Thursday, January 28, 2021

Why I Favor Relational Quantum Mechanics

I think Relational Quantum Mechanics (RQM), initially proposed by Carlo Rovelli, is the best interpretation of quantum mechanics.1 It is important to note right away, however, that I depart from Rovelli’s thinking in one important respect. He takes an anti-realist view of the wave function (or quantum state). As I will discuss below, I endorse a view that sees the wave function as representing something real (even if imperfectly and incompletely).

There are two reasons I prefer RQM. First, I think it makes better sense of QM as a successful scientific endeavor compared to other interpretations. Second, it fits neatly with an attractive ontology for our world.

Quick Introduction

Orthodox or “textbook” QM features a closely knit family of mathematical models and recipes for their use. The models describe the state of a microscopic system characterized by certain physical quantities (typically given in the form of a wave function). It gives a formula for calculating how the system evolves in time (the Schrödinger equation). Notably, because of the nature of the mathematical formalism, one typically cannot ascribe definite values to the physical quantities of interest. However, QM also offers a procedure for calculating (probabilistically) the outcomes of particular measurements of these quantities. The problem with taking orthodox QM as a universally applicable physical theory can be described in several ways (this is usually called the measurement problem). One simple way is to note an inconsistency arising from the presence of what appears to be two completely different kinds of interaction.

In the absence of any interaction, a system evolves in time as described by the Schrödinger equation. But interactions are handled in two different ways. On the one hand, we have the measurement process (utilizing the Born rule), that is, an interaction between the quantum system under investigation and a scientist’s experimental apparatus. On the other hand, we can also describe an interaction between two systems that are not subject to measurement. In the first kind of interaction, a definite value of a system’s physical quantity is found (we say the wave function of the system collapses). In the second kind of interaction, we represent two (or more) systems, previously considered isolated, as now correlated in a composite system (we say they become entangled). This system evolves in the same fashion as any isolated system. And as such the composite system may be in a superposition of states where no definite values for a given quantity can be ascribed.

In a nutshell, the RQM solution is to stipulate that a physical interaction is a measurement-style event. However, this is only true for those systems directly involved: the systems are merely entangled from the standpoint of other “third-party” systems. The appearance of two sorts of interaction arises from a difference in perspective. This is weird, of course, since particular values of the physical quantities revealed in an interaction are manifest only relative to the interaction partner(s) involved. They don’t exist in a fully objective way. All interpretations of QM ask us to accept something unintuitive or revisionary. This is the “ask” made by RQM.

Reason One: RQM Validates Quantum Theory as Successful Science

Before discussing the interpretation further, I can quickly outline a reason to prefer RQM to many competing approaches. This point is primarily a negative one. In contrast to other approaches, RQM is an interpretation that delivers a satisfying account of QM as a successful scientific theory: one that draws appropriate connections between the results of our experimental investigations and a meaningful picture of the world around us.

I obviously won’t be doing a deep dive into all the options, but will quickly sketch why I think RQM is superior. First, for a quick cut in the number of alternatives, I eliminate views that are merely pragmatic, or see QM as only describing what agents experience, believe, or know. I insist that alongside its other aims (such as prediction and practical control), a scientific theory should contribute to our understanding of nature. To do so, the theory should offer successful explanations of worldly phenomena, that is, ones that tell us (broadly speaking) what kind of things are out there and how they hang together. This means, in turn, that at least some of the elements of the mathematical models that we use should represent features of the world (allowing that the fidelity of any given representation is significantly constrained by reasons having to do with the aims of the scientist and the tools employed). I will outline in the next section of this post how I think this works in the case of RQM.

As for the remaining alternatives, I will limit the conversation to the three most prominent broadly realist approaches to thinking about QM: Everett-style interpretations, Bohmian mechanics, and objective collapse approaches, such as Ghirardi-Rimini-Weber (GRW) theory (the implied ontology of these approaches might be fleshed out in more than one way, but I will not pursue the details here.)

For these alternatives, a different issue rises to the fore. An interpretation should not just consider how the features of formal QM models might correspond to reality. It should also respect the status of quantum theory as a hugely successful experimental science. Orthodox or “textbook” QM includes not just the mathematical formalism, but also the recipes for how it is used by investigators and how it connects to our experiences in the laboratory. And here is where I think Everettians and Bohmians in particular fall short.

Note first that all three of the alternative approaches depart from orthodox QM by adding to, subtracting from, or modifying its basic elements.2 GRW changes things by replacing the Schrödinger equation with a new formula that attempts to encompass both continuous evolution and the apparent collapse onto particular outcomes observed in measurement. Bohmian mechanics adds new elements to the picture by associating the quantum state with a configuration of particles in 3D space and adding a new guidance equation for them. Everettian approaches just drop the measurement process and seek to reinterpret what is going on without it.

For the Everett framework in particular, I’m not sure the extent of its departure from orthodox QM is always appreciated. It is sometimes claimed to be the simplest version of QM. This is since it works by simply removing what is often seen as a problematic element of the theory. But in doing so it divorces QM from its basis in experimental practice. This is a drastic departure indeed.

To see this, note that to endorse Everett is to conclude that the very experiments that prompted the development of QM and have repeatedly corroborated it over nearly a century are illusory. For the Everettian, to take one example, no experimental measurement of the spin of an electron has ever or will ever have a particular outcome (all outcomes happen, even though we’ll never perceive that).

