Wednesday, October 26, 2005

The World is not Enough

Picking up the thread on modal metaphysics (most recent post here): If I follow Armstrong’s truth/truthmaker approach to metaphysics and I insist it apply adequately to modal truths regarding necessity and possibility, it seems to lead (contra Armstrong’s own conclusion) to a modal realism involving possible worlds. David Lewis is the leading proponent of the theory that all possible worlds exist concretely. So what are the specific strategies for those who want to avoid joining Lewis? I “hit” the Stanford Encyclopedia of Philosophy to learn more. A brief summary of two relevant articles is below (keep in mind that this stuff is new to me and I’m even more prone than usual to misreading something – please check out the source articles if you’re interested).

There are two broad options here. First, try to deny any need to appeal beyond our single actual world. Second, substitute an account of abstract entities for Lewis’ concrete ones. This latter approach I will come back to in a future post.

Christopher Menzel wrote the SEP article called “Actualism”. Actualism is the thesis that there are no non-actual individuals or worlds. The article discusses various strategies to defend this thesis. Menzel discusses modal logic, and the fact that the simplest modal logic can be made to generate theorems which are troubling to the actualist. One of them is something like this: the statement {it’s possible that a flying pig exists} implies the statement {there exists something which is possibly a flying pig}. Next, he then summarizes how Kripke and others introduced modifications to modal logic meant to prevent the derivation of these sorts of statements while preserving the ability of the logic to do its modal work. The article leads one to conclude these efforts have not met with success: there isn’t a way to have a fully robust modal logic which has an actualist metaphysics as its analogue.

The article also discusses other programs to defend actualism (“world stories"/"world propositions”) which deflate the status of troubling implied statements into something innocuously only about propositions, not individuals. According to Menzel’s account these attempts also have serious objections – mainly they don’t do justice to analyzing the role modal statements really play in our language and thought. (He also devotes a section on Plantinga’s system of abstract possible worlds; this is something I will spend more time on before commenting).

Another strategy, which Armstrong himself once advocated, is called “Modal Fictionalism” – the SEP Article on this is authored by Daniel Nolan. This is the idea that this talk of possible worlds is a useful fictional construct not meant to be taken at face value. While this sounds attractive, the strategy suffers from objections, too. These include technical objections (logical formulations of modal fictionalism can lead to contradictions or circularity). Also, modal statements have more “objectivity” than authored fictions - if they’re not actual, they would be more like “hard” abstractions (mathematics being the paradigm example). A related point is that modal fictions are incomplete since they suffer from the author’s ignorance about many modal statements. Several other objections are outlined in the article as well.

Now as I said above I’m new to all of this, and it’s possible that some strategy exists or will be developed in the future which does justice to analyzing modal language and its role in rational thought while keeping to a deflationary actualist metaphysics. All I can safely say here is that all the attempts in the literature mentioned in these articles are described as having serious outstanding objections.

Monday, October 17, 2005

Materialists Missing the Point

I want to discuss 2 strategies I see used by advocates of materialism when trying to counter the devastating objection that materialism cannot account for the existence of first-person phenomenal experience. Both of the strategies make an insightful point, but then overstate the traction of this point on the essential problem thereby showing the materialists don’t really "get" the problem.

The first strategy is to improve upon the traditional materialist argument that experiential states are necessarily identical to brain states (“internalist materialism”). Rather, we should identify the contents of experience with external happenings. Here, brain states represent contents which themselves are external to the body (e.g. the impact of light waves on the surface of the apple). I just saw a reference to this strategy in this review of Gregg Rosenberg’s book by Paul Skokowski. Skokowski misses the point. Arguing that (at least some of) the contents of consciousness (“qualia”) are outside the cranium is a good idea, but experience itself is not thereby reduced to a material explanation. First off, I still believe the contents have a qualitative character which resists reduction; but perhaps more importantly, qualia are only one aspect of the 2-sided nature of experience itself: phenomenal contents exist only in order to be subjectively experienced. As Rosenberg explains better than I can here, experience is a process which by its nature has inseparable dual aspects of an experiencer as well as the experienced. Even if you could reduce one aspect of the process (qualia) to the physical, you cannot reduce both aspects of the process to the physical without effectively eliminating experience from your world-model altogether. Now, to repeat my point from above, I do think the externalist concept of qualia is an important insight to consider. The best description of this I have read is from Max Velmans, whose book Understanding Consciousness I recommend. Because Velmans truly understands the issues here, however, he is not a materialist.

The second strategy is most famously included in Daniel Dennett’s Consciousness Explained. It is a straw man argument which tries to show that the experiencer doesn’t exist. It proceeds by first arguing that the common sense notion of our first-person experience requires the existence of a homunculus which is the observer of qualia (thus breaking into distinct parts what really is an intrinsically dual-aspect process). Then it proceeds to show that our everyday idea of the self (which is like a homunculus) is an illusory concept. Here, the valid insight is that our reflective, introspective sense of self is a fragile and flawed construct which is at least one step removed from experience itself. Many studies show the “self” to be less unified and robust than we tend to think, and Libet’s experiments even put into question whether this self-construct has the ability to impact our actions! But while careful phenomenology will concur that the reflective (deliberative, introspective) self is a psychological construct of sorts (see for instance this post), it has as its precedent and its foundation real and unmediated first-person experience. So the argument that our naïve idea of self is a flawed concept has no impact on the reality of experience itself.

