Kriegel’s “Animal Rights and Conscious Experience”

(Note: this is half of what will be a two-part post.)

Uriah Kriegel, assistant professor of philosophy at the University of Arizona, has posted this draft paper which seeks to advance the discussion on animal rights in light of progress in the study of consciousness. The most important part of the paper, in my view, is his formulation of how to explicitly make the (likely) presence of conscious experience the key component of a framework for assigning moral status to animals.

Before getting to his own proposal, Kriegel considers how the most influential consequentialist approach to animal rights (prominently associated with Peter Singer) suffers from a lack of an up-to-date analysis of the science of consciousness. This consequentialist framework, which emphasizes maximizing pleasure and minimizing pain, typically doesn’t incorporate a sophisticated understanding of exactly which animals might have conscious experience of pleasure and pain, as opposed to an unconscious functional analogue of these feelings. The former are presumably the intended recipient of moral consideration, not the latter.

Kriegel uses his own work on (human) consciousness to show how the view of animal rights would be influenced by a more detailed account of consciousness. Kriegel starts with his own proposal for locating the neural correlate of consciousness (NCC) in humans. This proposal, which he calls the cross-order integration hypothesis (COI), is detailed in a paper published in the journal Consciousness and Cognition. Then he argues that a comparison of brain structures between animals and humans should inform a view of whether animals share the NCC, and hence are conscious.

Without getting into all the details here, Kriegel’s COI theory implicates activity in cortical structures, presumed to be involved in higher order monitoring work, as a necessary part of the NCC. Because our mammal cousins share these structures while non-mammals lack it, this would provide evidence that the former are conscious, but the latter are not. In considering the consequentialist approach to animal rights sketched above this analysis would serve to help define the circle of moral consideration: in this case, mammals are on the inside, other animals are on the outside (“looking in”).

While Kriegel has some confidence in his approach, he clearly notes in the paper that his moral stance will be tempered by the uncertainty around the empirical conclusions underlying such a moral calculus (his preference is to couch any moral formulas incorporating the empirical claims in terms of probability). And I should stress that the general point on methodology has value even if one’s theory of the NCC differs: just plug in your own preferred NCC and try to judge how far it extends into the animal kingdom. For myself, while I like Kriegels’s “top-down” approach to the question of locating the NCC (i.e. beginning with a theory before you look at the experimental data – see an old post on Kriegel’s philosophy of mind here), I don’t have a high level of confidence in his (or any other) specific NCC proposal yet. The field is still in its early stages.

Still, even if one gains confidence in identifying the NCC in humans, there is a very big step to cross when considering the consciousness of animals, which Kriegel may underestimate. Because brains and bodies have demonstrated a robust ability to adaptively implement analogous functions using distinct structures, I would be very cautious in assuming that the work performed by our late (evolutionary) vintage neural structures couldn’t be implemented differently in animals. Even cephalopods, whose nervous systems have little in common with ours, show behaviors very suggestive of consciousness. Reinforcing this concern is my own philosophical bias to see consciousness as something which comes in degrees. An animal without a cortex could have an attenuated version of consciousness, as opposed to a lack of consciousness.

After the lengthy discussion of the how his kind of empirical analysis can help in evaluating the consequentialist ethical approach, Kriegel shifts gears and discusses a different non-consequentialist framework for the problem.

(To be continued.)

Contemplating the Deeply Strange

I watched this bloggingheads.tv dialogue between Robert Wright, whose latest book (The Evolution of God) I reviewed in the prior post, and Tyler Cowen, economics professor and prolific blogger at Marginal Revolution. They discussed Wright’s book but also expanded somewhat on each of their own views. One thing both men have in common is that they are non-believers, but take the challenge of responding to religious impulses seriously. I wanted to highlight here a good point made by Cowen. (The relevant parts of the dialogue span a couple of minutes beginning at 38 minutes in, then a few more starting at the 47 minute mark.)

Paraphrasing, Cowen says most non-believers should think more about religion and should specifically take the design/fine-tuning argument seriously: contemplation of this often leads to the concept of a complicated multiverse. He says we need to consider that our common-sense view of the world is wrong, and that there is room for a “deep strangeness” in reality. He mentions quantum mechanics and says one has to come to terms with a reality that seems absurd. He says his alternative to believing in God turns out to be something believing strange as well.

I would add that the multiverse concept in particular, is not only strange, but, if embraced, commits one to acknowledge something transcendent (a reality far beyond our observable universe). Investigations of our world have led to several ways to motivate the multiverse: in addition to the fine-tuning argument and the interpretation of QM, there are extensions of specific cosmological theories (eternal inflation, the string theory “landscape”), and there is the modal realism of philosophers. If a non-believer is motivated to explore deeper explanations of reality, he or she will almost surely end up somewhere well beyond a common-sense starting point.

Once you rule out the supernatural entities and interventions of traditional theism, there’s still a lot of hard work to do to explain what’s given to us: and the journey may lead to places one didn’t intend to go.

The Evolution of God, by Robert Wright

Robert Wright is an intellectually curious journalist and a fine writer whose previous books I enjoyed (these days he is also editor-in-chief of bloggingheads.tv). In 1994’s The Moral Animal, he summarized and popularized ideas from the burgeoning field of evolutionary psychology. In 2001’s Nonzero: the Logic of Human Destiny, he examined how game theory helps make sense of the development of human nature and human societies. In addition to presenting a digest of interesting research in these books, he laid out his own prism for viewing these topics: while our values can be explained entirely as natural phenomena, there is evidence of historical progress in the moral dimension of human affairs which seems to possibly point to something more transcendent. Wright’s new book, The Evolution of God, fits right into this theme: he explores the character of religion through history, and, by marshalling summaries of scholarly work, shows how religious ideas developed in response to changing social and political circumstances. The explanations make no appeal to the supernatural. But, as in his other books, Wright sees progress (however haphazard and intermittent) in the moral dimension of religion through time, which leads him to speculate that this phenomenon actually points to the existence of something worthy of being named divine.