Bohmian mechanics also turns our experiments into fictions. For the Bohmian, there is actually no electron and no spin involved in the measurement of an electron’s spin. Rather, there is an orchestrated movement of spinless point particles comprising the system and the laboratory (and the rest of the universe) into the correct spatial positions.

GRW-style approaches are different, in that they are testable alternatives to QM. Unfortunately, researchers have been busy gradually ruling them out as empirically adequate alternatives (see, e.g., Vinante, 2020). It is also worth noting, however, that GRW also distorts the usual interpretation of experimental results by stipulating that all collapses are in the position basis.

Unlike these approaches, RQM is truly an interpretation, rather than a modification, of orthodox QM, a successful theory that was motivated by experimental findings and is extremely well supported by decades of further testing. The measurement process, in particular, is not some problematic add-on to quantum theory – it is at the heart of it. Human beings and our experiences and interventions are part of the natural world. RQM does justice to this fact by explaining that measurements—the connections between quantum systems and ourselves—are just like any other physical interaction.

Reason Two: RQM Offers an Attractive Ontological Picture

Laudisa and Rovelli (in the SEP article) describe RQM’s ontology as a “sparse” one, comprised of the relational interaction events between systems. This event ontology has attractive features (akin to the “flash” ontology sometimes discussed in conjunction with objective collapse interpretations). There is no question of strange higher-dimensional spaces or other worlds: the events happen in spacetime. Also, one of the goals of science-inspired metaphysical work is to foster the potential unification of scientific theories. Importantly, a QM interpretation that features an event ontology offers at least the promise of establishing a rapport with relativity theory, which is typically seen as putting events in the leading role (see a recent discussion by Maccone, 2019).

But does giving this role to interaction events preclude a representational role for the wave function? Given that physical properties of systems only take definite values when these events occur, perhaps systems should not be accorded any reality apart from this context. And, in fact, Carlo Rovelli has consistently taken a hard anti-realist stance toward the wave function/quantum state. In his original presentation of RQM he gave it a role only as record of information about one system from the point of view of another, and thought it was possible to reformulate quantum theory using an information-based framework. This conflicts with my insistence above that such anti-realism was inconsistent with the aims of a good scientific theory.

Thankfully, there is no need to follow Rovelli on this point. Instead, I concur with a view outlined by Mauro Dorato recently. He suggests that rather than view non-interacting systems as simply having no real properties, they can be characterized as having dispositions:

In other words, such systems S have intrinsic dispositions to correlate with other systems/observers O, which manifest themselves as the possession of definite properties q relative to those Os. (Dorato, 2016, 239; emphasis original)

As he points out, referencing ideas due to philosopher C.B. Martin, such manifestations only occur as mutual manifestations involving dispositions characterizing two or more systems.3 Since these manifestations have a probabilistic aspect to them, the dispositions might also be referred to as propensities.

So, here the wave function has a representational role to play. It represents a systems’s propensities toward interaction with a specified partner system(s). The Schrödinger equation would show how propensities can be described across time in the absence of interaction. Now, it is true that the QM formalism does not offer a full or absolute accounting for a system’s properties, given its relational limitations. But here we should recall that models across the sciences are typically incomplete and imperfect. In addition to employing approximations and idealizations, they approach phenomena from a certain perspective dictated by the nature of the research program. But we can say the wave function represents something real (if incompletely and in an idealized way). Reality has two aspects, non-interacting systems with propensities, and the interaction events that occur in spacetime.

The idea that properties are dispositional in nature is one that has been pursued increasingly by philosophers in recent years. It fits well with physics, since both state dependent and independent properties (like mass and charge) are only known via their manifestations in interactions.4 While advocates disagree about the details, the idea that the basic ontology of the world features objects that bear dispositions/propensities has also been used more widely to address a number of difficult philosophical topics (like modality). Most importantly, perhaps, dispositions and their manifestations provide a good basis for theorizing about causation.5

Fitting Both Quantum Systems and Scientists Into the Causal Web

To conclude, I’ll briefly describe how I would flesh out this ontological picture, putting an emphasis on causation.

I mentioned above the role representational models play in explanation. To be more specific, scientific explanations are typically causal explanations: they seek to place a phenomenon in a structured causal context. When successful explanations feature models, then, these models represent features of the world’s causal structure. The suggestions above on how to view the ontology associated with RQM fit into a particularly attractive theory of this structure.

This is a modified version of Wesley Salmon’s causal process account (Salmon, 1984). Here the basic entity or object is labeled a causal process, and there are two dimensions of causation: propagation and production. Propagation refers to the evolution of a causal process in the absence of interaction, while production refers to the change that causal processes undergo when an interaction occurs. As described by Ladyman & Ross:

The metaphysic suggested by process views is effectively one in which the entire universe is a graph of real processes, where the edges are uninterrupted processes, and the vertices the interactions between them (Ladyman & Ross, 2007, 263).

According to Salmon, a propagating causal process carries or “transmits” causal influence from one spacetime point to another. The character of this causal influence is then altered by interactions. I theorize that this causal influence takes the form of a cluster of dispositions or propensities toward mutual interactions (aka a propensity profile). The interactions produce a change in this profile.6

To summarize:

1. The web of nature has two aspects: the persisting causal process and the causal interaction event (a discrete change-making interaction between processes).

