Peter Lupu has come out in favor of emergentism in the philosophy of mind. Here is an argument he could use to defend the thesis that mental properties are emergent properties:
1. Materialistic Anti-Dualism: Human beings are nothing more than complex material systems.
2. Anti-Reductivism: Mental properties are not identical to physical properties, nor do the former logically imply the latter.
3. Anti-Eliminativism: Human beings do in fact instantiate mental properties.
4. Anti-Panpsychism: The basic constituents of the physical world do not have mental properties.
Therefore
5. Mental properties are emergent properties, which implies that there are emergent properties.
The cases for (2) are (3) are overwhelming, so I consider them 'off the table.' Peter agrees. Panpsychism ought to be investigated, but Peter finds it highly implausible, so let's assume it to be false for the sake of this discussion. The crucial premise -- the dialectical bone of contention if you will -- between Peter and me is (1). He accepts (1) while I reject it. It is worth noting that there are at least three ways of rejecting (1): by being a substance dualist, or an idealist (see John Foster's work), or a Thomistic hylomorphic dualist. So I would argue from ~(5) to ~(1). But for now we assume that (1) is true.
For the above argument to work, a clear concept of emergence must be in play. We should distinguish between synchronic and diachronic emergence, and between property and substance emergence. For now we are concerned solely with synchronic property emergence. James Van Cleve offers this definition:
If P is a property of w, then P is emergent iff P supervenes with nomological necessity, but not with logical necessity, on the properties of the parts of w. ("Mind-Dust or Magic? Panpsychism Versus Emergence," Phil. Perspectives 1990, p. 222.)
Synchronic property emergence is thus a species of supervenience. Van Cleve refers to Jaegwon Kim for a definition of supervenience. Let A and B be families of properties closed under such Boolean operations as complementation, conjunction and disjunction. A strongly supervenes on B just in case:
(SS) Necessarily, for any property F in A, if any object x has F, then there exists a property G in B such that x has G, and necessarily anything having G has F.
Now how does emergence as defined by Van Cleve differ from strong supervenience as defined by Kim? One difference is that (SS) is defined for a single domain of objects: the supervenient properties are properties of the same objects as are the subvenient properties. But the extension to multiple domains seems easy enough. Emergence is a kind of multiple domain supervenience inasmuch as the emergent-supervenient properties are properties of a whole the proper parts of which instantiate the subvenient properties. A second difference is that the relation between the supervenient-emergent properties and the subvenient ones is not logical but nomological.
Some Questions About Synchronic Property Emergence
A. True Emergence Versus Epistemological Emergence. Talk of emergence might in the end be merely epistemological. Suppose system S has an observable feature F that cannot be explained in terms of the properties of the parts of S or in terms of the relations of these parts to each other or to things external to S. It could turn out that the parts of S have properties that we have not yet discovered and that F derives from these properties. Or it could be that there are parts of S that have yet to be discovered and that the properties of these parts imply F. For these reasons, Thomas Nagel feels sure that "There are no truly emergent properties of complex systems." ("Panpsychism" in Mortal Questions, CUP 1979, p. 182.) On this approach, talk of emergent properties merely signals our ignorance.
So here is a challenge for Peter: Are there some nice clear examples of complex systems that exemplify truly emergent properties? No doubt there are plenty of wholes that have properties that are not properties of the parts of these wholes. For example, the set of natural numbers is infnite, but no member of this set is infinite. For a second example, a wall whose weight is x lbs is not such that each of its constituent stones weighs x lbs. But a property of a whole that is not a property of its parts is not eo ipso an emergent property of the whole. In the case of a wall made of stacked stones (and nothing else), the weight of the wall is the sum of the weights of the constituent stones and is therefore logically determined by them. Therefore, the weight of the wall is not an emergent property of the wall. For a property of a whole to count as truly emergent it would seem that its connection to the properties of the parts of the whole would have to be logically contingent. This desideratum is captured by Van Cleve's definition supra.
B. The 'Magic' or 'Poof' Objection. If mental properties are not logically implied by physical properties, then it might seem that they emerge from their physical base 'by magic.' If this were the case, then emergentism would leave physicalism behind. For an unconvincing and needlessly polemical presentation of the 'Poof' objection see here. If the connection between base and emergent properties is not logical but nomological then perhaps the 'magic' objection can be defused. Non-logical derivation need not be 'magic' derivation. This ought to be more carefully examined in a separate post.
C. My Objection. Consider the mental property of feeling anxious. Assume it is truly emergent from certain base properties of the brain and central nervous system. Surely a property cannot be anxious. It is not the property, but that which has the property, that is anxious. For a materialist, the subject of anxiety or of any mental state can only be a material entity, the brain or the brain-cum-CNS. But for reasons given elsewhere, it is difficult to see how how the brain or any physical thing could be that which is conscious, how it could be the subject of conscious states.