The bulk of the book is an interesting run through research findings from anthropology, archaeology and textual analysis on the topic of historical religious ideas and practices. The tour begins with a look at hunter-gatherer style animism and the role of gods and religion in tribal cultures. Religious ideas in these milieus are seen to fit into and lubricate social organization. Then Wright examines the development of the various pantheons of gods in civilizations beginning with Mesopotamia and Egypt: the theme is how religion changed hand in hand with conquests, trade, and internal politics. In all cases there seems to be a plausible explanation of religious ideas (and the lineup of gods acknowledged) changing in concert with the “facts on the ground”.

This sets things up for the larger sections on the Abrahamic traditions. Wright, drawing on scholarly research, looks at the development of the religion of Israel from polytheistic roots, to monolatry (veneration of only one god), to the beginnings of true monotheism. The relationship of the tribe/nation of Israel to its neighbors through episodes of conquest, defeat, vassalship, and exile is seen as the prime driver of these developments. Christianity gets its turn in the barrel, as Wright sets out to show that its incorporation of the ideals of love and ethnic fellowship (and their backward projection onto the figure of Jesus) are best seen as an outgrowth of the mission to the gentiles in the context of a multi-cultural Roman empire. The expression of ideas in the Koran (including the fluctuations from tolerance to intolerance regarding infidels) is likewise tracked to the stages in the earthly career of Muhammad and his followers. (Eastern religions are left mostly undiscussed, but it is a long book as it is*).

The general theme is reinforced throughout: changes in religious ideas track earthly events. As nations make war, their gods intone contempt for non-believers. As empires digest conquests, they co-opt the gods of their new subjects. More positively, as societies enter into non-zero sum relationships with a wider circle of neighbors, their gods become more universal and more supportive of a broader moral vision.

I enjoyed these parts of the book and raced through 400 pages quickly. I found most of conclusions very plausible. I predict that one group of people who will have some problems with this material are the actual scholars who work in these fields: to them Wright’s account will surely seem superficial and far too quick to seize on conclusions which are the subject of significant debate and controversy. I think The Moral Animal could be criticized for confidently presenting plausible-sounding conclusions from evolutionary psychology that look shakier today. In any case, however, Wright has his eyes on the big picture, and the thrust of the ideas here was persuasive to me even if some of the details are in error.

In the last fifty pages of the book Wright presents his own thoughts on what it all means (some of these have of course been broached in previous chapters). Here the terrain became more difficult and I found some of his discussion to be repetitive. But watching him grapple with the ideas was nonetheless thought-provoking. First off (repeating the theme from Nonzero), Wright argues that with the passage of time, humans have expanded their circle of moral consideration, and that this constitutes an arrow of moral progress through history. I think he is on firm ground here: as we include more and more people (first extended family, then tribe, then nation, then international trading partners) in our field of empathy, we can see this properly as progress. However, I think it’s difficult to tie this to the main topic of the book: can we point to the evolution of our ideas regarding gods or God (more loving, less vengeful), and say that this adds anything to the story of moral progress? He does show that religion mirrors the state of play in the moral calculations of nations and peoples. But his analysis doesn’t provide evidence that religion drives moral progress – it seems to mainly reflect it.

In the final section (the Afterword), Wright proposes that the existence of an historical arrow of moral progress might be evidence for an objective moral order which transcends nature. He argues that even if the traditional idea of a personal God seems highly implausible given naturalism, it might nonetheless point (however imperfectly) towards truth. Maybe there is some kind of Logos of divine origin present in the temporal unfolding of human events. He draws an analogy between a traditional religion’s imperfect conception of God and a physicist’s imperfect conception of an electron (it’s not like a particle or a wave or anything else we can picture, yet we know it’s there from its manifestations).

Wright doesn’t commit to a conclusion that God exists, but he clearly wants to embrace the idea that our moral progress points to something transcendent. His arguments for this position aren’t strong, however, consisting as they do of analogies and a repeated appeal that something special must be going on to account for the moral axis of human affairs. I don’t think many traditional materialist-atheists will be convinced.

This is unfortunate because I think his intuition is sound. I think that any naturalist worldview needs to be expansive enough to account for first person experience and the meaning and values which arise from our engagement with the world. A purely third-person materialist description is incomplete. What’s missing from Wright’s argument (and it would take another book, of course) is a convincing metaphysical story of how this all fits together. Specifically, we need to account for how these first-person truths are rooted in the fundamental (pre-biological) fabric of nature -- a main goal of this blog. If we can do this, then we’ll build a foundation for Wright’s further story of how biological natural selection and cultural dynamics have shaped humanity.

Still, I admire Wright’s contribution in these books. And in particular I find his vision of moral progress to be inspiring. As he says, the forces of interconnectedness and globalization in today’s world offer the possibility that we can expand our circle of moral concern to finally cover the planet. As I’ve drafted this review over the past week, millions of people from all corners of the world have been morally identifying with protestors in Iran via the internet. A vision of progress toward a world of peace is right there before us.

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* I should also mention that there is a good appendix which examines the roots of our religious impulses in evolutionary prehistory. He doubts we’ll find a “god gene” but discusses how different aspects of human and primate nature set the stage for religious impulses.

Physics Links and Notes

Here are three interesting things I read recently.

1. Lee Smolin has an article titled “The unique universe” in physicsworld (hat tip: Not Even Wrong). It covers some of the same ground as the video I had earlier posted here. In it he argues against some ideas which have been recently popular among physicists when considering the shape of the next fundamental theory of cosmology. First, many now argue that our universe is just one of a vast or infinite number of others: the multiverse. Also, it is argued that the fundamental theory will be timeless, since they see our experience of the flow of time as an emergent local phenomenon. This leaves us with a vision of a timeless and static multiverse.

Smolin says advocates of this vision are led by mistaken reasoning. One problem arises when physicists take the essentially Newtonian schema we use to evaluate systems within the universe (deterministic laws + initial conditions) and try to apply it to the entire cosmos. This leads them to try to describe a process for selecting our universe from a landscape of many universes (anthropically or otherwise). Smolin argues that we would do better to explore theories which take time to be fundamental, and where laws can vary in a process of cosmic evolution.