2. The quantum formalism offers a partial representation of the propensity profile of a causal process. It is partial because these are only the propensities toward manifestations that take place in interactions with (one or more) designated reference systems. The Schrödinger equation represents the propagation of these propensities from one interaction to the next.

3. All manifestations are mutual, and take the form of a change in the profile of each process involved in the interaction. A quantum measurement is an interaction like any other. Humans may treat the wave function as representing the phenomena we are tracking, but we are also causal processes, as are our measuring devices. It is just that the changes manifest in us in an interaction (our altered propensity profiles) are conceptualized as epistemic.

4. Per RQM, when two physical systems interact, they are represented as an entangled composite system from the perspective of a third system. This relational representation of the composite system might in practice be thought of as a limitation on what the third system “knows.” Under certain conditions, however, this entanglement can have a distinctive indirect impact on the third system—interference effects—revealing it is not only epistemic (as always, decoherence explains why we rarely experience these effects).

There is much more to flesh out, of course. I would add to this summary an account of how composite systems form higher-level propensities of their own, based on the pattern of repeated interactions of their constituents. Also, there is an interesting question of how serious of a (relational or perspectival) scientific realist to be about the properties identified in quantum theory. My preference is to be a realist about the (singular) causal network, but view the formalism as offering only an idealized depiction of regularities in the propensity profiles of the underlying causal processes.


1 For background, see the Stanford Encyclopedia article (Laudisa & Rovelli, 2019). Rovelli’s original paper is (Rovelli, 1996 - arXiv:quant-ph/9609002). Good philosophical discussions include Brown (2009; link via, Van Fraassen (2010; link via Van Fraassen website), Dorato (2016; preprint here, but note final version has significant changes), and Ruyant (2018; preprint here).
2 For a recent attempt to carefully describe the principles of orthodox QM, see Poinat (2020); link (researchgate).
3 What Martin calls “reciprocal disposition partners.” See Martin (2008), especially Ch. 5. 
4 In addition to contemporary work by Dorato and others, there have been a handful of theorists over the decades since QM was formulated who have employed dispositions/propensities to interpret QM. See Suárez (2007) for a survey of some of these.
5 Important work here includes Chakravartty (2007) and Mumford & Anjum (2011).
6 The main changes from Salmon’s own work are as follows. The first is to be a realist about dispositions/propensities, whereas Salmon’s version of empiricism drove him to reject any suggestion of causal powers. He characterized causal processes in terms of their transmission of an observable “mark” or, in a subsequent version of the theory, the transmission of a conserved physical quantity. The second change is that causal processes cannot be said to propagate in spacetime, as Salmon envisioned, since this would be inconsistent with the non-local character of quantum systems.


Brown, M. J. (2009). Relational Quantum Mechanics and the Determinacy Problem. The British Journal for the Philosophy of Science, 60(4), 679-695.
Chakravartty, A. (2007). A Metaphysics for Scientific Realism. Cambridge: Cambridge University Press.
Dorato, M. (2016). Rovelli's Relational Quantum Mechanics, Anti-Monism, and Quantum Becoming. In A. Marmodoro, & D. Yates (Eds.), The Metaphysics of Relations (pp. 235-262). Oxford: Oxford University Press.
Ladyman, J., & Ross, D. (2007). Everything Must Go. Oxford: Oxford University Press.
Laudisa, F., & Rovelli, C. (2019). Relational Quantum Mechanics. Retrieved from The Stanford Encyclopedia of Philosophy, Winter 2019 Edition:
Maccone, L. (2019). A Fundamental Problem in Quantizing General Relativity. Foundations of Physics, 49, 1394-1403.
Martin, C. (2008). The Mind in Nature. Oxford: Oxford University Press.
Mumford, S., & Anjum, R. L. (2011). Getting Causes from Powers. Oxford: Oxford University Press.
Poinat, S. (2020). Quantum Mechanics and Its Interpretations: A Defense of the Quantum Principles. Foundations of Physics, 1-18.
Rovelli, C. (1996). Relational Quantum Mechanics. International Journal of Theoretical Physics, 35, 1637-1678.
Ruyant, Q. (2018). Can We Make Sense of Relational Quantum Mechanics. Foundations of Physics, 48, 440-455.
Salmon, W. (1984). Scientific Explanation and the Causal Structure of the World. Princeton: Princeton University Press.
Suárez, M. (2007). Quantum Propensities. Studies in History and Philosophy of Modern Physics, 38, 418-438.
Van Fraassen, B. (2010). Rovelli's World. Foundations of Physics, 40, 390-417.
Vinante, A., (2020) Narrowing the Parameter Space of Collapse Models with Ultracold Layered Force Sensors. Physical Review Letters, 125, 100401-100401.

Thursday, April 16, 2020

Metaphysics and the Problem of Consciousness

In a recent post I talked about different frameworks for addressing the subjective dimension of consciousness. One path used ideas from philosophy of mind, the other looked to evolutionary biology. Of course, many who ponder solving this and related aspects of the mind-body problem take a more overtly metaphysical turn. Here I’ll briefly discuss why I don’t think these efforts are likely to get it right.

