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.
Wednesday, October 12, 2005
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.
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.
Tuesday, September 27, 2005
Notes on Determinism, Modality and Causality
Below are some thoughts I was trying to develop. Everyone is welcome to point out where I'm getting off-base.
1. If determinism is true, there is no modality: everything is necessary. So, if you take modalities like possibility and contingency to be real, determinism is false.
2. If determinism is true, there is no “real” (non-Humean) causality: everything is connected necessarily and symmetrically; the world is fixed forever. Real causality implies modality: things could have happened differently if causation is assumed to involve real “work”. Like modality, real causality is opposed to determinism.
David Lewis would be able to embrace both modality and determinism by postulating concrete possible worlds (which are causally unconnected to ours) as the vehicle for modality. But he is a Humean about causality. There is no real causation in his system.
The only way to embrace modality and real causation is to reject determinism. This implies that the world includes an intrinsic selection or choosing among possibilities within causal events.
An assertion that only objectively random choosing occurs at this point is ad hoc: it has no particular advantage over asserting that choosing is non-random.
1. If determinism is true, there is no modality: everything is necessary. So, if you take modalities like possibility and contingency to be real, determinism is false.
2. If determinism is true, there is no “real” (non-Humean) causality: everything is connected necessarily and symmetrically; the world is fixed forever. Real causality implies modality: things could have happened differently if causation is assumed to involve real “work”. Like modality, real causality is opposed to determinism.
David Lewis would be able to embrace both modality and determinism by postulating concrete possible worlds (which are causally unconnected to ours) as the vehicle for modality. But he is a Humean about causality. There is no real causation in his system.
The only way to embrace modality and real causation is to reject determinism. This implies that the world includes an intrinsic selection or choosing among possibilities within causal events.
An assertion that only objectively random choosing occurs at this point is ad hoc: it has no particular advantage over asserting that choosing is non-random.
Tuesday, September 20, 2005
Dreyfus-in-the-World
A philosopher I like is Hubert Dreyfus, the existentialism and phenomenology scholar. Years ago I got more out of Heidegger by virtue of reading his commentary volume Being-in-the-World. Dreyfus is famous for his criticism of artificial intelligence, especially in the early days when many thought HAL from 2001: A Space Odyssey might soon become a reality! His What Computers Can’t Do from 1972 turned out to be prescient when the early versions of AI (now called “good old-fashioned AI” or GOFAI) started hitting tough obstacles.
I just finished reading Dreyfus’ APA Pacific Division Presidential Address, which was called “Overcoming the Myth of the Mental: How Philosophers Can Profit from the Phenomenology of Everyday Expertise.”
When working on the foundations of knowledge and many other problems, many assume (explicitly or implicitly) that our conceptual thinking facility is the primary dimension of mind. Dreyfus argues that our capacity for detached conceptual thinking rests on top of (is derived from) our non-conceptual embodied engagement with our environment.
The fundamental core of mind is not detached, deliberate, rational, or conceptual; it is our facility for skillful coping with the world. This is a key insight derived from Heidegger and Merleau-Ponty. It is also consistent with an evolutionary perspective on the human mind: after all, this core of skillful coping is what we share with animals and infants. What differentiates the mature human mind is that “we can transform our unthinking non-conceptual engagement, and thereby encounter new, thinkable, structures.” Accounting for this transformation is the research project recommended by Dreyfus.
I have liked this line of argument, and think Dreyfus’ perspective can serve to make the problems of perception and knowledge more tractable, reducing a bit the seemingly huge divide between the mental realm and the rest of the world.
I just finished reading Dreyfus’ APA Pacific Division Presidential Address, which was called “Overcoming the Myth of the Mental: How Philosophers Can Profit from the Phenomenology of Everyday Expertise.”
When working on the foundations of knowledge and many other problems, many assume (explicitly or implicitly) that our conceptual thinking facility is the primary dimension of mind. Dreyfus argues that our capacity for detached conceptual thinking rests on top of (is derived from) our non-conceptual embodied engagement with our environment.
The fundamental core of mind is not detached, deliberate, rational, or conceptual; it is our facility for skillful coping with the world. This is a key insight derived from Heidegger and Merleau-Ponty. It is also consistent with an evolutionary perspective on the human mind: after all, this core of skillful coping is what we share with animals and infants. What differentiates the mature human mind is that “we can transform our unthinking non-conceptual engagement, and thereby encounter new, thinkable, structures.” Accounting for this transformation is the research project recommended by Dreyfus.