2. Many people are optimistic that an information-theoretic perspective will lead to new insights in exploring the foundations of quantum mechanics, and this multi-authored paper, called “A new physical principle: Information Causality”, is an interesting effort in this regard. Information causality is, according to the authors, a principle which helps pick out QM from a space of possible theories which, like QM, feature entangled correlations but allow no faster than light signaling. While the principle seems simple when stated (“communication of m classical bits causes information gain of at most m bits”), the fact that other (hypothetical) theories which feature strong correlations don’t meet it is notable. Hat tip goes to this post by the Quantum Pontiff which has some helpful discussion.

3. I had come across the essay “Free will, undecidability, and the problem of time in quantum gravity” by Rodolfo Gambini, which was submitted to the FQXi contest (see here), but I didn’t immediately catch on to his arguments. But now having reviewed two papers on Arxiv by Gambini and colleagues (here and here) I have a better idea what his program is. The key starting point is this: the mathematics of quantum mechanics treat time as an external infinitely divisible classical variable; Gambini et.al. think that fundamental limitations on the practical measurement of time within the physical world have implications for how we should interpret the problem of quantum measurement. For instance, if we look at decoherence theory, we see that a quantum superposition involving a system, a measuring device and the environment can evolve such that the degrees of freedom responsible for interference are dispersed. But decoherence itself says nothing about a measurement taking place -- the system is still evolving unitarily. Gambini et.al. argue that a point comes where no possible mechanism is available to tell whether or not a measurement outcome (or event) has or has not taken place. They think this undecidability threshold can be seen as the marker for when an event has occurred. (Then, in the essay, Gambini waxes philosophical and speculates that this undecidability between evolution and collapse might create space for free will.) A thread about this in physicsforums is here.

I liked reading Gambini’s papers, but I think the calculations regarding the undecidability point are controversial, given that a full explanation would require a theory of quantum gravity. And if my preferred approach to QG is right -- where time is a fundamental aspect of a pre-gravity microscopic quantum theory, and the particles and space-time geometry of current theories are emergent regularities -- then I suspect that the constraints on describing a physical clock would not arise in the same way as it does here.

5th Blogiversary Post

Thank you to everyone who has visited. I’m extremely grateful to those who have commented: the discussions that have taken place have been very valuable.

(Brief retrospective meta-blogging follows.)

Actually, I “cheated” at the beginning. The first ten posts from June 2004 were drawn from an essay I had previously written and distributed to some friends and family members, which I called (tongue-in-cheek) “Steve’s Guide to Reality”. After a little while, though, the blog started to show some life, becoming more interactive (thanks to Justin and Peter for early comments). While the equilibrium frequency of posting turned out to be pretty low, it has held fairly steady.

I’m happy with the results. In addition to the comment and e-mail dialogues the blog has engendered, it has helped organize and record my thoughts much more effectively than the previous battered-notebook approach. Also, blogging has obviously facilitated taking advantage of the explosion of resources available to read and link to on the internet. I’m indebted to all the scholars, students and fellow laypeople who blog or otherwise post their work online.

Blogging is, then, a valuable tool which is helping me toward a goal: the development of a metaphysical worldview. This has been my number one “hobby” since I was a teenager, and I think I’ve made more progress in these last five years then ever before.

Thanks again.

The Free Will of Fruit Flies

I liked this short essay in Nature by Martin Heisenberg on free will (HT). Heisenberg is a neurobiologist (and the son of Werner), and his perspective is shaped by the work he’s done on more primitive organisms – in the essay he talks about bacteria and also the fruit flies (the famous drosophilia) which have been the subject of his own work. In short, the combination of microscopic randomness (ultimately sourced from the quantum realm) and an adaptive self-directedness (primitive intentionality -- see also here) comprise freedom.

In the human case, the discussion is obscured by the focus on the will found via introspective self-consciousness and its relation to our actions. But introspection is an extreme latecomer in evolution. Heisenberg suggests we have a kind of real freedom, shared with many other organisms, irrespective of whether our introspective picture is accurate or flawed. He says: “I maintain that we need not be conscious of our decision-making to be free. What matters is that our actions are self-generated…Why should an action become free from one moment to the next simply because we reflect upon it?”

John P. Meier: A Marginal Jew Volume 4

While it's off the main topic of the blog, I've long been interested in research into the history of early Christianity, and have a few posts in the archives on books and articles I've read. I have a series of posts about the first three volumes of A Marginal Jew -- John P. Meier's opus on the historical Jesus (here, here, and here). Now the fourth volume is out, and I'm unlikely to get to it for some time. It happens there is a great summary and review at Loren Rossen's blog, the busybody; so I will happily outsource the work this time.

On a related topic, April DeConick has an interesting series of posts on the beginnings of Christianity going at her blog (first post in series here). I had a post reviewing her book on the Gospel of Judas here.

Fine Idea on the Measurement Problem

Following up on the topic of the last post, I found this paper by Arthur Fine, called “Measurement and Quantum Silence”. I found it to be a clearly written summary of Fine’s approach to the quantum measurement problem (which was I was introduced to by the work of Mauricio Suárez.)

The term “quantum silence” refers to the Copenhagen interpretation-motivated suggestion that we just shouldn’t ask about the reality of the quantum system in superposition: there is no need “to talk about the value of an observable unless the state of the system is an eigenstate, or a mixture of eigenstates, of the observable in question.” We prepare a quantum system and calculate that its pure state evolves according to the Schrödinger equation. The problem is that when we measure the system it behaves “as if” what was evolving was only a mixture of the eigenstates of the particular observable we’re measuring. Fine introduces an interesting perspective on this, which is that the measurement process involves an information loss. It certainly seems that the rest of the information contained in the evolving pure state vanishes or becomes irrelevant when a measurement takes place.

Fine reviews other proposals (hidden variable and GRW-type collapse theories) and assesses how they deal with this loss of information, and he finds that while they try to replace the “brute” measurement process with a physical process meant to be more explicable, they don’t really explain the loss of information. And perhaps this can’t be done.

So, Fine makes his own proposal, which I described in the last post (although in this particular paper Fine doesn’t label the idea as “selective interactions”). Since the system behaves “as if” it was an evolving mixture rather than a pure state, why not assumes that it actually what happens. Rather than look to explain the loss of information which takes place in a measurement “farther down the line”, he proposes that the preparation actually replaces the full state with the mixture in advance.