Against “vertical” metaphysical relations

My first post in this recent series was prompted by reading Philip Goff’s book presenting his panpsychist approach to the problem of consciousness.1 In the sections where he addresses the combination problem, Goff considers alternative strategies for situating a macro-size conscious subject in the world: several of these involve appeals to “grounding”. To sketch, grounding (in its application to ontology) is a kind of non-causal explanatory metaphysical relation between entities, with things at a more fundamental “level” of reality typically providing a ground for something at a higher level. For example, a metaphysician fleshing out the notion of a physicalist view of reality might appeal to a grounding relationship between, say, fundamental simple micro-physical entities and bigger, more complex macro-size objects. It’s a way of working out the idea that the former account for the latter, or the latter exist in virtue of the former. There are a variety of ways to explicate this kind of idea.2 Goff presents a version called constitutive grounding. He thinks this faces difficulties in the case of accounting for macro-sized conscious subjects in terms of micro-sized ones, and discusses an alternative approach where the more fundamental thing is at the higher level: he endorses a view where the most fundamental conscious entity is, in fact, the entire cosmos (“cosmopsychism”). In this scenario, human and animal concsciousness can be accounted for via a relation to the cosmos called grounding by subsumption. Goff motivates these various notions of grounding with examples that appeal to how certain of our concepts seem to be linked together, or to how our visual experiences appear to be composed.

Please read the book for the details.3 Here, I want to comment on why I don’t find an approach like this to be very illuminating. It is actually a part of a more general methodological concern I have developed over time. Certainly, trying to uncover the metaphysical truth about things is always a somewhat quixotic endeavor! But I think it is extremely likely to go wrong when done via excavation of our intuitions in the absence of close engagement with the relevant sciences.4 To make a long story short, I’ll just say that here I concur with much of Ladyman and Ross’s infamous critique of analytic metaphysics.5 But to get more specific, I have a deep skepticism in particular about the whole notion of synchronic (“vertical”) metaphysical relations. Not only panpsychist discussions but a great many philosophy of mind debates are structured around the idea that ontological elements at different “levels” are connected by such relations as part-whole, supervenience, or grounding. Positing these vertical relations, in turn, has contributed to confusion in debates about notions of (ontological) reduction and emergence. The causal exclusion problem, I believe, is misguided to the extent it is premised in part on the existence of these vertical relations.

I see no evidence that there are any such synchronic relations in the actual world investigated by the natural sciences (although they may characterize some of our idealized models). At arbitrary infinitesimal moments of time there exist no relata to connect: there are no such things as organisms, brains, cells, or even molecules. All these phenomena are temporally extended dynamic processes. Any static conception we employ is an artifact of our cognitive apparatus or our representational schemes. Reifying these static conceptions and then drawing vertical lines between entities at different scales is a mistake. My view is that all relations of composition in nature are diachronic.

Solve the problem with a new metaphysics of causation?

Given this, I think questions about how phenomena at different scales relate to each other involve a causal form of composition. So, one might ask whether thinking about the nature of causation help can with the problem of consciousness. Even before doing my own deep dive into research on the topic, I was drawn to those panpsychist approaches that explored this avenue. As mentioned in the earlier post, Russell’s account takes a causal approach to the structuring of subjects, although he himself doesn’t go on to offer a detailed theory.6 I think Whitehead’s speculative metaphysics can be characterized, at least in part, as an attempt to use a rich metaphysics of causation to account for the integration of mind and world. In more recent times, Gregg Rosenberg developed an account that found a home for consciousness in the nature of causation.7

Over time, however, I have also become skeptical of these more expansive causal theories. This is in spite of my view of the central role causation should play in any account of the composition of natural systems. Here, the problem is that these approaches go too far by baking in the answer to the mind-body problem from the beginning. Methodologically, I believe we should resist the urge to invent a causal theory that is so enriched with specific dualistic features that it directly addresses the challenge. For example, in Whitehead’s system every causal event (“actual occasion”) already has in place both a subjective and an objective “pole.” For Rosenberg, two kinds of properties (“effective” and “receptive”) are involved in each causal event, and this ultimately underpins the apparent dualism of the physical and mental. In contrast to these speculative solutions, we should be more conservative and pursue a causal theory that makes sense of our successful scientific explanations of natural phenomena, and then see how that effort might shed light on the mind. I’ll discuss my view on this in a future post.

1 Consciousness and Fundamental Reality. 2017. Oxford: Oxford University Press.
2 Here’s the SEP article on grounding.
3 Also, check out Daniel Stoljar’s review.
4 A quite different way metaphysics can go wrong is when those who are truly and deeply engaged with science (specifically physics) succumb to the tendency to (more or less) read ontology off of the mathematical formalism.  But that is a discussion for another time.
5 Everything Must Go: Metaphysics Naturalized. 2007. James Ladyman & Don Ross. Oxford: Oxford Univerisity Press. See. Ch 1.
6 At least this is true of The Analysis of Matter (1927), where the view now known as Russellian Monism was most fully developed.  In his later Human Knowledge: Its Scope and Limits (1948), he presents a bit of a theory via his account of “causal lines:” specifically, this comes in the context of an argument that such a conception of causation is needed to account for successful scientific inferences (part VI, chapter V).  As an aside: by this time, Russell seemed to come quite a long way toward a reversal of the arguments presented in his (much more cited) “On the Notion of Cause” from 1913. There, Russell argued that the prevailing philosophical view of cause and effect does not play a role in advanced sciences. Someone looking to harmonize the early and late Russell might argue that the disagreement between the two positions is limited: one could say the later Russell is developing causal notions that better suit the practice of science as compared to the more traditional concept that is the focus of criticism in the earlier article. However, I think it is clear that the later book’s perspective is quite a sea change from the earlier paper’s generally dismissive approach to the importance of causation to science.
7 A Place for Consciousness. 2004. Oxford: Oxford University Press. I have some older posts about the book.