Note on Terminology: I’ve been noticing that both advocates and critics are returning to the use of the term “materialism” rather than “physicalism” to label the position. The idea is that even though we know that the word “material” is unable to do justice to the nature of the phenomena described by present day physics, materialism seems an easier and less obscure term compared to physicalism. BTW, while the incidence of this may be declining, I continue to emphasize that it is a mistake to conflate materialism with naturalism. Naturalism is a broader term which includes materialism as a sub-theory but can also encompass theories which expand upon the entities and/or processes of physics without invoking traditionally “supernatural” entities or processes such as mind/spirit substances or ad hoc divine interventions.

Wednesday, October 12, 2005

Chalmers Still on the Case

David Chalmers (home page, blog) has a new paper (The Two-Dimensional Argument Against Materialism) which provides a definitive and comprehensive update of his work on the “conceivability argument” and related issues. Defense of this argument over the last decade has led him to broaden the turf: the bulk of the paper goes beyond the mind/body issue to a general defense of the premise that conceivability implies metaphysical possibility; in other words, an epistemic premise (about what one can conceive) can lead to a modal conclusion (about what is possible).

I won’t try to summarize the paper in this post (other than a bare-bones sketch of the original conceivability and 2-dimensional arguments below). It is very thorough and I found the cumulative impact of Chalmer’s responses to various critics to be powerful.

I also think a section tucked in late in the paper is thought provoking(Section 10 – Modal Rationalism). Here he steps back and wonders about the implications of his defense of the premise that conceivability implies possibility. He talks about the crucial role modality plays in our capacity for rational thought. We need modal concepts to analyze various phenomena rationally -- he says you might call this logical modality and make use of logically possible worlds. And given Chalmer’s analysis in the body of the paper, there is no reason to think logically possible worlds and metaphysically possible worlds are different animals. Interesting stuff. I wonder, as always, about the ontological implications of this also. By virtue of what outside of ourselves is our capacity for rational modal thought based?

Sketch of conceivability and 2-dimensional arguments:

The conceivability argument has 3 premises (my paraphrase of the basic argument – the argument is presented in iterations of increasing precision over the course of the new paper): 1. A world physically just like ours with no first-person conscious experience is conceivable. 2. If such a world is conceivable, it is metaphysically possible. 3. If it is metaphysically possible, than materialism is false, since materialism is a metaphysical thesis which says physical facts necessarily entail all other facts, including experiential ones. The paper responds to a wide variety of objections posed, but most of the attention is on the second premise.

Let me just mention that the two-dimensional argument of the title (a version of which was already included in Chalmer’s 1996 book) was constructed to respond to what was the most common sort of this objection to the second premise. It is one of this sort (exemplified by using an example of Kripke’s): we can conceive of a world where water is not H2O, but it isn’t metaphysically possible -- we know that water is H2O. Chalmers breaks down the idea that {“water is not H2O” is conceivable} into two senses: the first (primary) is that there is a possible world where there is watery stuff (doing the job of water) which is not H2O. This is clearly conceivable. The secondary sense is that the stuff in the possible world isn’t watery stuff – it really is water! – then it is not conceivable that this water is not H2O. It is the primary sense of conceivability which we utilize in Chalmer’s second premise.

Friday, October 07, 2005

Armstrong on Modality

I read D. M. Armstrong’s new book Truth and Truthmakers. Armstrong is a great philosopher and metaphysician. He is also someone who insists on a materialist-naturalist metaphysics: there is one actual spatio-temporal world, and nothing more. I wanted to see how he handled the topics of modal truths and causality (my recent posts relating to this topic are here and here). I came away very disappointed. So, below you will find the spectacle of an untrained layperson criticizing a brilliant and prominent scholar on a blog. I ask anyone interested to please be willing to point out where I’m mistaken here.

First, let me offer some praise and briefly lay some groundwork. Armstrong is engaged in realist metaphysics in a serious way. The idea of truthmakers is a great one: every proposition, if true, has a truthmaker which makes it true. There must be “some way the world is in virtue of which these truths are true” (p.1). By considering different kinds of propositions, we build up and fill out a metaphysical structure which provides the truthmakers needed. The book introduces and describes the truth-truthmaking relation and his methodology for using it for metaphysics.

Next, Armstrong reviews his building blocks for truthmakers, in particular, his “states of affairs”. His version of this idea, introduced in previous papers and books, is central to the system. I’ll sketch it here and mention a concern with this approach, before I get to the specific issues of modality and causality.

Armstrong asks: What is the truthmaker for a proposition that a particular has some property? It’s probably not enough to say that the truthmaker just is that particular. What if it has other properties besides the one in question – do they come into play? What if it has relational properties which involve other particulars – do they come into play? How do we combine and delineate the relevant parts needed for a truthmaker?