Here’s how he motivates the idea: “There is a physical rationale for this procedure. It is that in making a measurement we do not interact with all the variables of the measured object. We only observe the particular aspect of the object that corresponds to the variable being measured….” The information that is lost pertains to aspects of the object to which the measuring device does not respond. The “aspects” here are what Suarez adopts as “propensities” in his work.

So, what to think? Well, in a nice aside in this paper, Fine credits philosopher of science Heinz Post* for suggesting a “conservation law” for problems in quantum theory: if you resolve on aspect of quantum strangeness, this tends to just shift it elsewhere. In Fine’s case, he addresses the puzzle of the measurement process with an account which says that the way we prepare a system alters the system from a pure state to a mixture prior to evolution. It’s an interesting idea and the pursuit of it offers additional illumination of the landscape of quantum mechanics. But in my case I’m happy to have collapse as an additional natural process which describes physical interactions between systems – I don’t feel a need to shift the strangeness in the way Fine suggests. And I don't think interpreting quantum systems as bearers of propensities turns on whether you adopt Fine's proposal.

*I would provide a link for mentioning Heinz Post, but very little comes up in an internet search. He was a professor at Chelsea College (which later merged into King's College, London). You get the impression he was an influential colleage and mentor, but published hardly at all.

Suárez on Quantum Propensities

Interpreting dispositional or power properties as propensities seems to me to be a very promising avenue for ontology. This is because theories employing powers (the ones I’ve seen) don’t get the modal structure of the world correct: by assuming that powers entail their manifestations, they fail to provide truthmakers for possibilities. Taking powers to be probabilistically manifested propensities solves this problem. It also bolsters a realist account of causality: actualizing propensities into specific outcomes gives causation some “real work” to do.

Finally, propensities can serve as a link between a philosopher’s ontology and the interpretation of quantum mechanics.* I was happy to find recently (via Philpapers) that propensities have a champion in Mauricio Suárez, a philosopher of science at Complutense University of Madrid. In several papers he has explored and advocated the propensity approach to understanding the properties of quantum systems. He also has pointed out the value of propensities to the dispositional/power property approach to ontology.

Popper and propensities

Propensity theory seems to be a relatively neglected topic these days. The work of Karl Popper may be one reason for this. Given Popper’s stature, the fact that his propensity interpretation of probability is widely regarded as a failure is discouraging. But Suárez makes a strong case that the problems with Popper’s theory are the result of his emphasis on interpreting quantum probabilities specifically, and also due to some particular assumptions which can be set aside or modified.

Popper wanted to interpret quantum probabilities using propensities, and he also thought propensities could be used to interpret probability in an objective manner generally. This effort has been roundly criticized. An important criticism is that known as Humphreys' paradox (after Paul Humphreys, see this paper). Humphrey pointed out that the asymmetric causal nature of propensities made them inconsistent with the symmetric character of conditional probability. But this paradox is only a problem for propensity interpretations of probability. When it comes to quantum theory, Suárez makes a wise point when he says that what we want to do is interpret quantum mechanics, not quantum probabilities. The probabilities observed in experiments would be explained by our account of quantum mechanics. This “clicked” for me: in my own reading of papers on interpreting quantum probability, I had found that the arguments tended to point toward subjective or Bayesian interpretations (see posts here and here), but this work didn’t seem to help one progress toward a satisfactory ontological interpretation of the physics. Perhaps it is better to interpret the ontology first.

With regard to some of Popper’s other assumptions about the nature of quantum propensities, Suárez explains in the paper “On Quantum Propensities: Two Arguments Revisited” how two other criticisms of Popper’s view may be avoided by a revised account of propensities – specifically Suárez’ ”selective propensities” proposal.

Selective Propensities

In addition to the paper mentioned above, Suárez has two other papers which discuss his selective propensities approach. In “Quantum Propensities”, he looks at some other historical attempts to employ propensities to interpret QM, and then contrasts his own proposal. 2004’s “Quantum Selections, Propensities, and the Problem of Measurement” develops the approach in the most detail, showing how it builds on Arthur Fine’s “selective interactions” solution to the quantum measurement problem.

Suárez’ approach is new to me and I’m still trying to understand it (I had not been exposed to Fine’s work before either). It seems that in the selective propensity interpretation, a quantum system possesses a number of dispositional properties coinciding with the observables we measure in experiments involving particles. These properties manifest themselves consistent with the probability distributions we observe in QM. We assert that in a measurement one interacts only with the property of the system selected. The interpretation then says that to explain the result, we can employ a mixed state of that property’s eigenstates to describe the initial preparation, rather than plugging in the full quantum state of the system. (The full quantum state encompasses all of the system’s properties.) We can still interpret the interference effects which result in some experimental setups as due to the interplay among the system’s various properties consistent with the full state superposition of the system.

This seems to imply that the description of the initial state of the system (setting up either a mixed state over one observable or the full state) is altered by how we set up the experiment. This seems strange at first glance, but I guess there’s always going to be something strange when you’re working with QM. I also wonder how to think about generalizing this scheme to understand how interactions work beyond the laboratory setting.

I’ll try follow up with more after re-reading and digesting this material further.
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* I’ve often thought about the issues involved when philosophers try to make sure their metaphysical ideas comport with physical theories. On the one hand, philosophers very much want to avoid proposals which seem to conflict with science. On the other hand, since our physical theories are provisional (and likely to be replaced in time by improved theories), perhaps philosophers shouldn’t worry if well-motivated ideas imply revision to current scientific understanding. I’ve seen relativity theory invoked to criticize philosophical positions (e.g. presentism in the discussion of time – see an abstract of what looks like an interesting paper here), but many recent research programs in quantum gravity explore the idea that relativity is an effective (low-energy regime) theory rather than something fundamental. The search for a theory of quantum gravity implies relativity, quantum mechanics or both will need to be revised.

So, while I personally want my metaphysical theory to accommodate quantum mechanics (and worry less about conflicts with relativity), I realize that this is tricky territory. It seems best to just be explicit about one’s presumptions.

GPPC 2009 Public Issues Forum

This annual Greater Philadelphia Philosophy Consortium event is coming this Saturday afternoon April 25th, hosted at Drexel University. The topic this time is Just War Theory.