I have liked this line of argument, and think Dreyfus’ perspective can serve to make the problems of perception and knowledge more tractable, reducing a bit the seemingly huge divide between the mental realm and the rest of the world.
Friday, September 16, 2005
Philadelphia-Area Philosophy
Check out the updated website for the Greater Philadelphia Philosophy Consortium (GPPC). The GPPC is a cooperative effort including the philosophy departments of 13 area universities which sponsors conferences and other events. The 2005-2006 program is up, and also see the link to the regional calendar which includes talks open to the public at the various schools (although you need to confirm these events with the schools as the dates approach.
Friday, September 09, 2005
Fetal Pain
Recently, JAMA published a survey article on Fetal Pain (the abstract is here, the full text requires a fee). The authors reviewed a large number of research papers relevant to the stage of development at which a human fetus feels pain, and, secondarily, on techniques available for direct fetal anesthesia or analgesia in the case of abortion (or therapeutic interventions). Despite the evidence of reflex responses and hormonal responses by the first and second trimester respectively, the authors conclude that analysis of nervous system development indicates fetal perception of pain is unlikely before the third trimester (29 or 30 weeks gestational age). They note that withdrawal reflexes only require peripheral sensory nerves which connect to motor neurons through the spinal column. They assert psychological awareness of pain requires relatively full cortical functioning, which they conclude comes at about 29-30 months.
The article includes a paragraph acknowledging the context: proposed federal legislation which would require physicians to inform women seeking abortions at 20 or more weeks that the fetus feels pain and to offer anesthesia for the fetus (evidently statutes like this have been enacted in Georgia and Arkansas).
Given the highly charged politics of abortion, the article caught a good deal of attention in the press, and a number of critics have disputed the conclusions and/or complained about pro-choice bias given some of the authors’ past affiliations (links here and here: William Saletan’s take on Slate here). I argue below that a different conclusion from the authors' can be reached from the same set of facts.
My interest in this was similar to my angle in my Terri Schiavo and animal consciousness posts: we have a tendency to think of conscious experience as an all or nothing thing, and I’m interested in exploring the evidence that there is more of a continuum of first person experience from minimal to full tilt.
Echoing what I’ve read elsewhere, the authors say the seat of awareness is in the thalamocortical circuitry. While they found no studies of such circuits in fetuses as they relate to pain specifically, they (reasonably) infer conclusions from looking at work on other pathways (like visual and auditory). Now, curiously, the specifics of these studies don’t seem to precisely support the survey article’s conclusion, since they show thalamic projections reaching the cortex at 23-27 weeks. A later part of the paper on electrical activity is invoked to buttress the 29-30 week figure in the conclusion, but this seemed to my amateur eyes less compelling (more indirect) evidence on the question.
Importantly, the authors include a paragraph noting that others have proposed that connection to the cortex could be established indirectly if afferents from the thalamus reach a transient cortical subplate which appears earlier while the layers of the mature cortex are still forming. This happens by 20 to 22 weeks. Given the lack of firm evidence that this connection conveys pain information (as we understand it in fully developed context) the authors don’t give it weight in their conclusion.
The authors do not address the broader question of whether something similar to pain (if more primitive in some sense) exists during development absent any pathway to even a primitive cortical subplate. Is there something in-between the reflex arc and the cortical arc which gives rise to pain-like sensation? At this point we probably have no evidence and can only speculate. But I think it is a reasonable intuition that in different stages of development, intermediate stages of experience may exist.
My problem with this article is not with the factual content, but with the way this is parsed to reach a conclusion. In the absence of compelling evidence that fully developed pain awareness exists prior to 29-30 weeks, the authors conclude it doesn’t. I might place the emphasis differently: while we lack definite confirmation, something similar to our pain awareness might exist at 20-22 weeks, and we just don’t know if a neural response worthy of being compared to pain might exist earlier than that.
I continue to support the legality of abortion; however, I also continue to believe relatively more emphasis should be placed on the procedure being done as early as possible.
The article includes a paragraph acknowledging the context: proposed federal legislation which would require physicians to inform women seeking abortions at 20 or more weeks that the fetus feels pain and to offer anesthesia for the fetus (evidently statutes like this have been enacted in Georgia and Arkansas).