Armstrong digresses to briefly outline all the combinations of approaches to particulars and their properties which have been proposed: (are properties universals or tropes, do they adhere to a particular’s substance or is a particular just a bundle, etc.) Armstrong notes some of the advantages and disadvantages but also says not all of these are important for truthmaker theory (he happens to favor immanent universals as properties, by the way). The most crucial issue appears to involve how to think of the relation between the particular and its properties. Armstrong says there “must exist states of affairs to get us beyond the ‘loose and separate’ entities” and thereby provide the truthmaker. He says: “States of affairs must be introduced as additions to the ontology.” (Emphasis original p.49). So, states of affairs are introduced to hold the particular and its properties together by fiat.

Moving from old-fashioned individuals to states of affairs brings in extra ontology for free. It seems to me this is going beyond traditional materialism. I was impressed by Bill Vallicella’s in-depth critique of this notion in his recent book, but I won’t try to do justice to his argument now. I’ll just express my feeling that Armstrong’s binding of properties into individuals via states of affairs seems too easy.

You might also appreciate this when you see how Armstrong builds up to larger states of affairs. Larger states of affairs can encompass and bind smaller ones to provide appropriate truthmakers when needed. To provide a truthmaker for negative truths about the world (e.g. there are no unicorns), Armstrong utilizes the notion of a general or maximal state of affairs for the whole world. This mega-fact sets limits for what is actually in the world. The fact that there is no unicorn supervenes on the highest-order state of affairs. And just as we bound a property to a particular at no ontological cost, Armstrong asserts that the mega-state of affairs encompasses the conjunction of all its smaller constituent states of affairs with no additional cost, despite being “something more than the mereological sum of its constituents” (p.72). (there is an obvious regress issue here, but Armstrong argues it is a benign one.)

The issue of contingency vs. necessity comes up in a few contexts in the book, for instance in whether the connection between a particular and its property is contingent or necessary. But chapter 7 is explicitly on the question of what the truthmakers are for modal truths.

He starts it off thus: “It seems to me very surprising that so many good philosophers consider that huge metaphysical commitments must be made in order to give an account of these truths.” (p.83). He mentions David Lewis and Alvin Plantinga specifically. In Lewis’ system (simplified), something is necessarily true, if it is true in all possible worlds; it is possibly true if it is true in a subset of worlds. Something in our world is contingent if it is possibly not true in other worlds. Famously, Lewis says these possible worlds all exist concretely. Armstrong says “...we ought to be looking for quite modest truthmakers, fairly deflationary truthmakers, for these fairly unimportant truths of mere possibility.” (pp.83-4)

Here’s his truthmaker argument for a contingent truth (my paraphrase-see p.84 for this in his notation):
1. Assume that (state of affairs) ‘T’ is the truthmaker for truth ‘p’.
2. Assume p is contingent (my emphasis).
3. p entails 'it is possible that not-p' (from #2 and the definition of contingency).
4. Therefore, T is also a truthmaker for 'it is possible that not-p', and so T is a truthmaker for a contingent truth p. (This is via #1, #3, and from something Armstrong calls the 'entailment principle' that he argues for earlier in the book).

That's it: there's no more. But shouldn't truthmakers for modal truths distinguish a contingent truth from a necessary one? We could use this argument's structure equally well for the case where p is assumed to be necessary. Therefore there is nothing in the truthmaker which determines the truth to be contingent vs. necessary. Therefore it is NOT an adequate argument for a modal truthmaker at all!

I was stunned by what seemed to me to be the obvious inadequacy in the argument here. Could I have missed something? I have read the chapter more than once, but I'll keep at it. As I said in my introductory paragraph I invite anyone reading this that is familiar with this to “set me straight”.

Here’s something Armstrong says to close this section of the chapter (7.2, p.86): “…I still favor the hypothesis that particulars, properties, states of affairs and laws of nature are all of them contingent beings.” There is no argument for this, it is just a preference. While it is a hypothesis that certainly seems consonant with our human intuitions, it in no way follows from his system. With no way to distinguish the contingent from the necessary, I would think it would be more consistent and simpler for him to give up the intuition and argue that all of these constituents and relations are necessary.

I will skip over more material and just briefly touch on Chapter 10 which deals with causation. Armstrong wants to affirm real causal connections, not just Humean regularities. He terms this “singular” causation. How does one do this? He acknowledges the difficulty of the problem and mentions some possible approaches. You can’t just add causal connections between states of affairs without seeming to add still more gratuitous ontology. He favors an idea that the universals which are parts of states of affairs might be vehicles of causal or “cause-like” connections at a higher level than the state of affairs involved. Using universals to do the work would help explain the existence of lawful regularities across the states of affairs of the world.

This work on causal structure within his framework of states of affairs seems fine on its own. But I hold that without an explanation of modality, the discussion is relatively empty. I have thought the heart of real causality is the idea that things could have been some other way. So the earlier lack of adequate treatment of modality makes Armstrong’s discussion of causality of minor interest to me.