The three speakers:
Larry May (Washington University) on "Collective Responsibility in Warfare"
Robert D. Sloane (Boston University School of Law) on "The Cost of Conflation: The Dualism of Jus ad Bellum and Jus in Bello in the Contemporary Law of War"
Peter Tramel (U.S. Military Academy at West Point) on "Conscientious Objection and Volunteer Military Service"
Chair: Anil Kalhan (Earle Mack School of Law at Drexel)

April 25, 2009 1:00-5:00 pm Room 140 Earle Mack Law School, 3320 Market St., Drexel University, University City Campus, Philadelphia (Directions).
(Reception to follow).

Revisiting Actualism

Modal truths regarding possibilities and necessities need truthmakers, as much as anything does. If we conclude that our actual world cannot provide these truthmakers, this implies that reality must outstrip the actual: modal realism is the thesis that we must include possibilities in our reckoning of what exists. Actualism is the name for stances which would limit reality to the actual, and yet try to find adequate ground for modal truths.

This post is repetitive of previous ones (prior posts detailing my readings and evolving views on modal truthmaking are listed below), but I continue to think about this a lot, and recently read some new papers by philosophers on the topic. It struck me that there is something insightful about the insistence of some actualists on grounding modality in the features of the actual world.

Hardcore Actualism

These papers reminded me that in addition to the dispute between modal realists and actualists, another dividing line involves the use of worlds as truthmakers. Most often, modal realism is associated with the use of concrete possible worlds as truthmakers (as proposed by David Lewis). However, some actualist accounts make use of worlds as well, but propose that they still be considered part of the actual world, treating them as abstract or fictional, etc. (What makes this a bit confusing is that a model using abstract worlds could also be considered modal realism if the worlds truly transcended our own – existing platonically rather than as sets of propositions or “world-stories” or whatnot).

Actualism which rejects worlds of any sort is referred to as “hardcore” actualism in this paper by Gabriele Contessa. He favors this approach, as does Jonathan D. Jacobs in this paper. Jacobs explicitly endorses a power-property based approach to grounding modal truths.

A motivation for hard-core actualism is that our intuitions tell us that possibilities are grounded in the properties or causal powers of actual things. This is especially true if we consider the local, everyday, possibilities of life. I could have gone for a run this morning (although I didn’t). I know this is true because I have the natural capacities needed to do so, and in fact, it is something I often do. Why do I need to postulate something as extravagant and disconnected as a possible world (at which my counterpart did run) to provide a truthmaker for this homely fact?

Power-properties as truthmakers?

Jacobs makes reference to a number of philosophers who favor an approach which grounds modal truths in properties of actual things (one is Alexander Pruss, whose work I had commented on once here). There are two problems with these that I see. The first critique often raised is that these accounts seem ill-equipped to deal with more distant, but still intuitive possibilities. It seems possible that our universe might not have existed at all – what properties of the “actual world” could ground this possibility? I will leave this problem aside for now, because I think it might be addressable if we had an answer for a more pressing second problem. This is the fact that the power-property accounts I have seen to-date, while differing in their ontological set up, treat the powers (or dispositions) as entailing their manifestations. The entailment relation seems to assure (to my reading) that given two instances of precisely identical power-property complexes, the same manifestation would occur (I discussed this previously in the context of George Molnar’s work here).

So while the theory asserts that the powers could ground possibilities, in fact I don’t see that they really do the job. In my example, it appears my natural powers ground the possibility that I could have gone for a run, but the relation between power and manifestation in these theories doesn’t seem to explicitly account for the indeterminism involved here: if we somehow could “rewind the tape” and replay the events of this morning, what aspect of the ontology accounts for the fact that the manifested outcome REALLY could have been different?

Propensities at Work?

I have thought (with quantum mechanics in the back of my mind as usual) that instead of powers entailing their manifestations, the properties involved should be seen as propensities: causal powers with truly probabilistic rather than entailed outcomes. The set of unactualized possible outcomes, in this case, are real – they are rooted (and constrained) by prior actuality, but are not just theoretical entities. If this is right, then we’re not, strictly speaking, talking about actualism, anymore, of course, but a species of modal realism. However, at least the hard core actualist might be pleased that we’re not creating entire worlds out of whole cloth. Possibilities are manifestations -- I see them as events or event complexes -- they are not worlds.

What about possible worlds semantics?

Jacobs is so disenchanted with possible worlds as truthmakers, however their reality is conceived, that he wants to develop a replacement for the traditional modal semantics which utilizes worlds, and sets out on a path toward constructing an alternative. Fortunately, a good thing about my idea, I think, is that we can have a firmer basis for rationally constructing abstract worlds based on our acquaintance with these real local possibilities. Basically, we utilize the “replaying the tape” notion and utilize what we know about how probabilistic causation works in the actual world to construct alternatives for how the world could have been different. (This kind of approach was discussed by philosophy student Damon Woolsey in his modal realism papers – see here; also, Richard Chappell used the rewind/playback metaphor in a paper here). The further back you take this rewinding, the more distant possibilities you can envision. Note that counterparts are a bit different in this scheme – it seems either I’m in a world or I’m not given how they are constructed.

Can the set of these sorts of “worlds” ground the truth that our actual world might not have existed at all? Maybe – if you allow me to conceive of an initial probabilistic event which turned out to be the first seeding of our universe, but which was in no way guaranteed.
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A Bloggy Exploration of Modal Truthmaking and Modal Realism
(in chronological order)

Whole Lotta Worlds
Notes on reading David Lewis’ On the Plurality of Worlds

Armstrong on Modality
About my inability to find modal truthmakers in D.M. Armstrong’s book Truth and Truthmakers

The World is Not Enough
On Actualism and Modal Fictionalism

Notes on Plantinga’s Modal Realism
A self-explanatory post title!