Given the highly charged politics of abortion, the article caught a good deal of attention in the press, and a number of critics have disputed the conclusions and/or complained about pro-choice bias given some of the authors’ past affiliations (links here and here: William Saletan’s take on Slate here). I argue below that a different conclusion from the authors' can be reached from the same set of facts.
My interest in this was similar to my angle in my Terri Schiavo and animal consciousness posts: we have a tendency to think of conscious experience as an all or nothing thing, and I’m interested in exploring the evidence that there is more of a continuum of first person experience from minimal to full tilt.
Echoing what I’ve read elsewhere, the authors say the seat of awareness is in the thalamocortical circuitry. While they found no studies of such circuits in fetuses as they relate to pain specifically, they (reasonably) infer conclusions from looking at work on other pathways (like visual and auditory). Now, curiously, the specifics of these studies don’t seem to precisely support the survey article’s conclusion, since they show thalamic projections reaching the cortex at 23-27 weeks. A later part of the paper on electrical activity is invoked to buttress the 29-30 week figure in the conclusion, but this seemed to my amateur eyes less compelling (more indirect) evidence on the question.
Importantly, the authors include a paragraph noting that others have proposed that connection to the cortex could be established indirectly if afferents from the thalamus reach a transient cortical subplate which appears earlier while the layers of the mature cortex are still forming. This happens by 20 to 22 weeks. Given the lack of firm evidence that this connection conveys pain information (as we understand it in fully developed context) the authors don’t give it weight in their conclusion.
The authors do not address the broader question of whether something similar to pain (if more primitive in some sense) exists during development absent any pathway to even a primitive cortical subplate. Is there something in-between the reflex arc and the cortical arc which gives rise to pain-like sensation? At this point we probably have no evidence and can only speculate. But I think it is a reasonable intuition that in different stages of development, intermediate stages of experience may exist.
My problem with this article is not with the factual content, but with the way this is parsed to reach a conclusion. In the absence of compelling evidence that fully developed pain awareness exists prior to 29-30 weeks, the authors conclude it doesn’t. I might place the emphasis differently: while we lack definite confirmation, something similar to our pain awareness might exist at 20-22 weeks, and we just don’t know if a neural response worthy of being compared to pain might exist earlier than that.
I continue to support the legality of abortion; however, I also continue to believe relatively more emphasis should be placed on the procedure being done as early as possible.
Friday, September 02, 2005
Desert Phenomenology
{UPDATE 24 March 2008: Please note the 'Desert Landscape' blog is defunct and the links were broken. A shame}
Uriah Kriegel at Desert Landscapes has had a number of interesting recent posts on phenomenological topics. The most recent discusses Alva Noe and Sean Kelly's take on perceptual constancies, which I discussed in previous posts (here and here). He leans toward Kelly's view as I did.
Uriah Kriegel at Desert Landscapes has had a number of interesting recent posts on phenomenological topics. The most recent discusses Alva Noe and Sean Kelly's take on perceptual constancies, which I discussed in previous posts (here and here). He leans toward Kelly's view as I did.
Thursday, September 01, 2005
Whole Lotta Worlds
I enjoyed reading David Lewis’ On the Plurality of Worlds. Of course, for me it was like entering a theater in the third act: my eclectic self-education has big holes in it which inhibit my comprehension of such a work.
The usefulness of expressing modal concepts in terms of possible worlds seems clear enough (here’s a blog post which outlines this well – hat tip to the latest philosophy carnival). David Lewis argues that the value and utility of possible worlds in modal thinking points to a metaphysical or ontological argument that the full set of possible worlds exists concretely. In the book he defends this thesis.
Most other philosophers would say possible worlds are abstract, like mathematical objects. Even setting aside that the ontological status of mathematical objects is highly controversial topic, Lewis moves from his usual modest tone toward vehemence in criticizing these views as insufficient in supplying the full structure needed for possible worlds; further the question of how the actual world is selected from the set of abstract possibilities is either inadequate or “magical” in competing accounts.
In other words a sufficient proposal for a modal metaphysics either needs to have Lewis’ ontological panoply of concrete worlds, or else we need a fuller account of the ontological status of the abstract world along with a detailed mechanism for selecting the actual world (in Lewis’ scheme, “actual” just means the world we happen to be in, but there is nothing else special about it relative to the other worlds). Note that this means a system with only one actual concrete world and no ‘abstract realm+selection’ endowment is simply an inadequate metaphysics. While Lewis takes this for granted, I think it's interesting that seemingly only a small subset of philosophers would endorse either the Lewisian system or an abstract alternative with full mechanisms for addressing the Lewisian critique. They are presumably content to deal with modality in epistemological and linguistic arenas unburdened by the metaphysical worries.