Tuesday, March 31, 2020

A Panpsychist Surprise Ending

While I have been catching up on some reading relating to panpsychism lately (see recent posts here and here), I had turned back to thinking about another topic, the philosophy of quantum theory, when following up on some references led me to a surprise endorsement of panpsychism.

Specifically, I have long been interested in relational quantum mechanics (RQM), an interpretation first introduced by Carlo Rovelli in the 1990’s (good SEP article here).  I now suspect it is the interpretation that best fits with the theory of causation I am attracted to for independent reasons – but I will talk about that another time.  A philosopher whose views I find interesting and compatible with my own approach to thinking about quantum theory is Mauro Dorato.  He has a fine article discussing some of the philosophical issues raised by RQM (pre-print here; note there are some differences from the final article).1

Dorato, when discussing briefly the general stance that relations might be a fundamental metaphysical category, referenced a paper I had not read (though I imagine it is familiar to many who are interested in structuralism): “The Mathematical Structure of the World: The World as Graph,” published in 1997 (link) by Randall R. Dipert.2   Dipert, who passed away just last year (see here), was a scholar focused on a number of areas, including the thought of C.S. Peirce. The paper offers reasons to take (symmetric) relations forming (asymmetric) graphs as metaphysical bedrock (not expressed via logic or set theory, but as fundamental components in and of themselves).  In any case, while it is a wide-ranging and fascinating paper, I was surprised by the turn taken in the last paragraph:
There might at first seem to be no place in these cold graphs for minds, consciousness, and other mental phenomena unless, that is, everything is mental. Although within the dialectic of this essay it is wild and possibly irresponsible speculation, we should perhaps consider seriously the possibility that something like the pan-psychism of Spinoza, Leibniz, or Peirce is true, and that vertices are pure feelings (Peircean "firstnesses"), constituting a distinct thought or object only when connected to other such entities (358).
I take it Peirce was a panpsychist of sorts (see here), and evidently Dipert was as well.

1. Dorato, Mauro. 2016. Rovelli’s Relational Quantum Mechanics, Anti-Monism, and Quantum Becoming. In The Metaphysics of Relations, ed. Anna Marmodoro and David Yates. Oxford: Oxford University Press.
 2. Dipert, Randall R. 1997. The Mathematical Structure of the World: The World as Graph. The Journal of Philosophy, (94) 7, pp. 329-358

Wednesday, March 25, 2020

Different Approaches to Subjectivity

In the last post, I endorsed a Russellian approach to the mind-body problem (specifically the view labeled "panqualityism"), noting that one of the important tasks this framework leaves us with is explaining the subjective dimension of consciousness. This problem arguably requires less of a deep dive into metaphysical waters, but rather a consideration of the ways a naturalistic approach can tackle the phenomenon, once isolated from the other aspects of mind.

From Philip Goff’s book, Consciousness and Fundamental Reality, I learned that versions of panqualityism has been recently defended by philosophers Sam Coleman and Tom McClelland.  When it comes to addressing subjectivity, both draw upon what one might call the philosophy of mind toolkit.  Philosophers of mind have long been trying to understand conceptually how different aspects of our mental faculties might be understood.  The relationship of this activity to work in the relevant sciences (neurobiology, cognitive science) varies: a common approach for the philosopher is to try to keep up with the sciences, avoiding inconsistency, but then to proceed to theorize in advance of what is known (from the proverbial armchair) in pursuit of possible solutions.

In a recent article defending his approach, Coleman invokes higher-order thought (HOT) theory as a tool to understand the subjective character of conscious experience.1 HOT theory was put forward by David M. Rosenthal: roughly the main idea is that a mental state is conscious when we also have a thought about that state (the higher-order thought).  While HOT theory has faced many objections as an overall approach to consciousness, perhaps it can be applied to solve the relatively stripped-down question of what makes a mental state subjective. McClelland, on the other hand, invokes a self-representation model of subjectivity.2  Here (referencing work by Uriah Kriegel), the idea is that a state is subjective when, in addition to representing something else (say, an aspect of the external world), it also represents itself (unlike HOT theory, there is only one state involved rather than two).  The discussion of by the authors about how both ideas work out in conjunction with a Russellian framework is interesting and worth more consideration.