Local vs. Global Possibility and the Link to Causality
Alexander Pruss’ Aristotelian approach

Modal Realism, Modal Rationalism
Musing on how we know about modal truths

Modal Tenses
Parallels between modal and temporal metaphysics

Woolsey’s Modal Realism
An intriguing paper by Damon Woolsey found on the internets

Modal Problems with the Theory of Powers
Critique of powers as modal truthmakers in George Molnar’s theory

Actual as Indexical, After All?
Multiverses – Physical and Metaphysical
2 posts with more of my own musings

Points of View are Irreducible

I’m an admirer of the relational interpretation of quantum mechanics (RQM), due originally to Carlo Rovelli. The revised SEP entry on RQM by Federico Laudisa and Rovelli made reference to two new papers about RQM by philosophers of science Bas C. Van Fraasen and Michel Bitbol. Unfortunately, Van Fraasen’s paper is not yet published, and Bitbol’s paper (entitled “Physical Relations or Functional Relations?”) is in French. However, in the course of looking for this, I found another interesting paper by Bitbol in English, which was published in a journal called NeuroQuantology: “Consciousness, Situations, and the Measurement Problem of Quantum Mechanics.”

In this paper, Bitbol looks at the history of discussions about the putative role of consciousness in the measurement process. He concludes that it is a mistake to think that human minds need have anything special to do with the measurement process; but a careful analysis reveals that QM does necessitate at a minimum taking into account particular viewpoints. His analysis places Bitbol in the same general camp as RQM and also the “Perspectivist” interpretation I described in these posts which referenced Paul Merriam’s papers.

The bulk of Bitbol’s paper is his careful presentation of a thought experiment which shows the difference between classical and quantum physics as it relates to the role of the observer in a measurement. (This exposition is similar to the thought experiment known as “Wigner’s friend” -- see Henry Stapp's discussion in this doc file). Wave functions characterize the observables of a system relative to interaction with another particular system –- in fact we can characterize a whole chain of interactions via a wave function -- until the chain comes to the end with our observation. But, Bitbol says the following:

"I am not saying that WE are unique or privileged beings in nature (this would be collective solipsism of an absurd sort), but only that we are privileged beings for US! As soon as we establish a relation with an element of the measurement chain, this element acquires a determination relative to US. Nothing has thus to be changed in the physical description, since determinations of the measurement chain are still relative to something. But everything is different for US, since the determinations of the measurement chain are now relative to US. And a relation of which WE are one term is something quite peculiar, even if it is only peculiar…from OUR point of view."

As he says, in classical physics, the fact that we are situated subjects with a point of view can be “bracketed”, and we can view ourselves as just another object. In quantum mechanics, this “situatedness” is irreducible. This doesn’t mean we can’t naturalize ourselves in picturing the world - we don’t need to think human consciousness is something distinct from the rest of nature. But QM teaches us that this process of naturalization has a boundary – points of view cannot be reduced or eliminated from the picture.

Quantum Computing and Mind Simulation

At the end of a recent discussion (in the comments to this post), Allen and I started to discuss whether quantum computing theory had something to say about the potential for simulating the human mind on a computer. I then read a couple of review articles on quantum computing he referenced. Before getting to what I learned (below), I wanted to explain my prior philosophical view on the simulation question.

The Russellian Stance, Functionalism, and Simulation

I endorse a form of the Russellian approach to solving the hard problem of consciousness. Russell described the world as a causal network of events, and he noted that physical theory only describes the extrinsic or dispositional nature of these events. These events also have an intrinsic nature which ultimately grounds the qualitative and experiential character of consciousness. I think quantum mechanics provides support for this view: quantum measurements seem to fit perfectly into this Russellian picture as the base-level events which ultimately underpin both the physical and experiential facts.

Functionalism is the thesis that the mind can be described as an abstract causal system. As a practical matter, the functionalist’s description is taken at a coarse-grained level – i.e. there is some minimal scale below which the actual physical details of the brain/body system are assumed to be irrelevant to its function. It follows that such a functional model could be realized in any number of physical ways, including via computer. Computationalism is the variety of functionalism which pursues the computer modeling approach.

Now, I think the Russellian stance on functionalism and the potential for simulation is nuanced. On the one hand, functionalism is seen as misguided because it only considers extrinsic causal structure. On the other hand, unlike an old fashioned dualist, the Russellian shouldn’t rule out the possibility that the mind could be simulated. The mind, after all, is a product of a natural system – we don’t need extra immaterial stuff to explain it. Perhaps a simulation can get the functional structure right and the correct intrinsic experiential character will come along “for free.”

The problems come with the coarse-graining. In every functionalist account I’ve seen, this takes place at a scale where quantum mechanics is assumed to be safely irrelevant. But every process in the body ultimately is grounded in molecular, atomic and sub-atomic activity which must be described quantum mechanically. So, a coarse-grained, approximated simulation of the brain/body’s causal structure on some physical device would likely miss crucial details which lie at the quantum level (details I think simultaneously crucial to both extrinsic function and conscious experience)

How would a functionalist respond to the quantum question? First, many believe distinctive quantum phenomena effectively “wash out” in a macroscopic system like the human brain/body. This belief is often based on the presumed impact of environmental decoherence. I’m not going to pursue this issue in this post (I discuss this in some of my posts on quantum biology). Another response to the quantum question is an appeal to a commonly believed thesis that any physical system (including a quantum system) can be modeled by a classical computer -- so the traditional functionalist/computationalist approach wouldn’t be missing anything distinctive anyway. This is the view that I wanted to explore by reading up on quantum computing theory.

[Please note the discussion that follows may suffer even more than usual from by my ignorance of the subject matter.]

Simulation and the Church-Turing thesis

So, is it true that any physical system, including a quantum system, can be simulated by a classical computer? Well, this idea has been defended by appeals to versions of the Church-Turing thesis. The original Church-Turing thesis states (in a formulation from this article) that any effectively calculable function can be computed using a Turing machine. (For a description of a Turing machine, see here.) Now it seems that what this thesis really meant can probably only be appreciated by studying its original logical/mathematical context. In his SEP article on the C-T thesis, Jack Copeland first traces the development of the ideas associated with the thesis in the pioneering work on calculation and computing by Turing, Church and others beginning in the 1930’s. Then, Copeland spends much of the rest of the article objecting to how the thesis has been misunderstood and misused by philosophers and computing theorists. The C-T thesis did not purport to say that all physical systems, or even all machines regardless of architecture, could be simulated by a Turing machine. It certainly did not prove anything of the sort. (This discussion reminded me of similar debates over the philosophical applicability of Gödel’s incompleteness theorems beyond their original context – see old posts here and here.)