While Lewis doesn’t explicitly address it much in this book, the other way to parse the metaphysics is in terms of causality. Lewis’ approach enables him to be a Humean about causality. Everything in the world just happens. If we want to talk about what counterfactual situations could have possibly happened to us, say, then we are talking about things that happen to our counterparts in other worlds. If we want to say there is only one concrete world where things happen and these are caused in a way which could have happened differently (they are contingent things), then we need a model of “real” causation that can handle this selection process. These two alternatives exclude the common assumption many seem to share that there is only one world, but a simple billiard ball notion of causation is all we need. In such a world there is no possibility or contingency at all. Again, this would be an inadequate metaphysics.
So, what do I think of Lewis’ proposal? I don’t like the Humean/fatalistic aspect of it. I would like to think a selection process happens rather than think that every possible world exists in an even-handed way, and we just happen to be in one. But at this point this is a preference on my part, not an argument.
What I get out most out of this is what I’ve been emphasizing in this post: Lewis is an obstacle to those who think they can “get away with” a minimalist metaphysics like single-world physicalism. It’s not enough.
The usefulness of expressing modal concepts in terms of possible worlds seems clear enough (here’s a blog post which outlines this well – hat tip to the latest philosophy carnival). David Lewis argues that the value and utility of possible worlds in modal thinking points to a metaphysical or ontological argument that the full set of possible worlds exists concretely. In the book he defends this thesis.
Most other philosophers would say possible worlds are abstract, like mathematical objects. Even setting aside that the ontological status of mathematical objects is highly controversial topic, Lewis moves from his usual modest tone toward vehemence in criticizing these views as insufficient in supplying the full structure needed for possible worlds; further the question of how the actual world is selected from the set of abstract possibilities is either inadequate or “magical” in competing accounts.
In other words a sufficient proposal for a modal metaphysics either needs to have Lewis’ ontological panoply of concrete worlds, or else we need a fuller account of the ontological status of the abstract world along with a detailed mechanism for selecting the actual world (in Lewis’ scheme, “actual” just means the world we happen to be in, but there is nothing else special about it relative to the other worlds). Note that this means a system with only one actual concrete world and no ‘abstract realm+selection’ endowment is simply an inadequate metaphysics. While Lewis takes this for granted, I think it's interesting that seemingly only a small subset of philosophers would endorse either the Lewisian system or an abstract alternative with full mechanisms for addressing the Lewisian critique. They are presumably content to deal with modality in epistemological and linguistic arenas unburdened by the metaphysical worries.
While Lewis doesn’t explicitly address it much in this book, the other way to parse the metaphysics is in terms of causality. Lewis’ approach enables him to be a Humean about causality. Everything in the world just happens. If we want to talk about what counterfactual situations could have possibly happened to us, say, then we are talking about things that happen to our counterparts in other worlds. If we want to say there is only one concrete world where things happen and these are caused in a way which could have happened differently (they are contingent things), then we need a model of “real” causation that can handle this selection process. These two alternatives exclude the common assumption many seem to share that there is only one world, but a simple billiard ball notion of causation is all we need. In such a world there is no possibility or contingency at all. Again, this would be an inadequate metaphysics.
So, what do I think of Lewis’ proposal? I don’t like the Humean/fatalistic aspect of it. I would like to think a selection process happens rather than think that every possible world exists in an even-handed way, and we just happen to be in one. But at this point this is a preference on my part, not an argument.
What I get out most out of this is what I’ve been emphasizing in this post: Lewis is an obstacle to those who think they can “get away with” a minimalist metaphysics like single-world physicalism. It’s not enough.
Saturday, August 13, 2005
Summer Break
I'm taking a break from my rigorous once a week (at most) blogging schedule. My beach reading assignment is David Lewis. Here's a naive question: should one's opinion of modal realism be influenced by the fact that physicists for their own reasons are increasingly postulating the existence of multiple worlds?
