemical properties would presumably be just as natural as the physical ones.

So, why would we call non-supervenient mental properties non-natural, if we wouldn’t call non-supervenient chemical properties non-natural? It can’t be just because chemical properties are the province of a science, namely chemistry. For mental properties are the province of a science, too, namely psychology.

While we’re exploring this corner of logical space, consider this view:

  1. Chemical properties do not supervene on physical properties, and mental properties do not supervene on physical properties either, but mental properties do supervene on, and even reduce to, physical and chemical properties.

I’ve never met an advocate of (2). It would be a very strange view. But here is one that, I think, is not actually all that strange:

  1. Biological properties do not supervene on physical properties, and mental properties do not supervene on physical properties either, but mental properties do supervene on, and even reduce to, biological properties.

I think view (3) is worth thinking about. Most of the people who have tried to reduce the mental have tried to reduce it to the physical, but perhaps a reduction to an irreducible biological level would be more promising.


Heath White said...

I think the heart of naturalism is that fundamental realities are not persons (particles, etc.) The heart of non-naturalism is that fundamental realities include persons (God, people).

Thus if chemical properties were fundamental and did not supervene on physics, that would still be naturalism. If psychological properties were fundamental, though, that would mean minds--persons--were in some sense fundamental. Hence that would be non-naturalism.

Christopher Michael said...

It’s (3) Searle’s view?

Alexander R Pruss said...

As far as I can tell, Searle thinks that the biological does not reduce to the physical, but it does supervene on the physical.

Alexander R Pruss said...

Oops: I deleted Christopher Michael's correction of "It's" to "Isn't". Sorry.

Heath White said...

Clarification: in my view, consciousness (phenomenal states) is neither necessary nor sufficient for personhood. I therefore believe that a naturalist could accept the view that consciousness was a fundamental property.

Intentional states, on the other hand, seem to require personhood. (At least full-blown versions; so that your dog only analogically has propositional beliefs.) Therefore I believe that a naturalist could not accept the view that intentional states were fundamental.

William said...

Dr. White:

Have you ever considered personhood zombies, which would be conscious human beings with consciousness but not what you would consider personhood? What would these be like?

Heath White said...


I don't think I can conceive of that.

William said...

Dr. White:

Nor I.

Michael Gonzalez said...

To White and William: I'm inclined to think "personhood" is a social status predicate; not a substance one. If you mean "agent capable of intentional states", then I wonder what those really amount to. Most of the so called "intentional objects" are no such thing (at least not in the Brentano sense). And a grammatical and conceptual analysis of when we use intentional-type statements clears away any of the supposed mysteries about it.

I guess my point is that the "intentionality talk" may not be sufficiently clear or meaningful to warrant a substance claim or a defeat of naturalism.

Michael Gonzalez said...

As to the original post, I think Pruss is onto something fundamental and extremely important. After all no one thinks that we can satisfactorily speak of chemistry (and certainly not of biology) using only the vocabulary of physics. There simply are not enough words or concepts in physics to deal with explanations of a chemical or biological nature. Even the typical naturalist, when they try to reduce mental phenomena or explain them in naturalistic terms, appeal to the activity of brains, neurons, etc. I guess they're just assuming that, since brains are physical objects, the reduction from that to mere physics will be no big deal; and so the important thing is just to reduce the mental to the biological/neurological...?

At the end of the day, the biological certainly does NOT reduce to the merely physical. Living things are categorically different from non-living ones, and obviously animate, self-moving creatures are yet another level distinct. How much more so, if you build on top of those two levels a third level of a language-using (and therefore rational) creature with the attributes and powers associated with mental predicates?!

Alexander R Pruss said...

It's interesting how Michael's point "no one thinks that we can satisfactorily speak of chemistry (and certainly not of biology) using only the vocabulary of physics" gets used in the philosophy of mind in the opposite direction, namely to *support* reductionism about the mental. The standard line of argument is:

1. Obviously, the chemical and biological reduce to the physical.

2. But the vocabulary of the chemical and biological cannot be replaced by that of the physical.

3. So, reduction does not require vocabulary replacement.

4. So, the fact that we cannot replace the vocabulary of the mental by that of the physical does not challenge the reduction of the mental to the physical.

(That said, I am sympathetic to the claim that vocabulary irreducibility does not imply ontological irreducibility.)

Michael Gonzalez said...

Pruss: Rather than "vocabulary", I would say "conceptual scheme". The conceptual bounds of physics simply don't seem sufficient to deal with all of chemistry, and they are manifestly insufficient for biology (what would "wellbeing", "life-cycle and death", etc mean in physics terms?). Indeed, it is rather easy to conceive of living things made up of totally different stuff, and yet we'd say similar things about their life, death, well-being, what is good for them or bad for them, etc. What they are made of may constrain them in various ways, but it does not fully describe or explain them.

I think the whole enterprise of "explanation" by means of saying what smaller parts are doing is based on a scientific tradition that started with machine-makers and mathematicians. It works fine for those machines, but living things are not machines. Nor even "systems" in the physics sense. If there had been a decent biologist among them (you'd have to look back all the way to Aristotle for that), they'd realize that they weren't paying due attention to first and second order active and passive powers, characteristic of the kind of entity.

If "naturalism" just means "only physical objects/bodies exist", then my objection comes from the modal contingency, finite history, fine-tuning, and other such aspects of the physical world, which point to something beyond it. But, if it means "only things describable within the conceptual scheme of Physics", then it is manifestly false, since coffee breaks are not within the conceptual scheme of Physics.

Haweh said...
This comment has been removed by the author.
Haweh said...

Here is a list of objections to property dualism being naturalistic:
1. Naturalism is defined normally as what the natural sciences can discover on their own. If it's immaterial you have a lot of explaining to do with this.
2. Biological phenomena are different than mental as you can a generalized form in a law of nature describing all facts about it. How would you do the same about time and GR, for example, or the first-person account of consciousness?
3. If there are laws they must be the most fundamental level outside of properties of matter and if consciousness is irreducible then you run into a circular reference of whether laws of nature are on top or not. That's a problem and it also goes for causation as well.
4. Naturalism is normally meant to be strictly third person or everything can be described in a metaphysics similar to 3rd only perspective in the natural sciences.

These should be enough to show the problems with it.