For now, I want to just make a meta-philosophical point by contrasting these approaches to subjectivity with a very different one. In a recent paper, Peter Godfrey-Smith examines the evolution of subjectivity as a biological phenomenon.3  One of the benefits of having a philosopher of science/biology like Godfrey-Smith working on the problem of mind is that it expands the territory of the possible solution space being considered.  This paper is very rich, and includes a great discussion of different biological features that appear relevant to the concept of subjectivity and their role in different kinds of organisms.  Given our common intuition that consciousness extends beyond humans at least to some extent, this kind of work can make a critical contribution for philosophy of mind.  I think it is especially relevant from the perspective of a divide and conquer strategy like panqualityism: a position that implies subjectivity is an aspect of phenomenal consciousness that should be relatively tractable to scientific explanation.

1. “Panpsychism and Neutral Monism: How to make up One's Mind,” In Jaskolla Brüntrup (ed.), Panpsychism. Oxford University Press (2016).  A preprint can be accessed here.
2. In “The Neo-Russellian Ignorance Hypothesis: A Hybrid Account of Phenomenal Consciousness”, Journal of Consciousness Studies, 20, No. 3–4, 2013, pp. 125–51.
3. See (open access) “Evolving Across the Explanatory Gap,” Philosophy, Theory and Practice in Biology (2019) 11:1. Seel also this paper: "Varieties of Subjectivity."

Friday, March 20, 2020


I have been enjoying following some debates about the problem of consciousness on twitter and in blog posts.  In particular, philosopher Philip Goff has been tirelessly advocating the merits of panpsychism.1   As usual, this meets with a mixture of principled objections and more ungenerous responses.  I thought I would revive my blog to make a few comments, beginning with some reflections about my past thinking.  As a caveat, while I earned a PhD in philosophy recently (it's never too late!), it is not on this topic.2  My remarks are informal and tentative, and I invite corrections and reading suggestions.

My Long History with Panpsychism

I have always enjoyed puzzling over the mind-body problem.  It is one of the things that got me interested in philosophy early on.  In the 1990’s in particular, the explosion in attention the subject received (recast as the problem of phenomenal consciousness/the explanatory gap/the “hard” problem) had me riveted.

When I started my philosophy-oriented blog in 2004, it was one of my main topics, and I was a fan of panpsychist approaches. I reasoned that we know our own conscious experience exists (as well as or better than we know anything), and it doesn’t appear to be the kind of thing that can be scientifically explained using wholly non-experiential ingredients. I embraced the idea that in order to explain the character of our first-person conscious experience we must go beyond the relevant science to philosophically re-assess our assumptions about the fabric of the world.


While panpsychism is the common name for the idea that consciousness is a ubiquitous part of nature, on my blog I originally preferred to use “panexperientialism”.3  So how does panexperientialism differ from panpsychism?  The difference might seem to be just marketing.  “Panpsychism” implies that some inanimate things have minds, and that is a big affront to our usual intuitions: conscious minds seem to be something that only humans and some animals possess. Perhaps we can more easily picture “experience” as a phenomenon that might extend in attenuated fashion into the less complex building blocks of nature. A defender of panpsychism would reply by noting that the notion of experience certainly seems to require a subject of experience. And positing the ubiquity of experiencing subjects brings us right back to panpsychism.

But it seemed to me that there could be a principled difference lurking here.  While, despite some efforts at reading Whitehead, I was not well-versed in process philosophy myself, I took to heart the importance of resisting a static view of nature.  “Mind” and “subject” have static, object or substance-like connotations, while “experience” conveys the notion that consciousness is an ongoing activity. Panpsychists face a big hurdle (the much discussed “combination problem”) in explaining how small parts of nature that possess minds (particles, neurons) could combine to form a larger mind like ours. But if we view the natural world as a dynamic evolving web of processes, perhaps we can make sense of how a subject of experience could come about by degrees. The question, of course, is whether this suggestion can be fleshed out. In particular, it seems to put an emphasis on the need to understand the relationship of experience to causation (and causal forms of constitution) in the natural world.

Turning to Russell

Sometime in the mid-2000’s I went back and took a more careful look at some of Bertrand Russell’s later philosophical work on the problem, which was receiving more and more attention in the contemporary debates.  (This was in contrast to the relative lack of attention given to his old collaborator Whitehead’s process metaphysics, which most find very difficult to penetrate and assess).

Russell set out to show how careful attention to the way physical theories are constructed can reveal a very general common framework connecting what we think of as the physical and mental realms.4  First, he argues that the subject matter of physics can be interpreted as the abstract description of events and their linkage in causal relations. He then argues that the mental realm can likewise be described in terms of events, and that, given a causal theory of perception, we can view perceptual events (“percepts”) as connecting with physical events. And a key point is that our knowledge of the physical events (which is inferred and ultimately derived from observation) includes nothing which is known to be inconsistent with the mental. Russell speaks of events (or groups of events) as having “intrinsic qualities” or “intrinsic character”. Qualitative character is known to be an aspect of percepts, but is not part of physics, given its abstract structure. Russell doesn’t assert that events described by physics must have qualities like those of percepts – he is agnostic -- but he argues there’s no reason they couldn’t.5

In contemporary debates, these ideas are typically recast in the following way (although I think a bit is lost in this translation). The idea is that physical models seek to represent the relational, extrinsic, or dispositional properties of natural systems, but leave untouched the non-relational, intrinsic or categorical/qualitative properties. This latter sort of property is a fundamental aspect of nature that provides a suitable building block for underpinning consciousness in a way that can’t be done with the resources of a traditional physicalist metaphysics.