Nevertheless, as long as one is careful not to inappropriately invoke the authority of the original C-T thesis, one can explore more expansive versions and try to evaluate their validity.

Physical Versions of the C-T thesis

In her review article on Quantum Computing, Dorit Aharonov presents two versions of the thesis. First, (p.3), she presents a simple “physical” version: “A Turing machine can compute any function computable by a reasonable physical device.” She says this is something which cannot be proven, but that no known counterexamples exist. In particular, quantum computers are not believed capable of computing functions non-computable by a Turing machine.

She quickly then notes that: “However, in the theory of computation, we are interested not only in the question of which functions can be computed, but mainly in the cost of computing these functions.” [Emphasis original] The way this is evaluated is by noting whether the computational resources needed rise as a polynomial or an exponential function of input size. It is the former which form the set of tractable computations.

After also discussing the superior efficiency of a probabilistic version of the Turing machine, she presents another thesis to consider (p.4): “The modern Church thesis: A probabilistic Turing machine can simulate any reasonable physical device in polynomial cost.” We have a great deal of evidence, though not proof, that this thesis is contradicted by quantum computers.

The Advantages of Quantum Algorithms

Aharonov explains first, that quantum computers can simulate classical computers, at little loss in efficiency. On the flip side, it appears classical computers can simulate quantum computers but only at exponential cost. What we really want, though, is a positive demonstration of how far quantum computers can outperform their classical counterparts.

The a priori expectation might be that the ability to manipulate qubits, which can be in a superposition of states as opposed to just to two states, would lead to great increases in computing power. Because of the necessity for conducting a measurement to extract results (collapsing superpositions), however, the power of this idea is muted. Other, more subtle sources of limitations on quantum computing are discussed later in the paper.

Despite this, however, many investigations into quantum computing over the years have found quantum algorithms which improve efficiency. One of these algorithms, Shor’s, gives a polynomial algorithm for factoring integers where all known classical algorithms have exponential cost, thus crossing the crucial boundary. It must be pointed out that as of yet there is no proof that a classical polynomial algorithm for factoring is impossible.

Conclusions

Most of what I’ve discussed in Aharonov’s article above comes from the introduction. In the ensuing 60 pages she goes into more detail about the nature of computers and computing, various models for quantum computing algorithms, the issues of noise correction and fault tolerance, and some of her own ideas of what quantum computing theory says about the boundary between quantum and classical regimes in physics.

On the key question of what quantum computers can do better than classical ones, one is left with the impression that the question is much more subtle than might first be imagined. We have some exciting theoretical results, but perhaps fewer than might have been anticipated on a naïve expectation. At the same time, it seems we’re still in the early phase of growth in our knowledge of the field. A lot of interesting work and new developments lie ahead. (The engineering efforts underway toward building quantum computers and the challenges they face is another interesting topic).

Let me return to the question about what all this might mean for the philosophy of mind, assuming (as I do) that the quantum level grounding of biology contributes meaningfully to the mind’s function. I think a modest conclusion is called for. The fact that a classical computer can simulate a quantum computer only at an exponential cost suggests that the project of simulating a human mind is impractical, though not blocked in principle. This conclusion is broadly consistent with my philosophical stance regarding the simulation project.

[P.S: after drafting this I recalled there was a good debate (thanks to Tanasije and Mike) on the simulation topic in the comments to this May 2008 post on Russellian theory. My memory is awful.]

John Heil Gets Very Close…

…to solving the mind/body problem.

John Heil’s 2003 book From an Ontological Point of View consists of roughly three components. The first part is a thoroughgoing critique of analytic philosophy based on the central role it gives to language. The second part is his positive ontological account: this is centered on his theory of power-properties. The third section discusses the application of his ontology to philosophical problems, notably the mind/body problem.

Being a blogger, I’m only going to discuss one aspect of how his account of properties (as part of a substance/property ontology) gives him a leg up on solving the mind/body problem, although I think he ultimately falls short of the goal. For an appreciation of his overall approach to philosophy, see this paper by Ross Cameron and Elizabeth Barnes. A Notre Dame book review penned by Gary S. Rosenkrantz is here. (There is also a whole volume of collected responses to the book available -- I have not read this).

Powers and Qualities

For Heil, properties are powers (or dispositions). Properties are distinguished by their contribution to the causal powers of their possessors. There are many potential advantages for this approach in constructing a realist account of ontology and causation. One advantage as it relates to philosophy of mind is that the ubiquity of powers offers a natural home for intentionality in the world. Powers have an “aboutness” – they are always directed towards their manifestations (I discussed this at greater length in my posts on George Molnar’s powers ontology).

But the biggest innovation in Heil’s account compared to other treatments of power properties is his treatment of qualities. Qualitative properties are usually considered to be separate from dispositions. They are often identified with the so-called categorical properties of objects. Heil proposes that qualities and powers are the same thing. He calls this the identity theory: “If P is an intrinsic property of an object, P is simultaneously dispositional and qualitative… (p.111 – page references are to the paperback edition)” Furthermore, this is not to be seen as a dual aspect theory: P’s nature is truly and simultaneously dispositional and qualitative. (Heil gives credit to the late philosopher C.B.Martin for this idea).

Heil’s defense of this identity theory was persuasive, in my opinion. He starts by giving some homely examples (size, shape, color) of how objects can be seen as having effects by virtue of their qualities. He then notes that while physics is silent on the subject of qualities, this in no way contradicts the identity theory. If middle level objects have qualities, it makes sense that their constituents do as well. (Heil strongly objects to ontological accounts which feature distinct “levels” of reality).

Qualities in the Brain

Turning to the mind/body problem, we can see that if properties which are both dispositional and qualitative make up the world then there is no special problem with the fact that conscious experience seems to possess qualities. Still, Heil wonders, could it be that these qualities are just qualities of, say, neurological activity? He notes that the qualities we should focus on in considering this question are not the simply representational qualities of experience, but the “diaphanous” qualities associated with having an experience. The qualities of experience outstrip their representational qualities, and these residual qualities are key to the question.