I conclude that property emergentism is quite unavailing for the purposes of the naturalist who wishes to account for mind in wholly naturalist terms. What the emergentist must do is to try to make sense of substance or individual emergentism. I am not a property but a thinking individual. So even if mental properties are true emergents, it doesn't help. If the thinking individual that I am can be said to be emergent then the naturalist may have a viable position. At this point we need to consult William Hasker's The Emergent Self.
Bill, you could also be interested in David Oderberg's case against the emergence of life from non-life in his Real Essentialism, ch. 8.3. http://books.google.cz/books?id=gO_40ZwgdkMC
Posted by: Vlastimil Vohánka | Tuesday, May 12, 2009 at 11:17 AM
V,
Thanks for the reference!
Posted by: Bill Vallicella | Tuesday, May 12, 2009 at 11:48 AM
I think the arguments against some style of panspychism are weak. Typically they reduce to making the facile claim that things like water clearly don't have minds. However the stronger panpsychic view is that there are elements of proto-consciousness in the universe but these constitutents are not like minds as we conceive of them. Rather they have properties out of which minds can emerge without the radical emergence that folks like Lupu and others argue for. (Rather implausibly in my mind)
The strongest argument for panpsychism is that it only demands unknown constitutent properties, doesn't have the failings of substance dualism, and isn't just a cop out for some desired end the way emergence is.
Posted by: Clark Goble | Tuesday, May 12, 2009 at 11:48 AM
Clark,
Your comment is off-topic. The topic is emergentism, not panpsychism. Comments should address the content of the post and nothing else. Please don't leave comments like this. And saying that emergence is a "cop out" is a silly thing to say.
But you are right that the panpsychist is not committed to maintaining that every macro-object exhinits mentality.
Posted by: Bill Vallicella | Tuesday, May 12, 2009 at 12:46 PM
Hi Bill,
Nice post. For my part, I find the 'poof' objection rather compelling. In the absence of some fairly detailed explanatory account of how a given mental state (token or type)can emerge from a given physical state (token or type), talk of emergence reminds me of the cartoon in which a mathematician inserts "... then a miracle occurs ..." in the middle of a complex proof.
Hasker's book is worth reading. While his defense of emergence does't satisfy me, he does have an interesting analogy to offer. He compares the emergence of a mental self to the emergence of a magnetic field. The field nomically supervenes upon and emerges from the electric current flowing through a wire, and it seems to have causal powers in its own right (e.g., it can deflect a compass needle).
Posted by: Alan Rhoda | Tuesday, May 12, 2009 at 01:47 PM
Hi Alan,
I am aware of the cartoon you mention, and its seems quite apropos when people like Dennett speak diachronically of free will or intentionality evolving or emerging.
In the synchronic case, if there are laws that bridge the mental and the physical, would that not defeat the 'poof' objection? If the laws were mere Humean regularities, then I agree (with Nagel) that the 'poof' objection remains in force. But if the laws were of a stronger form, mightn't that defeat the objection? That is what Van Cleve seems to be saying. I'm not clear on the matter.
I recall that example of Hasker's. It is a good one. The field is clearly dependent on the current flowing through the wire, but it is a particular not a property, and its has causal powers all its own.
But if it is the nature of mind to be emergent in that way, then how can Hasker, consistently with that, believe in a God who is a nonemergent mind?
Posted by: Bill Vallicella | Tuesday, May 12, 2009 at 03:01 PM
Bill, you're welcome.
Another tip on emergence I remember:
Tim McG at W4, in the comments: http://www.whatswrongwiththeworld.net/2008/12/an_open_letter_to_heather_macd.html
Posted by: Vlastimil Vohánka | Wednesday, May 13, 2009 at 02:09 AM
Sorry about that Bill. Mea Culpa.
Posted by: Clark Goble | Wednesday, May 13, 2009 at 09:13 AM
Bill, you write:
"For a property of a whole to count as truly emergent it would seem that its connection to the properties of the parts of the whole would have to be logically contingent. "
I am not so sure that definition serves as a rigorous definition. According to a physical theory like chaos theory -- butterfly wings in China leading to a storm in Tennessee -- a small change in initial state can lead mathematically (and/or logically if you will) to a final state of periodic orbits. But a periodic orbit seems to be an epistemological emergent property.
The development of life from DNA is logically emergent isn't it? Life's connection to the DNA part of the whole is logically and/or (i.e., scientifically) consistent (and despite the facts we don't know, e.g., the creation of a phenotype, etc.)
It doesn't matter how small the item of life is either. A one celled organism is simpler than Man, but we can point to it and call it living.
It is interesting to me that defining emergent properties is so fiendishly difficult -- how do you define life? -- yet we know it when we see it, with finality like Bishop Berkeley’s rock.
Perhaps an emergent property can only be defined post facto -- we know it when we see it, and that too is a property of true emergent property.
Posted by: Joe | Monday, May 18, 2009 at 01:55 PM