In his recent book defending panpsychism (Consciousness and Fundamental Reality6), Goff takes the Russellian framework to be a more promising alternative to physicalism, then describes how it can be further fleshed out in a number of different ways on the way to offering his preferred solution. These ways include panpsychist theories (the building blocks of nature are conscious subjects), and panprotopsychist theories (the intrinsic properties of the building blocks do not directly involve consciousness but somehow help give rise to consciousness).

Another view Goff discusses (but does not endorse) is panqualityism: this is the view closest to that of Russell himself.  This approach begins by noting that phenomenal consciousness actually has two distinctive problem-causing aspects: its qualitative character and its subjective character.  As Russell stressed, physical models, being formal and abstract depictions of a causal “skeleton”, do not capture the intrinsic qualities inherent in natural systems.  But we are acquainted with this aspect of nature via consciousness, so we conclude it is ubiquitous. As for the fact that consciousness is something subjective (that is, it is not public or third-person, but rather private or first-person), Russell posits that subjects are constructions from causally linked networks of elementary events (in the same way our familiar macro-objects are constructed).  He does not offer a satisfying fleshed-out account of this idea (and in fact gives no theory of causation – a concept he had once famously derided7 ), but a deflationary or reductionist approach to the subject is clearly intended. Again, we are pointed to thinking more about the nature of causation and its role in complex natural systems when thinking about the problem of consciousness.

Panpsychism is Half Right

Right now, my thinking about the mind-body problem continues to be very much in line with Russell’s.  My study of philosophy of science, especially on the nature and use of scientific models, has tended only to reinforce my view that there is something right about the central Russellian insight: a view of nature derived solely from the content of physical theories will fall short of accommodating consciousness because it doesn’t encompass qualities.

On the other hand, I suspect that some of the recalcitrant intuitions we have about the nature of conscious subjects (e.g. as irreducible things) can be defeased.  Questions about which natural systems are subjects and how this works can succumb to scientific inquiry, assisted by an understanding of how successful causal explanations (including constitutive causal explanations) work in the natural sciences.  I’ll look to follow up on this topic in a future post.

  1. See @Philip_Goff on twitter and the links on his website. Goff has a new book for a popular audience, called Galileo’s Error: Foundations for a New Science of Consciousness. By coincidence the copy I ordered arrived as I was writing this post. I shall read it shortly.
  2. My research is in philosophy of science, with a focus on causation and scientific explanation.
  3. The term is due to the Whiteheadian process philosopher David Ray Griffin.
  4.  The main source here is The Analysis of Matter (1927), Nottingham: Spokesman. See the SEP article on Russellian Monism here.
  5. I wrote in a bit more detail on Russell in the draft paper attached to this prior post.
  6. Consciousness and Fundamental Reality (2017). Oxford: Oxford University Press. See Chapter six.  Contemporary philosophers mentioned by Goff who pursue a panqualityist approach are Sam Coleman and Tom McClelland.
  7. In “On the Notion of Cause” (1912-13/1918). In B. Russell, Mysticism and Logic (pp. 142-165). London: Longmans, Green & Co.

Monday, September 08, 2014

GPPC Public Issues Forum

UPDATE:  For the latest schedule of GPPC-sponsored events please see the GPPC website.

Please join us for this GPPC co-sponsored event at Rosemont College, Rosemont, PA.  It should be a lively discussion.

Ethics in Business: A Public Issues Forum on Corporate Responsibility

Saturday, September 27, 2014, 1:00 p.m. – 4:30 p.m.

The Rotwitt Theater of the McShain Performing Arts Center
Dorothy McKenna Brown Science Building
Rosemont College
1400 Montgomery Ave., Rosemont, PA 19010

This Public Issues Forum will explore the ethical dimensions of the relationship between business and society. Speakers include philosophers and business ethicists whose work has focused on Corporate Responsibility, Stakeholder Theory, Organizational Ethics, Moral Imagination, and Ethics and Capitalism.

Free and Open to the Public. Refreshments will be served.

R. Edward Freeman, University Professor and Senior Fellow at the Olsson Center for Applied Ethics, University of Virginia: “New Models of Business in Society
Patricia Werhane, Wicklander Chair in Business Ethics and Director of the Institute for Business and Professional Ethics, DePaul University: “Globalization and its Challenges to CSR and Industrialized Capitalism
Gary Weaver, Professor of Management, University of Delaware.
Topic: Fostering ethical behavior in business organizations

Chair: Alan Preti, GPPC Board of Directors and Director of the Institute for Ethical Leadership and Social Responsibility at Rosemont College.

Saturday, August 23, 2014

Wesley Salmon's Early Interest in Whitehead

I was reading Probability and Causality: Essays in Honor of Wesley C. Salmon, and was interested to see it included an annotated bibliography, where Salmon provides contextual commentary regarding all of his publications up to that time (1988).  The first entry was an interesting surprise.  While his post-doctoral work was squarely in the mid-twentieth century empiricist tradition of philosophy of science, his MA thesis in 1947 was on the topic “Whitehead’s Conception of Freedom”, about which he comments: 

“A relic, best forgotten, of the days when I was totally committed to Alfred North Whitehead’s metaphysics.” 

