On Physicalism (I)
I have been reading some interesting papers on the proper characterization of physicalism. A good one is 'Physicalism' by Andrew Melnyk, from the Blackwell Guide to the Philosophy of Mind. Another one was 'Varieties of Supervenience', by Robert Stalnaker, in Philosophical Perspectives 1996.
Melnyk introduces physicalism as the thesis that all entities (objects, properties, events, etc) are either physical in a narrow sense (physical_N), that is, entities posited by physics, or physical in a broad sense (physical_B), which are appropiately related to the physical_N. Of course, the central question is how to characterize that relation between physical_N and physical_B. One important candidate is the notion of supervenience: A supervenes on B iff, any possible world that is B-identical to the actual world is A-identical.
Melnyk argues that this notion of (global) supervenience might be a necessary condition for physicalism, but not a sufficient one, because there are accounts of, say, the mental, such that mental (globally) supervenes on the physical_N but is not, intuitively, physical_B, since on that account, the mental and the physical_N are distinct entities, causally related. These accounts satisfy global supervenience, but they do not seem to be physicalist accounts.
Melnyk suggests to complement supervenience with a realization claim. A kind X is realized by the physical_N iff X is a functional kind and some physical_N entity satisfies the functional role associated with X.
Melnys argues that realization seems to be a possible explanation of supervenience.
I think this sounds plausible. However, conceivability arguments are just committed to supervenience being a necessary condition for physicalism. In other words, CA assume that physicalism entails a supervenience claim, which is compatible with a realization-based notion of physicalism (since, plausibly, realization of X by the physical_N entails supervenience of X on the physical_N).
posted by Esa @ 6:25 PM
12 Comments:
I guess it will all depend on which exactly are the views that, for Melnyk, vindicate global supervenience but not physicalism, and why s/he thinks so. Any clue?
Let's see. I was talking about the notion of global supervenience, that is, "A supervenes on B iff, any possible world that is B-identical to the actual world is A-identical."
Oscar says that according to this definition, if B causes A (at @)then A supervenes on B. I guess this depends on what possible worlds are quantified over in the definition above. If it involves only nomologically possible worlds, then if B causes A (at @) A will supervene on B because all nomologically possible worlds will share the same causal laws, and therefore, B will always cause A. But if the definition of global supervenience quantifies over metaphysically possible worlds, where not all of them share our laws, then it is possible that B causes A but A does not supervene on B. For in some possible world, B might not cause A.
In your original post, you suggested that Melnyk held the view that if the mental is caused by the physical(-N) then it globally supervenes on the physical(-N), and I think this is what worries Oscar.
What is exacly what Melnik thinks?
Dan and Oscar, thanks for this. I get Oscar's point now. I realize that I was not very clear in my original post. I don't remember Melnyk's exact formulation of the problem for a supervenience-based characterization of physicalism, but I think it can be put as follows.
There is at least one candidate view about the metaphysics of the mental such that (i) the mental supervenes on the physical_N, and (ii) it is not physicalist, according to the intuitive idea of physicalism.
According to this view of the mental, the physical_N causes the mental, by means of causal laws that hold in any possible world. So, then, any possible world physically identical is mentally identical too.
OScar says that this view of the mental pressuposes that the causal laws are necessary. This pressuposition is controversial, I agree, but the point is that it is not an obviously incoherent idea. The relevant claim is that there is a CONCEIVABLE view about the mental such that it satisfies supervenience but it does not seem physicalist enough. This is enough to undermine a supervenience characterization of physicalism, I think.
In any case, we can make the same point without relying on that view of the mental being coherent. We can imagine another view of the mental, which posits a kind of 'pre-established harmony' between the physical_N and the mental, such that they are distinct entities but connected necessarily, by a link other than causation. Well, maybe someone could reply that this is not coherent after all... but, why not? If you don't assume Hume's dictum (e.g. that there cannot be necessary connections between distinct entities), then I don't see why that (weird) view is not coherent.
Well, in other words, if you endorse a supervenience-based notion of physicalism, you have to assume Hume's dictum. By, why should we do so?
I think I agree with Oscar that it is not completely clear that these views are coherent, after all: it will all depend on the particular details about them. Does Melnick provide them? I seem to remember Kim had some discussion on this as well, is this right?
Is this issue important for CCC? I thought the discussion only required that physicalism requires global supervenience, so that one could leave open whether in addition physicalism issues from global supervenience.
In any event, what is the connection between the old, nice, and true analytic functionalism and the (alleged) contingency of causal laws??? ;-)
Hi there! Dan and Oscar, thanks again, I'm enjoying this discussion very much!
Dan, I agree that this question on the definition of physicalism does not affect much the discussion on conceivability arguments. As I said in my original post, "conceivability arguments are just committed to supervenience being a necessary condition for physicalism. In other words, CA assume that physicalism entails a supervenience claim".
Oscar, thanks for putting your point so nicely. But I'm afraid I don't see how analytical functionalism, even if it was a priori true, would rule out the truth of (a) and (b). If I get it right, the main point of analytic functionalism is that mental terms can be analysed a priori in functional terms. Then, we have to find our a posteriori what properties satisfy those functional roles. It is a posteriori and contingent, then, that physical properties satisfy the functional roles associated with our mental terms. If this is so, then (a) and (b) are not ruled out a priori. For it is compatible with the (alleged) functional analyses of mental terms that the properties that satisfy those functional roles are non-physical properties, which might be necessarily connected with physical properties, by means of causal laws or some other necessary connection. That is to say, the conceptual core of analytic functionalism is compatible with either (a) or (b) being true. Of course, serious analytic funtionalists such as Lewis also held that the properties that realize the functional roles are physical, but it was clear that this is an posteriori truth.
Dan, is your worry similar to this?
Cheers!
Hi Oscar!
A few points. First, what is physical_W? Is it different from my physical_B? (That is, physical states broadly conceived, i.e. that are related to the physical-N by some intuitively appropiate relation R). Or do you mean topic-neutral states?
Second, let's consider the view that mental states are functional states realized by some states that are neither physical_N nor physical_B (according to our intuitions of what is broadly physical). You seem to accept that this is compatible with analytic functionalism, but you also seem to suggest that, on that view, since mental states would be defined in functional terms, this would not be a counterexample for physicalism. Well, I think that if mental states' functional roles are realized by non-physical states that are caused by the physical-N, it is obvious that physicalism is false, that is, mental states are not physical_B because they are not related to the physical_N by a link strong enough.
Just a quick question, for clarification. Is it obvious in this debate that physical-B entities are not closed under casuation?
I meant causation, of course ;-).
I was yesterday in Frank Jackson's very enoyable inagural David Lewis Lecture here. I hope to post on this further at bleb.
But one of the things he offered was precisely a characterization of phsycalism that seems interesting in the light of the discussion here.
He first introduced the notion of the physical-c(ore) as that of entities mentioned in the phsycial sciences and then psysical as those emergent from the former via aggregation.
What do you think?
I guess something along the lines of: everything is an aggregate of physical-c things whose properties are determined by the physical-c properties of its parts. I haven't found Jackson's paper online, but some of the issues seem to be covered by his The Case For A Piori Physicalism.
BTW What would you think about 'Apriori' vs 'Aposteriori Physicalism' vis-à-vis 'Type-A' vs 'Type-B Materialism'?
It is not that the truth of physicalism is apriori knowable, rather that it truth require there being the relevant apriori passages.
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