Thursday, August 04, 2005
Philosophical Physicists
As I’ve written about before (here), theoretical physics has seemed stuck in recent years. Astronomical observations continue to uncover new features of the universe (like dark energy), but these mostly add new mysteries to the list which cannot be explained by current theories. The jury is also definitely still out on older ideas about the early universe (such as the inflationary scenario). Physicists await with great expectations the 2007 debut of the Large Hadron Collider, which offers the possibility of revealing new phenomena at higher energies which may assist theorists. In the meantime, there is plenty of time for physicists and philosophers of science to step back and consider conceptual issues which underlie physical theories. Here are a couple of examples of this I came across recently.
Lee Smolin has a new essay (hat tip to Peter Woit’s blog): “The case for background independence.” The context of the essay is the ongoing difficulty in constructing a theory of quantum gravity. Smolin thinks what has ultimately stymied the most popular quantum gravity research program--string/M theory-- is its use of a space-time backdrop as a “given”, rather than having space-time emerge from relations of variables within the theory. The essay starts with a historical sketch of the absolute and relational views of space-time, then summarizes how this is playing out in the different quantum gravity research programs (Smolin is one of the founders of the approach called loop quantum gravity, which attempts to preserve the background independent flavor of general relativity). Lots of interesting ideas in the essay. Also, for a debate on string theory see this post and comment thread on the excellent new team physics blog, Cosmic Variance.
As an aside, the debate between absolute and relational theories of space-time was most clearly personified in the personal rivalry between Newton and Leibniz. A fun coincidence is that I’m now working my way through the second installment (The Confusion) of Neal Stephenson’s Baroque Cycle, which features this rivalry as a minor subplot. The Confusion has a nice scene where Leibniz explains the relational view to a colleague.
On a related topic, the interpretation of quantum mechanics, I enjoyed this paper revisiting the philosophical conflict between Bohr and Einstein by N.P. Landsman (from PhilSci archive, via Brian Weatherson’s invaluable papers blog).
Einstein was famously frustrated by quantum mechanics, despite being one of the founders of the theory. Landsman summarizes his view as one where physical thought and physical laws require (classical) separability and locality (which QM doesn’t provide). Bohr accepted that while classical (objective) thinking was indeed necessary for science, the classical world in which physicists work incontrovertibly sits next to a quantum realm which has a nature which will not reduced to the classical. Landsman importantly also brings out the interesting “flip side” to Bohr’s thought, which is that it is equally true that a full quantum description of the world which leaves out the classical is impossible (many physicists and philosophers seem to miss this point). The implication is that there are necessarily two modes of reality: the quantum realm of spread-out potentials and the classical world of interactions/measurements.
Lee Smolin has a new essay (hat tip to Peter Woit’s blog): “The case for background independence.” The context of the essay is the ongoing difficulty in constructing a theory of quantum gravity. Smolin thinks what has ultimately stymied the most popular quantum gravity research program--string/M theory-- is its use of a space-time backdrop as a “given”, rather than having space-time emerge from relations of variables within the theory. The essay starts with a historical sketch of the absolute and relational views of space-time, then summarizes how this is playing out in the different quantum gravity research programs (Smolin is one of the founders of the approach called loop quantum gravity, which attempts to preserve the background independent flavor of general relativity). Lots of interesting ideas in the essay. Also, for a debate on string theory see this post and comment thread on the excellent new team physics blog, Cosmic Variance.
As an aside, the debate between absolute and relational theories of space-time was most clearly personified in the personal rivalry between Newton and Leibniz. A fun coincidence is that I’m now working my way through the second installment (The Confusion) of Neal Stephenson’s Baroque Cycle, which features this rivalry as a minor subplot. The Confusion has a nice scene where Leibniz explains the relational view to a colleague.
On a related topic, the interpretation of quantum mechanics, I enjoyed this paper revisiting the philosophical conflict between Bohr and Einstein by N.P. Landsman (from PhilSci archive, via Brian Weatherson’s invaluable papers blog).
Einstein was famously frustrated by quantum mechanics, despite being one of the founders of the theory. Landsman summarizes his view as one where physical thought and physical laws require (classical) separability and locality (which QM doesn’t provide). Bohr accepted that while classical (objective) thinking was indeed necessary for science, the classical world in which physicists work incontrovertibly sits next to a quantum realm which has a nature which will not reduced to the classical. Landsman importantly also brings out the interesting “flip side” to Bohr’s thought, which is that it is equally true that a full quantum description of the world which leaves out the classical is impossible (many physicists and philosophers seem to miss this point). The implication is that there are necessarily two modes of reality: the quantum realm of spread-out potentials and the classical world of interactions/measurements.
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