In his later career, when stretching his empiricist commitments in search of a realist approach to causation, Salmon developed his own causal "process” theory (Salmon 1984).  No mention of Whitehead, but perhaps some background inspiration?

Here’s a bit longer autobiographical excerpt from Salmon’s book on Hans Reichenbach:

“On the basis of personal experience, I can testify to Reichenbach’s qualities both as a teacher and a man. I was a raw young graduate student with an M.A. in philosophy from the University of Chicago when first I went to UCLA in 1947 to work for a doctorate. At Chicago I had been totally immersed in Whitehead’s philosophy; ironically, Carnap was at Chicago during those years, but I never took a course from him. My advisors barely acknowledged his existence, and certainly never recommended taking any of his classes. Upon arrival at UCLA I was totally unfamiliar with Reichenbach or his works, but during my first semester I was stimulated and delighted by his course, ‘Philosophy of Nature’, based upon Atom and Cosmos. Simultaneously, I continued my intensive studies of Whitehead’s Process and Reality. A severe intellectual tension emerged in my mind between Whitehead, the scientifically sophisticated metaphysician, and Reichenbach, the scientifically sophisticated anti-metaphysician.

     To the best of my recollection, the tension grew to crisis proportions when I heard Reichenbach deliver his masterful Presidential Address, on rationalism and empiricism, to the Pacific Division of the APA at its meeting in Los Angeles in December of 1947.  This lecture was precisely what I – as a naïve graduate student – needed to make me face the crucial question: on what conceivable grounds could one make reasonable judgments concerning the truth or falsity of Whitehead’s metaphysical claims? When I posed this question to myself, as well as to teachers and fellow graduate students sympathetic to Whitehead, I received nothing even approaching a satisfactory answer.  By the end of that academic year I was a convinced – though still very naïve – logical empiricist.”
Salmon, Wesley C. (1979). Hans Reichenbach, Logical Empiricist, Dortrecht: D. Reidel, p.8.

Wednesday, July 09, 2014

Metaphysical Intuitions; Blog Anniversary

First a housekeeping comment.  It turns out that this blog went mostly dormant when I began full time graduate work in philosophy two years ago.  It was a wonderful outlet for my thoughts when I had a different sort of day job, but now I have trouble making time for it. In any case, I note that its tenth blogiversary recently passed, and I’m grateful for all who have read or commented over that time.

One thing I’ve been thinking about again is whether our metaphysical (modal) intuitions are any good.  Reading Ladyman and Ross (Everything Must Go) was one trigger for this.  Another was reading (but not finishing) Peter Unger’s All the Power in the World.  The former included a strong critique of contemporary metaphysics, making the case that its disconnection from modern physics renders it futile.  The latter book can be viewed as L&R’s worst nightmare: a freeform conversion of imagination into metaphysical conclusions which is completely unconvincing.  (See Katherine Hawley’s review of L&R here, and Timothy O’Connor’s review of Unger here -- obviously most contemporary analytic metaphysics is much more disciplined and better argued than Unger’s book).

Clearly we make mistakes relying on our imagination and common sense intuitions.  What also perhaps could be better appreciated is the fact that leveraging insights drawn from physics (implicitly or explicitly) can easily go wrong.  This happens both because the physics is outdated (and is always provisional anyway), and because the formalisms of physics do not and arguably cannot represent all the relevant aspects of nature.

Still, along with my other interests, I will do metaphysics as best I can.  After all, I only have this one shot at trying to understand the world!

Monday, September 23, 2013

Philadelphia-Area High School Ethics Bowl

UPDATE: 8 December 2013

Congratulations to all the teams that took part in the ethics bowl.  A team from Cherry Hill High School East won the competition and will represent our region in the national competition in April 2014.  It's great that Villanova's Ethics Program, led by Dr. Mark Doorley, again organized the event and that so many volunteer judges and moderators made themselves available.
Also, the second Philadelphia area High School Ethics Bowl will be held on December 7th, again hosted by Villanova University.  Contact me if you would like information on volunteering to help with the event (I was a judge last year and it was a great experience).

GPPC 2013-2014 Program of Events

The Greater Philadelphia Philosophy Consortium 2013-2014 program is up on the website:

Please check it out.  Looking at the fall schedule, I’d ask you to please make special note of November 16th which is the date for our Public Issues event (see below). 

Save the Date
GPPC Public Affairs Symposium:
America the Philosophical by Carlin Romano and Public Philosophy in the U.S
Saturday, November 16th, 2013 1pm – 4:30 pm
Free Library of Philadelphia Central Branch (Main Auditorium)
1901 Vine Street, Philadelphia, PA 19103   Phone: 215-686-5300

        Anita Allen, University of Pennsylvania
        Peter Catapano Editor, "The Stone," The New York Times
        Cheryl Misak, University of Toronto/New York University
        Carlin Romano, Ursinus College

Carlin Romano’s book, America the Philosophical, argues that philosophy, has a deep and wide role to play in American intellectual life and culture.  The degree to which it fulfills this role today, or should do so in the future, is a question which fits naturally into our long-running Public Issues Forum series.  A great panel of speakers will join us, and we hope you will participate as well. (Here is an essay by Carlin summarizing his thesis: )