P.229: “The what-it-is-likeness of conscious experience stems from the nature of the representational medium…” as well as what is being represented. Heil makes use of a thought experiment based on an actual apparatus developed for the blind whereby a camera impresses images via pressure on the skin of the back or chest. After a while, the subject using such a device mostly forgets the nature of its implementation and just processes the images. But certainly the residual, non-representational experiential qualities are different between vision and this touch-analogue of vision.

So, do these “what-it’s-like” qualities differ from material qualities, or can we say that they are no different? Can we locate them in the brain? Well, Heil asks, why not? Perhaps these qualities are just are neurological qualities.

What about the First-Person Aspect?

The remaining question relates to the different way we are acquainted with these putative neurological qualities. P.234: “…we do seem to have something like ‘direct acquaintance’ with neurological qualities.” This means there still is a distinction here between the what-it’s-like qualities and other material qualities. Heil gives us an account that deals well with the qualitative character of experience -- after all qualities are ubiquitous in the world. But what about the subjective character of experience (my term)?

One might ask: is this subjective character also ubiquitous? Alas, Heil doesn’t want to take that leap. After all: “You might be worried that a conception of this kind leads to panpsychism or worse. (p.234)” Heil wants to maintain that all of the qualities of experience are perfectly ordinary qualities of brains. He concedes that it remains to be understood how this could be the case. But he hopes we’ll know more in the future as we learn more about neuroscience.

There’s one additional passage where Heil ponders this issue of the subjective character of experience (pp.237-9). He discusses the privacy of mental states, and acknowledges the difference between being in a state and observing the state. But he objects to treating this as indicating an ontological divide between subjective and objective properties. Conscious people are, after “objective” in the sense of being natural entities in the world. But again: “What, then, distinguishes conscious states from those that are not conscious? (p.239)” Could it be that there is a different functional role? This can’t be an explanatory strategy for Heil, since causal and qualitative roles are constituted hand-in-hand. I give Heil credit for raising the issue, but for him the privacy/subjectivity issue remains unexplained.

What about Zombies?

In his Chapter 20 (pp.240-249), Heil looks at the conceivability, or “zombie” argument against materialism. The bottom line is that zombies are not conceivable given Heil’s ontology: “The zombie possibility arises only against a particular ontological background, one according to which powers and qualities are only contingently related. (p.248)” Heil is right -- IF you define the zombie problem as being about qualia, rather than being also concerned with the subjective character of experience. As an aside, this is why I personally don’t use the term qualia when discussing the mind/body problem: first-person experience possesses both qualitative character and subjective character – discussions of qualia often ignore the latter issue (on this point see also a quote from philosopher Uriah Kriegel in this old post).

Conclusion

So, Heil comes close to solving the mind/body problem. By virtue of an ontology which places qualities in the world, the qualitative character of conscious experience is accounted for. The other dimension to experience, its subjective character, is left without an account. I think the only way to address this is to place subjective points of view into the natural world as well.

PS: My thanks go to Gualtiero Piccinini of the blog brains for his post on C.B.Martin, also suggesting Heil as a route to helping to understand Martin. This prompted me to read the Heil book, which I had been meaning to do. Martin's book is in the queue.

Montero on Russellian Physicalism

There is a lot of interesting material at the Consciousness Online conference currently underway. One paper I enjoyed reading was Barbara Montero’s entry on the Russellian theory of mind: “Russellian Physicalism”. In addition to Montero’s paper and powerpoint slides, there are links to responses by Emmett Holman and Daniel Stoljar, who have both also written on this topic in the past (see my old posts here and here).

Montero reminds us that the Russellian approach is a non-dualistic strategy for dissolving the conceivability argument against physicalism/materialism (most famously depicted as the “zombie” argument). David Chalmers' most recent paper updating the conceivability argument had as its conclusion: “materialism is false or Russellian monism is true.”

Russellian monism argues (roughly) that our knowledge of the physical world is only of its extrinsic or dispositional (causal) aspects. Physical entities also have intrinsic or categorical aspects. These hidden aspects are those responsible for consciousness. When we try to conceive of zombies, we fail because we are not conceiving of all relevant aspects of the physical world.

Montero’s paper focuses on the fact that while Russellian monism can be interpreted as a form of panpsychism (the intrinsic aspects are in some fashion mental or experiential in nature), it can also be cast as a variety of physicalism (where the intrinsic aspects are not to be seen as themselves mental).

I'll note parenthetically that both versions face further challenges. In the case of the physicalist version, it can be argued that the explanatory gap between the mental and the physical still isn’t bridged (even though the formal conceivability argument is defeated). In the panpsychist version, we arguably address the gap, but we are left with the “combination” problem: how do micro-phenomenal entities or properties combine to form macroscopic minds like ours?

The responses by Stoljar and Holman and further discussion in the comments mostly revolve around thorny issues of terminology. What do we mean by “physical”, “mental” etc. as it relates to these hidden intrinsic aspects of nature? I tend to like the approach Stoljar took in his book (finally out in paperback), where he threw out these terms and used experiential and non-experiential. Holman proposes using “subjective unity” as the key feature to distinguish things.

I enjoyed the discussion (which continues in the comments), and I hope that philosophers of mind continue to focus on this topic.

Postscript: I have a general quibble, which is that I think this all becomes clearer if you go back and read Bertrand Russell himself (Montero, taking Chalmers as her starting point, includes just one short quote from Russell). Russell’s approach, beginning in his Analysis of Matter, is distinctive for his careful critique of physical theorizing and for his use of a causal event ontology. Russell reminds us that physical theory consists of describing a causal structure connecting the experiential events which occur when we conduct empirical research. The physicists create mathematical models to allow them to generalize and extrapolate to describe events beyond our direct experience. He then argues that it is a philosophical mistake to ascribe reality to the mathematical models themselves (what Whitehead called the “fallacy of misplaced concreteness”). The causally connected events are the reality. We have no good reason to think the “physical” events which we infer have a different character from the events we experience directly. At a minimum we can be confident that an event is ontologically more than just a point in a mathematical model. Whether we think all events are experiential (leading to panpsychism) or not is something for further debate. Russell himself took the conservative option here, and was reluctant to posit panpsychism, while his former collaborator Whitehead went ahead and took the panpsychist step in formulating his process metaphysics (see also my post on Carey Carlson’s book on Russell and Whitehead).